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The simple 15′ vertical antenna shown mounted on the railing of our second floor deck has produced almost 200 countries worked around the world… VQ9’s in Chagos and 3B8’s on Mauritius in the Indian Ocean, TX0DX on Chesterfield Reef, VK0MM on Macquarie Island in the Antarctic region, BQ9P on Pratas Island off Taiwan, ZM7ZB on Chatham Island in the South Pacific along with FO0AAA on Clipperton, 9M0OO on Spratly Island in the South China Sea, JT1CO in Mongolia and on and on. What I hear, I can usually work with this little wonder and the small size and profile make it feasible for use in deed restricted neighborhoods.

A radio amateur friend and antenna designer came up with a simple design for a 10 meter vertical, which another friend and I modified to make work for the 14, 18, 21, 24 and 28 MHz ham bands. Its performance surpised us, and I’ll share it with you, in case you too are looking for a simple, inexpensive DX antenna that really performs well.

Main Antenna Concept 

The basic concept is to put up a piece of aluminum tubing with a telescopic section held by a small hose clamp to adjust the height. By attaching the center conductor of a coax feedline to the tubing, and the shield of the coax to a couple of radials from the base of the tubing you can load the vertical across quite a broad range of frequencies.

Of course, with a vertical element of approximately 15′ this is a non-resonant antenna for the 10, 12, 15, 17 and 20 meter bands. I chose this length on purpose to allow the system to be tuned to resonance with an antenna runer.

Tuning

Since the SWR in an antenna system of this type will be relatively high, an antenna tuner unit will definitely be required. You may need an external ATU if the one in your transceiver can’t handle the impedance mismatches involved. Here at K7ZB, I drive my TS570 (which has a built-in ATU) thru the amplifier, which then drives a high power ATU to the antenna. I put the SWR/Power meter between the amplifier and ATU to ensure a good match for the amp, and in cases where I run barefoot without the amp, I can still use the ATU to assist the transceiver’s ATU in ensuring a good match.

In this way, everything is matched for maximum power output: from the transceiver to the amp, and amp to the antenna. And, even though the SWR’s are high at the feedline and the antenna, it doesn’t matter because the system is matched with the ATU.

Mounting Scheme 
The picture below shows the details of the mounting scheme.

This picture shows the center conductor of the vertical connected to an SO-239 female coax connector. I used two pieces of insulated #14 AWG solid copper wire to provide a stiff means of supporting the connector to the metal bracket. Note that there is no true ‘ground’ connection to this antenna. The ground side of the connector simply connects to the hardware bracket, to which the two radials are connected. The bracket looks like a simple piece of offset metal used to mount a small flag pole or the like.

The two ~15′ radial wires are held to the bracket with a large sheet-metal screw, so the bracket is connected to the coax shield. Electrical isolation from the center conductor of the coax connected to the vertical element is provided by an insulating rubber sleeve. This is a piece of neoprene fuel line chosen because the dimensions fit the aluminum rod inserted into the lower 14″ of the aluminum tubing. However, we found the electrical isolation properties of neoprene fuel line leave a little to be desired at the high SWR’s of this system. After driving this vertical with 500 watts at high SWR in the middle of one of the DX Contests, I punched through the insulation. Obviously the original 10m antenna design was intended for lower power and lower SWR’s! This problem was solved by wrapping the neoprene sleeve with several layers of Teflon tape (the kind you buy for plumbing work at the hardware store). I also added a couple of layers of electrical tape (600V rating) for additional safety. These modifications are shown in the picture below with the vertical tubing removed – you simply add the tape over the sleeve. The vertical element is then secured to the bracket by a pair of hose clamps of suitable size.

A construction detail shown in the picture below is the solid aluminum rod that fits inside the lower 14″ of the main 8′ length of tubing. The solid rod is inserted at the bottom to ensure a good tight connection for the sleeve. This rod end can be drilled with a blind hole for a self-tapping sheet-metal screw to secure the solid copper wire from the center conductor from the SO-239. The tubing is secured to the rod with a hose clamp just above the top of the bracket.

A tip for ensuring good clamping force with hose-clamps and hollow tubing is to slit the tubing about two inches up from the bottom on opposing sides with a hacksaw. This will allow the clamps to grip tightly enough to prevent slippage. Also, insert a solid piece of rod about 8″ long inside the smaller diameter telescoping tube at the top of the vertical to prevent that tube from collapsing. The upper telescoping tube is adjusted to about 15′ overall length to give proper loading across all bands.

The final photo below shows the completed vertical attached to the railing with the coax looped about 6 times to give some measure of RF choke action to keep RF from entering the shack on the braid. I secured the coax loops with plastic wire-ties to the railing support to stress relieve the connector. You can also see the tubing and small hose clamp just above the neoprene sleeve along with the two larger hose clamps gripping the sleeve and rod to the bracket.

It is quite easy to remove the vertical tubing element and stow it when you are not operating, as I now do, thus fulfilling the need for an unobtrusive HF antenna.

All in all, a cheap and effective radiator for the higher HF bands!

Article originally available at pages.zdnet.com/radio_k7zb/id8.html.

[tags]antenna,hamradio,dx,vertical,coax antenna[/tags]

This construction will take your 1-2 hours and it will cost you about $25.
cost breakdown below is for the material actually used, longer tubing lengths may be required that inflate the apparent cost.

Materials :
1 x 6.1 metre length 19mmx1.5mm round aluminium tubing ($12.75)
1 x 1000mm length 16mmx1.2mm round aluminium tubing ($1.50)
1 x 200mm length 38×25mm rectangular aluminium tube (x 1.0mm wall) ($1.80)
4 x 12-23mm stainless steel worm-style hose clamps ($1.50 each)
2 x 16mm (tubing size) plastic chair tips ($0.70 each)
16 x aluminium pop rivets
50 ohm coax cable, eg RG58A/U, minimum length 3-4 metres
200mm x 32mm white outdoor conduit
Nylon cable ties etc…

Calculated dimensions @ 50.1 MHz
Long section : 4290 mm
Short section : 1423 mm
Feed point spacing : 140mm (external coax ‘Y’ style) **
Element spacing -metal tube outer to outer at closest dimension : 135mm

** This dimension is based on the original ‘Y’ external feed. Using a modified feed system, this distance is about 180 -210mm. Details of the modified feed are listed near the end of this page.
 

Construction :
Creating the shorting stub, this is the hardest part of the entire construction :

The critical dimension is the 135mm spacing between the elements but this dimension is not the centre-to-centre value, it is the spacing from tube outer to tube outer.
With 19mm diameter tube, adding 19mm gives the centre-to-centres of the holes as 154mm.
Therefore the outside to outside is 173mm so it does not leave much from our 200mm material.
Measure in 23mm from one end along the 25mm side section and then drill a pilot hole as a guide for a larger drill.
Making sure it is square, mark the hole position on the 25mm section opposite face and drill it.
Enlarge the hole to 19-20mm. I cheated here “I used a chassis punch” from each side to get a neat hole with about 0.5mm of play.

From the inner edge of the hole, measure and mark the position 145mm along the tube on one face and then repeat the process for the opposite face.

Drill these pilot holes and enlarge them to 19-20mm.

Not really hard unless you don’t have a suitable drill press with a drill or chassis punches to get the neat 19-20mm holes !

The separator : To provide mechanical rigidity, an insulating separator must be fitted near the top of the matching section joining both tubes.
It is similar in dimension and technique to the shorting stub but is made out of PVC electrical conduit rather than aluminium.

Use the same dimensions as in the construction of the shorting stub for the spacing of the hole centres and drill 19-20mm holes through the conduit
(the chassis punch works well on the PVC tube too). Make sure that the alignment of the holes is correct otherwise the aluminium tubes will not fit through.
The separator is held in place by nylon ties fed around the vertical aluminium tubes but placed within the end of the conduit and later tightened so as to not allow any slippage down the aluminium tubing – and without requiring additional holes.

The round tubing now needs to be cut to length and prepared for fixing :

From the 6.1 metre tube length, cut off 1300mm – leaving a 4.8 metre section for the main vertical radiator and mounting.
Cut a contraction slot in one end of each tube (4.8m & 1.3m) section for about 50mm.

Mark 4000mm from the slotted end of the main radiator. This is the position for the main shorting stub.

Assembly into the finished product :

• Slide the shorting stub along the main radiator tube until the upper edge lines up with the 4000mm mark (the stub will be on the shorter length side of the mark).
• Making sure that the tubing is square to the cross stub, drill clearance holes in the 38mm section sides for the pop rivets you are using and set the rivets. I recommend drilling one hole and installing the rivet before drilling the next hole etc.. Rivet both sides of the bottom stub tube to the main radiator tubing. This will pull in the 25mm dimension of the tube a little but that is the reason why it is so close to the end of the rectangular tube !
• Install the unslotted end of the matching tube ? the shorter length of 19mm section into the shorting stub with about 3-5mm protruding through the bottom.
• Making sure that this tubing is also square to the cross stub, drill clearance holes for the pop rivets you are using and set the rivets. As before, I recommend drilling one hole and installing the rivet before drilling the next hole etc.. Rivet both sides of the bottom stub tube to the matching section tubing.
• Slide a worm clamp down each 19mm tube down to the matching stub.
• Form a loop from a single nylon tie making sure it will fit over the 19mm tube (make 2 of these.)
• Fit a looped tie into one end of the separator and carefully feed onto the main radiator tube
• Slide the separator down over the long tube first then over the matching tube so that it is just above the slotted top of the matching tube. Install the second looped nylon tie into the other end of the separator tube and feed it down over the aluminium matching tube until it is just below the slotted section. Pull each tie tight so that it will not slip on the aluminium tubing. Multiple ties can be fitted if desired.
• Slide a second worm clamp over the slotted section on each 19mm tube and insert the 16mm tube and adjust the worm to just hold the clamp in position.
• Measure the main radiator tube from the top of the shorting stub and set the adjuster to 4290mm before tightening the worm again to just hold the tube in position. Do not overtighten at this stage.
• Measure the matching stub tube from the top of the shorting stub and set the adjuster to 1423mm before tightening the worm again to just hold this tube in position. Do not overtighten at this stage.
• From the shorting stub, mark a position 140mm up each 19mm tube. This is the position to attach the coax cable. Note that the coax inner goes to the main radiator while the outer goes to the matching stub tube.
• Slide the worm clamps up to these marks and lightly tighten in position.

Final steps : Cable connection and adjustment – standard ‘Y’ cable feed.

• Create an RF choke by winding 5 turns of the RG58 cable around a 125mm former and nylon tie it into a stable structure. Leave at least 400mm of cable free from the feed end. The other end (the tail) can either be terminated in a BNC or other coax connector to suit the cable type or can simply be the start of the feeder that takes it to the radio.
• Strip back 100 – 125mm of the outer on the feed end.
• Push the braid back a bit to loosen it up, then poke a ?hole? in the braid and ?fish out? the coax inner.
• Strip the inner back to about 75mm of exposed poly and the rest the inner conductor.
• Tin the inner conductor and then screw it under the worm clamp on the main radiator.
• Feed the braid under the worm clamp on the matching section and pull it until there is just a little slack in the cable. Cut it off, remove it and tin the braid before placing it back under the worm clamp.
• Mount the antenna vertically in a clear space in such a manner that it can easily be brought down to adjust at each of the following stages :
• Connect a suitable transmitter via a SWR bridge to the coax ?tail? and check the VSWR at say 50.160 Mhz. Do not use 50.110 MHz as a test frequency !
• Check the VSWR at various spot frequencies in that segment. If the VSWR goes up as the frequency rises, the tube lengths are too long and need to be shortened. If the VSWR goes down as the frequency rises, the tube lengths are too short and need to be lengthened. Lengthen both together but make sure that the main radiator adjustments are about triple the matching section?s length changes.
• Once the VSWR is minimum at the centre of the desired section of the band, it is time to adjust the feed point positions on both tubes to bring the VSWR down to the absolute minimum. Slide the clamps up or down the tubes TOGETHER and see where the trend goes.
• If the VSWR rises, move in the opposite direction. It should be possible to get the SWR down to 1.05 or better without any problem.

Final steps : Cable connection and adjustment – modified cable feed.

• Drill a 5/16″ hole about 200mm from the top of the shorting stub along the inner side of the matching tube(facing the main radiator tube) and remove any burrs.
• Feed the RG58 up the short tube and pull it out of the hole.
• Strip back the cable outer sheath for about 200mm.
• Push the braid back a bit to loosen it up, then poke a ?hole? in the braid and ?fish out? the coax inner right at the start of the exposed braid.
• Cut the braid off with about 25-30mm left and tin it with a soldering iron making sure you do not overheat the poly inner of the RG58.
• Slide the cable back through the hole and set the worm clamp to hold the braid on the tube adjacent to the feed hole.
• Feed the coax inner across towards the main radiator element making sure you have about 20mm of slack on the poly and enough inner to tin about 30mm before cutting it off.
• Feed a length of the black plastic coax sheath back over the inner to provide some protection against UV.
• Clamp the inner to the main feed directly opposite the feed hole as an initial location.
• Create an RF choke in the coax by winding 5 turns of the RG58 cable after it exits the tube around a 125mm former and nylon tie it into a stable structure and nylon tie it to the base of the matching section. The tail can either be terminated in a BNC or other coax connector to suit the cable type or can simply be the start of the feeder that takes it to the radio.
• Mount the antenna vertically in a clear space in such a manner that it can easily be brought down to adjust at each of the following stages :
• Connect a suitable transmitter via a SWR bridge to the coax ?tail? and check the VSWR at say 50.160 Mhz. Do not use 50.110 MHz as a test frequency !
• Check the VSWR at various spot frequencies in that segment. If the VSWR goes up as the frequency rises, the tube lengths are too long and need to be shortened. If the VSWR goes down as the frequency rises, the tube lengths are too short and need to be lengthened. Lengthen both together but make sure that the main radiator adjustments are about triple the matching section?s length changes.
• Once the VSWR is minimum at the centre of the desired section of the band, it is time to adjust the feed point positions on the radiator tube to bring the VSWR down to the absolute minimum. Slide the clamp up or down the tube and see where the trend goes.
• If the VSWR rises, move in the opposite direction. It should be possible to get the SWR down to 1.05 or better without any problem.

When all is done, the centre frequency is as desired and VSWR is negligible, it is time to put the plastic chair tips on the tops of the tubes, tighten the worm clamps and weatherproof as desired. Don’t forget to weatherproof the slotted adjustments and their worm clamps with a marine varnish to prevent excessive oxidisation. If using the modified feed, remember to seal up the hole where the coax feed exits across to the main radiator with a good silicone sealant.

Final dimensions at 50.1 MHz

Long section : 4425 mm
Short section : 1513 mm
Feed point spacing : 160mm
Element spacing : 135mm

This project was originally edited by VK4ADC, but this page has been removed, luckily I did saved a copy in my disk and this is a simple extract. All copy rights to the original author.

[tags]antennas,j-pole,hamradio,amateur radio,50 mhz,dx,antenna[/tags]

This small antenna can allow hams which lack space to install an antenna for 40 meters. This project has been originally  produced by F6CYV. I’m going to test this antenna in the coming weeks. I will try to setup this inside my balcony.

According to his experience, using it form inside the apartament, european singals are all very readable, he has worked over 150 countries.

The antenna is made of 2mm wire.

The 2 coils are constituted by 18 turns of 2 mm wire, distance of tunrs is also 2 mm.

The diametre of the coils is of 7,8 centimeters.

The Feed of the dipole is done with a 75 ohms tv coaxial cable.

A 1/1 balun would be recommand for a correct feed of the coaxial cable to the dipole.

It is not necessary  to use a coupler, it is enough to set the length of both extremities of
the dipole in order to have at 7.050 mhz a low SWR, and especially to pay attention what the lenght of the 2 sides of the dipole to be identical.
[tags]antenna,ham-radio,amateur radio,HF antenna[/tags]

G5RV verses Superloop 80

Many operators with small lots, a G5RV is what can fit for the 80 and 40 meter bands. The G5RV is 102 feet long and has a 34 foot
section of twinlead followed by coax into the shack, possibly with some sort of RF choke on the coax. The ends are typically supported by ropes up in
the trees. An 80 meter dipole would be about 134 feet long.

A tiny lot is limited in antenna potential and zoning laws prevent real towers.

RadioWorks “Superloop III” designed by Jim, W4FTU, and refined over the years, is a good alternative

PHYSICAL VARIATIONS

The standard arrangement is shown in Fig. 1. It looks like an inverted delta loop and is 112 feet across the top. It fit on the same ropes as my G5RV used and the coax even started at about the same point in space. The wire is heavy 14 gauge copper. If your space doesn’t quite allow this, the top corner insulators can be moved to shorten the 112 foot dimension; also additional insulators can be added to the diagonal wires to make a rectangular
shape and raise the bottom balun up in the air more. I also added 6 feet of wire to move the resonant freq closer to the band bottoms for digital work.

The loop can also be mounted upside down and slanted if you only have a single support available. As with all loops, the area enclosed is important and so is the average height; the standard inverted delta shape is a very good compromise.

ELECTRICAL CHARACTERISTICS

The “trick” to the Superloop is the 30′ length of ladder line hanging down from the center insulator. This length has been tuned so that appears to be a open-circuit stub on 40 meters; thus the antenna becomes two full-wave wires (at 40 meters) and is commonly referred to as the Bi-Square antenna. On 80 meters, it appears to be a short and the antenna becomes a single wave vertical loop. This happens automatically and no switching is involved.

A special balun is provided which gives a match between the 50 ohm coax lead-in and the higher resistance of the loop. For best matching, a 1/2 wavelength coax is recommended (e.g. 99′ of RG-8X); however mine is about 70 feet into my diff-T tuner and the SWR < 2 points are 3495 to 3787 but the short coax gives a minimum on 40 of 2.05 at 7090 KHz. If you need to run without a tuner, close attention to the coax length will help. The balun is the typical ferrite rod in a PVC pipe with foaming urethane inside. This has the effect of heat insulating; mine works fine on 500 RTTY watts contesting, but real high power may be a problem on RTTY; but those guys all have beams, right?

OPERATING RESULTS

The diagonal wires make it partially a vertical antenna with a nice reduction in polarization QSB. You can possibly double contacts on 80/40 over the G5RV. RITTY can help on the reception. The Superloop tunes up fine on the 20,15,10 bands Antenna, ropes, and coax will run you about $US 135. RadioWorks advertises in CQ and QST and have an interesting catalog.

Copyright and originally hosted at http://larc.hamgate.net/SuperLoop.htm

[tags]antenna,ham radio,amateur radio,loop antenna[/tags]

As much as I like my coax loops, I am also quite satisfied with small loops made with wire or tubing. They have the same or better performance as the coax loops, but might require that you invest in a balun to help maintain directivity and avoid common-mode noise ingress from the feedline. If you need to null local noise yet still be able to listen to most skywave signals, these loops really perform.

The antennas described below bridge the gap between operating as a constant-current small loop (0.10 wavelength or less circumference), and intermediate-sized loop a bit larger than 0.17 wavelengths long in circumference.

If you are interested in building loops made entirely from coax cable you may want to check out my earlier project pages on that subject. It has many operational notes and other items of interest that pertain to small plain wire loops as well as to coax types.

The voltage balun was essential to help me fight common-mode noise and maintain directivity. If you don’t use a balun and have good results, you may not have much noise to deal with in the first place, or the skewed directional pattern has a null that works for you – even if it isn’t textbook. See my balun notes below.

I initially chose 14 feet since my noise problem extends up into the 40 meter band; I didn’t want the antenna to be longer than 1/10th wavelength because you start to lose your nulls with larger wavelengths of wire. I just did a quick calculation: (1005 / 7.150 * 0.10)

Note that I have since opted to use 28 feet overall, because I wanted better sensitivity on 160 and 80 meters, and now at 40 meters the 28 feet of wire still gives me a slight null – adequate enough for me to null my local noise on 40. Unfortunately I don’t have the room for a full-sized loop, so I had to wind it with two turns. See the EZNEC® antenna modeling plots below.

Here are some quick construction tips to get you up and running quickly. I’m still studying the antenna and will improve the page as time goes on.

I am running the loop right at the operating position. Here is what I’m using:

• 14 feet of #12 gauge wire formed into a loop. Coax braid is an option.
• W2AU 1:1 voltage balun by Unadilla.
• 10 foot coax jumper from loop balun to tuner input.
• Common tee-type C-L-C antenna tuner.

The loop seems nearly omnidirectional for medium to high-angle skywave signals, yet has great noise-nulling directivity at very low angles from 160 – 20 meters. These two qualities make it a great general purpose antenna especially indoors.

Let’s take a look at the elevation angle for 20 meters. It shows good medium to high-angle skywave directionality. The other bands have much the same elevation pattern:

Look at the azimuth angle for 80 meters. 160 and 40 meters are similar. Notice the deep null; great for nulling noise by rotating the loop:

At 20 through 10 meters, the circumference of the loop is becoming progressively larger than 0.10 wavelength, and starts to have a nearly omnidirectional horizontal plane no matter how you rotate it. Fortunately I don’t have to null out any local noise on 15 and 10. On 20 meters I have a very minor noise problem, and the smaller null on 20 meters takes care of it.

This means that this 14-foot circumferential loop is performing as a small directional loop on frequencies of 40 meters and lower, and as an omnidirectional intermediate-sized loop on bands higher than 40.

The most efficient small HF loops are single-turn affairs. Multi-turn loops of this type are less efficient, but you may have no choice to wind a smaller loop with multi-turns if you can’t find the space for a single-turn, such as with indoor applications.

If you are really space constricted, you could cut the dimensions down and run a 7-foot circumference loop. Just don’t expect great performance on 160 or 80 meters. Rectangular loops might also be considered if you have a lot of vertical or horizontal space, but not much of both at the same point. Perhaps you have very high vaulted ceilings in which you can make long vertical runs for the sides of the loop whereas the horizontal runs would be much smaller.

Just remember that the key to small loop success is to enclose as much AREA as possible; keeping in mind that when your antenna starts to appear longer than 0.1 to 0.25 wavelengths in circumference, you’ll start to lose the deep nulls.

Strive for a single-turn loop, but if you must, you can wind multi-turns if you have to. To help reduce the proximity effect of the turns, (one of the elements of loss resistance) try to keep the multi-turn loop wires spaced one or two wire-diameters apart.

Skin-depth rf currents on closely spaced coil conductors have a tendency to reject each other and “pool up” on opposite sides of their respective wires, thus effectively reducing their own conductor area. I have had success by winding one turn on one side of my pvc mast, and the other turn on the back of the mast. However, I am not so sure that this is very critical for a receive-only application. More study required …

Balun experiments:

I have had the best results using a VOLTAGE balun at loop feedpoint. I tried a hefty commercial 1:1 CURRENT balun, and it turned my small loop into a noisy non-directional random wire.

(I’m not condemning the use of choke or current-type baluns, it’s just that the voltage-type balun seems to work better for me in this application.)

Since I wanted my loop to be general-purpose and work across several bands, I made no attempt to match the loop impedance to the feedline. This may be affecting balun performance somewhat, but so far it is performing adequately with the loads presented by the loop in this rx-only application.

I really didn’t want to use a balun, but found that I had to. I experimented with a direct connection to the coax without a balun, and got some directivity on 160 and 80 meters, but the common-mode cable ingress noise on 40 meters and higher was pretty bad. It also changed my tuner settings radically. Putting some clamp-on RF cable chokes on the feedline reduced the noise a bit. I reinstalled the 1:1 voltage balun, took off the chokes since they were no longer necessary, and got my deep nulls and quiet reception back.

Keep your balun connections neat and symetrical. For example, the 1:1 voltage balun I use is a W2AU type and it has small jumper wires behind the strain-relief eyelets. Connect the loop wires to the jumpers close to the eyelets, and then symetrically dress the remainder of the balun leads neatly. I made the mistake of letting the balun wires hang in a hay-wire fashion, and attached the loop leads to random points along the balun jumpers. Although the antenna worked well, tighter nulls and better overall balance was achieved just by being a bit neater with my connections. It’s worth the effort.

What about a 4:1 voltage balun? It works well! On a lark I thought I’d try a 4:1 balun and see how much worse it would be. To my surprise, I still have my low-angle bidirectional directivity, my nulls are sharp all the way from 160 to 20 meters, and my tuner settings require about half the inductance! (except on 160 where my inductor settings stayed the same). It seems that as long as I can tune out the reactance of the antenna system, the loop-to-feedline mismatch isn’t as much of a concern as I once thought. I can’t even begin to explain what’s going on with all the variables. I’d sure like to learn how to model small loops with differing balun ratios … until then I’m enjoying the loop with the 4:1 balun.

Quick Solutions:

I had a 50-foot piece of coax left over from my earlier coax loop experiments, so I thought I’d experiment with it by using just the braid as the antenna element (continuous braid loop – no gaps). I had to take into consideration noise-nulling vs sensitivity for my location. I prefer single-turn loops, but in some cases I had to wind them into multi-turns (with one wire-diameter spacing) to fit indoors. In all cases I used my tuner to resonate the whole system. The lengths listed below are not super-critical.

The first band listed is operating as a 0.05 wavelength loop, and the second listing is operating as a 0.10 wavelength loop.

160 – 80 meters optimized: 52 feet of wire

This is the best 160 meter loop I have used to date. To fit indoors, I had to wrap it into 4 turns. Deep nulls on 160, medium nulls on 80, everything higher in frequency turns omnidirectional. I really wish I had the space to open this up as a single-turn loop, but I have to make do with the space I have.

80 – 40 meters optimized: 26 feet of wire

I still have a noise problem on 40 meters, so I had to cut the length of the wire down to get my deeper nulls back. I still had to fit it indoors by wrapping it with 2 turns. Deep nulls on 80, medium nulls on 40, everything higher in freq omnidirectional. (I can still copy the locals on 160 ok, but since the loop is smaller than 0.05 wavelength on 160, it’s very inefficient. Considering that the loop is best for medium-to-high angle skywave reception anyway, this isn’t as bad as I thought on 160. So what if the locals on 160 are a bit weaker – the SNR of the loop makes it usable anyway.) I’ve also reduced the top-heavy weight of the loop by using less turns. This is now the favored loop size for my situation. In this case, less is more!

40 – 20 meters optimized: 14 feet of wire

This wire length now allows me to use a single loop of wire. Great nulls on 40, medium nulls on 20. Everything higher in freq omnidirectional. Since I don’t have a big noise problem on 20, I use the larger loop in the previous experiment. The loop is so light with only one turn that I’d probably use a much bigger conductor diameter for the loop if I wanted to maximize sensitivity on 40 meters.

Velocity Factor issues with outer coax braid (basically none!)

Since I’m using the outer braid skin of the coax as the antenna element, I can ignore cable velocity factors. In other words, the velocity factor is only applicable to the inner differential-mode currents, and not to the common-mode current that exists on the outer braid skin.

I’d like to offer my apologies to earlier readers where I indicated that the velocity factor of a loop using coax braid as the antenna element should taken into affect. I was wrong.

Wire diameters for 0.10 wavelength or smaller loops
I recommend using 1/4 to 1/2-inch diameter or larger conductor diameters for the loop if you desire them to be self-supporting. You can also use just the braid of RG-58 or RG-8 coax and affix it to a mast.

Small-gauges of wire don’t perform as well as tubing does with loops under 0.10 circumferential wavelength, and larger conductor sizes, while offering greater performance and a larger bandwidth, may present a problem when considering the cost, weight, and general hassle of construction. The general rule of thumb would be to use the largest diameter conductor that you find practical so that you can lower the loss resistance.

Tuner Notes
Since small loops are high-q antennas, it is very easy to mis-tune or mistake a peak in your tuner settings for an optimal match of the system. If you have a noise-bridge, or antenna analyzer handy, this can make finding the right tuner settings much less of a chore. I’m going to describe doing it “by ear”.

After building a new loop I usually get impatient and madly start adjusting the caps and inductor settings hoping that I can hear the peak quickly. Sometimes I get lucky, but more often than not, I dont’ find any peaks, or I end up on a very inefficient one. Sadly, I resign myself to the fact that I’m going to have to do it in a more methodical fashion and maybe eat up an entire afternoon to find the settings for most of the bands.

Let’s assume you have a typical C-L-C type tuner; a cap for the receiver side, an inductor, and a cap for the antenna side. You’ll want to do this when the band is open, or perhaps tune to a local noise source. Here is my generic method going from the lowest to highest freqs (tedious to be sure, but I don’t want to accidentally skip over a great match):

1. Set L for for maximum inductance.
2. Set both caps to zero, either fully meshed or fully open.
3. Set the antenna cap to 1
4. Rotate the receiver cap all the way through it’s range.
5. Set the antenna cap to 2
6. Rotate the receiver cap all the way through it’s range.
7. Continue with the above steps advancing the antenna cap by one.
8. If no peak is found, lower the inductor value, and try the caps again.

On the lower freqs, you may even want to advance the antenna cap settings by only half-steps until you find the peak. Ugh.

Even if you do find a nice peak, don’t give up just yet! Make a note of the settings, and try it again with the next inductance value. You might be surprised at how well the NEW match point works. This is pretty tedious stuff, but the result are worth it – don’t be tempted to be satisfied with the first peak you find!

After you’ve found the major match settings, you’ll probably need to make slight capacitor repeak adjustments when you tune the receiver from one band edge to the other, especially on the lower 160 and 80 meter bands.

originally hosted at www.greentech.com

This document was originally posted by K4WW on rttyinfo.net but this domain has expired since some months at time writing. I’ve archived a copy that I believe could be usefull for beginners.
This is not intended to be an “etched in stone” indication of how to operate a RTTY contest, so please don’t take it that way! Whatever works the best for you, is what you should do, as long as it allows your participation to be fun! These hints were obtained from RTTY contesters, world wide, and only reflect how they try to make their operation more efficient! The more efficient “we” make our contest exchanges, the more efficient we make it for all involved! Band conditions certainly play an important part in the exchanged data, so establishing a “different” buffer could make your exchange more efficient in “not so good” band conditions!

There are many web sites to obtain RTTY contesting information, and for fear of slighting anyone, I will only suggest that if you intend to participate, regardless of the level, that you visit rttyjournal and acquaint yourself with the rules, or at least the necessary exchange! Subscribing to rtty@contesting.com is also advisable, as most all RTTY operators, especially those primarily interested in contesting, can be found here. Someone there can answer most any question that you may have! Some contest managers do not allow points for “unique” callsigns in the submitted logs! There are varying definitions of “unique”, or the specific number of logs that a callsign must appear in to not be classified as “unique”! Having this knowledge, if you choose to just work your friend just to give them a point, make sure that you work a few (4-5) others, to insure that the contest manager will allow the contact with your friend!

RTTY For Newcomers

by Bill, W7TI

RTTY is a fun mode and easy to operate, but there are some questions every newcomer has. Please take a moment to read the following and much of the mystery will disappear.

MARK AND SPACE

A RTTY transmitter sends out a carrier that shifts back and forth between two frequencies. There is no amplitude modulation, only a pure carrier which shifts frequency. The lower RF frequency is known as the SPACE frequency and the upper RF frequency is known as the MARK frequency. The difference between the two is known as the SHIFT. For amateur radio, the SHIFT has been standardized at 170 Hz. It is customary to refer to the MARK frequency as your operating frequency. For example, if you say you are transmitting RTTY on 14080.00 kHz, which means your MARK frequency is 14080.00 kHz and your SPACE frequency is 170 Hz lower, or 14079.83 kHz. While 170 Hz is the standard shift, sometimes you will find stations using a shift of 200 Hz, but don’t worry about it. Your equipment will copy it fine in almost all cases.

FSK and AFSK

You will often hear the terms FSK and AFSK when talking about RTTY on the HF bands. FSK means Frequency Shift Keying and AFSK means Audio Frequency Shift Keying. Regardless of which method is used, the RF signal sent out over the air is identical. MARK is always the higher RF frequency and SPACE is always the lower RF frequency. If the transmitter is operating properly, the station receiving the RTTY signal can not tell any difference at all. So what is the difference? It’s the way your transmitter generates the RF signal.

With FSK, your transmitter receives a simple on-off signal which causes the carrier frequency to shift back and forth. This signal may come from a TNC (Terminal Node Controller) such as a Kantronics KAM, an AEA PK-232, HAL DXP-38 or some other, or it may come from a soundcard program via one of your computer’s com ports. FSK is simpler, easier and more foolproof than AFSK and is highly recommended if your transmitter supports FSK input. Check your owner’s manual if you’re not sure.

Since not all transmitters support FSK input, there is another method available – AFSK. AFSK can be used with any SSB transmitter. AFSK is a bit trickier to set up and use, but when it is done correctly, it works just as well as FSK and will transmit a perfect RTTY signal. Also, AFSK can do some things FSK can not, such as Automatic Frequency Control (AFC) of the transmitter. With modern transmitters, drift is not a problem and transmit AFC is generally not needed. With older tube-type equipment, it may offer some advantage.

To operate with AFSK, you put your transmitter in the SSB mode instead of FSK mode, and you put an audio signal into the microphone input (some transceivers have a rear connector for audio data input). When you transmit your TNC or soundcard will put out a pair of audio tones that cause your transmitter to send the required RF output. Sounds simple, right? Here’s the tricky part: The tones are two simple sine waves, but the frequency and amplitude of the tones is critical. Let’s say you want to transmit on 14080.00 kHz, as in the previous example. Remember that your MARK signal has to be on 14080.00 kHz and SPACE 170 Hz lower. How do you do that with AFSK? Here’s how. With your transmitter in the LSB mode (Lower Side Band), whatever frequency goes into the microphone input will be subtracted from what your dial says and be transmitted on that frequency. For example if your dial says 14080.00 kHz and you put in a 1000 Hz audio tone, your transmitter will put out an RF signal at 14079.00 kHz, exactly 1000 Hz lower than your dial. So in this case, if the 1000 Hz represented your MARK signal, you would have to set your transmitter to 14081.00 on the dial, and your MARK signal would be transmitted on 14080.00, just as you wanted. Ok so far? Now, what about SPACE? Remember, you want your SPACE signal to be transmitted 170 Hz lower, on 14079.83 kHz. What audio tone will give you 14079.83? Simple – 14081.00 minus 14079.83, or 1170 Hz. So the MARK audio frequency is 1000 Hz and SPACE is 1170 Hz.

There you have the basics of AFSK. Your TNC or soundcard generates the two audio frequencies and your transmitter converts them into two RF frequencies. For technical reasons related to harmonic generation, audio frequencies of 1000 Hz and 1170 Hz are NOT recommended. They are used in this example just to keep the math simple. The recommended audio frequencies are 2125 Hz for the MARK audio frequency and 2295 Hz for the SPACE audio frequency. Making the frequencies higher like this will reduce second harmonics while keeping the tones within the passband of your SSB transceiver.

If you’ve been paying close attention, you may have noticed the SPACE audio frequency is higher than the MARK audio frequency, just the opposite of the RF frequency. This happens because you’re using lower sideband. If you happen to forget and set your transmitter to USB instead, two things will happen. Because your MARK and SPACE are now reversed in your receiver, any RTTY signals you hear will not print correctly. All you will see is random characters that make no sense at all. The other thing is that YOUR transmissions will also be nonsense to the other guy. So just remember – always use LSB. In the real world of course, sometimes USB gets selected accidentally. Nearly all software has a means to quickly reverse the tones, either a keyboard command or an on-screen button to click. When you have a station tuned correctly but all you see is nonsense printing reverse the tones. Now you can print the other fellow and tell him he is “upside down”, as it’s called. After he reverses himself, just reverse again and you will both be back to normal.

Also, you should know that in some parts of the world, especially Europe, the standard is to use USB instead of LSB. This works fine as long as you also reverse the two audio tones. In the US, nearly all equipment defaults to LSB. If you prefer to use USB, be sure your tones are reversed all the time.

The really critical part about AFSK is the amplitude of the signal fed into the microphone connector (or rear panel connector), together with the microphone gain setting. You must NOT overdrive your transmitter or spurious signals will be transmitted. In general, keep the audio drive low enough that your transmitter does not generate any ALC voltage. Never try to drive your transmitter to maximum output. Around 80 to 90 percent of maximum is about right. Consult your owner’s manual for more information on how to do this. If you ever hear a station at two or more frequencies at the same time, the cause is almost always overdrive. None of this applies to FSK, of course. With FSK, you can run full power and not worry about overdrive.

FIGURES SHIFT and LETTERS SHIFT

RTTY uses the Baudot code, invented before radio even existed, and still widely used throughout the world. The Baudot code uses data bits to represent letters, numbers and punctuation, much like your computer does. Unlike your computer, which uses eight bits for each character, the Baudot code uses only five, plus a start bit and stop bit. Using fewer bits is good because it speeds up transmission and reduces the chance of errors, but there is a complication. Five data bits can only represent 32 different characters. Since there are 26 letters in the English alphabet plus ten numbers, plus some punctuation, 32 different characters is not enough, even if you only use capital letters, as Baudot does.

Mr. Baudot could have chosen to use six data bits or even more, but he found a better solution. He reasoned that most of what is sent would be letters rather than numbers or punctuation, so he assigned all the letters to the basic 32. He then had six characters left over and he did a very clever thing with two of them. He made one of them a FIGURES SHIFT and another a LETTERS SHIFT. The way it works is this: When sending one of the basic 32 characters, nothing special happens. But when a number or punctuation is to be sent, a FIGURES SHIFT character is sent first (it’s a non-printing character – you won’t see it on your screen). Whatever follows will still be one of the basic 32 characters, but the receiver will interpret it differently. For example the letter Q uses the same five data bits as the number 1, but when the receiver gets a FIGURES SHIFT, it prints the following character as a 1, not a Q. This continues until a LETTERS SHIFT character is received, at which time the receiver goes back to “normal” printing. All of this shifting is done by the system – there is no key marked LETTERS SHIFT or FIGURES SHIFT. It’s all-automatic and you will scarcely notice it happening.

In fact, the only reason to mention it at all is because we are using radio instead of wires, and radio is susceptible to interference from various sources such as lightning static, man-made noise, QRM, etc. If a burst of static should happen to wipe out a LETTERS SHIFT or FIGURES SHIFT character, the characters following will not print correctly until another LETTERS SHIFT or FIGURES SHIFT is received. For example, suppose you are sending a signal report of 599, but the FIGURES SHIFT character gets wiped out by a burst of static. Instead of printing 599, the other fellow’s computer will print TOO. TOO is exactly the same as 599, without the FIGURES SHIFT. So how can he read what you sent? It’s easy if he knows the secret. Here it is: Look at the top row of letter keys on your keyboard – QWERTYUIOP. Now look just above each key and to the left. Each of those number keys is the same as the letter key below and to the right, plus the FIGURES SHIFT. In our example, TOO = 599. Likewise, the word PIPE, if the LETTERS SHIFT were missed, would print as 0803. If 0803 lost its FIGURES SHIFT, it would print as PIPE. Some RTTY programs have a way to highlight the erroneous characters and change them to the correct shift.

TUNING INDICATORS

All TNCs and soundcard programs have to have some means of tuning in a RTTY signal. If you have that hearing ability known as “perfect pitch” you might get along with ears alone, but the rest of us need something to look at. For now, use what your equipment provides, but if you get really hooked on RTTY, you will probably want to invest in an oscilloscope. A scope works by having the MARK and SPACE tones from the receiver drive the X and Y channels, without any internal sweep. The pattern on the scope will be a pair of ellipses (flattened circles) at right angles to each other. When properly tuned, the ellipses are exactly vertical and horizontal. When the receiver is mis-tuned, they lay over at an angle. Properly set up, a scope provides an instant indicator of any tuning error. Fortunately, even a very inexpensive scope will do just fine. High speed and lots of bells and whistles are not needed.

BANDWIDTH and FILTERS

When the bands are nearly empty, you can use practically any receiver bandwidth with good success. Your SSB filters are probably between 2.1 and 3.0 kHz wide and as long as no other stations are nearby, copy will be fine. For optimum performance however, less bandwidth is better, in fact MUCH better. 170 Hz shift RTTY only needs about 250 Hz for proper copy. If you don’t have a 250 Hz filter, 500 Hz will do pretty well, but anything wider than that will not be satisfactory in the long run.

You may wonder why, for 170 Hz shift, you need a 250 Hz filter? Why not 170? The reason is that shifting the frequency generates sidebands adjacent to the actual signal and if the sidebands are attenuated, the signal will be degraded. RTTY (as used on HF) is actually a form of FM, and FM does produce sidebands, believe it or not. If you’d like to understand FM a little better, the ARRL handbook is a good reference.

Depending on your transceiver, you may or may not be able to use a narrow filter for RTTY. Some of the less expensive transceivers do not have a true FSK mode, and also are unable to select a narrow filter while in the LSB mode. Using an outboard audio filter between the speaker output and the TNC or soundcard input can make some improvement, but unfortunately, that will not prevent a strong adjacent signal from causing the receiver’s AGC circuit to reduce gain, often to the point where the desired signal disappears. The best solution is to upgrade to a transceiver which has FSK mode built in, AND which allows you to select a narrow filter while in that mode.

BAND PLANS

It’s easy to remember the HF band plans for RTTY. Most activity will be found between 80 and 100 kHz up from the bottom edge of the band, except for 80 meters which goes an additional 40 or 50 kHz higher, and 160 meters. 160 meter RTTY activity is rare, but when found, it is usually between 1800 and 1820. Avoid the CW DX window between 1830 – 1840. At present, there is not much activity on the WARC bands, although 30 meters can be active at times.
Here is where you will find most of the RTTY activity:
80 meters: 3580 – 3650 (3520 – 3525 in Japan)
40 meters: 7080 – 7100 in the US (see note below)
30 meters: 10110 to top of band
20 meters: 14080 – 14099 (avoid the NCDXF beacons at 14100)
15 meters: 21080 – 21100
10 meters: 28080 – 28100

RTTY allocations for 40 meters vary greatly all over the world. In the US, RTTY is permitted between 7000 and 7150, although most US activity is between 7080 and 7100. DX activity is often found between 7020 and 7045. The ARRL promotes 7040 as the RTTY DX calling frequency, but the CW QRP’ers use it as their calling frequency too. Be a gentleman!

For US operators, remember that RTTY is not allowed in the phone portions of the HF bands except on 160 meters, where it is legal anywhere in the band.

RTTY DX

Chasing DX on RTTY is highly popular with the RTTY crowd. As you might guess, 20 meters is the premier DX band for RTTY, and most rare DX stations and especially DXPedetions operate on 14080. Just as with CW or phone, if the DX is calling CQ and getting no answers, you can feel safe in calling him right on his frequency. If things are busy however, he will often work split, which means you should call him on a different frequency, usually 2-10 kHz higher. He will say “up 2-10″ or something similar at the end of his transmission, and that’s your clue. Your transceiver owner’s manual will explain how to do “split”.

RTTY CONTESTS

RTTY contesting is a passion with a lot of hams. There are more than two dozen major RTTY contests each year and when they are on, the bands will be full! Even if you don’t care to compete, it’s a great way to pick up new states or countries. Many of the rare DX stations are serious contest operators. A list of RTTY contest times and rules can be found on the web at:

in FSK the filter settings are built in

Unshift-On-Space – To Use It or Not?

USOS is not the easiest concept to understand. Here’s another way of thinking about it: The transmitting station and the receiving station must always be synchronized regarding LTRS case and FIGS case. When signals are strong this is no problem, but when sigs are weak or covered by QRM/QRN/QSB often the synchronization is lost. This is how we get those TOOAPPQAPPQ messages. Think of the space character as a “synchronizer”. With USOS ON (the default in most TNC’s), every time a space character is sent, the transmitter and receiver are BOTH re-synchronized automatically. This happens with EVERY space character, not just in the exchange. For example, when you send 599-001-001, the synchronizing is done only once – at the start of the transmission, just before the “5″. On the other hand, if you send 599 001 001, the synchronizing is done three times – once before the “5″ and once before each “0″. Your chance of receiving the correct FIGS character has improved significantly.

So, here’s a suggestion for folks who prefer using the hyphens: Set up a separate F-key with ONLY the significant part of the exchange, and do it WITH SPACES. For example, 001 001 001 001. Use it only when asked for a repeat. In this example, the “synchronizing” space character is sent four times, greatly improving the chances of correct reception. Use this only when requested and it should not impact your QSO rate/hour much at all, and I think you’ll find your repeats are reduced noticeably.

The key to the issue is a type of operation called unshift-on-space (USOS). USOS is used by most TNC’s by default, but there is a little quirk of contesting which can make it ineffective. Here’s a little background: As you are probably aware, the Baudot character set uses a figures shift character and a letters shift character to change between letters and figures and other punctuation. This is needed because Baudot only uses five bits and five bits can only display 32 characters – not enough for all the letters, numbers and punctuation. For example the letter Q and the number 1 are identical in Baudot – except the 1 is preceded by a figures shift character. This is a non-printing character of course; you don’t see anything on your screen. It is merely an instruction to your receiver to treat what follows as a figures-shifted character instead of a letters-shifted one. Likewise, when you return from sending numbers to sending letters, a letters-shift character is sent. This is how your receiver keeps things straight. The problem comes about when some QRN, QSB, QRM or whatever causes a loss of the shift character. Baudot was originally devised for wired communication where this is not a problem. With radio, unfortunately it is.
In an attempt to correct the problem, USOS was devised. What happens in your receiver is that when a space character is received, the receiver resets itself to letters-shifted characters. This works because your USOS transmitter knows that after sending a space character, if the next character is a number, the figures shift character has to be sent first. The reasoning behind this is that letters are much more common in ordinary conversation than numbers are and it works quite well for ragchewing… but contesting is a little different. Often in a contest exchange, what follows a space is a number, not a letter. The problem (follow me closely here) happens when the transmitting station does not send a space before the number, but rather sends a hyphen. For example, 599-001-001. If the ORIGINAL figures shift character is lost, the receiver will print TOOAPPQAPPQ, the hyphen being a figures-shifted “A”. In the same situation, but with a space in place of a hyphen the receiver would print TOO 001 001. The missing ORIGINAL figures shift character causes the 599 to print as TOO, but the subsequent (and more important) serial number prints correctly, thanks to USOS. The reason people use hyphens is that the transmission goes faster – a hyphen character takes the same time interval as a space, and (here is why it’s faster) the hyphen is also on the figures shifted set so therefore does not require sending another figures shift following the reset to letters shift caused by USOS.
I don’t blame you if you have to re-read that a few times. It is anything but readily apparent. To summarize, hyphens make the transmission faster, but spaces along with USOS make reception more accurate when QRM, QSB or QRN is present. I can understand the folks who want a fast transmission – in a contest, faster is better IF IT’S ACCURATE. But if it isn’t accurate, a lot of time is wasted asking for repeats. Anyway, I prefer accuracy, so you will always see my exchanges with spaces. For the folks who prefer speed, may I suggest setting up an F-key which repeats only the significant part of the exchange? You’ll be using it more than you would otherwise.
Now the contest is finished and you will want to submit your log to the proper contest manager. These may be found at http://www.rttyjournal.com/contests/index.htm along with the rules, recent year scores and email addresses for log submission. The following article written by Eddie, W6/G0AZT will give you step by step instructions to insure that your log is correctly formatted for submission.

Submitting Contest Logs and Files for 2001 and Onward

By Eddie Schneider, W6/G0AZT

There are generally four options for submitting logs for the major RTTY contests. Please follow closely these log submission rules for the specific contest. The options, in order of preference, are as follows:

1. Electronically, using the Cabrillo format.
2. Electronically, using the relevant files produced by your logging software, e.g. .all and .sum.
3. By mail, using only a correctly formatted and packaged 3.5 inch diskette with the information specified in alternatives 1 or 2 above. Note, larger diskettes will not be accepted.
4. By mail, on paper, either hand written or computer generated. However, if the log contains more than 100 entries in a CQWW contest, this option is not available; only options 1,2 or 3 may be used.

Electronically Submitted Files

The Cabrillo * format is here to stay. From November 2000, the ARRL accepts ONLY this format for electronically submitted logs. Both RTTY CQWW-DX and CQWW-WPX now require this format for any log produced by your logging software and containing more than 100 QSOs. BARTG Sprint, BARTG HF, SARTG, SCC and EAWW will also be requesting this format.

As more and more contest organizers realize the simplicity of a Cabrillo formatted log, they will no doubt follow suit in the not too distant future. If your favorite contest logging software does not support the Cabrillo format yet, get in contact with the author. An alternative would be to purchase a converter utility and/or log checking software from WT4I #

One of the main features of a correctly formatted Cabrillo log is that ALL the contest-specific data required is written to just ONE .log file.
There is no need to send a summary, dupe or multiplier sheet and generally, separate band files are no longer required either. Besides simplifying the entire process of log submission for the entrant, Internet bandwidth is reduced and assuming that the checkers have appropriate log checking software, their lives are made a whole lot easier.

Here is an example of how much time can be spent by a contest manager obtaining the correct files for just one contest. For WPX2000, I received 533 logs via e-mail. I generated over 1300 contest related e-messages in a five-week period. Deducting the 533 confirmation messages plus approximately 100 other e-mails, passing logs to the other two log checkers, leaves 360-odd e-mails asking entrants for missing files, incomplete summary sheets, unreadable .bin, .wl, .xls files etc. It is NOT the log checker’s responsibility to convert these files into a readable format! The onus is on the entrant to know how to produce the required files using his preferred logging software. In other words, if in doubt, read the manual

Contest managers, usually unpaid, are trying to reduce the delay in posting the results, so you can appreciate that spending time and effort having to ask for missing data could be well spent actually checking the logs and finalizing the results in a timely manner. Log submission deadlines are also being reduced in an effort to expedite the results.

Sophisticated log checking software # is now available to any contest manager interested in making his life a lot easier. This same software is also available to contesters who would like to thoroughly check their logs before submitting them.

If you operate in a single band class but make contacts on other bands to relieve boredom or help out friends, please submit CHECK logs for those bands. If you don’t submit a check log for those other bands, the other station(s) you worked on your non- competitive band, will lose credit for
those QSOs. So lets get down to the nuts and bolts of preparing and submitting an electronic log to managers who accept and/or require the Cabrillo format.

1. When converting your log to Cabrillo make sure that you complete FULLY and ACCURATELY the Cabrillo Header with the required information for the specific contest.
a. Call sign used. In the case of multi ops, all call signs of operators and names of persons involved in the contest, even the tea lady:-). For those of you using special calls, add your personal call sign in the appropriate field.
b. Class of operation, e.g. Single op, all band, high or low power where appropriate.

CAUTION. Be very careful when selecting your category. If your Cabrillo log indicates SOABH expect to see your results in THAT category when the final results are published, even if you actually operated as SOABL, SB or SOA. Any unnecessary summary sheet with a different chosen category from that recorded in the Cabrillo header will be ignored.
If the contest does not have ’special’ categories like Over 50, TB wires etc., leave those entries blank.
c. Claimed score.
d. Your name and FULL postal address. Adding an e-mail address in the ‘Soapbox’ field would be helpful in case of queries.
e: The name of the contest that the log refers to. This may seem obvious but we’ve had contestants send SSB or CW logs for CQWW RTTY!
f. For non US/VE entrants, select “DX” for the ARRL Section.
g. US/VE entrants select the appropriate state or province. For ARRL sponsored contests, select your US section or VE province/territory abbreviation.

Once you are satisfied that all the relevant information is accurate and has been included in the Cabrillo Header, now comes the part that many entrants have a hard time with, naming their files correctly in order to submit them via the Internet.

Contest managers are not at all interested in what you actually named your files on your hard drive. Names like QWWRTTY2000.x, WPXSOABL.x and so on, have little meaning and only cause confusion and possible errors if the manager has to rename them. So, number one priority is to rename all the files you intend to send, with the CALL SIGN you used during the contest. For example, XX0XXX.log, XX0XXX.sum
The second priority is to zip or ‘pack’ the files. By doing this, your original file format has less chance of being corrupted in transit.
Thirdly, make the subject line in your e-mail as meaningful as possible. If lots of files received by the manager are called CQWW2001, there is a good possibility that one or more logs will be accidentally over-written. Been there, done that So please use your call sign in the subject header.
Including the entry class would also be appreciated, e.g. XX0XXXsoabl, XX0XXXsoa etc.

Finally, do not forget to include your zipped file as an attachment to the electronic submission!

A note to home brew software writers and ASCII text editor users.

If you decide to write your own Cabrillo converter utility or wish to edit your log, PLEASE consider and adhere to the required format, The log checking software has been written specifically to read a correctly formatted Cabrillo file. Additional dots, dashes, and/or spaces inserted at random only mess up the specified format and create additional and unnecessary work for the log checkers who will inevitably have to re-Cabrillorize your submission.
[tags]ham radio,rtty,ham-radio,amateur radio,contest,dx[/tags]

]]> http://www.iw5edi.com/ham-radio/26/a-rtty-tutorial-for-beginners/feed 2 http://www.iw5edi.com/ham-radio/25/how-to-build-a-telegraph-key http://www.iw5edi.com/ham-radio/25/how-to-build-a-telegraph-key#comments Tue, 26 Sep 2006 22:49:25 +0000 iw5edi http://www.iw5edi.com/ham-radio/25/how-to-build-a-telegraph-key A Simple Telegraph Key
by Arthur R. Nilson, McGraw-Hill, New York, 1942

A professional looking radio key can be made by the beginner or experimenter at a cost of a few cents for parts. This key is very satisfactory in every respect, as will be seen from Fig. 15. It is made of a short piece of 1-inch-square brass rod and a few other parts easily procurable. Its construction is clearly shown in the mechanical drawings, Fig. 16. As exact dimensions are shown in the drawings, no difficulty should be experienced in making this key.


FIG. 15. — A homemade key. This key is very inexpensive to make and utilizes tungsten contacts.

A unique way of providing contact points that may be easily renewed when necessary by the ingenious builder is to use ignition contact points. These points may be obtained from almost any automobile supply store or direct from Sears, Roebuck and Company by mail. These points are usually listed in the mail-order catalogue indexes as Contact points, auto.

The point mounted on the circular-ended spring is used for the bottom contact as shown in Fig. 15. The other contact is removed from its spring by filing off its back and is soldered to the upper contact screw which passes through the arm of the key. A slight indentation is provided in the end of this screw by marking it with a punch and drilling, first with a small drill (about No. 38) and later with a slightly larger drill. The stem of the contact should fit into this hole to provide a support for the contact. The screw is then screwed through the arm, turned over, and held in position for soldering the contact to it. First tin the screw, and then put a speck of soldering flux on the back of the contact. With a pair of tweezers, hold it in position on the end of the screw, and apply the tip of the soldering iron. In a few moments the solder applied to the screw will melt and hold the contact firmly. The contact may now be cleaned off around its edges with a file, a excess solder being thus removed. It is now ready for use.

FIG. 16. — Mechanical drawing of homemade key.

The side thrust screws are drilled out at their ends, as shown in the magnified view of these screws in Fig. 16. The bearing rod on which the key arm swings is pointed at both ends and thus fits snugly into the thrust screws. An easy way to bring the bearing-rod ends to a point is to fasten a hand drill in a vise so that it may be turned with the right hand. The bearing rod is then fastened in the drill chuck and the drill rotated by turning the crank. With the left hand, hold a flat file against the end of the rod to be pointed. In a short time the file will bring the rod end down to a point. The rod is then reversed and the opposite end pointed in the same manner.

An excellent key knob may be made from the top of an ink-bottle cork. This knob is shown in Fig. 15. Remove the cork from the composition top, and scrape it clean, leaving only a shell. Next, solder a l-inch 8-32 flathead machine screw to a piece of circular brass or copper just large enough to fit into the composition top. Turn the top upside down, place the screw assembly in position, pack the knob with a plastic cement such as plastic wood or Tilette , and allow to harden. The knob is now ready to be screwed into the key arm. If desired, a regulation key knob may be purchased.

The key base may be finished with mahogany-varnish stain or in some other suitable way to suit the taste of the builder. When the key is ready for final assembly, the brass parts should be carefully polished. If possible, these parts should be given a coat of clear lacquer which will keep the key always looking bright and clean. The constructional work required to make this key will become clear from studying Figs. 15 and 16.

[tags]hamradio,morse code,cw,ham-radio[/tags]

]]> http://www.iw5edi.com/ham-radio/25/how-to-build-a-telegraph-key/feed 2 http://www.iw5edi.com/ham-radio/21/aeronautical-maritimes-radio-scanning http://www.iw5edi.com/ham-radio/21/aeronautical-maritimes-radio-scanning#comments Mon, 07 Aug 2006 21:49:16 +0000 iw5edi http://www.iw5edi.com/ham-radio/21/aeronautical-maritimes-radio-scanning During last years, waiting to obtain my licence I’ve spent a lot of my “radio-times” listening to broadcast stations and also trying to intercept unknown and strange signals. Monitoring “extra” bands for unknown signals, still give me that taste of misterious that fascinated me so much in past years.

Although in italy the “utility station listening” was not so popular, I’ve been in touch with some friends that were interested in this kind of excercise, expecially, aeronautical and marine listenings.

I do remember that one of the hardest information to obtain were frequency lists of course, and during the early 90’s, some photocopied tables with undeciphrable words and numbers were circulating among shortwave listeners.

Starting in the mid 90’s and the diffusion of the internet those informations become easier to find and more readable.
Today many sources are availbale for scanner enthusiasts, and frequencies are at public domain.
Here you can find some usefull resources.

• Radio Scanning links
• Monitoring Times
• Radio Scanner at wikipedia

I’ve also fond copied of articles originally hosted ad the WUN club, went QRT during this year, that are a bit old but still very interesting.

• Digital signals FAQ

• Government and Military Frequency Lists
• Marine Broadcasts
• Maritime band plan HF
• US Coast Guard Aircraft

  Many more info from old WUN club site, could be retrieved at the wayback machine
  [tags] hamradio, scanning, radio scanning, maritime, shortwave, amateur radio, vhf, ham radio[/tags]

  ]]> http://www.iw5edi.com/ham-radio/21/aeronautical-maritimes-radio-scanning/feed 0 http://www.iw5edi.com/ham-radio/14/ham-grids http://www.iw5edi.com/ham-radio/14/ham-grids#comments Sat, 17 Jun 2006 14:53:41 +0000 iw5edi http://www.iw5edi.com/ham-radio/14/ham-grids HamGrids will allow you to perform calculations with the popular Maidenhead Grid Square system. This grid system is used worldwide by amateur radio operators for many aspects of ham radio. Currently in version 0.5 Beta, with HamGrids, you can Convert Latitude and Longitude into a Grid Square, Convert a Grid Square into Latitude and Longitude, calculate the distance between two Grid Squares, and calculatea beam heading between grid squares.

  Require Windows 95/98/2000 or Windows NT 4.0 or higher, Visual Basic 5.0 Runtime DLL

  Download HamGrid

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