A plan for HF Log Periodic Antenna working 10-20 meters band by VA2PHI
A Mississippi Style 40 Meter Magnetic Loop
Ken Holland, K9FV
Edited by Brian Levy, W2BRI
It all starts with my friend Leon, K5BUL. Well, he’s a new ham of about 3 years who lives in Aberdeen, MS. He got into ham radio because he wanted to use it as part of cruising on his 35â€™ Fantasia sailboat. His life took a different turn after he bought a new â€™99 Goldwing motorcycle. Heâ€™s now a biker. He has even mounted a screwdriver antenna to his bike and has worked HF using his ICOM 706MKIIG on the motorcycle.
Iâ€™ve myself have been a ham since the mid-70â€™s (â€™75 I think) with the original call of WA4UBD, which I kept until a couple of years ago when I got the vanity call K9FV. Iâ€™ve used ham radio on my sailboat for years. In â€™99 when the XYL and I took an extended honeymoon for 6 months to the Bahamian Islands, ham radio stood us in good stead.
We had been in the Islands only a few weeks when Hurricane Dennis decided to visit. We found a protected place and rode out the hurricane. The first night out after Dennis, we headed out of the cove. We decided we wanted some something good for supper so we dove for lobsters. What was most unfortunate, however, is that while I was cleaning lobster, my XYL took a shower, slipped, and broke her pelvic bone! The next morning as the Intercoastal Waterway Net came on I reported my emergency traffic. Dr Jim of Miami came on the air and discussed my wife’s symptoms with me. We agreed that it did in fact sound like a broken bone, and she would surely need more medical attention. Needless to say, we needed more medical support than the island could provide. Another ham got on the air and did a phone patch, we were still anchored out, to my insurance company and to DAN (Divers Alert Network). I then upped anchor to the closest marina where we could access the island’s nurse and a pay phone. DANâ€™s staff doctor talked to the local nurse at the island, then the DAN doctor talked to my insurance company. The insurance company authorized a Lear jet ambulance to transport us to Fort Lauderdale for medical treatment.
Since that fateful experience, my XLY does not complain about any radio purchases I make. These days I just say â€œItâ€™s for safety on the boatâ€. She even bothered getting her Technician license â€“ KG4TIN.
From time to time, I also install a screwdriver antenna on my motorcycle. It’s an old â€™92 goldwing and it works just fine for HF mobile.
Let’s get back to the topic of Magnetic Loops. Leon and I both share an enjoyment for building things, and antennas are certainly included. Since I live on a 40â€™ sailboat, and he has the land for antennas â€“ we do most of our antenna work at his QTH. After reading Brainâ€™s post (W2BRI) on QRZ and eham.net, I visited his webpage and liked what I read. I spoke to Leon and sold him on the idea of a magnetic antenna before Christmas of 2002. By Christmas Leon had the basic loop built using electrical 3 inch aluminum conduit. This is a fairly heavy walled soft aluminum pipe that bends easy. Leon constructed the loop using â€œfactory 90â€™s.â€ These are pre threaded pipe which is bent into a 90 degree pieces. The loop is a 10 foot by 10 foot square with a 3 inch gap at the top of one side â€“ like we saw in Brian’s antenna plans on this site.
Leon and I got the Magnetic loop tuned and tested Dec 30th, 2002. Leon had the loop all made up and ready to be completed when I got there on Monday morning. We hung the 10 ft square loop from a tree limb putting the bottom about three feet off the ground. We added the feed and the capacitor and got the loop tuned up to forty meters.
We turned on the radio, and got ready to do our on the air comparison. We were located just north of Columbus, MS. We were able to test the antenna with a station in Talladega, Alabama against Leon’s permanent forty meter full wave loop at 30 feet. The gentleman in Talladega was located about 200 miles ESE of our location. WA4FMR near Knoxsville, TN was our second contact, who was located perhaps 400 miles NE of us. Both stations gave good reports on the magnetic loop, but did say the full wave 40 meter loop was better by about 1 or 2 S units. That was about the same results we saw on the S-meter when receiving the two test stations. This performance confirms what Brian had expressed to me earlier on the phone. The one major advantage with the loop however, is its small size. Leon liked the loop so much, he is now planning a 20 meter version. He hopes to compare it to his 20 meter bazooka one day.
Ken Holland, K9FV
Build a Motor Driven Magnetic Loop AntennaÂ 1.5 Meters Square for 3.5-10MHZ
By Neil Lowson, GM4XRF
- 4 1.5 mtrs 22mm copper pipe
- 4 22mm copper 90 degree bends
- 1 500pf 6kv capacitor
- 1 12 volt 4 RPM geared motor
- 2 flexible couplings
- 1 insulated if possible
- 1 6-1 or 10-1 reduction gear
- 2 small micro switches
- 1 5 pin SIN SKT@plug
- 1 400mm 4â€plastic pipe
- 1 4â€plug insert for bottom of pipe they have a rubber seal on (B)
- 1 4â€seal for top this a screwed on cover for access to the capacitor (A)
- 1 60mm *350mm *4mm paxolin for motor/capacitor
- 1 75*75 4mm paxolin plate for fixing mast to loop at bottom with saddles
- 2 12volt leds 1green 1 red
- 1 25mm PVC coupling
- 1 25mm broom handle
Assembly first starts with the capacitor and motor, this is the important part of the magnetic loop. Get the strip of paxolin and mount the capacitor at one end (top). Fit the insulated coupling to the capacitor shaft and then fit the reduction gear. The brackets will need to be made from 4mm aluminium. Then make up a bracket for the 2 micro switches.
They have to be set as to use the flexible coupling with a long 4mm screw in one of the holes for switching at min/max capacitance, see photo and wiring diagram. Next the 100mm /300mm plastic drain pipe (length to suit cap/motor) fits the bottom section of top plug with pvc. Glue and drill 2* 25 mm + holes 30mm down from top of pipe with the holes opposite one another for the 25mm copper pipe to be inserted in about 25mm. Then bolt cap/motor assembly into pipe. Connect capacitor to copper pipe with coax braiding and 6nmm brass bolts. Get the bottom plug fit the 25 mm coupling and the din socket connect to motor and fit with self-tapping screws and sealant on main pipe. Assembly of capacitor is now complete. Fit broom handle to coupling, I use this as the mast, also to attach the coupling loop with cable ties.
Assembly of the Loop:
4*1.5 mtrs 22mm copper pipe. Take 1 length cut 30mm of the length the pipet in half — this is the top portion ofÂ the loop. Clean the pipe and bends with wire wool and add flux. Then fit bends to pipe. Do this on flat surface and fix bends with self-tapping screws till you solder. You now have a square loop. Paint if required.
Coupling the Loop:
Coupling loop should be about a 1/5th size of main loop made from RG58U COAX but I always make it bigger. Then trim it by 15mm at each end till you get a 1-1 match (see photo). Then solder And seal with rubber tape.
I use small power supply unit you can buy for calculators/portable radios 3/4.5/6/9/12/volt at 1 amp — they are ideal for the small 12V motor. I built mine into a small box with the switches and the LEDs work well. There are more sophisticated control circuits that can be used but this was the easiest.
This article was available at http://www.standpipe.com/w2bri/article2.htm
TS-590 the K3 killer â€¦. ???
It could be possible, but to demonstrate who is the killer we need facts and features palpable, not noise. I would like toÂ explain my point of view on the above subject.Â Please excuse me if I may sound â€œaggressiveâ€ but we have to put light on same specific points to make real comparisons. K3 does not need a violin fiddlerâ€¦
For a comparison we do need tests that can avoidÂ personal interest orÂ love â€¦ First test could be the comparison of TS590 and K3 circuit diagram, looking at the receiver path, although we should look at the TX area for reduction of spuries emitted. Second test, an independent review like the ones made by Peter Hart, G3SJX, and published in RadCom (RSGB). Peter is a gentleman and does not usually â€œoffendâ€ the manufacturers but reports his reviews quite clearly, although he does not write as much as he was doing in the past century. If you look properly at Peterâ€™s measurement tables, you will understand the quality of equipments from the â€œmeasurementsâ€ point of you. K3 Review has been already published with good reports, see RadCom July 2008.
Sardine Can Antenna. is a BiQuad or Bi circle – wire length each side (8 x 1/4 waves ) 31 mm
Sardine cans have quite standard dimensions around the world, although the oval one shown here is lightweight aluminium & does seem (perhaps by chance ?)to have enhanced directivity compared with more normal steel Canadian “Brunswicks ” etc. It’s an ex. Latvian RICHTER “Smoked RIGA SPRATS” & perhaps first received publicity in the Nov. 2002 Australian “Silicon Chip” monthly ( author Stan. SWAN => firstname.lastname@example.org ), when it was first called a “Kipper Can”. ( For those readers who don’t recall Monty Python, Kippers are smoked herrings http://www.deliaonline.com/ingredients/ingredientsatoz/i_0000000135.asp. See refs & further construction dimensions/views/insights => http://www.manuka.orcon.net.nz <= Even an old CD can act as the reflector, exploiting the metalised layer of course, but the sardine version prooved far superior, no doubt due to the focusing side walls.
The hot melt glue shown here is not really needed if a rigid N connector is used, although a recent enhancement has been to form the radiating bow tie as tracks on a small PCB secured via nylon spacers. Gain is great -typically 10dB ( links to 10km LOS made & typically 2km more normal built up areas !).
Need a quickee antenna ? Got 10 minutes & simple tools ? You won’t get a simpler, cheaper or more compact design. The unit can be neatly hidden in a pencil case or plastic bag beside your road warrior notebook so it’s not intimidating for field use. It’s directional enough to even pin point the signal location ( using NetStumbler etc )in a multilevel building. RECOMMENDED !
Originally publihed at http://www.seattlewireless.net/SardineCanAntenna
Article by N9RET
THE INDOOR SPIRAL DIPOLE
Since well before getting my ham ticket in 1993, I had been interested in maximizing my antenna advantage within the limitations of my small living space. I would experiment with different arrangements for SWL, Scanner, AM/FM/TV and 11m antennas, mostly within the cramped confines of the attic of the efficient row house I grew up in.
Getting the best reception on my old Realistic DX-160 was challenging, to say the least. Ditto my scanner, TV, etc. Early on I put a VHF/UHF TV antenna up in the attic, fed with 300-ohm twinlead. Of course, back then, I’d just twist the two wires together at the radio end and twist it around whatever stub of an antenna was left protruding from the receiver of choice.
Even so, I noticed a difference, and from there I was hooked. I had to figure out the best combination I could possibly fit in the attic. I tried things randomly and without much success, until that fateful day in 1993 when I found out a co-worker was a ham. He clued me to the fact that there was no longer a code requirement for the entry-level ticket, and even got me the test prep materials.
Little did he know the beast he unleashed that day!
After finally embracing my inner Radio Geek, I committed to get my No-Code Tech ticket, thanks in no small part to my friend and elmer KC, kg9jp. In many ways, KC made this beacon station possible, even selling me the TenTec at a budget-friendly price to get me started on HF.
I soon became possessed with the desire to learn the code and upgrade my ticket, and the pursuit of this knowledge brought two things into focus; HF Beacons and Antenna Theory.
The beacons gave me the chance to practice my code reception in real-world conditions, and let me compare the effectiveness/directionality of different antenna arangements. It was a big kick to log a far-away new beacon, and a bigger kick to learn how little power they ran to make the distance! Suddenly, a beacon seemed do-able even at my little shack…
I also learned that a complex outdoor antenna array atop a high tower was NOT necessary to communicate effectively over vast distances (it sure doesn’t hurt, though!). It seemed that, with the aid of an antenna tuner and the proper feedline, you could basically just toss up a hank of wire and start making QSO’s!
Needless to say, I got my hands on a tuner and some good-quality 450-ohm ladder line, copped a LOOONG roll of thin 2-conductor wire and some wood-screw type feedline standoffs and crawled up into the cobwebs to try to put up the most wire possible in an orderly manner in the attic.
Many approaches were tried, but what ultimately worked the best is what I now call the Indoor Spiral Dipole antenna. The success that I met with after setting things up this way made it clear that this was a working approach to the problem. The thing tuned up from DC to Daylight (well, maybe that’s a bit of an exaggeration, but 10-80m is no problem) and made QSO’s as soon as I got down from the attic!
I was able to route the feedline discreetly down to my basement shack, and I never heard a thing from the neighbors regarding TVI! Granted, I run QRP power levels mostly, but I have run it at Full Throttle from the TenTec (maybe 70 watts at that time) without starting the microwave oven or causing the neighbors to run screaming into the street…
I posted a write-up about the antenna on the ARRL BBS way back when, and it still exists in their archives (Click Here to see it on the ARRL server). In case they eventually purge it from their servers, I will re-post it here as well.
Remember, this antenna uses two-conductor wire (like speaker wire), and one leg is seperated from the other for about four feet at the feedpoint. One of the seperated conductors ties in to the feedpoint attachment with the 450-ohm feedline, while the other “floater” conductor (now the long end of the antenna since we soldered together the ends at #1) can float as it would if it were an ordinary dipole, or we can jumper the ends together, making a long loop antenna.
The feedpoint (#2) is high up in the attic, while the floaters are at floor level. Run the 450-ohm feedline away from the antenna as perpendicular/vertical as possible (although mine runs horizontally along the floor of the attic for several feet before descending into the house).
Subject: Indoor antennas for HF
From: Tim, N9RET
This originated as a response to an inquiry about indoor antennas posted on the AES BBS 01/04/97. I have recreated it here for those in similar “postage stamp” size lots who would like to experiment with indoor wire antennas, and use some otherwise wasted space in their homes
As regards your indoor antenna- I am in a very similar situation, and my solution was to construct what I call a “Spiral Dipole” in my attic.
The basic concept is this; starting at the center of the attic at floor level, I hung two runs of 2-conductor wire from the roof joists, using wood screw type standoffs designed for 300-ohm twinlead (available from Radio Shack).
I spiraled each leg of the dipole up and in, using the 16″ on-center joists to maintain consistent spacing. When I reached the end of the spiral, I soldered the two attached conductors together, effectively doubling the length of each leg.
At the feedpoint, I used only one of the two attached conductors from each leg, feeding the array with 450-ohm twinlead ladder line to a tuner. The other conductor from each leg (closest to the feedpoint) is generally left floating, although I have experimented with connecting the two floating ends together, creating a loop-type antenna, with some success (apparent directional characteristics, etc.).
This antenna tunes up from DC to Daylight very nicely, and my first QRP contacts were well into South America. It also works well as a “Lowfer” reciever for the LW beacon band and (to some extent) the MW broadcast band (although it tends to overload my reciever at MW).
I have noticed some directional characteristics even when running it as a dipole (ends left floating), but until I figure a way to rotate the house,I’ll just have to live with the pattern.
***Keep all the flammable junk that tends to collect in an attic well away from any part of this set-up, and as an added measure, run as little power as you can get away with. I installed a smoke detector up in my attic, just to be sure.
I have a small corner townhouse, and I was able to make each leg of this antenna 115 feet long (twice that if you count the doubling of the two-conductor wire at the end of each leg). I am not sure of the principals at work here, but the darn thing works- often better than the ground-mounted 5-band vertical in my backyard!
If you have any further questions about this array, drop me a letter and I’ll include a pictoral diagram of the antenna- it’s neat, out of the way, and it works!
Good luck and happy DX’ing de N9RET!
Article originally available at http://n9ret.10mbeacons.com/isd.html
Today I’ve taken some time to test my latest portable antenna, the Buddistick.
By using an MFJ-269 antenna analyzer I’ve tried to find the main tuning keys for this small multiband antenna.
I’ve been able to find an excellent SWR and Impedance setting for the 20 meters band, but I’ve also learned that tuning this antenna is a mix of settings.
First of all the Coil, as stated in the official documentation, the coil can be tuned by simply moving the clip tillÂ you hear the highest noise.
The antenna analyzer confirmed this.
Another determinant factor is the counterpoise. The lenght and the presence of metal close to the wire can significantly impact on impedance and SWR readings.
Whip lenght, can also influenceÂ but not as much as coil or counterpoise position.
I’ve taken some notes for coming outdoor operations, and they are almost similar to the ones published by FK8DD in his web site.
Another important trick I’ve learned is the 1/3 coil / clip position. By simply placing a clip at 1/3 right or left of the coil can surely tune the coil lowering or shortening the antenna.
After having properly setup the antenna for the 20 meters band and having called CQ for a couple of minutes (with no answers) I’ve decided to approach the 40 meters band using the Higher Noise method. I’ve found in fact that setting the clip at the third turn from bottom, and leaving the couterpoise as was set for 20 m, the SWR reading on the FT 817 was showing 3 dots…. By sliding down the Whip the SWR reading become excellent. So I made a few calls even here.
I’ve not been able to make any contacts due to the very low time remained, but i’ve been certainly enjoyed plaing with antenna tuning, one of the most popular sports among hams 😉
I’ve just published an article on a recent comparison between MC-60A and handheld microphone.
While trying to improve Kenwood TS-590S SSB performances, I recently purchased an used MC-60A microphone.
After a couple of weeks in which I’ve been testing this preamplified desk microphone, I’ve sorted out by making a final on the air comparison.
According to my tests, the original handheld dynamic microphone works better that the desktop one.
Just taken this shot with my Nikon D-90
Transceivers: Kenwood TS-590S – Yaesu FT-857D
SWR – PWR Meter : Daiwa CN-801
Microphohe: Kenwood MC-60A
Morse Key: Begali Stradivarius
Power Supply: NisseiÂ MS280A 25A
Here a plan for a Morgain Antenna for 40 and 80 meters band.
This dualband antenna similar to a folded dipole permit to operate low bands by using a very limted space.