A windom antenna for 10 to 80 meters band – a design by PU1LHP
A windom antenna for 10 to 80 meters band – a design by PU1LHP
Let me first say I make no claims of originality for this item. It is intended as a simple, inexpensive solution for the newcomer to experiment across the 40m band (7.0–7.2MHz) when only restricted space is available. “A picture speaks a thousand words” so by including a couple I’ll keep it as short as possible!
With the rally season upon us, it is an ideal time to pick up those bits and pieces with which to experiment. The antenna described here consists of a 50R coax fed, inductor loaded 5.44m vertical section mounted on a 1m alloy tube driven into the ground and requires no radials although this may well depend on the local soil structure.
The vertical itself is a salvaged unit (probably ex. CB) consisting of 4 telescoping aluminium sections with an extended length of 5.44m and its mounting bracket.
The thick wire in the picture is the coax centre connection from the bracket mounted SO239 connector to the coil. Continue reading→
MANY of the DX men have been at a loss to appraise accurately their postwar DX accomplishments because the last revised Countries List was made up back in 1939 and, since that time, many areas have been shuffled about and postwar stations have cropped up in locations never before considered. To reach as satisfactory a revision as possible, a committee made up of G2MI for the R.S.G.B. slant, W6QD and his advisory group of several prominent W6s, and a five-man ARRL Headquarters group has been collaborating during the past few months to revise the list and polish off the rough edges. A number of changes have been made, but they have been made almost unanimously, so it is felt that the present list is a good cross-section of opinion. A careful check of the list will show that a number of countries have been added, and that several have been deleted or combined.
Naturally there will be some difference of opinion by some of the DX men, and the collaborators will be pleased to entertain any criticisms.
A coax atenna project by WB4CPO from the late 80s that can be considered a double bazooka antenna.
Type of coax needed — RC 58/U or RC 8/U. RC 58/U is the best.
Use the same type coax for antenna and feed line.
Maxium legal power can be used on the RG 58/U without fear of feed line breakdown.
80 meter example:
Start with 128 ft of coax and make center reference point. Measure from center reference point out each way for a distance of 30 ft 6 in. Solder the inner conductor to the shield at both points. This forms the 52 ohm matching balun. Waterproof both joints well. Next, at both ends of the antenna, short the center conductor to the shield but do not waterproof until after trimming for tuning purposes.
At the center reference point, remove one inch of the vinyl jacket (1/2 in each side of center).
Cut the shield in the center all the way around the coax.
DO NOT CUT THE INSULATION OR CENTER CONDUCTED.
Connect the feed line to the shield leads, one shield lead to the center conductor of the feed line and the other shield lead to the shield of the feed line.
Waterproof well and mount on a 4 in x 4 in piece of plexiglass to hang from outrigger up on tower.
For 75-80 meters the feed line lengths should be 57 ft, 87 ft, or 103 ft.
Separate feed lines must be used for each band.
In summary, the advantages of this antenna are:
A little over 60 years ago, a company called Times Microwave Systems (TMS) was born in Wallingford Connecticut. They made all kinds of wires and coaxial cables for many communications companies and the military.
First I want to make it clear that I do not work for or get paid by TMS for this article or any endorsement. I believe this coax to be the best for the money. I will never again use any other type of coax except TMS LMR type coax. I use LMR-400 for all of my antennas, and LMR-240 for short inside jumpers between devices. In the past I have used RG-8, RG-8X, Beldon 9913, and RG-214 coax throughout my 45 years in radio. I have seen how long different coax types last, and the kinds of losses they have. I have noticed how even the better Belden cables can leak and cause TVI and get into stereos, phones, clock radios, the bathroom pipes….etc. I have seen how they handle broadband antennas with regards to SWR. Continue reading→
I want to get into this subject because it is important to good audio practice. This article is actually a second part to another article called “Microphone Frequency Response” which should be read first to fully understand the audio that radios and microphones are capable of. Reading that article first may clarify some of the statements made here in this article.
This is one of those mics that only comes around once in a blue moon. Because of it’s quality and price, I thought it deserved a mention on my website. Read on and see what makes this mic so special.
When Icom came out with their new IC-7800 elite ham radio, they asked Heil to make them a mic that would really show off the high end audio quality of their new big expensive radio. Heil first made the PR-780. and it was good. Then Heil went a step further and made the PR-781. The 781 is a slightly improvement on the 780. Continue reading→
Have you searched and searched for a good speaker for your ham radio?
That perfect speaker that would let you hear voices through the noise and static without hiss? A speaker that isn’t fatiguing to your head after listening for a while to weak signals? If you are like me, then you answered yes.
There are several speakers on the market designed for communications. A lot of us long time operators use a good set of headphones to hear those weak signals, or to just enjoy the clean crisp audio of the strong signals. Headphones are probably the best for this purpose, but they can get annoying after wearing them for a while. I was using a small but good quality bookshelf speaker designed for lower powered stereo systems. It sounds pretty good, but it’s still not what I want.
The Grid Yagi (or Grid Quad) is a high performance yagi antenna that can be built with readily obtainable inexpensive materials. Described here is a 6 element 2 meter version with a boom length of about 1 wavelength.
The boom is made of 11?2 inch pvc pipe, although any suitable material can be used, such as steel, aluminum, fiberglass, or wood. The elements are cut from 2 inch by 4 inch galvanized welded wire fencing, with a wire diameter of 0.078 inch, which is what #14 steel wire becomes when it is galvanized. Continue reading→
Today, while I was playing with google map, i ended up inside the International Space Station.
I immediately realized thay all the ISS modules have been made available in 360° view, so I decided to look for the ISS amateur radio transceiver, from where astronauts use to talk to schools via the ARISS program.
After some minutes, I spotted the location of the ISS radio shack, that is composed simply by a Kenwood TM- D700A transceiver, and is located in the Zvezda Module of the ISS.
If you want to virtually walk inside the ISS, just follow the link to the Google Maps ISS Radio Schack
The Kenwood TM-D700A is a dual bander that allows APRS, GPS and SSTV transmission with 50W RF Output
The ISS configuration map will help you on orientation through the labyrinth