The AD5X Portable Vertical HF Antenna

I stumbled across an early version of Phil Salas' (AD5X) Portable Vertical HF Antenna article late one night and I immediately planned on building one. I ordered the coil before going to bed...and before realizing that more recent versions of the design existed. Oh well, I have a 2" coil rather than the 2-1/2" coil used in later designs.

The ARRL publication "More Vertical Antenna Classics" contains the most refined version of the design and, other than the coil used, is the design I followed. The picture (left) is the trial run of the antenna set up in my back yard. The first QSO was on 40m to a station in Indiana, Bob, NY6J/p9. There was a fair amount of S9 static crashes on his end and with my 15w signal, it required some effort on his part to copy it my S5 signal. None-the-less, we had a nice QSO. And I now have another viable portable antenna! (I have a simple 40m dipole that I can use for portable operations, but it requires trees or some other means of getting it up into the air -- I like the idea of not depending on trees!)

Here's a close-up of the loading coil with the adjustable jumper set for the 40m band. The 10 ft. telescoping whip (MFJ-1954) screws into the top fitting. There is a section of wooden dowel inside the coil to provide mechanical support. I sprayed the dowel with clear acrylic laquer before installing the coil to help prevent moisture absorbtion.

The base is a PVC 'T' fitting with a metal spike fitted onto the bottom, the S0- 239 Socket, and an adapter into which the antenna rods screw. Also included in the base assembly are two screws with wingnuts. The lower is connected to the feedline shield and the ground spike and used as a connetion point for the ground radials. The upper is connected to the antenna's radiator and the center conductor of the feedline. A capacitor can be used accross these terminals to improve the match on 30m and below (haven't tried this yet).

Shortly after completing this antenna, we visited my wife's parents in Tiverton, RI, and I took the opportunity to operate portable for a couple hours. First contact was on 20m. As soon as I turned on the rig and started tuning around, I heard a station ask if the frequency was in use and LY1FW started calling CQ. Turns out this was a station in Lithuania calling and I jumped right into the QSO receiving a 57 report. This isn't the first time I've gotten lucky and been there when a DX station just starting up. It's nice to be on the scene before the pile-up forms :-) I made four more contacts on 20m -- all California stations (I just happened upon the California QSO party event). I then switched to 40m and had a nice ragchew with Carl, W3BMK, in Chicora, PA that lasted 15 minutes or so -- got a 57 from him as well. Anyhow, here's a picture taken from my operating position on the deck -- nice view of the Sakonnet River with Common Fence Point right accross the way and Mount Hope Bay off to the right (that's Mount Hope off in the distance in Bristol, RI).

Here's a veiw of the antenna set up on the lawn.