This is a state-of-the-shack update. I’ve finally got a few temporary antennas up and am beginning to make contacts from the home station including a tiny bit of contesting.
The first antenna I tried from home was the Buddipole. Before taking it into the field for SOTA operations, I practiced with it one afternoon on the roof. It happened to be the weekend of the Ukranian DX contest, so I did a quick spin through 20m and worked about five stations one after the other with my FT817. I was happy to make any contacts, particularly on a crowded band. No doubt some of the credit goes to the Ukranian operators and their ability to pick out weak signals.
Although I think it would weather reasonably well, I wanted to take the BuddiPole to the field, so I didn’t leave it on the roof. Instead, I made use of an old C-band satellite TV antenna mount, and stuck a telescoping fiberglass pole in the base. From the upper end of the pole, I suspended a halfwave end-fed 20m antenna, vertical at the top, but then slanting off under tension to a string in my backyard. I would say that 70% of the antenna is above the roof line. Judging by reverse beacon hits, the antenna seems to radiate well enough, but being essentially vertical, background is high. I have worked some SOTA stations on it from Ireland and Poland, but it’s a real battle pulling them out of the noise. Max power on this antenna is 25W, but I typically operate at 20W.
My final antenna is a Little Tarheel 2, a small screwdriver antenna that used to be on the back fender of my car when I drove around Washington, DC. I have reworked a mobile mount using some angle iron and the antenna is attached to the metal rail around the roof. I have also added some ground wires cut to no particular length. The feed line and motor control line run down to the ham shack. Tuning the screwdriver antenna is a bit of a pain — peak for noise and then hone in on minimum SWR, but at least it allows me to get on all bands between 6m and 80m, albeit with horrible efficiency, I’m sure.
I tried putting all of this to work a couple weekends ago for the OK/OM contest. At first, I just wanted to make a few contacts to test the system, but once I got going, I started actively searching and pouncing, and on the second day, even calling CQ at times. Due to both antenna efficiency and propagation path, 20m was my main band, with 85 confirmed contacts:
I had one other contact on 80m and about fifteen on 40m thanks to the screwdriver antenna, but I had the sense that my signal was very weak on these bands.
I was happy to place in the top ten (just barely) for 20m low power in this contest, particularly since most of the other operators in the category were probably using five times more power than I was.
As of last week, I have about 300 contacts from 5B/AI4SV, combining portable operation at 5W and home operation mostly at 20W (and a few on the screw driver at 45W). More antennas are no doubt coming.
A final item: I’ve submitted my request for a Cypriot callsign.
2 thoughts on “Some antennas and a contest”
Your SOTA ops are very interesting, in such a scenic country.
Do have a question about the vertical configuration you were running with your Buddipole.
Could you elaborate a bit on how you config the vertical Buddipole?
Thanks very much,
Sure. I just follow the instructions on this PDF.
Briefly, I set up the tripod base somewhere flat and not too far from some bushes. I connect the red feed wire to the top (blue) connector on the Versatee and I connect the black feed wire to the black connector. On top of the versatee, from top to bottom, I screw in a fully extended telescoping whip, the red coil, and an extension arm. I have played around with settings on the coil, but the ones in the PDF seem to work really well, much more so than suggested settings for dipole configuration. I have crimped a lug onto a piece of wire and that wire serves as a the counterpoise. I connect the lug to the black connector on the versatee and then reel out as much counterpoise as I need to get a good vSWR minimum near my intended operating frequency. I’m not sure if it matters, but I use a 25′ BNC cable for this and monitor the vSWR using a RigExpert stick (great for full sun, operates forever on a USB-rechargeable internal lithium battery, and I can see the vSWR sweep without needed to be very close to it). A couple hints: 1) I prepared the counterpoise wire with some color-coded heatshrink tubing so I could reel about approximately the right amount for each band (although often you need plus/minus some distance); 2) the lug does not always make a good connection to the versatee. It helps to jam the banana plug from the black wire next to the lug and screw down on to both of them. 3) Buddipole banana plugs get loose after a while and tend to pop out at the worst possible times, I suggest always taping them down with electrical tape; 4) The counterpoise wire is wound on a plastic form. I found it helpful to list the band, coil position and counterpoise color on a little sticker that I stuck on the handle. That way, I always have a reference. Also, the PDF is downloaded to my phone. 5) The counterpoise needs to be elevated. A lot of folks recommend a fiberglass driveway reflector. Here, the ground is too dry or rocky for that to be convenient, so I use nearby bushes. Even on the baldest hill there is a bit of scrub. If I need, I pick up the antenna and move it relative to the bush to get the required distance. 6) When paying out counterpoise wire near a cliff, do not walk backwards.