Back in June 2011 I put up a horizontal delta loop for 40m and I wrote about it at some length here. Since then, I’ve made a few changes to my aerial for the lower bands, experimented with an off-centre fed dipole, a resonant dipole for 40m and a doublet fed through my SGC smartuner before ending up back with a delta loop. Initially I used a 4:1 current balun which allowed it to work on 80m as well as 40m but but in the second version, I fed it with a quarter wave (adjusted for velocity factor) of 75 ohm coax as a matching section to make it a true single band aerial. Of course, being a horizontal loop at less than 20ft AGL, it was always a cloudwarmer but very good for inter-G and western Europe – I never had to call more than twice to break any pileup I tried to work, normally making it first time.
I’ve been frustrated for some time that I’ve not had aerials for 160m, 80m, 60m and 30m so yesterday after the BARTG RTTY sprint contest I lowered the delta loop and extended it with another 8m or so of wire. I then disconnected the length of 75 ohm coax and connected the loop directly to my SG-237 smartuner.
It only took a couple of minutes for me to determine that the tuner was happy with the length and so I can now use it for 160m, 80m, 60m, 40m and 30m. It will be a compromise on 40m compared to the previous configuration but I can live with the inconvenience of that as it allows the other bands to be used.
Now we all know that just because a tuner can make a random piece of wire appear to resonate, that doesn’t mean it actually radiates very well so to test this, I had a quick half an hour tune from the bottom of 160m during the CQ160 CW contest yesterday evening working a few stations. I worked into OH0, ON, E7, 9A, ES, UA, DL, GM, OH, OM, HA, YL, LY, PA, S5, SP and UR so it clearly does work. That’s taken my all time DXCC count on top band from a mere three up to twenty!
I also ran a quick WSPR session on 30m running just five watts where I was heard throughout Europe and over to the east coast of America.
This was a good result for just an hours work yesterday and I’m very pleased that I can now get some RF into the air on the lower bands.