Sunday, November 17, 2019

On the air with new antenna!


You can see our new 86 ft inverted-V-non-resonant dipole on top the "Whitfield" building at Evergreen Woods, our new QTH.  Fed by 400 ohm ladderline to our 2nd floor apartment at the right, it was a long slog to get installed.  Lots of help from friendly facilities staff, however.  A 4:1 balun connects our ladderline to either the Flex-6500 directly or through a Heathkit SA-2060A Antenna Tuner.

First test shows it's a good 40 M antenna, easily matched with the built-in ATU of the Flex-6500.  Other bands can be a challenge, but the SA-2060A will tune this system over 160 - 6 M -- at least if you're willing to crank those knobs!

My first on-air test was on 80 M with the SA-2060A.  This is a difficult match, because the 86 ft dipole is close to a quarter-wave at 3.6 MHz.  Does it work?  I set it up with WSPR at 5 W transmit power to see what came back.  Partial results of the first few minutes:

Timestamp Call MHz SNR Reporter RGrid km az
2019-11-18 02:36 AA6E 3.570022 -24 HB9TMC JN46lj 6279 55
2019-11-18 02:38 AA6E 3.570021 -24 PA0O JO33hg 5815 48
2019-11-18 02:36 AA6E 3.570022 -24 TF1VHF HP84wl 4091 34
2019-11-18 02:34 AA6E 3.570025 -27 KA7OEI-1 DN31uo 3263 284
2019-11-18 02:34 AA6E 3.570023 -18 VE6JY DO33or 3250 309
2019-11-18 02:38 AA6E 3.570022 -27 KX3DX DM79 2723 276
2019-11-18 02:34 AA6E 3.570022 -25 N6GN/K DN70ll 2697 279
2019-11-18 02:34 AA6E 3.570022 -26 N5SNT EL09wq 2618 249
2019-11-18 02:38 AA6E 3.570018 -25 KI5WA EM11jk 2435 251

So I think we pass.  Best DX is HB9TMC in Switzerland, 2279 km = 3901 miles, with a Kp index of zero suggesting OK propagation..

I had been worried about interference from our building HVAC and other systems. It's there, but so far it's no show-stopper.  My first tests, inside the apartment, were a total disaster, but being 20-25 feet above the roof gets rid of most of it.