I recently bought an “EARCHI end-fed antenna”:www.earchi.org/proj_home… put it together in about 30 minutes (20 of which were winding and re-winding the toroid) and have been testing it out, by which I mean, trying to get it to tune
- in the attic,
- using the included 30' wire with and without a counterpoise,
- with and without an RF choke
- outside the attic
- with a longer wire and a counterpoise
I switched out the 30' wire they included with a 53' length, and here’s where things stand right now, using the internal ATU of the radio. The matchbox end is just inside a second story attic window, with a 16' counterpoise in the attic. The main antenna element slopes down to a nearby tree to about 6' above ground. It’s not ideal, but it’s the closest tree I have. Herewith the latest results:
| Band | SWR |
|---|---|
| 6m | 1.1 |
| 10m | 1.0 |
| 12m | 1.0 |
| 15m | 1.0 |
| 17m | 1.0 |
| 20m | >3 across board |
| 30m | 1.0 |
| 40m | tunes under 3 down to 7.180. Below that, it spikes over 3. |
| 60m | nope |
| 80m | ok > 3.600. Below that, no |
So on the one hand, here are a whole pile of new bands! On the other hand, losing all of 20m and the bottom edge of 40m sucks because I just started working JT65, JT9 and PSK31 there. The consensus is that an external tuner will do the trick. Hard to fault the built-in one too badly, though. I will add an air choke back to the feedline at the matchbox, though, and see if it makes a difference. If nothing else it’ll minimize RF coming into the shack. Now if only the weather would clear out so conditions would improve a bit…