hasan schiers wrote:

I wondered if I could EVALUATE the effectiveness of the 80m inverted L
on 40m as a half wave, by temporarily taking an antenna tuner with wide
range (T-network matches almost anything) out to the feedpoint and
matching it there. If it hears well, and works ok at 300w (tuner
limit), then it might be worth investing in the coil/cap/relays to
switch a more standard high-Z feed in and out. What do you think?

The configuration of 35ft vertical + 35ft (or so) horizontal worked well
for me on 40m at the old QTH, and was quite effective on 80m DX. For
160m, I added a 100ft loading wire to bring the total length up to about
130ft, and that configuration doubled as an end-fed half-wave for 80m
short-skip.

Having a QRO auto-ATU made band changing easy, so it wasn't necessary to
resonate the antenna on any band. However, the quarter-wave resonances
on 80m and 160m could have been trimmed to length.

Coming back to the difference between the 40m vertical quarter-wave and
the bent half-wave, I compared the bare 35ft mast and the same mast with
the added loading wire and didn't find much difference. For DX, the
bent-half-wave should have been down on the quarter-wave (because some
of the radiation was being wasted at high angles); but in contests, both
antennas seemed to work the same regular DX stations. The bent half-wave
was louder for short-skip, which meant more QRM at night, but made it
easier to continue making low-point contacts during daylight hours.

If you use an 80m trap, the antenna could still work on 40m but the
horizontal section would be way over-long. Unless rapid band changing
between 80m and 160m is a priority, I'd suggest you use a physical
disconnect at the end of the 35ft horizontal section. (My setup made it
very easy to loosen a rope and lower the connection into reach, so I
used simple banana plugs, with snap links to add either wire or plain
cord.)




--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek