Trapping my 80m Inverted L for 160?
 

I'm having great success with my 80m inverted L (45' up and 25 or so feet
out), with 26 radials (now). (Hung off the side of my tower)

I had a thought for something to just "get me on" 160. Is there any reason I
couldn't put an 80m trap (design freq, please?) at the end of the 80m
horizontal wire and stretch it out for 160? I read the article on W8JI's
site
about coaxial vs other traps. Since I'm not going for broke, but just want a
quick and dirty solution, I was thinking about making a coaxial trap for 80m
out of RG8/X coax (or I could buy some 58a/u) that I have laying around. Not
running more than 500w, so this size coax should be fine.

My questions:

1. What freq should I "design" the trap for?

1a. The program referred to on W8JI's web site (trap design) has no entry
for 8x, but manual values can be entered. Anyone have ready access to the
parms for 8x that I
need to enter?

2. I assume the trap will detune the 80m section, making it longer. Any
ideas for a starting point on how much to shorten it, or should I just cut
and try?

3. Will there be any degradation on performance on 80m from adding the trap
and wire extension to enable 160m?

4. Any suggested starting wire length after the trap to resonate 160
towards the lower (DX) part of the band?

I don't want to ruin the excellent performance I'm getting on 80m, no matter
what I do, so if I can't do this without compromising 80m, I'll think about
another alternative.

Thanks for any ideas you may have. I wan't to get this done before the snow
flies!

73,

....hasan, N0AN

about coaxial vs other traps. Since I'm not going for broke, but just want a
quick and dirty solution, I was thinking about making a coaxial trap for 80m
out of RG8/X coax (or I could buy some 58a/u) that I have laying around. Not
running more than 500w, so this size coax should be fine.

I did that once to make a dual-band inverted L, and it worked fine (I
also used a coax-cable trap). I tuned the trap for 80m.

Here is another alternative to think about that might be even easier:
simply put up a second wire for 160m, and feed it in parallel with the
80m wire.

For a while I had up a 160m inverted L with a vertical part of about
75'. I had a 80m wire (full 1/4 wave) running parallel to the 160m, and
spaced about 3 feet away. At the base, they both connected to the
feedpoint. I used a beta match coil across the feedpoint to match
the 160 wire, which had little effect on the 80m swr. It worked
quite well on both bands.


Tor
N4OGW