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Old July 19th 06, 07:03 PM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Jul 2006
Posts: 34
Default Length & number of radials

Good thinking, Richard, as I may try to get this inverted L to do 160 in the
fall/winter by adding a trap to the 80m inverted L and extending the wire
for 160m resonance.

Incidentally, over the weekend I tried to add a 40m wire parallel to the 80m
L...it was a complete failure. (I used a "fan" approach with 6" standoffs
for the 33' vertical wire). I thought I might get 2 fer 1 at the feedpoint,
but it just didn't work worth a darn. Very low noise level, signals were
significantly weaker than my Carolina Windom 80 (on 40m) up 42'. I did work
a few DX stations with it, but just not up to my expectations. A properly
performing 40m 1/4 w vertical over very good soil and a full radial field as
described in my prior message should have been outstanding. It wasn't. It
was very hard to tune, showed no better than a 3:1 VSWR at resonance, and
was only marginally better on a very few signals between sunset and sunrise.
Very disappointing.

So...your suggestion for 160m is a good one. I could do a trap pretty
easily. If I wanted to try 40m with the same feedpoint, I could put a
parallel tuned circuit at the feedpoint and run the 80m inverted L as a 40m
half-wave. Of course, this requires switching at the feedpoint and I'm not
sure I'd bother. I also have to get a 1.9 uH coil and 250 pf variable cap to
do the tuned circuit (per ON4UN's Low Band DXing Handbook). I found an
acceptable cap for 40 bucks and coil stock is readily available. I just have
to get motivated and work out the relay switching.

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?

Thanks for your input.

73,
....hasan, N0AN
"Richard Clark" wrote in message
...
On Wed, 19 Jul 2006 11:48:47 -0500, "hasan schiers"
wrote:

So...what should I do:
2. Add 20 radials, maintaining my 50' length that I originally used.


Hi Hasan,

Build for the future. Anticipate working 160M. Enjoy the advantages
(as slim as they may be) at 80M.

73's
Richard Clark, KB7QHC



 
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