If you are looking for 50 ohms at the feedpoint, the antenna you are
using probably won't do it for you.
Most verticals (no matter how many radials are attached to that plate)
will have a feedpoint impedance around 35 ohms ... thus the SWR you
mention (50/35 = about 1.3) If the feedpoint impedance is much less
than 35 ohms, the SWR will be even higher.
Without a tuner placed AT THE FEEDPOINT, don't expect any 'magic' way
to make all those antennas work at low SWR.
73,
Don
N8DE
Quoting Gary Smith <Gary@ka1j.com>:
I did some spring maintenance on my antennas and need advice on how
to get a 1.1 match.
I have a radial plate with somewhere around 50 130' radials. I have 5
wire antennas attached to this and use an Ameritron remote coax
switch to select which antenna to use. There is a sloper for 160,
INV-L for 80 and verticals for 40, 30 and 20. 17 & 24M are obtained
by selecting either the 160 or 80M antennas. No tuner.
I took the Antenna analyzer down to the antennas today and found 80M
is SWR 1.8, 40 is SWR 1.9, 30M is SWR 2.35 to give some values. The
lowest SWR I could get on 30M is 2.35 and the antenna is cut for the
right length for minimum SWR at 10.100 MHz. This gives me the lowest
SWR on the bands.
I would like to get the SWR down as low as 1.1 at my desired
frequencies If I can do so, but I'm not sure of the best way to do
this. I suspect inductance from a coil at the individual feed points
would work after I get the to SWR dip the lowest at the desired
frequency but if this is the solution, what would be a good way to
know do make such coils for each of the antennas?
The antennas are 350 feet away, in the woods & onto a salt marsh and
for me, right now, walking is very difficult to do and I want to make
as few trips as possible.
Suggestions appreciated.
73,
Gary
KA1J
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