Your feedline is about 350 feet. That is (with RG213 -velocity 0,66-) close
to 1 wavelength. With 1 wavelength feedline, the TX antenna is floating when
the feedline is open in the shack.
Just wrong once more. !!
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Topband Reflector Archives - http://www.contesting.com/_topband
Your feedline is about 350 feet. That is (with RG213 -velocity 0,66-) close
to 1 wavelength. With 1 wavelength feedline, the TX antenna is floating when
the feedline is open in the shack.
I'm sorry to say that , but the concept is wrong, the TX antenna resonance
as structure has nothing to do
Paul,
Your feedline is about 350 feet. That is (with RG213 -velocity 0,66-) close
to 1 wavelength. With 1 wavelength feedline, the TX antenna is floating when
the feedline is open in the shack.
Depending on your transceiver configuration (if the TX antenna is completely
decoupled when using
The main use of the coax loop or any loop for that matter is not gain but low
noise directivity. Placing it on a small TV rotator allows for the nully of
local noise to help improve the SNR for the desired signal. A preamp may not be
necessary especially of it increases the desired signal and
Hi Paul,
Modeling the effect of the feedline and the receiver terminating the
feedline is tricky. Some are able to short or open the TX feedline in the
shack due to a "favorable" length from the antenna to the shack. The brute
force method is to install a vacuum relay at the feedpoint which
Paul, I suggest you talk to Gary KD9SV as he built a Hi-Z around his TX
antenna.
Incidentally the ground radials under the Hi-Z is not a good idea. I suspect
you would have to use NEC4 to see the real effect of the radials. I have not
made a test myself to see how close radials could be.
My TX antenna is 60ft from my vertical WF and my horizontal WF is at the top
of my TX antenna. I am using a Folded Unipole configuration, it is a skirt
with 3 wires forming a cage. The skirt detune the tower during RX and help
the TX with a huge broad band.
In your case, just open the T
For transmit I use a 160M T antenna with on ground radials. I am
considering installing a Circle-8 receiving array such as one made by
Hi-Z. The receive array would be very close to the T, maybe within 100
feet. I am using EZNEC to see how the transmit antenna proximity
affects the pattern of
I goofed with those gain numbers. Forgot to do the average gain test in
EZNEC. The program was making big errors due to too many segments.
The real answer is that there is only 2.4 dB less gain for the
horizontal loop.
Jerry, K4SAV
On 9/30/2016 9:50 AM, K4SAV wrote:
A small loop mounted
A small loop mounted horizontally will be omnidirectional, mostly
horizontally polarized and with a null overhead. An omnidirectional
antenna isn't usually a very low noise receiving antenna. The gain will
drop by a lot if the antenna is at low heights. A square loop 5 ft on a
side placed
I have a 160 meter rcv loop - kc2tx product - I want to employ this season.
I don't have a lot of band noise here in s/w Utah and don't want to bother with
a rotor socan I mount the loop in a horizontal configuration and expect
some improvement in rcv signal strength? I seem to recall Tom,
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