Jim
" What I am asking is if anyone has any, on-the-air experience and would
recommend one antenna system over the other for *most conditions*. In other
words, will an antenna that has a less lower elevation pattern generally
outperform an antenna that has a narrower beam width, but a higher elevation
angle? "
I understand your question now. Yes I have exactly that, a low elevation
narrow bean VWF, that works best at 20 degree or lower and a same narrow
bean but high elevation angle HWF best at 40 degree. I keep a record of new
countries worked with one or another.
The high elevation angle outperform the low elevation angle 95% of the
time, in special near SS or SR. But the low elevation angle was the only
antenna that can hear South Asia direct path due north. 9M2AX , BU2AQ, 4W6
over or near the North Pole.
Let me say the same thing in another way. For DX signals coming due North
330 to 30 degree , the vertical low angle outperform the high angle always.
It is based on the direction the signal is coming from and the interaction
with the dip magnetic field. Like 9M4SLL on Mar 13th 2013 was strong 340
degree only heard with VWF, on Mar 17th the signal was coming SSE and the
high angle was better, but copy with both antennas.
95% is a big number however the 5% could be a new country. Like 706T in the
first and second night only copy on the vertical low angle, after they move
to a new location the high angle RX antenna was better.
They are complementary to each other, hard to pick one.
73's
JC
N4IS
-----Original Message-----
From: James Wolf [mailto:jbwolf@comcast.net]
Sent: Thursday, December 18, 2014 1:30 PM
To: 'JC'; 'Top Band Contesting'
Subject: RE: Topband: Non-resonant receive antennas
Thanks JC,
I agree that the RDF number is significant when evaluating a receive
antenna. I agree that no one antenna system will work all of the time.
Consider we have two scenarios: One RX antenna system that consists of two
parallel antennas (Broadside) , and the other is the same antenna configured
in-line, toward the desired signal (Delayed series fed).
What I am asking is if anyone has any, on-the-air experience and would
recommend one antenna system over the other for *most conditions*. In other
words, will an antenna that has a less lower elevation pattern generally
outperform an antenna that has a narrower beam width, but a higher elevation
angle?
I think in this we need to consider the arrival angle of atmospheric noise
in a broadside array vs. atmospheric noise in a series fed array. Since
atmospheric noise propagates and the arrival angle will change, which
scenario would provide the general overall better performance?
Jim - KR9U
_____________
Jim
RDF is everything ! The RX antenna system is the only way to improve
signal to noise ratio. All electronic device is not perfect and introduce
noise and deteriorate the signal to noise ratio, including your radio too
RDF is one way to measure directivity .
You may do not need directivity to improve signal to noise ratio if you are
operating from a very quiet location or a desert island on the pacific
without man made noise.
If you deal with noise at your location you will select the antenna with
better directivity. That's adds another component how to cover all
directions.
Better RDF equals to better signal to noise ratio.
That's is true for all bands, try to work 20 meter contest with a vertical
with 1 kW and compare with a 5 elements Yagi with 100W. Your TX signal will
be the same however for sure you will prefer to receive on the Yagi due its
directivity. You won't hear much on the vertical
Regards
JC
N4IS
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
|