Posted by
Jim Brown-10 on
Aug 27, 2010; 4:56am
URL: http://elecraft.85.s1.nabble.com/Need-K3-dB-Measurements-on-new-160M-Antenna-tp5468244.html
Crew,
I've put up a pair of new antennas for 160M that are predicted to have
about 3dB of gain over my existing vertical. Without going into a lot of
detail, each antenna is a wire sloping off of my 120 ft tower, one going
east, one going west. The tower acts as a reflector. The tower and each
wire have 4 elevated radials. The antenna is working -- I've made four QSOs
with VK, one with FK8, and one with FO in about two hours -- but I need to
figure out if it's working better than my existing omni vertical.
By doing a lot of listening, I can clearly confirm the predicted 6dB or so
of front to back, but QSB makes it hard to get a handle on gain, and I'm
only expecting 2-3dB. That's where the dB meter in the K3 comes in handy.
My method is to key down on one antenna for a while, let you get a reading,
switch to the other and do the same, then back and forth between them,
again for long enough for you to get a good reading. There IS a lot of QSB
on the band, so you'll need to do a lot of mental averaging. Please let me
know, OFFF THE LIST, if this is something that you would like to help me
with. I need reports from stations that are between about 30 degrees
azimuth and 120 degrees azimuth of my QTH south of San Francisco. In other
words, my antenna is aimed at about 75 degrees (ENE), and I need reports
that are within 50 degrees of being on axis. I could also use measurements
from KH6 of the antenna that goes in that direction.
BTW -- to access the dB meter in the K3, you need to hit the Display button
once, then rotate the second VFO knob clockwise until you see a reading in
mV. Let the knob in that position for about 15 seconds, then rotate it one
more position clockwise. Now, the dB reading will be relative to whatever
the average IF output was when the knob was in the mV position. Note also
that the reading goes plus and minus.
73, Jim K9YC
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