I have the following Transmit antenna questions, relative to Common Mode.
Please let me describe what I have.
Linear>30'RG213>W0MLY 5 position Coax Switch in shack.(Does not Ground unused
centers) with 3 antenna ports used:Then at the W0MLY Inputs:Antennas:(1)160M
Inv. "L"(Infamous Bird Feeder)using 80' LMR400 to feed point..6 radials into
Marsh, 2 Ground rods all connected to Shield, no balun. Ant 33' Vert, 90+ ft
horiz.Feedline buried.(2) 50' of RG-213 to OCF Dipole 80-6 Balun Designs 4114
balun. No other "Current Balun" in line. (3) 50' LMR400 to Steppir Big IR w/
numerous radials/ground screen,Ground rod in marsh. Feedline buried under
screen.** All 3 Antennas in close proximity of course due to short coax feeds.
My objective is to do whatever I need to minimize noise but still use the W0MLY
Box to switch antennas if possible. I have some 2.4" cores, Mix 31 on the way
to build chokes per K9YC.I have some RF in shack/house/computer which usually
manifests when use the OCF dipole at High Power. Questions: Is it OK to
connect the grounds and radials in common at the Feedpoint I
nv L? Should I just connect Radials but ground coax shield when it comes in
shack?Do I need a choke Balun there(feed point)? A 5,000 Ohm described by
K9YC. Do I need to ground the W0MLY Box? There is one about 5' away on the
other side of the wall. Should I have separate Chokes for each feed at their
inputs at the box? Should I replace the W0MLY with a Grounding-Unused coaxes
type? Is the Box re-radiating noise by having all shields connected at the
box? Should I put a K9YC Common Mode Choke at the output side of the Linear? I
know this is a lot to ask. Any comments would be appreciated and may apply to
many other amateur's situation and help others. There are some real
knowledgeable guys here who really know this stuff I cannot comprehend. I have
been trial-and-erroring for so long I am praying some positive results come
from this inquiry. I am hoping to clean up the station a little and be more
prepared for some new ones even though I am using the smallest antenna
for Top Band probably on the East Coast. Fortunately, the feed is about one
foot from Salt Water. I'm gunning for the FT5. and VK9s. and, JT1 for my last
Zone. If this is too much for the reflector, please reply direct and I will
later condense the suggestions. Thanks in advance. 73Val
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