Aloha to all again,
In response to my reported ground pattern below,
> Now you have a pattern something
> as follows: __
> /
> |
>
> Lengths in that are not to scale, but the shape is close to correct, hi.
Tom wondered:
"Why drive a rod in at an angle?? What is the magic in the odd
spacing?"
I was told that this pattern had come from
others in the LA area, I think he said the phone or power company.
He thought the spacing had to do with providing different path
lengths for differing frequencies returning to ground. However, I
have now come to understand from others that the principal purpose
of the rods is to return lightening currents, not rig RF currents to
ground --- at least I think that is what I have learned, hi.
> Now, I also recv'd another input which takes a different approach to the
> RF "ground" situation in the shack, from Chuck Constantine KR6C,
>
> "What you're interested in is a equi-potential ground reference. That
> means ALL equipment is at the same potential. You do NOT need a (earth)
> connection for a RF ground reference. People seem to think the earth is a
> magical RF sink where spent electrons go. They want to get back to their
> source...not necessarily earth (Kirchhoff's first law
To the above, Tom wrote:
"While it does keep all the equipment at the same potential, it does
nothing for potential between the equipment and everything else in
the world.
This [plate] ground would never help with RFI or lightning, except for
stuff in the room with the ground plate."
Some more from the original snipped, then Tom comments:
"A "ground plate under the rug" isn't a bad RF idea for eliminating in
shack RF, especially at the higher frequencies, but it is NOT a
good RF ground or lightning ground. It will not prevent common
mode current from getting back in the power or telephone lines on
lower bands. It does little to improve lightning protection.
"If feedlines are properly treated outside the shack, and the
equipment is anywhere reasonable in design, it won't be necessary
to use a shack ground for RF. "
Now that is really interesting!!
My Yaesu FT-1000D has a separate receiving antenna input, an actual
SO-239 on a plug in module, the BPF-1. This feeds only the sub-rcvr.
But, unlike the main antenna input, which is the only port of the rig
used for transmit output, there is no relay which opens on transmit.
So, when a separate rcv antenna is connected to this port, and
one transmits on the main channel, RF will be picked up by the
separate antenna and brought directly into the rig. I know this
happens.
On 40 meters, if I output, via a solid state linear anything over
250 watts or so, I can hear "clicking" sounds within the FT1000,
but these sounds go away if I disconnect the coax from the separate
antenna from the BPF-1 subrecvr input module!! So, I must give
up my "binaural" 40 meter QSK CW antenna diversity rcv capability,
but it sounded so neat!
Instructive thread for me, at least.
73, Jim, KH7M
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