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HFguy · December 20th 06, 12:15 AM posted to rec.radio.shortwave

wrote:
HFguy wrote:

wrote:

I have read that the best way, quiestest, to hook into a random wire is
at the far end, attach a balun, go thru a ground block attached to a
ground rod, bury the coax as it runs to the house, go thru another
ground block which is connected to another ground rod then into the
house.

I have 2 options here, one is the above (about 150 feet of coax), the
other is to hook into the random at the near end, thru a balun, feed
into the attic to a ground block that has about 40 feet of ground wire
attached coming from the ground rod, then to the receiver.

Which is the better? Is there enough difference to warrant the extra
expense of the 1st option, more coax, over the 2nd?

The first method is better because you can use a short ground wire
between the balun and the ground rod to make an effective RF ground. The
balun should be located close to the ground (earth) so the grounding
wire to the rod can be kept to a minimum length (no more than 2-feet).
The ground wire in the second method is much too long to be an effective
RF ground. It could act more like an antenna for picking up common mode
noise.

I am still having a problem getting my head around the short ground
connection to the rod.

What is the difference between say 40 ft. of ground wire to the ground
block versas the outer coax jacket going 40 ft after the ground block
that is 2 feet from the rod.

Would either not act as an antenna for picking up common mode noise?

Brian

When the coax (shield) is grounded near the balun which is located close
to the ground rod at the bottom of the random wire's vertical section of
wire, a common mode signal picked up on the coax shield going to the
house, can not feed back into the center conductor of the coax through
the antenna connection at the balun. When the coax ground is *only* on
the other end of the coax, the shield can pick up noise and feed it into
the center conductor at the antenna end where it becomes a differential
mode signal that the radio can receive.

http://www.hard-core-dx.com/nordicdx...eed/feed1.html

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