"Michael Lawson" wrote

"Jack Painter" wrote in message
news:J%sud.3067$7p.1654@lakeread02...

"Michael Lawson" wrote

Which reminds me....

I was perusing the ground articles in hard-core-dx.com,
and I was curious about one of the articles there (probably
was one of John's) stating that a good way of eliminating
common mode interference is to ground the shield separately
away from the 9:1 transformer. That I can do easily, but I
was curious about the next statement about attaching the
ground directly to the shield.

My thinking is that it would be smarter to attach the ground
to the shield via a ground block, but the only ground blocks
I can find use the F connectors, not the 239/259 ones. Is it
necessarily a good idea to strip the coating off the coax,
exposing the shield, and clamping that shield to the ground
rod? Seems like you'd be exposing the connection to the
elements, probably hastening the demise of the coax at that
point. Not to mention the changing of the interaction of
the two conductors by changing it's form...

--Mike L.

http://www.harger.com/catalog2004/4_3_1.pdf has examples of typical
Andrews
Wire Co produced shield grounding kits. It is advisable to cover
with
waterproofing materials any connection that is exposed to the
weather. There
is also no such " changing of the interaction of the two conductors
by
changing it's form..."

I dredged up my old Halliday and Resnick text, and
took a look. Yes, you are correct. The important part
is the shield surrounding the core.

Btw, my "noise limiting antenna" comes from an old design published
in Fine
Tuning's Proceedings, in which one side of a dipole-type Balun is
grounded
at the feedpoint (also on the ground) and the longwire antenna is
connected
to the Balun's other antenna connection. Coax feedline comes out the
bottom
of the Balun, and is shield grounded twice for lightning protection:
once at
the Balun and another time before it enters the station.

Besides an excellent and very quiet listening antenna, this is also
a
transmitter. It has worked over 500 miles on 2 Mhz and 3,000 miles
on 8 Mhz.

Thanks for the info.

--Mike L.


No problem Mike. Btw, the grounding blocks work fine too, I use them under
the house. But out in the field, and on towers particularly, the coax shield
ground kits can be easier to handle. Nothing stopping you from making your
own kit either, I just like Andrews products, already cut for your size
cable, etc.

Cheers,

Jack