I have been trying to improve the SN, that is to reduce
the noise as much as I can, while prserving the desired signal.

This has been an on going battle evry since radio began.

The Doty antenna (http://www.anarc.org/naswa/badx/antennas/)
is a good starting place. This link (members.aol.com/WA1ION/nrants.pdf)
is a good improvement. I dropped his matching resistors and isolated
the braid on the output of the 9:1 step down. A minor improvement.
Took care of slme stubborn birdies from my equipment. I was troubled
by some odd "bleed through". While lloking into RG174 from a friend's
"hidden" antenna installation, I found a refference to an article
by John Brynt "Is Your Coax Lead-In Actually An Antenna"
(www.dxing.info/equipment/coax_leadin_bryant.pdf) that suppled some
answers that really helped me understand what is hhappening.

I did some experiments with "normal", or at least more common
braid only coax and compared it to braid+foil coax. The foil really
helped reduce the engress from one stuborn local MW. But it wasn't
completly removed. I was able to recude it to the level of leakage
directly into my reciver by placing a ferite toroid as Sugested by
John Brynt in the "coax" link.

A BIG step forward. But I still had a lot of QRM. While changing
my coax I decided to do some simple experiments. I was replacing
my antenna wire at the same time, so I snipped the horizonatal
section off leaving only the the vertical. My signal strength was
down a little, but the noise was as loud as ever. So I ran some
coax up to the support and reattatched the horizontal wire to a 9:1.
This helped but I still had a lot of QRN, not near as much as before
but I decided to see what I could do tho help. A Torroid as used
by Brynt really helped. So I decided to see what Triax would do.
Triax is coax with an outer insulated additional shield. I fed the
antenna wire to the hiZ hot, the outer shield went to the HiZ ground,
and the low z was connected to the inner conductor and inner braid.
At the base I grounded the outer braid, and use a 1:1 to couple the
inner conductors to the coax that makes the run to the house.

This really reduced the noise. I tested it by placing an especially
nasty wall wort next to the feed line. Always before I would get a
rapid jump in RF noise as the wall wort was placed near the feedline.
No RF creeping back p the feedline to enter then antenna.

I used 50 Ohm Triax, but tested a piece of 75 Ohm triax and there was
no difference between them on a 20' run. &% Ohm is a lot more common,
almost every TV station in the USA uses it and as they switch to
fibre',
it should become very common and CHEAP. You could probably get a 30'
piece just for the asking(that is how I got mine).
Forget Triax connectors, they are around $100 and look somewhat like
a BNC on steroids.

I tried Triax last fall but must have wired something wrong,
becuase it just didn't work bery well.

Now if the never to be cursed T-storms would let up for a few days
I might be able to enjoy the reduction in the local QRM.

And this link shows why I hate wall worts.
http://home.computer.net/~pritch/shortwav.htm
Wall worts are the worst but any device with un-bypassed
Si diodes can be nasty.

Terry