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

FDR wrote:
Thanks for the posting.

I should have not complained about the T-storms.
I must have ****ed Thor or Odin off. We had a nasty
storm about 90 minutes ago and it took out the power.
I am testing a new PIII 800MHz laptop as a possible
replacement for my "big desktop PC".

My Holy Quest, or snipe hunt, for reducing the RF noise
around here will have to wait until the lightening
static moves out. No lights and I can't receive anything
but the closest MW.

Bad static!

I hope it helps just one person get better reception.

Terry

R200SW,

In article .com,
wrote:

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.

Snip

"Is Your Coax Lead-In Actually An Antenna"
I posted about using coax for an antenna here a few days ago. If the
coax is not grounded on both ends it can be a very good antenna. I'm
using a 40 foot coax loop to listen to New Zealand as I type this. They
are S7 to S9 nice and quiet with no interfering noise with the volume
turned up. I live in town at the beach, other homes and businesses
where there is local noise generation aplenty all around me. Yes I also
have AM stations in town a few miles away.

Most voltage sensitive antennas I have put up get noisier the lower in
frequency I try to use them. The AM broadcast band is terrible on these
antennas around here. The coax loop is as quiet or better than the
ferrite loop in a portable.

For a loop this size you should use a shielded type where the shield is
split in the middle of the loop to minimize voltage pickup. You want
the antenna to be picking up the magnetic component of the EM wave
only.

--
Telamon
Ventura, California

Telamon wrote:

"Is Your Coax Lead-In Actually An Antenna"
I posted about using coax for an antenna here a few days ago. If the
coax is not grounded on both ends it can be a very good antenna. I'm
using a 40 foot coax loop to listen to New Zealand as I type this. They
are S7 to S9 nice and quiet with no interfering noise with the volume
turned up. I live in town at the beach, other homes and businesses
where there is local noise generation aplenty all around me. Yes I also
have AM stations in town a few miles away.

Most voltage sensitive antennas I have put up get noisier the lower in
frequency I try to use them. The AM broadcast band is terrible on these
antennas around here. The coax loop is as quiet or better than the
ferrite loop in a portable.

For a loop this size you should use a shielded type where the shield is
split in the middle of the loop to minimize voltage pickup. You want
the antenna to be picking up the magnetic component of the EM wave
only.

--
Telamon
Ventura, California
--------------------------------------
I was addressing one's coax/feedline being an unintentional
antenna.
Triax is coax with an additonal outer shield that is insulated from
the inner shield.
See:http://bwccat.belden.com/ecat/jsp/In...d&P6=undefined

In the event line wrap kills this link, go to www.belden.com
and type triax in the search window.

I found the vertical wire leading up toy horizontal antenna was piking
up more noise then desired RF. I replaced it with coax but still had
some ingress. So I tried a piece of Triax. It removed all the noise one
the vertical
run.

Please see my post on "simple tests" to folllow.

Terry

In article . com,
wrote:

Telamon wrote:

"Is Your Coax Lead-In Actually An Antenna"
I posted about using coax for an antenna here a few days ago. If the
coax is not grounded on both ends it can be a very good antenna. I'm
using a 40 foot coax loop to listen to New Zealand as I type this. They
are S7 to S9 nice and quiet with no interfering noise with the volume
turned up. I live in town at the beach, other homes and businesses
where there is local noise generation aplenty all around me. Yes I also
have AM stations in town a few miles away.

Most voltage sensitive antennas I have put up get noisier the lower in
frequency I try to use them. The AM broadcast band is terrible on these
antennas around here. The coax loop is as quiet or better than the
ferrite loop in a portable.

For a loop this size you should use a shielded type where the shield is
split in the middle of the loop to minimize voltage pickup. You want
the antenna to be picking up the magnetic component of the EM wave
only.

--
Telamon
Ventura, California
--------------------------------------
I was addressing one's coax/feedline being an unintentional
antenna.
Triax is coax with an additonal outer shield that is insulated from
the inner shield.
See:http://bwccat.belden.com/ecat/jsp/In...=undefined&P3=
undefined&P4=undefined&P5=undefined&P6=undefined

In the event line wrap kills this link, go to www.belden.com
and type triax in the search window.

I found the vertical wire leading up toy horizontal antenna was piking
up more noise then desired RF. I replaced it with coax but still had
some ingress. So I tried a piece of Triax. It removed all the noise one
the vertical
run.

Please see my post on "simple tests" to folllow.

I look forward to reading your posts.

Yes the wrap broke the link. You can prevent this by bracketing the link
with and . I'll copy your link as an example. It's broken above and
working below.
http://bwccat.belden.com/ecat/jsp/In...P2=undefined&P
3=undefined&P4=undefined&P5=undefined&P6=undefined

I'm familiar with tri-ax.

The point I was making is coax that is not grounded on both ends is an
antenna whether it was intended be one or not. You can't properly ground
the end of the coax at the antenna because it is up in the air so your
only chance of the coax behaving as a shielded transmission line is that
it is terminated in its characteristic impedance. Those are the two
choices otherwise the coax is part of the antenna. Using tri-ax may help
but it won't be as good as either grounding both ends or terminating
both ends properly on a coax cable.

--
Telamon
Ventura, California