TV antenna ground plane?
 

After reading the following paragraph, I'm wondering if my TV
antenna is affecting my Antron 99 either positively or negatively...

11. If you mount two or more antennas close to each other, you will
alter the transmission patterns of each one. The affect may be either
positive or negative. We recommend that a minimum of 12" exist between
your CB antenna and other types of antennas.

http://www.firestik.com/Tech_Docs/63Things.htm

Both are clamped directly to the same pipe/mast. The TV
antenna is clamped 12" below the bottom of the Antron, and the highest
point of the antenna is about 6" below the Antron.

Another thing that's got me wondering if it is affecting the
radiation pattern is that fifteen years ago, I didn't have the TV
antenna under the Antron, and the neighbors whined so much about
hearing me in their telephones that I put all my CB stuff in the
attic. Now, I've put the exact same equipment back up two weeks ago,
with the addition of the TV antenna, and I haven't had one complaint.
Could the TV antenna be affecting my radiation pattern?

Glenn S.
Virginia Beach, VA
Rat Shack DX-399
66' x 15' "L" shaped copper wire

Glenn S. wrote in message . ..
After reading the following paragraph, I'm wondering if my TV
antenna is affecting my Antron 99 either positively or negatively...

11. If you mount two or more antennas close to each other, you will
alter the transmission patterns of each one. The affect may be either
positive or negative. We recommend that a minimum of 12" exist between
your CB antenna and other types of antennas.

http://www.firestik.com/Tech_Docs/63Things.htm

Both are clamped directly to the same pipe/mast. The TV
antenna is clamped 12" below the bottom of the Antron, and the highest
point of the antenna is about 6" below the Antron.

Another thing that's got me wondering if it is affecting the
radiation pattern is that fifteen years ago, I didn't have the TV
antenna under the Antron, and the neighbors whined so much about
hearing me in their telephones that I put all my CB stuff in the
attic. Now, I've put the exact same equipment back up two weeks ago,
with the addition of the TV antenna, and I haven't had one complaint.
Could the TV antenna be affecting my radiation pattern?

Glenn S.
Virginia Beach, VA
Rat Shack DX-399
66' x 15' "L" shaped copper wire

To answer your question, YES, it is very possible that the tv antenna
is affecting your Antron antenna. The signal could be reflecting off
the tv antenna at different points which will change the radiation
pattern. It is also possible that the tv antenna is affected, but if
so, probably as a positive as certain tv signals can reflect off the
other antenna onto the tv antenna. But if you have a ghost problem
with tv reception, it could be because of the two antennas being close
together.

Several years ago I lived in Fair Oaks, California, and had a large
Channel Master antenna mounted on a 40-ft mast with rotor. The
neighbor ACROSS THE STREET noticed their reception would go in and
out, and one day noticed my antenna turning as their signal went in
and out.

"Glenn S." wrote in message
...

After reading the following paragraph, I'm wondering if my TV
antenna is affecting my Antron 99 either positively or negatively...

11. If you mount two or more antennas close to each other, you will
alter the transmission patterns of each one. The affect may be either
positive or negative. We recommend that a minimum of 12" exist between
your CB antenna and other types of antennas.

http://www.firestik.com/Tech_Docs/63Things.htm

Both are clamped directly to the same pipe/mast. The TV
antenna is clamped 12" below the bottom of the Antron, and the highest
point of the antenna is about 6" below the Antron.


Because the 2 antennas are of opposite polarity- they will be essentially
invisible to each other- typical isolation runs in the 20-30dB range- making
interaction unnoticeable.

Dale W4OP
for PAR Electronics, Inc.

Glenn S. wrote:
After reading the following paragraph, I'm wondering if my TV
antenna is affecting my Antron 99 either positively or negatively...

As Dale says, due to the cross-polarization (and the fact that the TV
antenna is below the Antron) I doubt they're seriously affecting each
other's operation.

If you had a horizontally-polarized antenna 6" above the TV antenna (for
example, a 10-meter Yagi) it would be a very different story.
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com

In article ,
Glenn S. wrote:

Another thing that's got me wondering if it is affecting the
radiation pattern is that fifteen years ago, I didn't have the TV
antenna under the Antron, and the neighbors whined so much about
hearing me in their telephones that I put all my CB stuff in the
attic. Now, I've put the exact same equipment back up two weeks ago,
with the addition of the TV antenna, and I haven't had one complaint.
Could the TV antenna be affecting my radiation pattern?

RF can get into cables and equipment, and if there are nonlinear elements
like diodes or transistors or a corroded connection, they can act upon
the transmitted signals to create new signals and harmonics.

One time I was having huge problems with medium wave broadcast "intermod",
where all over the dial there were mixtures of two or more of the local
AM stations. It turned out to be a corroded connection on the FM antenna
for the hi=fi tuner. So a system designed to receive 100 MHz signals
was picking up 1 MHz signals, and spewing them all over 3-30 MHz range
to a receiver that had no connection with the source.

Figure that any long piece of metal within 100 feet of your transmitting
antenna is going to pick up (and reradiate) your signal, affecting
your transmission. And if it's not a very good piece of metal it can
do strange things. Roof flashing, railings, masts, guy wires ...

Also, if you have a TV signal booster on the antenna, it's getting
hammered with quite a bit of signal.

Mark Zenier Washington State resident

In article Is83d.3044$PZ4.2757@trnddc06,
"Dale Parfitt" wrote:

"Glenn S." wrote in message
...

After reading the following paragraph, I'm wondering if my TV
antenna is affecting my Antron 99 either positively or negatively...

11. If you mount two or more antennas close to each other, you will
alter the transmission patterns of each one. The affect may be either
positive or negative. We recommend that a minimum of 12" exist between
your CB antenna and other types of antennas.

http://www.firestik.com/Tech_Docs/63Things.htm

Both are clamped directly to the same pipe/mast. The TV
antenna is clamped 12" below the bottom of the Antron, and the highest
point of the antenna is about 6" below the Antron.


Because the 2 antennas are of opposite polarity- they will be essentially
invisible to each other- typical isolation runs in the 20-30dB range- making
interaction unnoticeable.

You mean vertical versus horizontal polarization?

--
Telamon
Ventura, California

"Telamon" wrote in message
...
In article Is83d.3044$PZ4.2757@trnddc06,
"Dale Parfitt" wrote:

"Glenn S." wrote in message
...

After reading the following paragraph, I'm wondering if my TV
antenna is affecting my Antron 99 either positively or negatively...

11. If you mount two or more antennas close to each other, you will
alter the transmission patterns of each one. The affect may be either
positive or negative. We recommend that a minimum of 12" exist between
your CB antenna and other types of antennas.

http://www.firestik.com/Tech_Docs/63Things.htm

Both are clamped directly to the same pipe/mast. The TV
antenna is clamped 12" below the bottom of the Antron, and the highest
point of the antenna is about 6" below the Antron.


Because the 2 antennas are of opposite polarity- they will be
essentially
invisible to each other- typical isolation runs in the 20-30dB range-
making
interaction unnoticeable.

You mean vertical versus horizontal polarization?

Or +45 and -45. The point is they must be orthogonal.

Dale W4OP

--
Telamon
Ventura, California