No. Not true. I run 6 feet on my 1000 mag. 1.1 swr's on channel 35.

Great antenna btw. I don't know if you can beat one for the
ease/money/performance.

Don

"Guntier C." wrote in message
...
I received and old wilson 1000 mag. mount and want to put it on my quad (4
magnet) mount. I hear that I need a 18 ft. piece of coax for a
counterpoise. Is that true? Any info appreciated.

Thanks,

G.C.

On Thu, 04 Nov 2004 21:59:02 GMT, sideband wrote:

tnom:

Explain this, then... CB radio in my Peterbilt, with a mirror mounted
Hustler HQ-27 on the driver's side.. 6 feet of coax shows a 1:1 on 19,
1.1:1 on 1, and 1.1:1 on 40... 12 feet of coax shows the same
readings... 18 feet of coax shows.. guess what? the SAME RESULTS.

IT IS possible to get near "perfect world" results with a little work,
and attention to detail.

By the way, I've gotten similar results on two meters with a magnet
mount 5/8 2M Lakeview whip on my old Ford LTLA9000. Had to shorten the
coax because I was sick of the bundle of it in the cab... no change in
SWR over a four MHz bandwidth...

There goes the "magmount theory" as well..

If changing the length of the coax changes the SWR, then there is
something wrong with the antenna.

-SSB

SSB;
I know this was addressed to Tnom, hope you don't mind my 2-cents
worth.

Very few mag mounts have an adequate "RF" ground, at least on 11
meters or lower. There isn't enough capacitive coupling to the
vehicle body. In some cases the length of the coax can matter, not
from a matching point of view, but as a counterpoise for the antenna.
I have seen mag mount installations where you could see the SWR change
just by moving the coax around.

"Lancer" wrote in message
ews.com...
On Thu, 04 Nov 2004 21:59:02 GMT, sideband wrote:

tnom:

Explain this, then... CB radio in my Peterbilt, with a mirror mounted
Hustler HQ-27 on the driver's side.. 6 feet of coax shows a 1:1 on 19,
1.1:1 on 1, and 1.1:1 on 40... 12 feet of coax shows the same
readings... 18 feet of coax shows.. guess what? the SAME RESULTS.

IT IS possible to get near "perfect world" results with a little work,
and attention to detail.

By the way, I've gotten similar results on two meters with a magnet
mount 5/8 2M Lakeview whip on my old Ford LTLA9000. Had to shorten the
coax because I was sick of the bundle of it in the cab... no change in
SWR over a four MHz bandwidth...

There goes the "magmount theory" as well..

If changing the length of the coax changes the SWR, then there is
something wrong with the antenna.

-SSB

SSB;
I know this was addressed to Tnom, hope you don't mind my 2-cents
worth.

Very few mag mounts have an adequate "RF" ground, at least on 11
meters or lower. There isn't enough capacitive coupling to the
vehicle body. In some cases the length of the coax can matter, not
from a matching point of view, but as a counterpoise for the antenna.
I have seen mag mount installations where you could see the SWR change
just by moving the coax around.

Please explain how a poor "RF ground" can be corrected by increasing coax
length??

Don

On Thu, 04 Nov 2004 21:59:02 GMT, sideband wrote
in :

tnom:

Explain this, then... CB radio in my Peterbilt, with a mirror mounted
Hustler HQ-27 on the driver's side..


Nice antenna! Installed one recently and plan on getting one for
myself.


6 feet of coax shows a 1:1 on 19,
1.1:1 on 1, and 1.1:1 on 40... 12 feet of coax shows the same
readings... 18 feet of coax shows.. guess what? the SAME RESULTS.


Your antenna mount has a good RF ground. Coax length is going to make
little if any difference.


IT IS possible to get near "perfect world" results with a little work,
and attention to detail.

By the way, I've gotten similar results on two meters with a magnet
mount 5/8 2M Lakeview whip on my old Ford LTLA9000. Had to shorten the
coax because I was sick of the bundle of it in the cab... no change in
SWR over a four MHz bandwidth...


Now -that- I find hard to believe. If you get relatively flat
bandwidth over 4MHz then your antenna is basically nothing more than a
dummy load, and coax length doesn't matter there either.


There goes the "magmount theory" as well..


You didn't read the results of my tests a few months ago, did you?


If changing the length of the coax changes the SWR, then there is
something wrong with the antenna.


Absolutely correct, and the problem is an inadequate RF ground at the
mount, which is typical of mag-mounts (unless they are so heavily
loaded with resistance that they act like dummy loads).






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On Thu, 4 Nov 2004 20:07:21 -0500, "M-Tech"
wrote in :

snip
Please explain how a poor "RF ground" can be corrected by increasing coax
length??


A given length of coax runs from the radio to the antenna mount. If
the shield is not adequately grounded (RF ground) then RF will crawl
onto the outside of the shield. When that happens your coax behaves
like an antenna, having resonant and non-resonant lengths. When that
happens, different lengths of the coax will put the antenna mount at
different phase angles, therefore changing the load impedance and SWR.
There are only two solutions: Provide a good RF ground to the antenna
mount (preferred), or change the length of the coax to 'tune' the
input impedance of the antenna.

That's all assuming your radio is fixed to a good RF ground.






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On Thu, 04 Nov 2004 21:59:02 GMT, sideband wrote:

tnom:

Explain this, then... CB radio in my Peterbilt, with a mirror mounted
Hustler HQ-27 on the driver's side.. 6 feet of coax shows a 1:1 on 19,
1.1:1 on 1, and 1.1:1 on 40... 12 feet of coax shows the same
readings... 18 feet of coax shows.. guess what? the SAME RESULTS.

Good for you. I bet that if you used 18' you'd get good results also.

IT IS possible to get near "perfect world" results with a little work,
and attention to detail.

Near is relative. Anything short of perfect can benefit from using the
manufacturers recommended length.

By the way, I've gotten similar results on two meters with a magnet
mount 5/8 2M Lakeview whip on my old Ford LTLA9000. Had to shorten the
coax because I was sick of the bundle of it in the cab... no change in
SWR over a four MHz bandwidth...

???rec.radio.cb.........11 meters........27mhz ???

There goes the "magmount theory" as well..

You haven't proven anything other than you are inflexible in your
belief that other antenna installation can't benefit from recommended
coax lengths. Your installations are obviously perfect because you are
perfect and being so you have done everything perfectly with your
perfect counterpoise in your perfect world.

If changing the length of the coax changes the SWR, then there is
something wrong with the antenna.

-SSB

No. When it comes to mag mounts on vehicles it most likely means
that you left the fantasy world behind and realize that you live in
the real world where things aren't so perfect.

Very few mag mounts have an adequate "RF" ground, at least on 11
meters or lower. There isn't enough capacitive coupling to the
vehicle body. In some cases the length of the coax can matter, not
from a matching point of view, but as a counterpoise for the antenna.
I have seen mag mount installations where you could see the SWR change
just by moving the coax around.

Please explain how a poor "RF ground" can be corrected by increasing coax
length??

Don

He never said that a poor RF ground could be corrected by coax length.

He said in effect that the side effects of a poor RF ground could be
reduced by a specific length of coax.

Dunno about you, Lancer, but the last thing I'd want is RF inside the
vehicle.. which is exactly what's happening if you're using the coax
braid as the counterpoise/image plane/groundplane...even partially.

-SSB

Lancer wrote:


SSB;
I know this was addressed to Tnom, hope you don't mind my 2-cents
worth.

Very few mag mounts have an adequate "RF" ground, at least on 11
meters or lower. There isn't enough capacitive coupling to the
vehicle body. In some cases the length of the coax can matter, not
from a matching point of view, but as a counterpoise for the antenna.
I have seen mag mount installations where you could see the SWR change
just by moving the coax around.

I said no change in swr... I should have been more specific.. I got
the same readings at 144.000, 146.000 and 148.000 on the original
length as I did on the shortened length. Sorry about the confusion.

-SSB

Frank Gilliland wrote:

On Thu, 04 Nov 2004 21:59:02 GMT, sideband wrote
in :


tnom:

Explain this, then... CB radio in my Peterbilt, with a mirror mounted
Hustler HQ-27 on the driver's side..



Nice antenna! Installed one recently and plan on getting one for
myself.



6 feet of coax shows a 1:1 on 19,
1.1:1 on 1, and 1.1:1 on 40... 12 feet of coax shows the same
readings... 18 feet of coax shows.. guess what? the SAME RESULTS.



Your antenna mount has a good RF ground. Coax length is going to make
little if any difference.



IT IS possible to get near "perfect world" results with a little work,
and attention to detail.

By the way, I've gotten similar results on two meters with a magnet
mount 5/8 2M Lakeview whip on my old Ford LTLA9000. Had to shorten the
coax because I was sick of the bundle of it in the cab... no change in
SWR over a four MHz bandwidth...



Now -that- I find hard to believe. If you get relatively flat
bandwidth over 4MHz then your antenna is basically nothing more than a
dummy load, and coax length doesn't matter there either.



There goes the "magmount theory" as well..



You didn't read the results of my tests a few months ago, did you?



If changing the length of the coax changes the SWR, then there is
something wrong with the antenna.



Absolutely correct, and the problem is an inadequate RF ground at the
mount, which is typical of mag-mounts (unless they are so heavily
loaded with resistance that they act like dummy loads).






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wrote:


You haven't proven anything other than you are inflexible in your
belief that other antenna installation can't benefit from recommended
coax lengths. Your installations are obviously perfect because you are
perfect and being so you have done everything perfectly with your
perfect counterpoise in your perfect world.


I gave two examples... there are many more..

It doesn't prove my inflexibility, it proves the inflexibility of
physics and my desire to achieve decent antenna results. I worked hard
to get the results I did, and because of it, more of my RF is "getting
out" than would have if I hadn't done what I did to achieve the
results I got. If you want to take the lazy man's way out and risk RF
inside the vehicle (and the associated problems, like the mic "biting"
your lips, windshield wipers running on their own, stereos changing
channel or powering on by themselves, speedometers waving at you as
you talk, etc) then go right ahead. I, for one, will work towards a
better antenna installation, so that physics can do its job.

Again, with a properly installed single antenna, coax length does not
matter.

-SSB