When mounting any yagi beam to a metal mast, is it best to insulate the boom
from the metal mast?

Are there any benefits in insulating the boom from the mast or not when
mounting?

Thanks

On Aug 22, 3:13*am, "barett" wrote:
When mounting any yagi beam to a metal mast, is it best to insulate the boom
from the metal mast?

No. At least from a lightning point of view. I never insulate the boom
from the mast.

Are there any benefits in insulating the boom from the mast or not when
mounting?

Not that I can think of.

"barett" schreef in bericht
...
When mounting any yagi beam to a metal mast, is it best to
insulate the boom from the metal mast?
No, yagi beams are electrically '0' in the middle of the
elements, so there is no need to insulate the boom
from the mast.

Are there any benefits in insulating the boom from the mast or
not when mounting?
I can think of no benefits to insulate. NOT insulating has the
benefit that static can run to ground if the mast is grounded.

Log-per antennas should be insulated from their masts as the
booms are part of the feed, and should not contact each other
or ground.

73 - Gerard - PE1OUD

E-mail:

I am causing TVI at the moment and I was told that if I insulated the beam
from the mast and choked the coax just below the beam it would guarantee to
solve my TVI problem and improve the efficiency of the antenna. What do you
think?

It's a lot of work to drop the beam back down to ground level to do this.


"barett" wrote in message
...
When mounting any yagi beam to a metal mast, is it best to insulate the
boom from the metal mast?

Are there any benefits in insulating the boom from the mast or not when
mounting?

Thanks

barett wrote:
When mounting any yagi beam to a metal mast, is it best to insulate the boom
from the metal mast?

The voltage at the center of the elements is supposed
to be zero. Therefore, the boom is supposed to have
zero potential and thus can be mounted to a metal mast.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

barett wrote:
I am causing TVI at the moment and I was told that if I insulated the beam
from the mast and choked the coax just below the beam it would guarantee to
solve my TVI problem and improve the efficiency of the antenna. What do you
think?

It's a lot of work to drop the beam back down to ground level to do this.

Get the guy who made the guarantee to do the work.
Don't pay him if it doesn't work.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

"barett" wrote in message
...
I am causing TVI at the moment and I was told that if I insulated the
beam
from the mast and choked the coax just below the beam it would guarantee
to
solve my TVI problem and improve the efficiency of the antenna. What do
you
think?

It's a lot of work to drop the beam back down to ground level to do this.


"barett" wrote in message
...
When mounting any yagi beam to a metal mast, is it best to insulate the
boom from the metal mast?

Are there any benefits in insulating the boom from the mast or not when
mounting?

Thanks

It might be a good idea to drop the whole thing and make sure there is no
corrosion anywhere, even at the cost of replacing hardware and any rusty
masts. rust and corrosion can actually cause broadband noise and harmonics
that doesn't come out of the transmitter. Perhaps there is an issue with
your rotor?

On Sat, 22 Aug 2009 15:49:14 +0100, "barett"
wrote:

I am causing TVI at the moment and I was told that if I insulated the beam
from the mast and choked the coax just below the beam it would guarantee to
solve my TVI problem and improve the efficiency of the antenna.

Stop listening to those people who "told" you this and "guarantee"
(whatever that means) it as a solution.

TVI is most frequently caused by your feedline's proximity to RF
sensitive devices AND the presence of Common Mode currents on the
feedline. Put a choke on the transmission line at the feed point and
another choke one quarter wavelength away from the feed point towards
the transmitter.

This is a very common topic here and if you were to Google the group's
combined postings about it, you would find a world of education that
goes beyond this simple prescription. (Google the terms TVI and
Common Mode and Choke.)

73's
Richard Clark, KB7QHC

"barett" wrote in message
...
When mounting any yagi beam to a metal mast, is it best to insulate the
boom from the metal mast?

Are there any benefits in insulating the boom from the mast or not when
mounting?

Thanks




Thanks all for your help. The search I did on Goole has given me loads to
read up on, so I should be fine now.
Thanks again

Kind of off topic but maybe interesting.

In Sydney in I guess the late 70's two broadcast FM stations came online
on 105 and 106MHz (Approx). Their antennas were both mounted on one of
the big TV towers in the northern suburbs.

Individual tests proved positive, good range etc etc. When they were
both turned on however they caused severe interference to the AM BC band
(1MHz or so) and also the CH10 TV (212MHz or so). As I remember hearing
the fault was a rusty rivet holding some tower sections together.

This information is anecdotal. I havent verified it!

Cheers Bob VK2YQA

JB wrote:


It might be a good idea to drop the whole thing and make sure there is no
corrosion anywhere, even at the cost of replacing hardware and any rusty
masts. rust and corrosion can actually cause broadband noise and harmonics
that doesn't come out of the transmitter. Perhaps there is an issue with
your rotor?