On 23/11/2022 08:15, Mark Carver wrote:
I really wouldn't worry about it then, it's only going to be a
problem it it obstructs your signal, which with it behind the
aerial, isn't going to be happening .
A lot of these answers are treating the antenna as a point source,
with only far field behaviour.
If the vane is close enough to be in the near field, the effects
could be difficult to predict.
A metal object behind the aerial, could reflect signals, and at some distances, the reflection could cancel the wanted signal.
If you consider a typical yagi, the directors are in front of the
main dipole, but rather than block it, they enhance the signal, so
blocking by a near field object could go either way.
The maximum distance between the antenna pole and the weathervane pole
would be less than 2 feet, and then the direction arms and the
revolving part would be considerably nearer.
It does sound as though there is too much to risk, especially with a
bespoke weathervane, which could not be returned fro a refund if it
affected the signal
I may have to abandon this idea. At least I have investigated it.
Thanks for the answers, everyone.
"Davey" <davey@example.invalid> wrote in message news:tll1st$c5oq$1@dont-email.me...
The maximum distance between the antenna pole and the weathervane
pole would be less than 2 feet, and then the direction arms and the revolving part would be considerably nearer.
It does sound as though there is too much to risk, especially with a bespoke weathervane, which could not be returned fro a refund if it affected the signal
I may have to abandon this idea. At least I have investigated it.
Thanks for the answers, everyone.
What a shame. I hope you manage to find a solution: either a
non-metallic vane near the aerial or else a metallic one on a
mounting that is out of the aerial's "field of view".
It does sound as though there is too much to risk, especially with a
bespoke weathervane, which could not be returned fro a refund if it
affected the signal
I may have to abandon this idea. At least I have investigated it.
Thanks for the answers, everyone.
--
Davey.
On Wednesday, 23 November 2022 at 11:58:23 UTC, Davey wrote:
It does sound as though there is too much to risk, especially with
a bespoke weathervane, which could not be returned fro a refund if
it affected the signal
I may have to abandon this idea. At least I have investigated it.
Thanks for the answers, everyone.
--
Davey.
In all my many years of TV aerial installation I've never had this
problem. There are lots of large metal chimney cowls that move round
when the wind changes and I've never known of one causing a problem.
Many schools have weather vanes and they don't cause a problem. In
the worst case scenario the weather vane might cause a reflection
that arrived at the aerial exactly out of phase with the main signal,
but even so that would merely cause a small fluctuation in signal
strength which would have no effect on reception, because the
reflection wouldn't be anywhere near as strong as the main signal, so significant phase cancellation wouldn't happen. Some years ago I
carried out a lot of surveys of the effects of ginormous wind
turbines on TV reception. Once digital came along it was next to
impossible to find any such effects because of the way digi works.
There were zero effects from reflections off the whacking great
blades. You could see the slight fluctuations in signal level on the
analyser but it was never anywhere near enough to affect reception.
It was possible to get visible-on-the-screen effects when the signal
was very weak and the path was through the area encompassed by the
blades, but that was all. Buy your weathervane and get it installed.
In the stupendously unlikely event that it affects your TV reception consider: 1. moving the TV aerial up or down a bit 2. Installing a
slightly taller mast than you envisaged, with the weather vane at the
top and the TV aerial beneath it, or vice versa. But it won't happen.
Bill
A shame my wife died during the summer, she won't see any of this.My wife was really worried about the frequent intruders so we decided to install automatic gates and high fences. She sat in the wheelchair many times and watched me as I did the preparatory work, but she didn't live to see the gates installed and
--
Davey.
On Thursday, 24 November 2022 at 08:24:41 UTC, Davey wrote:
A shame my wife died during the summer, she won't see any of this.My wife was really worried about the frequent intruders so we decided
--
Davey.
to install automatic gates and high fences. She sat in the wheelchair
many times and watched me as I did the preparatory work, but she
didn't live to see the gates installed and working. It was upsetting
because it was something I did for her. Bill
On Wednesday, 23 November 2022 at 11:58:23 UTC, Davey wrote:
It does sound as though there is too much to risk, especially with
a bespoke weathervane, which could not be returned fro a refund if
it affected the signal
I may have to abandon this idea. At least I have investigated it.
Thanks for the answers, everyone.
--
Davey.
In all my many years of TV aerial installation I've never had this
problem. There are lots of large metal chimney cowls that move round
when the wind changes and I've never known of one causing a problem.
Many schools have weather vanes and they don't cause a problem. In
the worst case scenario the weather vane might cause a reflection
that arrived at the aerial exactly out of phase with the main signal,
but even so that would merely cause a small fluctuation in signal
strength which would have no effect on reception, because the
reflection wouldn't be anywhere near as strong as the main signal, so significant phase cancellation wouldn't happen. Some years ago I
carried out a lot of surveys of the effects of ginormous wind
turbines on TV reception. Once digital came along it was next to
impossible to find any such effects because of the way digi works.
There were zero effects from reflections off the whacking great
blades. You could see the slight fluctuations in signal level on the
analyser but it was never anywhere near enough to affect reception.
It was possible to get visible-on-the-screen effects when the signal
was very weak and the path was through the area encompassed by the
blades, but that was all. Buy your weathervane and get it installed.
In the stupendously unlikely event that it affects your TV reception consider: 1. moving the TV aerial up or down a bit 2. Installing a
slightly taller mast than you envisaged, with the weather vane at the
top and the TV aerial beneath it, or vice versa. But it won't happen.
Bill
I have hone ahead with the weathervane. The supplier has no option for plastic on bespoke weathervanes, but is adamant that there will be no
effect on TV reception.
Let's hope. I have it in an e-mail message, if there is a problem.
I have hone ahead with the weathervane. The supplier has no option for plastic on bespoke weathervanes, but is adamant that there will be noSo you'd rather believe a person with no likely experience or knowledge, but does have a vested interest in selling, than those here who know a great deal about RF propagation?
effect on TV reception.
Let's hope. I have it in an e-mail message, if there is a problem.
--
Davey.
On Wednesday, 30 November 2022 at 10:41:48 UTC, Davey wrote:
I have hone ahead with the weathervane. The supplier has no option
for plastic on bespoke weathervanes, but is adamant that there will
be no effect on TV reception.
Let's hope. I have it in an e-mail message, if there is a problem.
--So you'd rather believe a person with no likely experience or
Davey.
knowledge, but does have a vested interest in selling, than those
here who know a great deal about RF propagation? Bill
On Wed, 30 Nov 2022 07:38:36 -0800 (PST)If I've never had the problem in a lifetime of work that means it's disappearingly unlikely that you will have it in one installation.
"wrights...@aol.com" <wrights...@f2s.com> wrote:
On Wednesday, 30 November 2022 at 10:41:48 UTC, Davey wrote:
I have hone ahead with the weathervane. The supplier has no option
for plastic on bespoke weathervanes, but is adamant that there will
be no effect on TV reception.
Let's hope. I have it in an e-mail message, if there is a problem.
Says the man who told me:--So you'd rather believe a person with no likely experience or
Davey.
knowledge, but does have a vested interest in selling, than those
here who know a great deal about RF propagation? Bill
"In all my many years of TV aerial installation I've never had this
problem."
Talk about mixed messages!
--
Davey.
On Wednesday, 30 November 2022 at 18:43:49 UTC, Davey wrote:
On Wed, 30 Nov 2022 07:38:36 -0800 (PST)
"wrights...@aol.com" <wrights...@f2s.com> wrote:
On Wednesday, 30 November 2022 at 10:41:48 UTC, Davey wrote:
I have hone ahead with the weathervane. The supplier has no
option for plastic on bespoke weathervanes, but is adamant that
there will be no effect on TV reception.
Let's hope. I have it in an e-mail message, if there is a
problem.
If I've never had the problem in a lifetime of work that means it's disappearingly unlikely that you will have it in one installation.Says the man who told me:--So you'd rather believe a person with no likely experience or
Davey.
knowledge, but does have a vested interest in selling, than those
here who know a great deal about RF propagation? Bill
"In all my many years of TV aerial installation I've never had this problem."
Talk about mixed messages!
--
Davey.
Bill
| Sysop: | Keyop |
|---|---|
| Location: | Huddersfield, West Yorkshire, UK |
| Users: | 297 |
| Nodes: | 16 (2 / 14) |
| Uptime: | 05:13:05 |
| Calls: | 6,666 |
| Files: | 12,213 |
| Messages: | 5,335,948 |