can I mount the aerial around the level of the middle of the chimney pot
I've mounted TWO 8" chimney strap brackets ... <https://www.blake-uk.com/8-stack-strap-ratchet-cradle-mitre-bracket.html>
Despairing on local installers ever coming back to me, I've started my
own TV aerial installation. It's going fine, but I have a technical questionrCa
Any advice on the height issue, and possible effects of the pot?
Java Jive wrote:
can I mount the aerial around the level of the middle of the chimney pot
I'd say best avoided, if it's a red/brown pot, maybe 10% iron oxide
content, higher if its blue/black pot.
-aI've mounted TWO 8" chimney strap brackets ...
<https://www.blake-uk.com/8-stack-strap-ratchet-cradle-mitre-bracket.html>
I found those to be brilliant, when I fitted my aerials (shame Blake cheaped-out with a steel bracket, no way I'll go upon the roof nowadays).
Despairing on local installers ever coming back to me, I've started my
own TV aerial installation. It's going fine, but I have a technical >question which I am not qualified to answer, and while searches on the >internet suggest that I don't have a problem, the results don't seem
quite definitive enough to satisfy me, so I would like some advice from >experienced installers.
My question is, can I mount the aerial around the level of the middle of
the chimney pot, which will be almost at right-angles to the left side
of the aerial, or will the pot itself affect the received signal so I
should make it higher? I need some sort of advice on this to decide the >length of the pole. If I need to mount it above the level of the pot >completely, I will have to use the full length of the pole, but, mindful
of the wind loading, I'm wondering if I can get away with putting it
about the level of the middle of the pot? A rough calculation leads me
to think that the surface of the pot will end up being about 450mm from
the centre of the mast, which will also be the nearest point of the axis
of the aerial.
Full details ...
The house is aligned with its longest side to Loch Shin, which lies
along an axis roughly 39 degrees off north-south, with the south end
being to the east and the north to the west. The Lairg relay (BV) is on
The Ord, a hill roughly SW of Lairg centre and approximately south of
here, so the aerial is to be mounted on the southernmost chimney.
There is a neighbouring property in the direction of the relay, but I am
on higher ground and from the level of the middle of the chimney pot,
quite a tall one, I can see the relay comfortably over the highest point
of their property.
There are three corners of that chimney where mounting an aerial could
see the relay comfortably, I chose the one to W-N-W because that is the >direction of the prevailing winds, so the mast will be in the stiller
air that there tends to be just in front of the chimney, and I feel
happier about the wind trying to blow the aerial onto the chimney rather >than it trying to rip it off either of the other two corners.
So, still thinking about the wind problem, I've mounted TWO 8" chimney
strap brackets ...
<https://www.blake-uk.com/8-stack-strap-ratchet-cradle-mitre-bracket.html>
... the higher being about 200mm from the top of the chimney proper,
about 250mm from the top of the flaunching, and the lower bracket almost >touching the upper (this is perhaps a little nearer the top of the
chimney than recommended, but the latter isn't tall enough to put the >assembly lower with the lower strap still being able to clear the roof
apex - I'm not too worried about this, the chimneys were remade about
10 years ago and, as far as I can tell from the pebble dashing, are
still in good condition).
It's not a very powerful relay, so I have a log-periodic with a masthead >amplifier, one of these (obviously, I'm not using the pole and mounting >supplied):
<https://www.screwfix.com/p/labgear-log-megaboost-tv-aerial/799jr>
Any advice on the height issue, and possible effects of the pot?
http://tx.mb21.co.uk/gallery/gallerypage.php?txid=1058
I'd be interested to see where that relay's Log's are pointed to and the
ERP which is probably the square root of not a lot.
Also I'd be tempted to use a larger log with an external amp if needed
its a watered down one that relay with not all MUX's available
I would have thought that the pot would not be that much of a problem as
log as the aerial points away , ish, from it ..
how far are you from that Tx?..
My question is, can I mount the aerial around the level of the middle of
the chimney pot, which will be almost at right-angles to the left side
of the aerial, or will the pot itself affect the received signal so I
should make it higher?
Despairing on local installers ever coming back to me, I've started my
own TV aerial installation.-a It's going fine, but I have a technical question which I am not qualified to answer, and while searches on the internet suggest that I don't have a problem, the results don't seem
quite definitive enough to satisfy me, so I would like some advice from experienced installers.
My question is, can I mount the aerial around the level of the middle of
the chimney pot, which will be almost at right-angles to the left side
of the aerial, or will the pot itself affect the received signal so I
should make it higher?-a I need some sort of advice on this to decide the length of the pole.-a If I need to mount it above the level of the pot completely, I will have to use the full length of the pole, but, mindful
of the wind loading, I'm wondering if I can get away with putting it
about the level of the middle of the pot?-a A rough calculation leads me
to think that the surface of the pot will end up being about 450mm from
the centre of the mast, which will also be the nearest point of the axis
of the aerial.
Java Jive <java@evij.com.invalid> wrote:
My question is, can I mount the aerial around the level of the middle of
the chimney pot, which will be almost at right-angles to the left side
of the aerial, or will the pot itself affect the received signal so I
should make it higher?
Although dependent on the exact design of the antenna, reasonably
significant sidelobes can be expected at 60 to 90 degrees to the main lobe.
So mounting the antenna at the same height as the chimney pot and at right angles to its sounds to be a very bad idea, unless the pot itself is made
out of radar absorbing materials.
Mount the aerial so that it is higher up, on two grounds.
Firstly, it will take the antenna side lobes away from the the chimney pot, thus reducing its effect.
Secondly, it will put the antenna further into the transmitterrCOs own vertical lobe thus increasing the received direct signal (think of the technique of rCOpecking the lobesrCO used by aircraft that want to minimise the
risk of being detected by radar).
On 2026-09-25 15:55, Java Jive wrote:
Despairing on local installers ever coming back to me, I've started my
own TV aerial installation.a It's going fine, but I have a technical
question which I am not qualified to answer, and while searches on the
internet suggest that I don't have a problem, the results don't seem
quite definitive enough to satisfy me, so I would like some advice from
experienced installers.
My question is, can I mount the aerial around the level of the middle of
the chimney pot, which will be almost at right-angles to the left side
of the aerial, or will the pot itself affect the received signal so I
should make it higher?a I need some sort of advice on this to decide the
length of the pole.a If I need to mount it above the level of the pot
completely, I will have to use the full length of the pole, but, mindful
of the wind loading, I'm wondering if I can get away with putting it
about the level of the middle of the pot?a A rough calculation leads me
to think that the surface of the pot will end up being about 450mm from
the centre of the mast, which will also be the nearest point of the axis
of the aerial.
I followed Tony's advice and installed the aerial to a height about 1/2
way up the chimney pot. I haven't finished tacking the lead to the side
of the house yet, but temporarily have brought the cable in through a
window and connected up. 100% signal strength & quality.
I count that as a win.
Thanks to Andy & Tony for their contributions.
Spike <aero.spike@mail.com> wrote:
Java Jive <java@evij.com.invalid> wrote:
My question is, can I mount the aerial around the level of the middle of >>> the chimney pot, which will be almost at right-angles to the left side
of the aerial, or will the pot itself affect the received signal so I
should make it higher?
Although dependent on the exact design of the antenna, reasonably
significant sidelobes can be expected at 60 to 90 degrees to the main lobe.
So mounting the antenna at the same height as the chimney pot and at right >> angles to its sounds to be a very bad idea, unless the pot itself is made
out of radar absorbing materials.
Mount the aerial so that it is higher up, on two grounds.
Firstly, it will take the antenna side lobes away from the the chimney pot, >> thus reducing its effect.
Secondly, it will put the antenna further into the transmitterrCOs own
vertical lobe thus increasing the received direct signal (think of the
technique of rCOpecking the lobesrCO used by aircraft that want to minimise the
risk of being detected by radar).
A further factor, which I forgot to mention, is that the chimney pot being >closer to one side of the aerial will detune some or all of the elements on >that side by the extra capacitance to rCOearthrCO caused by the presence of the
pot, and also probably to some extent by the presence of the chimney
itself.
The elements on the side that is away from the chimney and pot will also be >detuned but by a lesser extent, meaning the whole aerial array will not be >operating as designed.
There are good reasons why aerials are erected rCOin the clearrCO, and not >close to objects, and one of them is to avoid unwittingly detuning the
aerial in some unknown way. If any channels are close to the design
operating range, their signal strength as received may be sub-optimal.
None of this precludes the aerial supplying sufficient signal, but like a
car with a wheel missing, it can still work, but in an unknown regime due
to the radiation patterns being distorted.
In article <119ei3k$2m91j$1@dont-email.me>, Java Jive
I followed Tony's advice and installed the aerial to a height about 1/2
way up the chimney pot. I haven't finished tacking the lead to the side
of the house yet, but temporarily have brought the cable in through a
window and connected up. 100% signal strength & quality.
I count that as a win.
Thanks to Andy & Tony for their contributions.
Good! what aerial did you use in the end the one with the built in
pre-amp?
Not exactly overpopulated in that area is it;!..
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