[Dark Angel]

I'm helping a friend install some new TV aeriels, he's got a couple of these

http://www.screwfix.com/app/sfd/cat/...27265&id=33455

Of course if I try to install them on the same pole, the lower aerial is
going to have the pole poking between the elements.

Any reason why I can't put the fixing bracket (shown underneath on this pic)
on the side of the aerial so it will keep the elements out of the way of the
pole (obviously I'd also alter the V bolt so the elements were still
horizontally polorized)?


--
Best Wishes
Simon (aka Dark Angel)
"Dark Angel's Realm of Horror" - http://www.realmofhorror.co.uk

[Harry Bloomfield]

Dark Angel has brought this to us :
I'm helping a friend install some new TV aeriels, he's got a couple of these

http://www.screwfix.com/app/sfd/cat/...27265&id=33455

Of course if I try to install them on the same pole, the lower aerial is
going to have the pole poking between the elements.

Any reason why I can't put the fixing bracket (shown underneath on this pic)
on the side of the aerial so it will keep the elements out of the way of the
pole (obviously I'd also alter the V bolt so the elements were still
horizontally polorized)?

That method would seriously degrade the reception. You can either mount
them on two completely separate masts, or use a U shaped pole adaptor
so they mount on one mast but side by side.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

[Dark Angel]

"Harry Bloomfield" wrote in message...
That method would seriously degrade the reception. You can either mount
them on two completely separate masts, or use a U shaped pole adaptor so
they mount on one mast but side by side.

If I may enquire, how will that effect reception? All I'm doing is using the
bottom bracket as a stand off mast?


--
Best Wishes
Simon (aka Dark Angel)
"Dark Angel's Realm of Horror" - http://www.realmofhorror.co.uk

[Adrian]

Hi Simon

On Thu, 27 Jul 2006 21:56:22 +0100, "Dark Angel"
wrote:


"Harry Bloomfield" wrote in message...
That method would seriously degrade the reception. You can either mount
them on two completely separate masts, or use a U shaped pole adaptor so
they mount on one mast but side by side.

If I may enquire, how will that effect reception? All I'm doing is using the
bottom bracket as a stand off mast?

If I understand what you're proposing - you'll have the mounting
bracket for the lower aerial in the same plane as the actual elements
of the aerial.

Harry's right, in that this will detune the aerial and cause you all
sorts of problems.

You probably know about this (apologies if I'm teaching granny to suck
eggs) but it's not quite as simple as just wiring the two aerials
together. If you're trying to get a stronger signal than you need to
combine the signal from the two aerials properly, and the spacing
between the two aerials is also important....

Regards
Adrian

[Dark Angel]

"Adrian" wrote in message...
You probably know about this (apologies if I'm teaching granny to suck
eggs) but it's not quite as simple as just wiring the two aerials
together. If you're trying to get a stronger signal than you need to
combine the signal from the two aerials properly, and the spacing
between the two aerials is also important....

No it's not that, the 2 aeriels are for receiving 2 seperate regions, Yorks
and Central (I'm going to use a filtered combiner before you ask).

Obviously I want to avoid the pole from poking between the elements on the
second aeriel, which is why I was proposing using the bottom bracket on the
side instead of underneath to stand it away from the pole.

The elements won't be between the pole, and by adjusting the U-bolt
accordingly the aerial will still be the right polarity.


--
Best Wishes
Simon (aka Dark Angel)
"Dark Angel's Realm of Horror" - http://www.realmofhorror.co.uk

[Adrian]

HI Simon

On Thu, 27 Jul 2006 22:34:08 +0100, "Dark Angel"
wrote:


"Adrian" wrote in message...
You probably know about this (apologies if I'm teaching granny to suck
eggs) but it's not quite as simple as just wiring the two aerials
together. If you're trying to get a stronger signal than you need to
combine the signal from the two aerials properly, and the spacing
between the two aerials is also important....

No it's not that, the 2 aeriels are for receiving 2 seperate regions, Yorks
and Central (I'm going to use a filtered combiner before you ask).

OK - you saw which way I was thinking g


Obviously I want to avoid the pole from poking between the elements on the
second aeriel, which is why I was proposing using the bottom bracket on the
side instead of underneath to stand it away from the pole.

On an aerial like this you don't really want anything metallic in the
same plane as the elements - so, in a way, mounting the thing
'normally' so that the aerial mast is at right angles to the elements
is better than doing what you propose.

Ideally you'd want _no_ extra metal within the aerial - but having it
at 90-degrees to the elements would be better than your plan.


The elements won't be between the pole, and by adjusting the U-bolt
accordingly the aerial will still be the right polarity.

What you say is true - but it'll still be wrong g

Best solution is some way to put them both on top of the mast, but
separated horizontally (a piece of tubing like a very shallow
'u'-shape - don't know what they're called g) you want to get the
two aerials as far apart as possible...

Hope this helps...

Adrian

[Michael Chare]

"Dark Angel" wrote in message
...
I'm helping a friend install some new TV aeriels, he's got a couple of these

http://www.screwfix.com/app/sfd/cat/...27265&id=33455

Of course if I try to install them on the same pole, the lower aerial is
going to have the pole poking between the elements.

Any reason why I can't put the fixing bracket (shown underneath on this pic)
on the side of the aerial so it will keep the elements out of the way of the
pole (obviously I'd also alter the V bolt so the elements were still
horizontally polorized)?

See http://www.wrightsaerials.tv/stackingaerials.html

Also better to post in uk.tech.digital-tv

A wideband aerial is not always the best choice - particularly if you are short
of signal.

--

Michael Chare

[Andy Luckman (AJL Electronics)]

In article , Dark Angel
wrote:

http://www.screwfix.com/app/sfd/cat/...27265&id=33455

Of course if I try to install them on the same pole, the lower aerial is
going to have the pole poking between the elements.

On the Triax aerials, to overcome that problem, you can remove the clamp
and re-install it on the stub behind the reflector.

The spec of that aerial concerns me..... No mention of a balun and a gain of
5-12dB ???


--
AJL Electronics (G6FGO) Ltd : Satellite and TV aerial systems
http://www.classicmicrocars.co.uk : http://www.ajlelectronics.co.uk

[tony sayer]

In article , Andy Luckman
(AJL Electronics) writes
In article , Dark Angel
wrote:

http://www.screwfix.com/app/sfd/cat/...27265&id=33455

Of course if I try to install them on the same pole, the lower aerial is
going to have the pole poking between the elements.

On the Triax aerials, to overcome that problem, you can remove the clamp
and re-install it on the stub behind the reflector.


Much better grade of aerial that.. and available from www.cpc.co.uk

The spec of that aerial concerns me..... No mention of a balun and a gain of
5-12dB ???

That looks like a maxcack?...


And don't for get the CT100 for the aerial downlead;!....
--
Tony Sayer

[Andy Luckman (AJL Electronics)]

In article , tony sayer
wrote:

Much better grade of aerial that.. and available from www.cpc.co.uk

And us! It is our mainstay for installations.

That looks like a maxcack?...

I couldn't quite identify it from the picture. Claims to be branded Labgear.
However, they don't exist any more. Nearest I can think of is a Blake, but
the connector box is more like a cheap copy of the Triax.


And don't for get the CT100 for the aerial downlead;!....

WF100 please!

--
AJL Electronics (G6FGO) Ltd : Satellite and TV aerial systems
http://www.classicmicrocars.co.uk : http://www.ajlelectronics.co.uk

[tony sayer]

In article , Andy Luckman
(AJL Electronics) writes
In article , tony sayer
wrote:

Much better grade of aerial that.. and available from www.cpc.co.uk

And us! It is our mainstay for installations.

Good


That looks like a maxcack?...

I couldn't quite identify it from the picture. Claims to be branded Labgear.
However, they don't exist any more. Nearest I can think of is a Blake, but
the connector box is more like a cheap copy of the Triax.

Reckon Andy Wade could comment on that!..


And don't for get the CT100 for the aerial downlead;!....

WF100 please!

Yep tho I didn't want to complicate the issue. Is WF100 as widely
available as CT100 then?....
--
Tony Sayer

[Andy Wade]

tony sayer wrote:

In article , Andy Luckman
(AJL Electronics) writes

I couldn't quite identify it from the picture. Claims to be branded Labgear.
However, they don't exist any more. Nearest I can think of is a Blake, but
the connector box is more like a cheap copy of the Triax.

Reckon Andy Wade could comment on that!..

Well Philex do sell Labgear branded product, trading as their "Labgear
Division." They bought back the trade mark and some other assets after
Labgear Ltd. went into administration in 2004. I can't comment on the
aerial in question, although the chances are that it's imported.

Actually they're being unusually honest in quoting the gain spread
across the band. The gain of all so-called 'wideband yagi' types is
quite low at ch. 21 - these aerials really work as yagis at the HF end
of the band and as corner reflectors at the LF end, hence the need for
the large reflector. It's quite instructive to look at the gain
requirements for the various 'benchmark' standards of the CAI/DTG aerial
benchmarking scheme, which you can find in
http://www.dtg.org.uk/publications/b...rk_aerials.pdf

For wideband (Group W) aerials the gain requirements over ch. 21-36 are
as follows:

- std. 1 10 dBd (only one product approved in this category)
- std. 2 7 dBd
- std. 3 5 dBd
- std. 4 7 dBd (log-periodics)

So all the std. 3 benchmarked products (including the Unix 32W) will
only just exceed 5 dBd in the lower Group A channels. Most
manufacturers only publish the gain at the top end of the band, which of
course looks much better :-). If you don't need the extra gain at the
HF end then the std. 4 log-periodics are a good bet - much smaller and
less windage, and the gain is not drastically lower in the way some
people seem to assume.

And don't for get the CT100 for the aerial downlead;!....

WF100 please!

Quite agree.

Yep tho I didn't want to complicate the issue. Is WF100 as widely
available as CT100 then?....

It's certainly readily available. E.g. there's always a few reels in
stock at a certain establishment on Mitcham's Corner...

--
Andy

[tony sayer]

In article , Andy Wade
writes
tony sayer wrote:

In article , Andy Luckman
(AJL Electronics) writes

I couldn't quite identify it from the picture. Claims to be branded Labgear.
However, they don't exist any more. Nearest I can think of is a Blake, but
the connector box is more like a cheap copy of the Triax.

Reckon Andy Wade could comment on that!..

Well Philex do sell Labgear branded product, trading as their "Labgear
Division." They bought back the trade mark and some other assets after
Labgear Ltd. went into administration in 2004. I can't comment on the
aerial in question, although the chances are that it's imported.

Actually they're being unusually honest in quoting the gain spread
across the band. The gain of all so-called 'wideband yagi' types is
quite low at ch. 21 - these aerials really work as yagis at the HF end
of the band and as corner reflectors at the LF end, hence the need for
the large reflector. It's quite instructive to look at the gain
requirements for the various 'benchmark' standards of the CAI/DTG aerial
benchmarking scheme, which you can find in
http://www.dtg.org.uk/publications/b...rk_aerials.pdf

For wideband (Group W) aerials the gain requirements over ch. 21-36 are
as follows:

- std. 1 10 dBd (only one product approved in this category)
- std. 2 7 dBd
- std. 3 5 dBd
- std. 4 7 dBd (log-periodics)

So all the std. 3 benchmarked products (including the Unix 32W) will
only just exceed 5 dBd in the lower Group A channels. Most
manufacturers only publish the gain at the top end of the band, which of
course looks much better :-). If you don't need the extra gain at the
HF end then the std. 4 log-periodics are a good bet - much smaller and
less windage, and the gain is not drastically lower in the way some
people seem to assume.

And don't for get the CT100 for the aerial downlead;!....

WF100 please!

Quite agree.

Yep tho I didn't want to complicate the issue. Is WF100 as widely
available as CT100 then?....

It's certainly readily available. E.g. there's always a few reels in
stock at a certain establishment on Mitcham's Corner...

I'm sure he could quite well with an online outlet but the last time I
was in there the power-that-is prohibited the use of credit cards..

So olde world;!.....


--
Tony Sayer