Problem with Co channel interference.

Hi,
I am taking service from both Winter Hill and Long Mountain. The
problem I have is they are almost direct in the same line of sight as
each other.

I am able to pick up Winter Hill nicely enough at my position, but Long
Mountain is in the way. I am not getting enough signal from my
horizontal aerial with which i am getting my Winter signal, but then
again if I use a vertical aerial for service from Long Mountan then I
get effectively CCI problems and causing pixellation and lots of errors.
There seems to be a phase shift in this. The solution I thought of
was a UHF channel filter blocking channels 60 and 52 such that they only
appear on the line from the vertical aerial.

Hope this is clear enough.

Rob.

news.plus.net wrote:
Hi,
I am taking service from both Winter Hill and Long Mountain. The
problem I have is they are almost direct in the same line of sight as
each other.

I am able to pick up Winter Hill nicely enough at my position, but Long
Mountain is in the way. I am not getting enough signal from my
horizontal aerial with which i am getting my Winter signal, but then
again if I use a vertical aerial for service from Long Mountan then I
get effectively CCI problems and causing pixellation and lots of errors.
There seems to be a phase shift in this. The solution I thought of was
a UHF channel filter blocking channels 60 and 52 such that they only
appear on the line from the vertical aerial.

Hope this is clear enough.

Well it isn't all that clear. Could you tell us:
Channels required from each transmitter
Channels broadcast from each transmitter
Approx distance of each transmitter
Are the signals combined in some way, if so how?
What aerials are you using?

Bill

On 05/10/2011 11:46, Bill Wright wrote:
news.plus.net wrote:
Hi,
I am taking service from both Winter Hill and Long Mountain. The
problem I have is they are almost direct in the same line of sight as
each other.

I am able to pick up Winter Hill nicely enough at my position, but
Long Mountain is in the way. I am not getting enough signal from my
horizontal aerial with which i am getting my Winter signal, but then
again if I use a vertical aerial for service from Long Mountan then I
get effectively CCI problems and causing pixellation and lots of
errors. There seems to be a phase shift in this. The solution I
thought of was a UHF channel filter blocking channels 60 and 52 such
that they only appear on the line from the vertical aerial.

Hope this is clear enough.

Well it isn't all that clear. Could you tell us:
Channels required from each transmitter
Channels broadcast from each transmitter
Approx distance of each transmitter
Are the signals combined in some way, if so how?
What aerials are you using?

Bill
Yes Bill sorry..

I am wanting to take the two standard def Mux's from Long Mountain, ie
BBC1 Wales and ITV1 Wales, and receive the commercial stuff from Winter
Hill,ie Film 4 etc etc.

I have a horizontal and vertical polarity combind into a single downlead
in the loft. They both point in a similar direction as they are in the
same plain. I seem (obviously) to be recieving the same signals on both
aerials. I did think about a channel blocker for the horizontal aerial
for the Long Mountain signals.

I am about 5 miles away from Long Mountain, 80 miles or so from Winter.


Long mountain ||||||-----------|--------|------- Winter Hill
|
|
|
|
TV point(s)

Thanks,

Rob.

You wouldn't want to pay for the type of active filter that would
successfully combine 53, 57, and 60 with 55, 58, and 61.

If you could pick out a selection of channels from the two txs that
aren't adjacent you would be able to do it with passive filters.

Alternatively, if you combine with a simple splitter remember that the
phase relationship of the two feeds is important. Try moving one aerial
forwards and backwards along the line of the signal. The relative
strength of the two sets of signals is very important. Fit variable
attenuators and or amplification on each aerial feed before the
combiner, and experiment.

Despite the channels being adjacent, a notch filter or two could help a lot.

Try to mount the aerials high up and away from objects, because that way
the polarisation of the received signals will be better defined.

Look at the Winter Hill reception from the VP aerial and vice versa, and
minimise reception by fine adjustment of polarisation.

Try to mount each aerial where it is screened form the 'other' transmitter.

To be honest an analyser would make this a lot easier.

Bill

There is another way - go for different transmitters.

If you are high enough to get WH then what about Moel-y-Parc? A
wideband aerial (or log periodic) pointed somewhere between them
would probably get both if there is a path to MyP and they are
both horizontal.

Go for a different station to get the comm muxes - from Long
Mountain you could try The Wrekin, Sutton Coldfield, or even
Ridge Hill depending just where you are. Alternatively stay with
WH for comm muxes and go for a different source for WTV.

Have a look at www.ukfree.tv which may give you some ideas.



--
Woody

harrogate three at ntlworld dot com

On 05/10/2011 16:25, Woody wrote:
There is another way - go for different transmitters.

If you are high enough to get WH then what about Moel-y-Parc? A
wideband aerial (or log periodic) pointed somewhere between them
would probably get both if there is a path to MyP and they are
both horizontal.

Go for a different station to get the comm muxes - from Long
Mountain you could try The Wrekin, Sutton Coldfield, or even
Ridge Hill depending just where you are. Alternatively stay with
WH for comm muxes and go for a different source for WTV.

Have a look at www.ukfree.tv which may give you some ideas.



Actually The Wrekin might be useable now that the ERP has one up. It'd
be a damn sight simpler wouldn't it?

Thanks,

Rob.

On 5 Okt., 13:50, "news.plus.net" wrote:


For your information, the channels change
at Long Mountain October 19.
http://www.digitaluk.co.uk/transmitt...Oc tFINAL.pdf

Lars

WH = 62 59 54 - 58 61 55 (62, 61 will change)
LM = 60- 53 57 (from oct 19)

Lars

news.plus.net wrote:

Actually The Wrekin might be useable now that the ERP has one up. It'd
be a damn sight simpler wouldn't it?

What would be simpler, and give you almost every BBC and ITV region you could
possibly ever want would be a 45cm dish, and FTA satellite receiver !

--
Mark
Please replace invalid and invalid with gmx and net to reply.

www.paras.org.uk

reslfj wrote:

WH = 62 59 54 - 58 61 55 (62, 61 will change)
(from oct 19)

Really ? I know they have to change (along with many other Tx sites), but I
didn't know a date had been announced, at least for Winter Hill ?

--
Mark
Please replace invalid and invalid with gmx and net to reply.

www.paras.org.uk

On Wed, 05 Oct 2011 17:21:27 +0100, Mark Carver
wrote:

news.plus.net wrote:

Actually The Wrekin might be useable now that the ERP has one up. It'd
be a damn sight simpler wouldn't it?

What would be simpler, and give you almost every BBC and ITV region you could
possibly ever want would be a 45cm dish, and FTA satellite receiver !

- which is the correct answer to so many reception problems raised on
this NG and elsewhere.
It may deny the (real) professionals amongst us the intellectual
challenge of remotely sorting an unusual situation, but subject only
to getting a clear LOS it is the one guaranteed solution.