Diplexer

[Marty Wallace]

"Matt" <matt@noemail.net> wrote in message
newsan.2004.06.08.23.54.08.703000@noemail.net...

On Wed, 09 Jun 2004 11:22:09 +1200, Ken Taylor wrote:


Yes I think it is that way; capacitively coupled. I spoke to a friend
and
after telling him I put it in the roof he said that is probably why it
has
poor reception. Is the UHF signal not very strong compared to VHF?

Matt.....

Not necessarily, but it *is* more likely to be reduced by path losses.
Is
your roof a tin roof or tiles? Is there foil insulation up there? Does
the
antenna look through trees?

Another clue - which way do other people in your area point their UHF
antennas, and how big are they? (the antennas, not the neighbors).

Ken

The roof is tiled and brick on the outside. So it has to go through brick
and tiles. It has to go through a few trees. People around here only have
combination antennas. VHF/UHF. They are all pointing the same way. I
remember using the most crappy VHF antenna (on my roof) years ago and I
could pick up everything clearly. Now I think I made a mistake about
buying a seperate UHF antenna. Do you think there would be anything else
to improve the reception? Bricks and tiles must really knock the signal
down at least 50%.

Regards,
Matt

UHF is a lot more intolerant of a bad setup or bad cable. The line losses of
a bad cable are much greater when you go to the higher frequency. Make sure
your cable is of good quality and undamaged. Water often gets into co-ax
which is bad for UHF. Make sure your connections are good and sealed from
the weather. Try bypassing the diplexer to make sure the UHF can get to your
TV ok.

Marty

 

[Ken Taylor]

"Marty Wallace" <mart@geo.net.au> wrote in message
news:40c65114$0$15372$61ce578d@news.syd.swiftdsl.com.au...

"Matt" <matt@noemail.net> wrote in message
newsan.2004.06.08.23.54.08.703000@noemail.net...
On Wed, 09 Jun 2004 11:22:09 +1200, Ken Taylor wrote:


Yes I think it is that way; capacitively coupled. I spoke to a friend
and
after telling him I put it in the roof he said that is probably why
it
has
poor reception. Is the UHF signal not very strong compared to VHF?

Matt.....

Not necessarily, but it *is* more likely to be reduced by path losses.
Is
your roof a tin roof or tiles? Is there foil insulation up there? Does
the
antenna look through trees?

Another clue - which way do other people in your area point their UHF
antennas, and how big are they? (the antennas, not the neighbors).

Ken

The roof is tiled and brick on the outside. So it has to go through
brick
and tiles. It has to go through a few trees. People around here only
have
combination antennas. VHF/UHF. They are all pointing the same way. I
remember using the most crappy VHF antenna (on my roof) years ago and I
could pick up everything clearly. Now I think I made a mistake about
buying a seperate UHF antenna. Do you think there would be anything else
to improve the reception? Bricks and tiles must really knock the signal
down at least 50%.

Regards,
Matt

UHF is a lot more intolerant of a bad setup or bad cable. The line losses
of
a bad cable are much greater when you go to the higher frequency. Make
sure
your cable is of good quality and undamaged. Water often gets into co-ax
which is bad for UHF. Make sure your connections are good and sealed from
the weather. Try bypassing the diplexer to make sure the UHF can get to
your
TV ok.

Marty


The brick and tile shouldn't do too much to the signal as it appears you're

in a pretty good signal area anyway, so I go for the bad connection/cable
theory too. Are you using coax? (Sorry if this has been answered already,
I've lost track of the thread). The new antenna shouldn't, by itself, make
things worse, unless you've ended up overloading the TV. However, as we've
said a couple of times you need to make sure it's pointed with a bit
more accuracy than a smaller antenna, and make sure it's a half-decent
combiner.

As an aside, are you running the antenna into a VCR which has a
Local/Distant (or similar) RF setting? It may be either a switch next to the
antenna input, or a software setting via the menu. If you're overloading
then use the 'local' setting.

Cheers.

Ken