"patrick j" wrote in message
al.Net...
Hi

I'm planning on getting a Freeview TV. This will be the first TV I've had
in six years. I'm getting clearer about the actual TV I want and generally
I'm feeling quite good about that part.

The question really is what to do about radio. Currently I have a rather
good FM tuner in my living room and a Tivoli radio in my bedroom. Both of
these get the signal from a single FM aerial on a mast on my roof.

The FM aerial is an FM1083 Antiference all the cabling is CT100.

To get Freeview I want to put up an aerial suitable for DTT. If I want to
stick with the FM tuner then it's easy, I've learned that all I need to do
is use a diplexer. However, while I'm up on my roof it has occurred to me
that I should put a DAB aerial up there as well. This would mean that I'd
be completely covered, pretty much. If I decide to get a DAB radio then
I'll have the aerial already there.

So, my question is: can I put the signals from the three aerials down the
single CT100 cable?

For this would I need two diplexers or something?

Thank you

--
Patrick - Hove, UK
If you wish email me from my web-site: http://www.patrickjames.me.uk

The easiest way to sort that lot out is to have a TV aerial and another for
88-108MHz. The reason for that is the DAB band is harmonically related. So
a 1/4wave on 88-108 is a 1/2wave on DAB and provides acceptable performance.
(If you want stations outside your area a beam will be required.)
Put the TV aerial on the top of the pole, put the VHF dipole further down
the pole mounted about 2ft away. The closer it is to the pole the more
directional it will become, like a heart shape. You can use that to your
advantage.

Use good quality aerials, not the stuff from B&Q like Maxview. The VHF
dipole is held together with self tapping screws that the coax wraps around.
A poor design which allows water in.
Make sure the TV aerial has an F type connector, also get a proper VHF
dipole with screw terminals inside or an F type. Tape the joints and
connectors up well with self amalgamating tape.
Run the coax in to the distribution amp in the loft. Get one with a
separate input for VHF and TV.
Run a coax around to each room and simply use a shielded outlet with
VHF/DAB/TV outlets.

A diplexer or series of them will allow you to combine or extract certain
frequencies. They are just filters, so one only letting TV through would be
a high pass filter blocking anything below say 400MHz. You can also get a
duplexer that allows a number of frequencies to be used in any combination
of transmit and receive on the same aerial at the same time!