[UK-CONTEST] [CDXC] TV DISTRIBUTION AMPS

[Ian White GM3SEK]

Don Beattie wrote:
> 
>Firstly, sorry to cross-post to both reflectors, but I am looking for a quick
>reply !
>
>My one and only neighbour has a problem, which I need to help him get
>fixed. He has had, for some time, a TV distribution amplifier in his loft,
>and I had to fit torroids to it to make it immune to HF. Now, however the
>amplifier has gone unstable. We did some tests today, and it is awful -
>to much gain = oscillation. To little = lousy picture. He wants to replace
>it.
>
>The question is, does anyone know whether there is a "good"
>distribution amplifier which has reasonable high immunity to HF ? If so,
>I'd really appreciate details, as it would be nice to start with a
>reasonable level of immunity.
>

You're right to be looking for good immunity to HF (and VHF too - you 
just never know) so the amplifier needs to be definitely specified as 
"UHF-only", preferably including a specific lower operating frequency, 
usually 470MHz. It's also well worth getting one with a Tetra UHF filter 
built in.

For example, here is a professional 4-way distribution amp and PSU by 
Labgear, with good filtering and variable gain:
<http://cpc.farnell.com/labgear/puh141-psm114v/16db-variable-masthead-amp
lifier/dp/AP01497>

Specification is here, and note the rejection >25dB from DC-400MHz:
http://labgear.co.uk/downloads/webtables/9.xls

I have a single output fixed gain version of this amplifier, and it's 
nicely made and has given no problems. It comes with a PSU and a nice 
little weatherproof enclosure (which he won't be needing, but you can 
take off his hands). If 4 outputs aren't enough, any 3 of the outputs 
can be fed into further splitters to make more.

Don't forget the F connectors too.



-- 

73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek