[UK-CONTEST] TV DISTRIBUTION AMPS

[Ian White GM3SEK]

John Wilson wrote:
>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.
>>
>> 73
>>
>> Don, G3BJ
>>
>Don,
>
>You need  www.proception.co.uk   These amps were designed by an amateur
>friend of mine.  Two of the main design criteria were for them were a)
>to be unconditionally stable and  b) for the ones with built in
>filtering,  to have filters that cut off between 470 MHz and 440 MHz so
>that they don't get overloaded by 70 cms transmissions.
>
>John G3UUT
>

Thanks, John, that's good to know.

Proception is also available from cpc.co.uk (search for the brand name).

The Tetra/Airwave UHF network has done us a big favour by making UHF TV 
preamps available that include tight front-end filtering. That filtering 
will usually give a very a steep roll-off at lower frequencies ass well.

However, it's also up to us to *choose* UHF preamps with the Tetra 
filtering option, and NEVER buy one that also has VHF/FM capability.



-- 

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