BATC Forum

Hi All,
Does anyone know of a 'simple' 6MHz intercarrier sound circuit?
I'm looking for something I could knock up on vero-board / strip board or maybe dead bug style. Preferably locked to 6MHz rather than free running.

The reason is that I have a 23cm analogue video tx that has an input for the intercarrier but not the intercarrier itself. I have put a 6MHz sig-gen into the port and get the local repeater to fully quieten. The TX is free running so having a KNOWN 6MHz audio source helps to tune up the main TX as the repeater goes silent when on frequency.

I borrowed the sig gen from work so need to return it following my tests.

Any pointers much appreciated.

Bob,
Have a look at the BATC Wiki, ATV equipment manuals section, Solent/Worthing ATV TX. This has a simple 6MHz sub-carrier generator (free-running, but quite stable in my experience) with input amplifier capable of being driven by a mic.
73 Shaun G8VPG.

Thanks Shawn.
DO you, or anyone, know of a suitable replacement for the BB204 Varicap diode pair? That seem to be about the only component that's no longer around.
Cheers,
Bob
G1XIE

The MV104 from On Semi looks very close. It appears to be available from Mouser in the UK.

Sadly also obsolete (

There's a surface-mount device available from Farnell. Unfortunately it's 46.5pF rather than 42pF but that might be close enough.

biker_bob wrote:Thanks Shawn.
DO you, or anyone, know of a suitable replacement for the BB204 Varicap diode pair? That seem to be about the only component that's no longer around.
Cheers,
Bob
G1XIE

Its a bit of a late reply but try ebay ..theres a few BB204 s listed

http://www.ebay.co.uk/sch/i.html?_from= ... e&_sacat=0

Thanks for all the responses.
It's been a while and I can't remember what I used in the end but I did get it working.