[Collins] (no subject)

[Dr.Gerald N. Johnson]

Dr. Gerald N. Johnson, Electrical Engineer
----- Original Message -----
From: Glen Zook [mailto:gzook at yahoo.com]
Sent: 11/21/2005 8:08:36 AM
To: UFP at optusnet.com.au;collins at mailman.qth.net
Subject: Re: [Collins] (no subject)

> All of the 75S-1, 75S-2, 75S-3, and 75S-3A as well as
> the earlier versions of the 75S-3B and 75S-3C used two
> i.f. cans in the AM filter.  The later 75S-3B and
> 75S-3C receivers moved one of these i.f. cans to tune
> one of the mixer stages.  Collins put out a Service
> Bulletin on doing this to the earlier 75S-3B and
> 75S-3C receivers.  However, it is also easy to do on
> the 75S-1 through the 75S-3A and is well worth doing.
> 
> I have done this modification on my 75S-3A and both
> 75S-1 receivers.  It only takes a few minutes and
> definitely improves the performance.
> 
> Glen, K9STH
> 
> 
> --- "L.D. Ritta" <UFP at optusnet.com.au> wrote:
> 
> I saw someone selling a 75S3C and they mention the T9
> Mod. What is it and what does it do, etc. Remember I'm
> new to Collins.
> 
> Glen, K9STH
> 
Moving that IF can does two things. It reduces the leakthrough outside the mechanical filter pass band and it surely adds more safety for keeping DC of the filter. I hope it still can be used on AM without a mechanical filter.

73, Jerry, K0CQ Technical advisor to the CRA