[Collins] Which AM transmitter to go with S-line?

Sun, 6 Jul 2003 11:53:33 +1200

I have to say that I would not be interested in using this method of AM
generation myself- but it is obviously a possibility that may be useful for
some.  My two 32S transmitters are going to remain exactly as they are!
 I have a very fine Apache (apologies!!) with a modified audio driver lineup
that generates excellent AM although it is not used much these days.
Having been mixed up in the SSB transition period where A3H (old
designator-can't recall the current one) was used for a time on 2182 KHz
(compatible SSB or whatever it's called these days- carrier plus SSB
anyway!) I'm very aware of the modes shortcomings- but it does produce a
useable AM signal, although not necessarily a very good sounding one.
 73
 Dave, ZL3FJ

---- Original Message ----- 
From: "Dr. Gerald N. Johnson, electrical engineer" <[email protected]>
To: "Dave Brown" <[email protected]>
Cc: <[email protected]>
Sent: Sunday, July 06, 2003 12:47 AM
Subject: Re: [Collins] Which AM transmitter to go with S-line?

> Certainly is heresy and Art wouldn't have allowed it or it would have
> been a factory option for the transmitter as it was for the receiver.
>
> Fundamentally AM requires unbalancing the balanced modulator to pass
> carrier and probably bypassing the SSB filter to pass carrier and the
> other sideband. Remember the carrier level has to be 1/4 the
> transmitter's PEP capability.
>
> Its easiest (to get back to SSB) by switching in a DC bias to the
> balanced modulator. Bypassing the filter can cause more problems in lack
> of unwanted sideband suppression.
>
> I recall there was such a mod in QST about 40 years ago. In a Hints and
> Kinks column.
>
> I still prefer the performance of SSB sans carrier so I wouldn't abuse
> my 32S1 that way. It works fine with the antique WE model 2A legless key
> too.
>
> 73, Jerry, K0CQ, Technical Advisor to the CRA
> -- 
> Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
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