{Collins} Re: 30S-1 Screen voltage mods



The 30S-1 is a cathode driven amplifier with the screen at ground.  The
screen voltage is applied to the cathode and the RF drive is added to the
screen voltage.  Increasing the screen supply exceeds the screen voltage
rating when the amplifier is driven.  While you can add one or two dB in
power by increasing the screen voltage you will also be increasing the
intermodulation distortion by about 10 to 15 dB.  The net result is less
than one S unit power increase and about two S units of increased distortion
in adjacent frequencies.  The 30S-1 is the has the lowest IMD of any amateur
amplifier and increasing the screen supply changes this wonderfully linear
amplifier into an average amplifier.  Power should not be the only
consideration.

73, Alan - K6RFK

----- Original Message ----- 
From: "Benthic" <benthic@xxxxxxxxxxx>
To: <COLLINS@xxxxxxxxxxxxx>
Sent: Sunday, December 03, 2006 6:20 PM
Subject: {Collins} 30S-1 Screen voltage mods


> Hello everyone -- I'm looking for documentation describing the
> modifications for a 30S-1 amplifier, i.e., a screen voltage increase
> which leads to greater effective output.  Would someone on this list
> happen to have this information?  Many thanks.
>
> Regards,
> Jim
> N3ZM@xxxxxxxx
> Sponsored by the Collins Collectors Association
http://www.collinsradio.org
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Sponsored by the Collins Collectors Association http://www.collinsradio.org
Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central
Fri: 3.895 Mc-2000 Pacific / Sun: 14.263 Mc-2000 UTC
1st Wed (of the month) AM Net 3.880 Mc-2000 local (ET, CT, MT, PT)
Sun AM Net: 29.050 Mc-1200 Central






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