[ARC5] Receiver Voltages.

[Glen Zook via ARC5]

Unfortunately, some ISPs have stopped allowing editing of E-Mail replies.  Why?  I have no idea.  My "regular" ISP, sbcglobal.net is one of those.  Yahoo still allows editing. Glen, K9STH

Website: http://k9sth.net
      From: Brian <brianclarke01 at optusnet.com.au>
 To: Ian Wilson <ianmwilson73 at gmail.com>; Mike Feher <n4fs at eozinc.com> 
Cc: ARC-5 Maillist <arc5 at mailman.qth.net>; AKLDGUY . <neilb0627 at gmail.com> 
 Sent: Friday, May 1, 2015 9:17 PM
 Subject: Re: [ARC5] Receiver Voltages.
   
Hello Ian,

The supply to the Collins 51J family of receiver oscillators is not plate regulation; it is whole circuit supply regulation. Have a close look at the circuit; sure the circuit is fed by a 150 V regulated supply, but then there is an RC filter and then plate load resistors to each 6BA6.  Definitely NOT plate regulation. Care to have another throw of the die?

A VR tube works in cycles: as the Voltage applied reaches striking Voltage, the glow starts; but this causes a heavy current to flow and drops the Voltage across the tube below ignition and the low impedance becomes high impedance again ... and the cycle repeats. This is truly a noise generator, not a power supply noise attenuator.

Have you heard of tail trimming? Try it some time. Anyone reading this stream knows we are discussing Command receiver HT Voltages – we really don’t need reminding – and not trimming tails takes up a lot of bandwidth.