[Milsurplus] Re: PRC-25 Final

[Brooke Clarke]

Hi Hue:

Yes, I've given it a little thought.
The DC to DC converter (A1) has two outputs the +125 V for the final tube and 
also -45 V for the preceding two pre amp stages.  So if you just replace the 
final tube you still need the DC-DC converter for the prior stages.

To get the full benefit the last three amplifier stages (A7, A6 & A29) would 
need to be replaced.  But A7 and A6 are coupled to the mechanical tuning knobs. 
  It would be a complex thing to do just to end up with a PRC-77.

But a solid state version of the 2DF4 sounds like a good idea.  Note that power 
out is not very important for man pack use of the radio since the antenna size 
and height above ground sets the range.  For vehicle or fixed base use a 
"hotter" replacement for the final tube would be good and in that case power 
consumption would not be an issue.  That means there should be two versions:
1) manpack where the power out is about the same
2) vehicle or base station use where 5 or 10 watts would be nice.

Have Fun,

Brooke Clarke, N6GCE
http://www.PRC68.com
http://www.precisionclock.com

Date: Sun, 3 Jun 2007 14:45:17 -0700
> From: "Hue Miller" <kargo_cult at msn.com>
> Subject: [Milsurplus] Re: PRC-25 Final
> To: <Milsurplus at mailman.qth.net>
> Message-ID: <BAY125-DAV3F67FE8B041FFD76CF393E4220 at phx.gbl>
> Content-Type: text/plain;	charset="Windows-1252"
> 
> I understand the PRC-25 uses a hollowstate final. That would seem to be less than
> ideal, as it #1 will need to be replaced somewhere down the line, altho the actual
> duty hours of your PRC-25 are less than when it was working for a living, and #2
> the DC-DC supply required for the B+ has to be a power waster.  Has anyone
> thought about solidstating the final? For a watt or two level, it can't be that difficult
> a proposition.  -Hue Miller