|[AMRadio] Mod Transformer Available|
dogfaces at comcast.net
Mon Sep 26 21:58:12 EDT 2005
The model number is RCA 901769-501 and it has the original paperwork with
it. It says that the secondary current is .198 amperes, so I guess you need
2,500 volts to get 500 watts?? There was a page on the internet that said
max current for this beast is 450 ma., so I don't know if that is a
practical and not theoretical conclusion. Thanks for looking.
----- Original Message -----
From: "James M. Walker" <chejmw at acsu.buffalo.edu>
To: "Discussion of AM Radio" <amradio at mailman.qth.net>
Sent: Monday, September 26, 2005 3:40 PM
Subject: Re: [AMRadio] Mod Transformer Available
> I have that transformer as well, it is in the pair of 805
> modulator stage for my HB 304TL rig. The system runs at 1500 VDC
> For the plate supply to the modulator and also the RF deck.
> I rewired the speech amp to a pair of 2A3s to drive the 805s.
> I haven't done an audio sweep to check the range yet however.
> The ratings are 5500 primary 1.14 KVA, and 5500 secondary
> .198 Amp DC.
> ----- Original Message -----
> From: "Donald Chester" <k4kyv at hotmail.com>
> To: <amradio at mailman.qth.net>
> Sent: Monday, September 26, 2005 3:22 PM
> Subject: RE: [AMRadio] Mod Transformer Available
> > > I have a 1940s vintage 500 watt modulation transformer made by RCA
> > >sale. It has 5700 (approx.) ohm P-P primary and a 5700 ohm secondary.
> > >would like $250 plus shipping. Local pickup near Philadelphia
> > >I checked the windings and they have continuity. There is also another
> > >winding of a higher impedance maybe for screens. If interested please
> > >contact me directly at dogfaces at comcast.net
> > After WW2 those transformers flooded the market as surplus. You could
> > hardly attend a hamfest without seeing at least one.
> > They are not broadcast quality, but the quality is probably at least as
> > as typical trarsformers sold for ham radio use.
> > For years I wondered what they came from or what they were manufactured
> > go into. A couple of years ago I found out that they were not used in
> > transmitters at all, but in tone modulated CW rigs on board Liberty
> > during the war. So they were desgined to pass only a single tone
> > frequency, but they work passibly for voice. I would still prefer a
> > transformer designed for voice use, preferably something from a
> > transmitter.
> > Don k4kyv
> > ______________________________________________________________
> > AMRadio mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/amradio
> > Help: http://mailman.qth.net/mmfaq.html
> > Post: mailto:AMRadio at mailman.qth.net
> > AMfone Website: http://www.amfone.net
> > AM List Admin: Brian Sherrod/w5ami
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio at mailman.qth.net
> AMfone Website: http://www.amfone.net
> AM List Admin: Brian Sherrod/w5ami
More information about the AMRadio mailing list
This page last updated 13 Dec 2017.