[NLRS] [Fwd: [VHFtubeamps] Need some help with a tube cross-ref] MORE

[Dr. Gerald N. Johnson]

On Thu, 2006-09-07 at 03:19 +0000, Scott wrote:
> 
> Maybe someone can help out?
> 
> 
> 
> -------- Original Message --------
> Subject: [VHFtubeamps] Need some help with a tube cross-ref
> Date: Wed, 6 Sep 2006 21:38:48 -0500
> From: Jim Strohm <jstrohm at ev1.net>
> Reply-To: VHFtubeamps at yahoogroups.com
> 
> These shining dragon's teeth showed up in my latest ebay acquisition.
> 
> Eimac Y-739A, three each
> 
> I have been able to learn that they are coaxial-base microwave planar
> triodes, air-cooled, and are similar to a CPI 8940.  They look like
> about 200 - 300 watts CW and from what little I've been able to find,
> full rating power would be around 1200 MHz.  The chassis was marked
> "20kW Microwave Transmitter" and based on the size of the power
> supply and some other markings, these would be the right size for a
> pulse microwave RF generator of that power range.
> 
> I'm looking for a data sheet, ideally.  I can reverse-engineer
> voltages from the chassis they came out of, but data sheets make it
> easier, especially if they include a test circuit.
> 
> I have three of these with sockets and individual filament  and grid
> regulator supplies, and they look new -- but the chassis has almost
> 1300 hours on the hour meter.  These look like they've never seen use
> -- none of the usual scorched dust marks on them.  I'm thinking that
> one would be a whopping better tube than a 2C39 for use on 1296, and
> while it would not work in the same socket or cavity, might almost
> work on the same voltages.
> 
> Email or post here, please.
> 
> Jim N6OTQ
> 
OK, so I called the suggest number. The menu has changed, its not 1, but
3. I talked to a live person who dug into the files and came up with a
very tentative marked up rough draft of the Y-739 spec sheet. They
currently make Y-739E,F, and G. She will be sending me copies of the two
documents. The mark up dates from about 1973 to 1975. It might be a
really good idea to see if further tubes can be found before building a
PA from these.
-- 
73, Jerry, K0CQ,
All content copyright Dr. Gerald N. Johnson, electrical engineer