[Boatanchors] GB> Is 4657 same animal as the 8072?

[Sandy]

I really never worked in the land mobile department for an amount of time 
except to help out when I wasn't on a ship service call!

Cmc (Canadian Marconi Co.) at one time had a 450 Mhz mobile radio that used 
the 8072.  Never saw any of these little bottles in any other gear.  I 
suspect Motorola must have made a higher powered UHF Xcvr. that worked up in 
the 450-470 Mhz band with the 4657.

I remember when RCA went belly up (the electron tube division in Harrison, 
NJ) and we started getting 8122's with Burle's name on them.  We did have 
trouble with the 8072's in the land mobile rig and also with the 8122's n 
some JRC (Japan Radio Corp.) ship transmitters.  They seemed to prefer them 
rather than the old time tested and proven workhorse, the 4CX250B, which a 
lot of gear back then used.

I'll have to test the heater in this 4657 out and see what current it is 
consuming.  That will tip me off if it runs something other than the 1.3 amp 
range in the 8072.

73,

Sandy W5TVW

----- Original Message ----- 
From: "Scott Johnson" <scottjohnson1 at cox.net>
To: "'Sandy'" <ebjr37 at charter.net>; "'Glowbugs reflector'" 
<glowbugs at piobaire.mines.uidaho.edu>; <boatanchors at mailman.qth.net>
Sent: Sunday, October 18, 2009 7:21 PM
Subject: RE: GB> Is 4657 same animal as the 8072?


Sandy-
RCA (Now Burle) started with the 8072 conduction cooled tetrode, and made
all sorts of tubes, both conduction colled and forced air cooled,pins or
coaxial base connections,and at least two different heater voltages (13 and
26 V, based upon the 8072 design.  The 8072 is 13V, conduction cooled, the
8121 is 13V, transverse air cooled, the 8122 in 13V, axial forced air
cooled, the 4677 is like a 8122 but 26V heater and with a much larger axial
cooler for low velocity cooling, the 6884 has a coaxial base with transverse
air cooling and a 26V heater,6816 is a 6884 with a 6.3V heater etc., etc.
If a 4657 looks like an 8072, it is probably a 26 V heater variant, or
perhaps pulse rated, or some other difference. Also these tubes are not
planar construction, they are coaxial.

Regards,
Scott W7SVJ

-----Original Message-----
From: owner-glowbugs at piobaire.mines.uidaho.edu
[mailto:owner-glowbugs at piobaire.mines.uidaho.edu] On Behalf Of Sandy
Sent: Sunday, October 18, 2009 2:43 PM
To: Glowbugs reflector; boatanchors at mailman.qth.net
Subject: GB> Is 4657 same animal as the 8072?


Some of you land mobile radio people may be able to tell me if.......a
Motorola 4657 planar conduction cooled beam power tube is equivelent to the
RCA 8072 tube?

I have several of these NOS and curious to know.

All indications are they are the same, but I'd like to hear it from somebody

that has dealt with them before.

73,

Sandy W5TVW



************ The Glowbugs E-mail List Website is: ***************
*********** http://www.mines.uidaho.edu/~glowbugs/ **************
*** Send subscribe and unsubscribe requests to this address: ****
************** majordomo at piobaire.mines.uidaho.edu **************




--------------------------------------------------------------------------------



No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.422 / Virus Database: 270.14.20/2444 - Release Date: 10/18/09 
09:04:00