[Boatanchors] compairson of 5R4 tubes

[Richard Knoppow]

----- Original Message ----- 
From: "John King" <k5pgw at yahoo.com>
To: <boatanchors at mailman.qth.net>
Sent: Sunday, December 30, 2012 6:36 AM
Subject: [Boatanchors] compairson of 5R4 tubes


I note that there are various 5R4 tubes with different 
letters after the 5R4, which I suspect refers to the bulb 
shape, height or other style designations. I am going to 
order a number of 5R4 tubes for older transmitters such as 
DX 100s and early Viking transmitters. Is there any 
difference other than style between the various 5R4 tube 
versions? Some versions are significantly cheaper than other 
versions. What are your thoughts regarding the best bang for 
the buck for these old boatanchor transmitters? Thanks and 
73, John, K5PGW

     I can't find complete data on the type in my tube 
handbooks but there were at least three variations:  5R4GY, 
5R4GYA, 5R4GYB, and the familiar 5R4WGB. The first three are 
in semi-pear-shaped envelopes with low-loss mica-filled 
bases, the WGB is in a special high-altitude envelope with a 
large gray base and heavy tubular envelope.  These were 
designed to work up to 100,000 feet.  The W in any receiver 
tube type number indicates it was supplied to a government 
contractor, there is no consistent meaning other than that.
     My experience is that the WGB is the most common and 
cheapest, the original brown-base GY the hardest to find. 
Any will work in the same socket.
     My experience is also that I've had more trouble with 
the WGY than with the others.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com