And, just to complicate things a bit, the 4CX250R is stated to provide
more output than the 4CX250B. I think it is rated for repeater usage,
although the bias and characteristics are different than the 4CX250B.
73, Colin K7FM
On 12/28/2014 1:34 PM, Fuqua, Bill L wrote:
I suspect when EIMAC came out with the 7034 they wanted to suggest that they
were a good replacement for the
4X150A. Military particularly wanted to use the same part number when replacing
tubes in their radios, and I suspect that
EIMAC wanted to not only promote the 7034 they wanted to make one tube type
rather than 2.
There are subtle differences between the two tubes, besides plate
dissipation limit. The characteristic curves for the 4X150A does not show any
area where there is a negative flow of screen current, while this is an obvious
issue some times with the 7034 and 4CX250B.
This could be a problem in some cases when interchanging these tubes. There are
other differences, one is that
when operating the 7034 at 500MHz it does produce the same output power but
requires 1/3 the drive power.
73
Bill wa4lav
________________________________________
From: Amps [amps-bounces@contesting.com] on behalf of Colin Lamb
[k7fm@teleport.com]
Sent: Sunday, December 28, 2014 8:15 AM
To: Peter Voelpel; amps@contesting.com
Subject: Re: [Amps] Power from Pair of Eimac 4 x 150 a / 7034?
"The Eimac data sheet does not confirm that
http://www.r-type.org/pdfs/4x150a.pdf
The RCA 4X150A/7034 data does:
http://pdf1.alldatasheet.com/datasheet-pdf/view/241849/ETC/7034-4X150A.html";
The RCA data sheet refers to a 4X150A only, which is a different tube than the
4X150A/7034.
73, Colin K7FM
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