[Collins] 572B and the 30L1

[Glen Zook]

The original post was about replacing the 811A tubes
in the 30L-1 with 572B tubes.  My original reply was
to be careful when using the Chinese manufactured 572B
tubes in linears like the Collins 30L-1 linear and
Heath SB-200 that have them mounted horizontally
because those particular tubes are notorious for being
manufactured with the elements not in the same plane
as the original U.S. manufactured tubes and that the
elements tend to "sag" and short out.

In the 30L-1 linear you won't get any more power
output from 572B tubes than you will with the original
811A tubes because the power supply just cannot put
out any more.  In the Heath SB-200 you will definitely
get only about half of the power if you put in 811A
tubes in place of the 572B tubes.  The major benefit
of replacing the 811A tubes in the 30L-1 linear is
much longer tube life.

By the way, you do know that the 30L-1 linear was not
the first equipment produced by Collins Radio Company
with the model number 30L-1.  When the 75A4 came out
Collins announced the 30L-1 SSB transmitter and ran
full color advertisements in various amateur radio
magazines, in the ARRL Amateur Radio Operator's
Handbook, etc.  However, after the ad "blitz" Art
Collins decided to change the model number to KWS-1. 
If you look closely at the early KWS-1 ads you will
see that the unit pictured actually has 30L-1 on the
front.

Also, Collins advertised the 32W-1 SSB exciter at the
same time.  The 32W-1 was the 30L-1 (KWS-1) without
the linear amplifier.

Glen, K9STH


--- Frank <frank at k5dkz.com> wrote:
Have you considered using 811s?
 
They are cheaper, run cooler, fit better, and you get
just about the same power out.









Glen, K9STH

Website:  http://k9sth.com


 
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