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[Amps] 2006 ARRL Handbook

To: "AMPS" <amps@contesting.com>
Subject: [Amps] 2006 ARRL Handbook
From: "Bob Maser" <bmaser@tampabay.rr.com>
Date: Fri, 7 Oct 2005 17:20:05 -0400
List-post: <mailto:amps@contesting.com>
After a month wait, my ARRL 2006 handbook finally arrived.  I have been 
looking forward to  looking at the 3CX1500D7 amplifier designed and 
constructed by K8RA, Jerry Pittenger.

The most original section of the amp was the use of an automatic tuned input 
sold by LDG Electronics.  Jerry chose the 100W version whereas I would have 
opted for the 200W one that LDG offers, which would handle the 200W exciters 
that are available from Japan these days (when is TenTec going to wake up?). 
Also, why put in any automated tuned input?  My exciter already has one. It 
may not be as smart as the LDG tuner, not does it have >4000 memory 
capability but it will look for a better setting if it senses high SWR.  The 
LDG costs ± $250.

I don't understand how the step start circuit is supposed to work because 
the circuit shown keys both K1 and K2 simultaneously instead of sequenced. 
I assume they drew the schematic wrong because K1, which is supposed to get 
things going, should have been connected before the time delay relay, not 
after it, as is K2.   Also, there are far too many errors in the component 
labeling.  T2 and T3 are identified in one way on the schematic and reversed 
in the text.  The 4 Crydom solid state relays shown in the picture are 
described as Potter/Brumfield in the text and they are shown as 2 relays in 
the schematic.  The design calls for a 50ohm 50watt glitch resistor in 
series with the B+.  He says that for example, if 5A is called for from the 
RF deck, this will result in 1250 watts needing to be dissipated and the 
resistor will quickly fail.  I think that a better description would have 
been "a deafening explosion causing the power supply to levitate off the 
floor with the shrapnel destroying everything nearby" would be more 
appropriate,  at least that's what mine sounded like during some "debugging" 
at my QTH.

All this probably sounds like gibberish if you haven't seen the new 
handbook.  If so, please excuse the use of bandwidth.

Bob Maser  W6TR 

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