Date: Sat, 3 Nov 2012 12:18:22 -0700
From: "Jim W7RY" <w7ry@centurytel.net>
To: "AMPS" <amps@contesting.com>
Subject: [Amps] Drake L4B and L7 QSK Board
The Drake L4B and L7 QSK Boards are here!
EBay item number 281016230575
Or http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=281016230575
Thanks and 73!
Jim W7RY
## slick. I own 4 x L4B’s. The only problem with using a reed relay for the
input side
is that you then can’t calibrate the internal wattmeter ! To calibrate the
internal wattmeter
in the L4B, the amp has to be on bypass, and another amp with say 1 kw applied
to the drake
amp...then an accurate external wattmeter + dummy load etc.
## That implies the L4B must be able to handle a kw on bypass mode, which the
oem 3PDT
will easily do. I string several L4B’s nose to tail, in series, and then tune
em up on different bands.
A simple rotary switch, whose input goes to the xcvr’s key line..and has
several outputs, one per amp.
That ensures that only one amp can ever be keyed at any one time. In normal
operation, each amp
is switched to operate mode, The 12 position rotary switch not only is used
to activate each amp,
it also places em in standby mode.
## IE: pos #1 = amp 1. Pos #2 = bypass Pos #3 = amp 2 etc etc.
Positions 1-3-5-7 are used
to activate amps 1-2-3-4.
## Positions 2-4-6-8-10-12 are not wired to anything = bypass mode. This
way, any amp can easily be switched
from operate to standby, by simply rotating the 12 pos switch either one
position CW or CCW.
## for qsk use, or just fast, quiet vox, I used TWO vac relays, one for the
input, and another one for the output.
The reed relay is simply replaced with another vac relay.
## But if you only have one amp, and no requirement to calibrate the internal
wattmeter, but want QSK, the new board
is the ideal ticket. It’s a well designed board, I like it.... and it
eliminates the mech clunker.
Jim VE7RF
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