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[Amps] Yaesu Quadra power output / meter accuracy / serial port

To: <amps@contesting.com>
Subject: [Amps] Yaesu Quadra power output / meter accuracy / serial port
From: "Mark Hill" <g4fph@mjha.co.uk>
Reply-to: g4fph@mjha.co.uk
Date: Wed, 11 Feb 2009 10:27:22 -0000
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Folks,

According to an external power meter, my Quadra amp seems a little shy at
making its rated output on the lower HF bands.  One these bands, the power
meter display in the Quadra seems, however, to mostly to paint the 'up'
side:

Band / Drive / Quadra meter / Bird meter
160 / 50 / 1100 / 900
80 / 60 / 1100 / 950
40 / 65 / 1100 / 980
30 / 45 / 1100 / 960
20 / 50 / 1100 / 960
17 / 40 / 960 / 1050
15 / 40 / 900 / 1050
12 / 45 / 1050 / 1100
10 / 35 / 800 / 1000

Pressing the amp with more drive, I can (just) get it to spec. as told by
the Bird but, in so doing, I suspect any attempt at linearity lies bleeding
in the dust.  Interestingly, above 20 metres, the Quadra power meter seems
to switch into pessimistic mode.  Reckoning that the Bird is at best
accurate to 5% of FSD (and I was using a 2500H slug which was not ideal) and
the power meter in the amplifier is probably more like 10%, I'm not overly
concerned as it's all near enough for jazz.  However, I wondered whether
anyone on the reflector that has made similar measurements and would care to
comment?  I believe there was an ARRL product review of the Quadra back in
Jan. 2002 which might have shed some light, but I can't find a copy on the
Web.

Having recently acquired a service manual for the Quadra, I note that there
is a second serial port on the main CPU, the TX and RX lines to which are
(possibly!) brought out to pins 13 and 14 respectively on the band-data 2
(15-pin D-type) connector. I say possibly because there is conflicting
information on the two CPU card circuits included in the manual.  Has anyone
ever investigated what data these lines might carry?  I ask because I drive
the Quadra from a Kenwood TS-2000 which is part of my Internet Remote Base
setup and would love to be able to get some data back from the amplifier
telling me what it was doing when in operation as I dislike flying blind.

Regards,

Mark.

*******************************************
Mark Hill - G4FPH
E-mail: g4fph@mjha.co.uk
Current web pages at: www.g4fph.net
Old web pages at: www.qsl.net/g4fph
----------------------------------------------------------------------
Dipoles resonant on 1940 / 3685 kHz
----------------------------------------------------------------------
Remember - SIDE for HV safety:
S witch off
I solate
D ump
E arth
*******************************************


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