[Swan] Re: Swan 700CX power measurements

[Dave Meitzen]

Thanks -- Mine was converted to 6LB6 finals - I wonder if this makes a
difference? When the unit is in TRAN mode the PA Plate controls do not do
anything? What is the TRAN position there for?

Thanks
Dave

-----Original Message-----
From: swan-bounces at mailman.qth.net
[mailto:swan-bounces at mailman.qth.net]On Behalf Of Mark Shaum
Sent: Friday, November 04, 2005 6:16 AM
To: swan at mailman.qth.net
Subject: [Swan] Re: Swan 700CX power measurements


Dave,

I have a 700CX with SS-16B fancy filter.  Conequently the tune-up procedure
is modified even more due to the inability to insert "full" carrier in the
ususal tune-up mode.  This is why the manual addendum for 500's and 700's
with the narrower SS-16 filter does not even recommend trying them in AM
transmit mode (carrier plus one sideband).

Anyway.. with new, beefier filter capacitors in the 117X/230X power supply
and a pair of new old stock 8950's in place, the annual maintenance card I
keep in my manuals for each rig notes that the 700CX managed 325 watts CW
output and 420 peak SSB watts out on 75 meters a year ago.  This is within
the realm of original advertising of 700 watts peak INPUT power.  Hard to
measure actual peak power input without measuring peak plate current, which
I have not bothered to do.  I figure 60-65% efficiency is about right on
lower frequencies for class AB1 or AB2 finals in these rigs.

For comparison, my 500CX card lists a measurement of 280 peak watts output
on the same band (75m) with a stock power supply.  I don't have what I can
confirm as top condition finals for the 500CX (no spares) so can't say if
this is normal or not.  I did not check CW output at the time the 500 was on
the bench over a year ago.

If I were to use the 700CX for any frequent operation (I would if it had
RIT, which I could add, but no time..) I would probably figure out a method
to reduce the screen voltage on the finals and run it at reduced power.  I
do NOT want to start a search again for another good pair of 8950's!

73! - Mark K9TR
http://www.qsl.net/k9tr

----- Original Message ----- >
> I think 220 watts for a couple of sweep tubes is pretty strong. BTW this
> unit has been modified to use the 6LB6 in place of the 8950's.
>
> Any words of wisdom will be greatly appreciated. Has anyone seen 700PEP on
> this rig?
> Thanks
> Dave


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