What version of PowerSDR are you using?  Changes added today to SVN
requires the PA to be recalibrated. 


-Tim

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Mark Amos
Sent: Wednesday, August 01, 2007 6:52 PM
To: FlexRadio@flex-radio.biz
Subject: [Flexradio] Transmit problem

Flexers,

I'm having a transmit problem with my SDR1000.  
Here's the lineup:
SDR1000 with all the options (ATU, PA, RFE, transverter) Edirol FA66 USB
cable All audio lines isolated between computer, Edirol and the radio.
Ferrite clamps on all of the audio and control cables.
Radio gear, computer, tuner, etc. all connected to common shack ground.
Palstar tuner
Butternut vertical

The problem is that on 40 Meters, when I key the transmitter, the
forward power goes up over 200 watts with any setting over 10W "drive"
setting.  At that point the SWR (as shown on the Palstar and on
PowerSDR) goes through the roof, and the power output from the Flex does
as well.  It ONLY happens on 40 meters and ONLY when connected to the
antenna (i.e. there is no problem transmitting into a dummy load.)

I substituted a dummy load at each location between the transmitter and
the antenna and thus ruled out issues with the coax, bulkhead
feedthroughs, tuner, etc. 

So, it appears to be an antenna problem (perhaps a short or open that
only shows up at power above 10 watts...)

What puzzles me is the SDR1000 cranking out such high power (as reported
by PowerSDR, the tuner and an in-line wattmeter) under a high SWR
condition.  PowerSDR shows "High SWR" on the panadapter display, but
doesn't cut back the power.  

So, here's my question: would an RF feedback / antenna problem account
for this behavior?

Mark



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