[TenTec] Delta 580 Questions
Winston F. Jones
Thu, 22 Jun 2000 19:22:13 -0000
I have a Delta 580 and have never had the problems you described. From your
description, the problem is apparently a parasitic oscillation in the final
amp. I'm interested that you have no problems with a dummy load. What type
antenna are you using and what level of SWR? Are you using open wire
feeders? Is the chassis grounded? I once had a similar problem with an
Argonaut 509, using a Windom antenna. Too much RF was getting back into the
shack and my rig wasn't grounded and no tuner.
Hope this helps.
73, Winston K4CWQ
----- Original Message -----
From: Bob & Linda McGraw K4TAX <RMcGraw@blomand.net>
Sent: Thursday, June 22, 2000 04:14 AM
Subject: [TenTec] Delta 580 Questions
> In trying to get an old Delta 580 running I've run into an instability
> on the 10 meter band. The PA takes off into a sing once I hit it with
> some drive. Reducing the drive to zero does not cause the output to go
> away. Oscillation is in the 10 meter band, but the PA is maxed out at
> about 90 watts. ALC light is on. The only way to stop it is to return
> it to receive. The PA is stable with a purely resistive load on 10
> meters. Connect an antenna with a little reactance, bring the drive up
> and it bangs to the rails. I've checked internal connections etc.
> Removing the output cable from the low level amp to the PA will stop the
> oscillation. Looking at the output of the low level amp, it seems
> stable with the PA unplugged.
> All other bands look clean and stable. Any clues or suggestions will be
> Thanks in advance.
> Bob K4TAX
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