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Re: LA-1K overdrive warning


George Robbins
 

开云体育

I have driven my LA-1K with my IC-7300, my IC-7610, and my Kenwood TS-830S – all without a band change cable.? I let the amplifier sense the band and frequency.? Never any problems, not one.? Until recently I had two LA-1K amps in parallel with the Palstar splitter/combiner handling those chores.? I drove that configuration with both my 7300 and my 7610 – again with no problems.? There is a photo of that configuration on my QRZ.com page.?
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George
W7GDK.?
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From: Jerry Webb
Sent: Wednesday, March 8, 2023 12:07
Subject: Re: [la1k] LA-1K overdrive warning
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I agree with Bob's evaluation.? I used an Icom 7600 with my LA-1K? w/o and issues. My TS-890S has no issues.? I suspect that the SDR-function on the IC-7610, and it's "younger kin" IC-7300, might be the design problem.
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On Wed, Mar 8, 2023, 13:54 Thomas NE7X <thomasne7x@...> wrote:
I am using an ICOM IC-7610 with my LA-1K and HF-AUTO tuner. I have been having intermittent "OVERLOAD" issues. I can run the amp for several hours, then it starts "OVERLOADING" every time I speak into the microphone. When I AC power cycle the amp and back on, everything is back to working normal. Then a few minutes later, it goes into OVELOAD again. It does it mostly on SSB, however I have seen it happen also when first key on CW and RTTY.

I called Palstar tech support and talked wtih Mark. He indicated ICOM IC-7300 and IC-7610 transceivers put out a HIGH PEP power spike on SSB and CW key-ups which exceeds the threshold value of the amplifier input station, causing the LA-1K to go into OVERLOAD.? He suggested using an ALC connection between the ICOM transceivers and the LA-1K, and playing with the ALC settings on both the ICOM transceivers and the LA-1K to find a value that stops the RF OVERLOAD peaks. He also suggested flattening out the transmitter audio using compression and mic gain levels, so no high RF peaks are being produced at key-up.

I have been trying Mark's recommendations and the jury is still out. Still having intermittent OVERLOAD issues, however not a frequent. I'm still trying to find that perfect sweet spot.

Another local ham said maybe I am having floating RF in the shack causing the amp to go into OVERLOAD. I checked all my cables, connections, and I have everything connected to earth ground buss in the shack. No sure what else I can check there.

Anyone else have any input or recommendations?

Thomas NE7X...

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