[OT] 15m self oscillation

[mikerodgerske5gbc]

Not necessarily with a k3 but any rig. I and others have had issues with a 706 on 15 or 17 and I don't remember which.
I had a weird swr issue and maybe self oscillation on 15. Blew my lpa board again.( it's my understanding that there is no swr protection for that board yet because of so few problems but this my third).
I don't know if this could be caused by a dirty roller inductor, I'm going to clean it.
When I switched over to the 706 I noticed intermittent the cross needles go straight up. May have been self oscillating, don't know. I believe they would stay straight up with no modulation.

Ideas?
Thanks

Mike R

Sent from my spy ring
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[Don Wilhelm-4]

Mike,

The first response is "what happens if you transmit into a dummy load".
If the problem disappears when connected to a dummy load, you either
have a parasitic oscillation or you have  problem with your antenna system.

Since this situation occurs with multiple transceivers, I highly suspect
an antenna system problem.  An antenna analyzer may reveal the problem.

73,
Don W3FPR

On 7/21/2011 7:19 PM, Mike Rodgers wrote:

> Not necessarily with a k3 but any rig. I and others have had issues with a 706 on 15 or 17 and I don't remember which.
> I had a weird swr issue and maybe self oscillation on 15. Blew my lpa board again.( it's my understanding that there is no swr protection for that board yet because of so few problems but this my third).
> I don't know if this could be caused by a dirty roller inductor, I'm going to clean it.
> When I switched over to the 706 I noticed intermittent the cross needles go straight up. May have been self oscillating, don't know. I believe they would stay straight up with no modulation.
>
> Ideas?
> Thanks
>
> Mike R
>
> Sent from my spy ring
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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[Phil Salas]

"...I and others have had issues with a 706 on 15 or 17 and I don't remember
which.
I had a weird swr issue and maybe self oscillation on 15..."

There was an instability problem with the IC-706MKIIG on 15 and 17 meters.
Icom published a service bulletin on this (Bulletin 928).  It has to do with
making a better internal ground in the radio.  I have a copy of this service
bulletin on my website, as well as an easier way to accomplish the fix.
Check the "Equipment Modifications" section at www.ad5x.com.

Phil - AD5X

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