I hope this is ok to post on this reflector if not accept my apology.
Wanted to share this with the group and ask for any further suggestions.
Wanted to thank my mentor and friend NI0G for guiding in the right
direction.
Station description:
I have two rigs
FT1000mp
IC 765
Linear Amp
I am using a KAM dual port tic with hookup to hf radio and vhf radio for
local
packet.
Using a Astron Power Supply
2 meter radio
Both rigs have experienced rf feedback into the speakers as well as the
earphones.
Did not get this problem on cw.
Did not happen on low pwr but running amp and working SSB/RTTY I got
some
feedback into the speakers while transmitting..
I have tried using some toriods but saw no help.
I thought my problem was the cause of old grounding so I ran new
grounds to a new ground setup described below:
Placed 4 - 10 foot ground rods outside the basement wall.
purchased #4 copper wire from my local Home Depot store.
Connected #4 wire to all 4 ground rods and ran inside to shack.
Copper cold water pipe is too far from the shack.
Bought 1 inch copper strap and grounded tuner to amplifier then to #4
ground
wire. Next.
Ran a copper strap from the rig to the ground.
Problem did not go away with the new ground arrangement so I started a
hunt for the cause.
Next moved the Astron power supply and disconnect the vhf radio.
Problem appeared to clean up in 80meters on low and with liner but when
I went to 20 meters to chat with a friend in Brazil I used the linear
and the problem was back.
Well I cured one problem but now the problem moved.
Could not under stand what was going on but the lightbulb came on.
Only thing I had not done was remove the KAM cable from the back of the
FT1000mp. This cable provides the digital mode and the 25din cable from
the back of the KAM goes to computer.
Could it be the db25.. No.
I removed it from the Kam and prob was still there.
What's next?
Light bulb went on again and then Success:
The cable from the KAM to Ft100mp was still connect.
By removing the cable from the Kam to radio cleared up all feedback and
rf.
Next work today will be to run grounds to all equipment
KAM
Astron Power Supply
Ameritron Ant switch box
and anything else I can my hands on in the shack
While what I have said is not unique it does pay to use good grounding
methods on everything.
.Next thing my friend suggested is to try a ferrite on the Kam cable to
the FT1000mp.
Has anyone else experience this prob??? with the Kam to the radio ???
de
Mike
KQ0B
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