10 meter SSB audio distortion

[Andrew Catanzaro]

I get excellent audio reports on my K2 audio on all bands but 10 meters.
People tell it sounds like RF is getting back into the radio.
I have the KAT100 tuner and an RF Works isolator that should prevent RF
from getting back into the radio, and the K2 itself is gorounded.  The disortion
is present with the Heil H-5 microphone element as well as the MH2 mike and the Heil
boom mike for the K2.  It happens at all settings of mike gain and/or compression.
It happens with or with out the KP100 amp in line.  The distortion is present at all power levels
and when the radio is driving a dummy load.

Suggestions?  

Andy W9NJY
K2 serial number 2651with all the A->B mods.
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[Stuart Rohre]

Is the mike cable shield grounded to the radio mike connector shell and thus
the radio case?
It should be to preclude RF effects.  It sounds like you have an unbalanced
or end fed antenna?
If that is a case a dipole/ doublet will be a better choice in that location
where you have some RF coupling back into the shack.  End fed antennas are
often a problem creating RF in the shack, as are coax fed doublet/ dipole.
Make sure the feedline is not an odd multiple  of a quarter wave, ie 8 feet
at 10m is a quarter wave and sure to cause a problem, and any odd multiple
like 24 feet, 40 feet, 56 feet, etc.
-Stuart
K5KVH


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