[Mobile-Portable] self -QRM on 40m

[Art Clemons]

ka5mgl@conwaycorp.net wrote:
> Hi everyone; 
> 
> My HF mobile installations works well, but suffers from one annoying problem.  On 40m (only), the tachometer moves with my speech;  like a VU meter.   The rig is an Icom 706MKIIG feeding a hamstick mounted off the rear bumper of 1990 Nissan KingCab pickup.  The SWR is less than 1.5.  The same thing happens elsewhere on 40m -- but *only* on 40m.  Operating on 75m, 20m, and 10m doesn't do this.  
> 
> Thoughts, comments, suggestions?


Well, if nothing else is going crazy, you can try ferrites on the tach 
cable.  Of course this problem does indicate the likely need for a 
better ground system in your vehicle but if you're otherwise happy, 
ferrites should work.