[Amps] RF ground

[Richard]

>"On single point grounding, you can have as many grounds as it is convenient 
>to
>have but you only want one lead connected to your equipment. If you have two
>leads like the power ground lead and your installed ground lead connected to
>your equipment you have created a ground loop."
>
€   I use a Hertz antenna  (end-fed multi half-wave; high feed-Z).  Equal 
currents flow into the antenna and the antenna tuner ground.  The lead to 
the ground system is 5' of two-inch wide copper strap (c. 200nH of 
inductance).  Thus, there is an RF voltage drop across the tuner ground 
lead.  If the tuner ground is connected to the radio ground, the radio 
becomes hot with RF.  I installed a coaxial choke balun to prevent RF 
from going back to the radio.  
>
>This sounds like you can't have a separate safety ground and rf ground.  
>This is a new one to me.  It sounds like you have to either clip the 3rd 
>prong on your power supply cord plug and use your rf ground or hook your rf 
>ground to your safety ground wiring somewhere and use the ac safety for all 
>your grounding.  Not getting this.
>
>I set my shack up in my basement and started out with a 1" tinned heavy 
>braided 8' strap from a copper bus at my equip. table to my cold water 
>entrance for rf.  cold water was a nice lead pipe coming up through the 
>concrete floor from outside.  Had rf all over the place; mic bites; 
>distortion on audio; linear didn't want to put out more than a few hundred 
>watts without distorting.  Put in coax line isolators (1:1 ununs) and 
>ferrite chokes all over everything in shack and at feed point--that helped  
>Ran a 22 foot 1/2" o.d. copper cable across my basement to 5 cu rods 8' long 
>outside, four in a square tied directly to one in the center.  All well on 
>80, 40, 20; low output from linear on 15 and 10.  Dismantled shack; moved 
>whole station across basement (cable making nice high XL "ant." on 15 & 10); 
>cut gnd cable to 6.5', gnd. bus down to 12" from 8', put xmatch and linear 
>right at the bus, one on top of the other, brought all rigs and p.s.s etc. 
>gnds over to the bus with 1" tinned braid.  Now everything puts out rated 
>limits es sounds beautiful.  Unless ur low power, I think you need a rf 
>ground--I'd try to get on the 1st floor or basement.  I know bc stations run 
>FM & TV txs from the tops of buildings but I'm not a prof. rf engineer.
>My 2 cnts but maybe only worth 1 SH green stamp.
>
>Rob Atkinson
>K5UJ
>k5uj@hotmail.com
>
>_________________________________________________________________
>Join the worldís largest e-mail service with MSN Hotmail. 
>http://www.hotmail.com
>
>_______________________________________________
>Amps mailing list
>Amps@contesting.com
>http://lists.contesting.com/mailman/listinfo/amps
>


-  R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, 
www.vcnet.com/measures.  
end