[Elecraft] K3: 6M SSB audio hash

[Jim Brown]

On Sun, 8 Jun 2008 20:33:15 -0400, Joe Subich, W4TV wrote:

>I'm aware that a short jumper is "wrong" from the purist point 
>of view.  However, it is much better than mic return that is 
>held above ground by an RF choke!   Most of the rigs I've seen 
>have relatively good grounding for the "PTT ground" - the jumper 
>is 1 cm or less or the circuit board layout includes the "PTT 
>Ground" pin in a wide (large) ground plane.  

>Fortunately, most amateur equipment is not operated in strong 
>(multi hundred KW ERP) UHF fields.   

This is NOT purist. The cell phone interference being discussed in 
another thread could easily be the result of a jumper that short. It is 
in those mics!  The field is determined by inverse square law. A 2W 
radio (cell phone) puts a pretty strong field at 6-12 inches. Back in 
Chicago, I ran 160M and 80 on a long wire that ended at the transmitter. 
With only 13W (K2 barefoot) I could lock up the keying loop between the 
computer and the radio. 

>Which article?  I used many of the Neuman and AKG mics 30 years ago 

The AES paper on RFI in condenser mics has the greatest detail. I've 
summarized it and used it tutorially in other publications. 

73,

Jim Brown K9YC