[Elecraft] Data transmission on 30 meters with PX3 problem

[John Oppenheimer]

On 09/02/2018 07:56 AM, Don Wilhelm wrote:
> That W3EDP antenna is a strong suspect, as is any off-center fed antenna 
> or end fed antenna.  They can produce large amounts of RF in the shack.

Hi Gwen,

Don is correct. The W3EDP with a large choke Balun, as pictured, between
the Unun and KX3 is an OCF Doublet with a resonant frequency of 11 MHz.
It is rather difficult, if not impossible, to isolate a dipole end
impedance using a choke Balun. The KX3, being at the high impedance
point on 30 meters, will experience a rather high RF voltage.

A way to determine if the rig is part of the antenna is to use what I
call a "touch test." Observe SWR while transmitting, if touching the KX3
antenna BNC jack causes the SWR to change, then the KX3 is part of the
antenna. At the extreme, the touch results with a RF burn. I have
experience RF burn at 15 watts.

John KN5L