[Elecraft] K2 cellphone interference

[Jim Brown]

On Mon, 09 Jun 2008 08:43:25 +0100, David Woolley (E.L) wrote:

>Incidentally, this thread has shades of the pin 1 problem thread, 
>because the K2 case violates the Faraday cage principle at UHF.

The pin 1 problem and the shielding problem are two VERY different 
coupling mechanisms, although they have in common antenna action 
and RF detection. The shielding problem lets the RF in the box, 
where it couples to internal wiring by antenna action. The pin 1 
problem takes RF that has been put on EXTERNAL wiring by antenna 
action and puts it onto internal wiring because the shield goes 
inside, not outside. 

I agree that the seams are the likely open door in the shielding. 
As noted, the proper hardware to seal the box at these frequencies 
is not inexpensive. Ham gear need not be "perfect" enough for a 
high stakes military mission or a flight into space. It must be 
designed to meet a budget. IMO, the shielding is sufficient for 
all ham installations I can think of as long as the ham maintains 
a reasonable distance between the rig and any GSM or TDMA phones. 
:) 

The pin 1 problem and the unshielded transformers, however, are 
another issue. This can readily cause problems at HF and at 
baseband (hum, buzz, RFI), and should be fixed. Luckily it is easy 
to do that by modest redesign that can actually REDUCE the cost. 

73,

Jim Brown K9YC