[Elecraft] can rf interference get into a k2?

[Jack Brindle]

Wow. Perhaps we can get a bit more helpful. Pretty much every wire  
going into or coming out of the K2 presents a very good possibility  
for RFI intrusion. This is true for any rig. The low-level microphone  
signals are a very good place for this to occur - for me it seems  
that having a regular microphone attached things work OK, but connect  
it to a sound interface box and you are asking for problems. The  
serial port KIO2 or KPA100's port has quite a few of these  
opportunities. Even the power cord could be a conduit for RF.

My own station suffers from RFI on 40 meters, where I have an antenna  
running just 20 feet over the K2/100. Through various methods of  
shielding, the use of ferrite cores and other methods, I have reduced  
this problem quite a bit. But I have yet to eliminate it (It's sort  
of become a crusade...).

There is a lot of information available discussing the subject. Jim  
Brown, K9YC, has an excellent collection of RFI information that I  
currently believe to be the best available on the web. There is a lot  
of information at his site, some directly discussing ham rigs, most  
discussing RFI in audio systems. See:

http://audiosystemsgroup.com/publish

One of the things Jim advocates is the use of twisted pair to carry  
signals in and out of the K2. By doing this, the signals essentially  
become carried in a differential mode of operation, where the  
interference tends to cancel itself out. I can't say this is the  
ultimate solution, but it is the direction I am taking my own station.

Good luck tracing down the problems. Some folks are really lucky,  
while others have a great learning opportunity for dealing with EMI  
and RFI. learning new things is what it's all about, right?


On Feb 2, 2006, at 5:59 AM, jferg977 at aol.com wrote:

> I'm having problems with rf interference when attempting to  
> transmit.  I have a list of possibilities which don't need exposure  
> here, but I do want to know if the K2 with the rear cover it comes  
> with with all of the unfilled openings can allow rf into a place  
> where it could be a problem?
>
> Should I block the holes?
>
> I would be delighted to find out this isn't a possibility in any case,
>
> 73,  John Ferguson KI4NGH
> _______________________________________________


-Jack Brindle, W6FB
=======================================================================