can rf interference get into a k2?

[jferg977]

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
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[Don Wilhelm-3]

John,

I have never heard of a problem that required covering the holes, but then I
have not run any tests of RF leakage either.  I would suggest that you first
examine the integtity of the contact with the case at the 2D connector
locations - be cetain all the masking has been removed and there is no paint
at those locations.

73,
Don W3FPR

> -----Original Message-----

>
> 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
>

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[David A. Belsley]

John:
   It is very highly unlikely that the holes are a problem.  I think  
you can discount that one.  It would help to know what sort of RFI  
you are experiencing and what your antenna arrangement is (everything  
between the K2 and the ether and a description of the nature of and  
proximity to surrounding objects).

best wishes,

dave belsley, w1euy



On Feb 2, 2006, at 8:59 AM, [hidden email] 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
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
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> Elecraft web page: http://www.elecraft.com

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[Ed - K9EW]

A good starting point would be to operate into a dummy load.  If there's no
interference, then you're dealing with energy radiating from the antenna -
not a K2 problem.  If there is interference, that narrows the possibilities
to the K2, the dummy load, the coax, and ... the power supply.

Hope this helps.
ed - k9ew


On 2/2/06, [hidden email] <[hidden email]> 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
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

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[Bill N2BC]

I doubt it's the cover holes.  I've done some testing with the top and
bottom covers off while interfacing my newly built K2 to a 1500W
amplifier without any problems.  (QRP is fun, but sometimes...)

Is your problem band sensitive?  Is your antenna resonant?   I would
suspect grounding problems.

Good luck!   73, Bill  N2BC

[hidden email] 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

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Post to: [hidden email]
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[Stewart Baker]

Is this rf interference (rf feedback ?) on SSB, CW or both ?

73
Stewart G3RXQ

On Thu, 02 Feb 2006 08:59:54 -0500, [hidden email] 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
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

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[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, [hidden email] 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
=======================================================================


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