[Elecraft] [K2] Tuning a magloop with KAT100

[Rick WA6NHC]

Brian,

Magloops have a VERY narrow bandwidth and putting RF power into them can 
cause significant damage if the ANTENNA is not tuned.  Plus you'd be 
experiencing significant line loss on your feed if the SWR wasn't 
right.  That's two major drawbacks of your plan.

I would suggest that bypassing the KAT100 and tuning only with the 
controls for the magloop is a far better way to go.  A mistuned magloop 
will also show substantial  LOSS at the desired frequency so all tuning 
should happen at the antenna for best operations.  First peak the 
receiver noise as you adjust the antenna controls, then apply only 
enough power to get a response from the SWR meter (say 5-10 watts); fine 
tune the antenna controls for a good match.  Do NOT use the tuner in the 
radio.

I was given one, have tried it and frankly I'm unimpressed with the 
operation and performance.  I was hoping for better as it would make a 
nice RV antenna, but a dipole works MUCH better.  If it is all one can 
manage (HOA or lot limitations), it works but it is so narrow that 
typical S&P ops are rather challenging, you're never tuned for that new 
frequency.  As one that changes bands often and quickly, it would 
severely hamper how I operate.  Tuning requires patience and time on the 
lower bands, even a 20 KHz frequency change requires retuning.

But the bottom line is that in this case you must tune the ANTENNA, not 
match it externally.  Good luck!

73,
Rick wa6nhc

On 11/30/2015 11:20 AM, Brian - N5BCN via Elecraft wrote:
> I've recently acquired a magloop that will be used with a K2/KPA100/KAT100
> and I wanted to double check my tuning procedure.
>
> My plan was to tune the KAT100 into a dummy load (ATU in AUTO mode) and then
> place the ATU into SWR (x.x-1) mode.  Then use the TUNE button on the K2 to
> tune the loop to resonance, then operate.  Repeat for any band changes or
> when encountering significant SWR.
>
> Does this sound reasonable or am I missing a step or two?
>
> Brian, N5BCN
>