[Elecraft] Tuning Random-Length Wire Antenna with K3 Internal Tuner??

[Grant Youngman]

I can’t help but think we’re over-thinking this.

I think the original post was regarding ‘portable' operation.  When I go portable I don’t carry a large antenna with lots of wire or weight.  I usually carry a 41’ (non-resonant) wire with a 9:1 unun rated at 300w watts, and a throwing line and weight to get the far end of the wire up in a tree. I have a large OCFD and a 40’ fiberglass’s mast to get it up, but frankly, for quickie portable, getting the center pole staked and up and guyed is more trouble than its worth.  If it was for a weekend or a week, maybe.  But I’d rather spend the time operating.  I’ve used the simple wire with both a K3 and KX3 with internal ATUs.  Works fine.  Nothing has ever cooked.  The internal ATUs typically get SWR to 1.2:1 or better.  Feedline is 25 feet of RG-58 choked off a foot before the radio termination.

Sure, some power is getting lost in the tuner, the balun, the feedline, the connectors, human absorption, whatever.   But … 

Grant NQ5T


> On Dec 13, 2020, at 2:19 PM, donovanf at erols.com wrote:
> 
> Examining the KAT3A circuit board, I doubt it can handle more than 
> 1000 volts that a worst case random wire -- or a fault -- could cause 
> at the output of the KAT3A tuner when the K3 is producing full rated 
> output. But its unlikely that the KAT3A can produce full rated K3 
> output because of inevitable low tuner efficiency at high VSWRs. 
> 
>