[Elecraft] KX3: use at <500-KHz

[Dyarnes]

Hi All,

This issue seems to come up with just about every rig that offers general 
coverage.  I know it was a topic of discussion with the K3 when it first 
arrived.  It has always been my understanding that offering general coverage 
on a ham rig meant compromise somewhere.  Most of the earlier rigs that 
started offering general coverage tended to compromise on the ham band 
performance in order to accomplish the wide RX capability.  That's why many 
didn't even try to offer it.  I think Elecraft's approach has been to offer 
it, but without degrading the ham band performance, which means the wide 
band stuff may be a bit lacking, particularly at the low end.

I've only checked the BC band performance on my KX3 once or twice, and just 
to see if I heard much of anything!  Actually, I could hear things pretty 
well, but probably not like I would on a more specifically designed radio. 
I also suspect the antenna I was using wasn't a very good match.  Wayne's 
explanation seems to at least make good sense to me, and I'm sure the 
technical issues involved are real.  Heck--just about every radio I own 
drops off somewhere!  I just want the least adverse effect to occur on the 
ham bands.  Also, I wonder what the internal ATU does (or is capable of 
doing), if anything, when I tune down to the BC band.  From a strictly 
intuitive standpoint, I know that a lot of tuners tend to lose capability 
below 80 meters, so I wonder if the KX3 ATU can/does even function at the BC 
band.  My guess is that it doesn't!  You can't activate it down there, so I 
don't know what's happening.  Does that mean you really need an antenna that 
is reasonably resonant at that frequency?  I suspect there have been some 
"tricks" applied to generate some sort of performance that low, but I really 
don't expect much.  Seems like we may be chasing ghosts to expect too much.

Dave W7AQK