[Elecraft] 3 technical questions

[Fred Jensen]

I understand what direct sampling is and how it works.  Why is it 
preferable [or whatever other positive term you might want to use] to 
the superhet design of the K3(s)?  I'm curious what sampling the entire 
spectrum from 0.1 MHz to 54 MHz buys me?

If I understand the "Superhet" option for the K4 correctly 
[problematical at best], it provides RF and mixer stages to an IF [~8 
MHz??] which is then directly sampled by the base K4.  Since that IF 
bandwidth can be adjusted by xtal filters and will be MUCH narrower than 
0.1 - 54 MHz it will also be far less susceptible to overload from 
strong signals not in that passband.  Is this what's going on?

For reasons I cannot remember now, I thought the K3(s) oversampled the 
15 KHz 2nd IF with a delta-sigma 1-bit ADC and decimated to the 
equivalent of a 22-bit word.  Some of the thredlets here have now caused 
me to reconsider that belief.  Have I got it wrong?

73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County