[Elecraft] [KX3] JT65 and JT9 possible TX issues

[Jim Brown]

On Sat,5/9/2015 2:14 PM, Bob Towers wrote:
> As far as I'm concerned, JT65 is a weak signal mode and in my book 
> even 5 watts is probably too much!

Don't confuse "weak signal mode" with QRP. It is considered good 
operating practice on the HF bands to run low power -- I'd guess that 
3-30 W is pretty much the range. This is because the noise rejection of 
JT65 and JT9 makes low power and wet strings possible on the HF bands, 
AND because running higher power can drive cheaper receivers into overload.

All of the WSJT modes are often used at high power for weak signal 
communication -- like meteor scatter, moonbounce, and long range tropo 
at VHF, and for long hauls on 160M. A few years ago, I heard a ZS 
calling CQ on 160M. That's a 7,000 mile path for me, so I called him 
with the highest power I had available. I didn't work him. :)

The K2/100 and K3/100 will switch in the 100W amp at some power level 
determined by software. I don't recall what those levels are, but I'm 
certain that going to 18W will get you there. That's less than one 
S-unit, so you're not going to make a mess of the JT65 "window" at that 
power level. A bit of experimentation with the power control will get 
you the answer. And if 5W is too much, go to 3W. That's only 2 dB less.

73, Jim K9YC