[Elecraft] Sidetone with harmonics at 400 Hz...

[Ron D'Eau Claire]

The basic issue is that the sidetone is, indeed, a square wave, followed by
a filter to reduce the harmonic content. 

Like most Hams who've been around a number of years, I've listened to every
sort of "sidetone" from a sawtooth wave to the squawks and bleats produced
by keying a rig with the receiver still energized, so the K2's sidetone
sounds just fine to me! 

As you reduce the frequency of the sidetone in the K2 the original filter
values are less effective and you start hearing more of the harmonic
content. The mods you mentioned were worked out by some builders to make the
filter more effective at lower sidetone frequencies. You might want to try
it. Whether it's enough to make the sidetone sound pleasant depends upon the
individual.

I don't think Elecraft ever modified the sidetone circuit because most
owners seemed to prefer 600 Hz, where the "stock" filter is most effective
at producing a reasonably clean, low-harmonic content sidetone. 

Ron AC7AC 

-----Original Message-----
I have a K2, serial #2289, that has a second harmonic in the sidetone. The
sidetone is set for 400 Hz because I do much better with lower pitches. The
sidetone at 400 Hz has a definite square wave sound to it. The problem
certainly is not present at 600 Hz, and I don't even want to try 500 Hz. I'd
go lower than 400 Hz if the K2 allowed it.

I talked to Don Wilhelm about this and he seemed puzzled. There is a post
off of the Elecraft web site about this at
http://www.qsl.net/ve3mcf/elecraft_reflect/K2_Sinewave_Sidetone.txt. But
that thread is dated Winter 2000. I would think the K2 has gone through
enough evolutions to correct this. Perhaps not?

Has anyone had this problem and corrected it? The sidetone is useable but
annoying. It also makes zero beating a signal a lot harder.

73,

Steve N6VL