[Elecraft] Sidetone or zero beat

[Brett gazdzinski]

I find the K2 and other modern rigs hard to zero, as I
have NO tone matching judgment.
What I do is jump between cw and cw reverse until I cant
hear any difference, that sometimes takes some time....


The homebrew receiver is easy though, I turn the bfo on
and adjust the tuning till I get below say 20 Hz.

The receiver and audio chain are good to at least 20 Hz and below
that the S meter wags back and forth and the speaker cone
(10 inch) goes in and out slowly.

The BFO is a 455 KHz xtal oscillator and if I zero beat
the signal, its centered in the passband.

I think most modern receivers have a problem getting below
200 Hz in the audio chain, nor will the little speakers
do anything but self destruct if they did get down to 20 Hz.

That has nothing to do with CW I suppose, but it does on AM.
That's why I hope the K3 will pass audio to 20 Hz, at least
at the line level output.

I can see on CW and SSB you want to restrict the audio to eliminate
noise, but on AM its wonderful to have good fidelity at times.

That's one reason why I have stuck with AM operation so long,
I cant tune ssb so it sounds 'right' to me, and a good AM signal
sounds like someone is in the room with me, or better!

Brett
N2DTS

> 
>  Most modern transceivers, including
> the Elecraft rigs, have virtually no output within 100 Hz or so of the
> carrier frequency, thanks to the excellent I.F. filters they 
> use. That makes
> finding zero beat with the sidetone mandatory to avoid an 
> error or 100 Hz or
> more in trying to tune onto the other station's frequency.
> 
> Ron AC7AC
> ==================================
> My Drake R4C had good IF filters but I could move the filter 
> over to the
> carrier frequency with the excellent passband tuning and 
> "see" the beat note
> on the (analog) S meter.  The needle would go from a fast 
> vibration to a
> slower one with more movement as I approched zero beat.  No 
> hearing needed.
> This was how I set the xtal calibrator to zero beat with WWV. 
>  Then , I
> could read a frequency to the nearest khz, something I could 
> only dream of
> with older rigs.
> 
> 73
> Rick Dettinger
> K7MW
> 
>