I don't particularly care for the KH1's sidetone for two reasons:
First of all, it sounds terrible and I find it to be reminiscent of a code practice oscillator I built as a kid.
Second, there is no way to zero-beat a station based on how their pitch relates to your own sidetone.
Neither of these reasons matter too much - the KH1 is a utilitarian radio designed for a specific purpose - quick deployment in scenarios where other stations are doing the calling (and therefore the zero-beating).
But I wondered: What exactly are the audio components that produce the KH1's sidetone? Nothing in the KH1's manual gives any indication of how the sidetone is generated.
Spectroid to the rescue!
For comparison, here is my Elecraft KX2, with its sidetone set for 560 Hz:
And here is the KH1's sidetone, comprised of many discreet frequencies between 1000 and 11,000 Hz:
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UPDATE (20 Nov):
Wayne N6KR mentions on the KX Group.io that I must have taken the reading in "SPOT" mode which would include a bit of background (receive) audio in the spectrum plot. So I made another measurement - key-down - not spot.
Here is the plot for the sidetone (and only the sidetone).
Again, the KH1 sidetone is a broad-spcetrum audio signal consisting of tones from 1000 to 11,000 Hz (thus the raspy sound):
:
Anyone with a KH1 can verify this via one of the many audio spectrum apps available for smartphones.
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For that price you'd think the filtering would be a little better on the audio.
ReplyDeleteGood morning John, knowing Elecraft and how excellent they are at listening to their ops I wonder if a firmware up grade can look after that?
ReplyDelete73,
Mike
VE9KK
Hi Mike - I haven't heard many people complain about it so maybe it's just not a Big Deal given the purpose of the rig. I certainly couldn't listen to that tone for a 4-hour Sprint though!
Delete73,
John
Great analysis John. I'm still waiting for my KH1, but all the videos I've seen demonstrate this awful sidetone. I hope a simple firmware update can improve this. If you can, you might want to share this with the KX Group.io group. I know Wayne is an active participant. It would be interesting to see his response, as well as others on the group. In any case, I look forward to a POTA activation by you with the KH1.
ReplyDeleteBest 73,
George
K2WO
Hello George - I'm sure we'll have a KH1-KH1 contact soon. I want to try an NVIS-type activity with it on 40m and you are within the ideal radius of me for that.
DeleteRegarding the sidetone, I think the KH1 is a big departure from how other Elecraft rigs operate. All other E rigs produce the sidetone from a portion of the transmitted RF. I've read the KH1 manual but there is no mention of the sidetone in the Circuit Description portion of the manual, nor is there a schematic. I think we are stuck with the sidetone as it is, based on how it's produced, regardless of any future fw updates :-(
73,
John
From Wayne N6KR on the KX-Group.io:
ReplyDeleteHi John,
KH1 sidetone is adjustable over a wide range in both volume and pitch. There's also a SPOT function (sidetone and RX audio heard together). See the "Basic Operation" section of the owner's manual.
The sidetone is generated with PWM, then filtered. A firmware change is in the works that will keep the PWM waveform at 50% and vary the volume using a different method. This will greatly improve the timbre at low volume settings.
73,
Wayne
N6KR