CW Sidetone

w3ub
Posts: 50
Joined: Fri Dec 14, 2018 6:32 pm
Location: Lunenburg, NS/Florida

CW Sidetone

Postby w3ub » Wed Dec 16, 2020 3:03 pm

This is the first time I am trying CW with my 7000DLE.

Thetis 2.8.11, P2
Using VAC
Using MPR40 to send CW via a Com port
DUP enabled

When using semi-break in, I can't get any sidetone (or received version of the TX signal).
When using QSK I can get the sidetone, or perhaps more accurately I am hearing the actual TX signal in the monitor?

I would like to avoid QSK for now to save wear and tear on my amplifier relays.

Why can't I get the sidetone using semi-break in?

/Doug
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w-u-2-o
Posts: 2981
Joined: Fri Mar 10, 2017 1:47 pm

Re: CW Sidetone

Postby w-u-2-o » Wed Dec 16, 2020 4:43 pm

w3ub wrote:This is the first time I am trying CW with my 7000DLE.

Thetis 2.8.11, P2
Using VAC
Using MPR40 to send CW via a Com port
DUP enabled

When using semi-break in, I can't get any sidetone (or received version of the TX signal).
That is correct.

When using QSK I can get the sidetone, or perhaps more accurately I am hearing the actual TX signal in the monitor?
You are hearing your own TX signal.

I would like to avoid QSK for now to save wear and tear on my amplifier relays.

Why can't I get the sidetone using semi-break in?
You can't because it is not a supported function. Unfortunately, the developers chose not to develop a signaling method that would produce PC output of sidetone (via VAC) with sufficiently low latency to make it usable, not for either a PC-based keying source (such as you are using) or a keying source plugged into the hardware unit. In the latter case the assumption is that if you are using a key plugged into the hardware unit you will also use a speaker plugged into the hardware unit, and the hardware unit produces sidetone in the FPGA.

Unfortunately the same assumption is obviously not true for someone that is using VAC audio. In order to work around this limitation you have to go old school, which is to add a local tone generator across the key/paddle/keyer.

The problem can be mitigated via some rework of the VAC audio code, if a developer was sufficiently interested in doing so.
w3ub
Posts: 50
Joined: Fri Dec 14, 2018 6:32 pm
Location: Lunenburg, NS/Florida

Re: CW Sidetone

Postby w3ub » Wed Dec 16, 2020 7:09 pm

OK, got it. Thought I was missing something there for a second ...

It seems like setting the QSK delay to 300msec or so is equivalent to the semi-break in mode.

Doug

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