Re: LF: JT9-5 decodes in km07ks

[Markus Vester <markusvester@aol.com>]

Attached are a couple of screenshots showing my setup for SpecLab frequency conversion. It's pretty straightforward - the RX instance uses analog "mic" input, the mixer configured as a 500 Hz USB downconverter, and VB-cable for audio output, whereas the TX instance has VB cable, USB upconverter and "Speaker" output.

Rik, removing only the TX restriction would already be very helpful. Feeding low audio frequencies directly to a SSB transmitter may also produce undesired in.band audio harmonics if the drive level has not been carefully adjusted.

BTW Stefan and I noticed that the "tune" tone has a slow frequency modulation.

Best 73,
Markus
 


-----Ursprüngliche Mitteilung-----
Von: N1BUG <paul@n1bug.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Sa, 29. Dez 2018 12:18
Betreff: Re: LF: JT9-5 decodes in km07ks

On 12/29/18 4:47 AM, Rik Strobbe wrote:
> Hello Markus,
>
> Thanks for your help with the JT9-2 and JT9-5 resampling.

Markus, I wish to add my thanks also for helping with this project.

> Lifting the frequency restriction on TX is "peanuts", but on RX I
> would need to implement frequency conversion in SpecLab style.
>
> I will have a look to that (maybe I should ask Wolf for advice).

Rik, my impression is that is a lot of work but if it can be done,
and if it does not introduce too much reduction in sensitivity it
would be a very nice thing!

It is difficult for many transmitting stations to move far down the
band. But receiving stations usually don't want to change their dial
from 136.000 and lose ability to monitor other modes.

73,

Paul

SpecLab4_RX.png
Description: PNG image

SpecLab8_TX.png
Description: PNG image