Hello LF, I am pleased to report a successful "Coherent BPSK" QSO between DF6NM and IZ7SLZ on LF using EbNaut program of Paul Nicholson. QSO took place in the night between Friday 2015-09-18 and Satu
EbAnut is a new one here - I hadn't heard of it. After Googling I found the page and read up / downloaded the software. Unfortunately, I see it is not standalone, and requires Spectrum lab to act
Some years ago I proposed GPS / UTC seconds locked coherent signalling on LF, but didn't have the expertise to write the software - and certainly not to implement strong FEC ! Andy G4JNT Somewhere ar
Hello Andy, all thanks for interesting at this test. Yes, Spectrum Lab is the right program to manage the audio from receiver also in this case. The SL configuration used in LF_EbNaut experiment bas
Somewhere around February, 2004, Bill de Carle, VE2IQ, came out with a version of AFRICAM that implemented GPS-synched BPSK. A number of us played with it in the 160-190 kHz U.S. "Lowfer" band. The G
That gives me an idea ... For some time I've been toying with the idea of writing a utility that reads audio in blocks based on UTC timings and saves to a .WAV file . It woudl form part of a long te
Hi all, If it helps, I could add all necessary settings in the "Quick Settings" menu, including the decimators, SR calibration, etc etc. But for the timestamps in the I/Q recordings, it's very handy
Very nice to see this working at LF with short symbols. The phase was stable enough for the 20 or so minutes of each transmission on this path of circa 1000km. S/N of IZ7SLZ at DF6NM suggests that a
Yessss... Hadn't appreciated that was what it was doing until I read the description in more detail. I suppose that if soundcards are going to be used as the interface some sort of locking will hav
The soundcard becomes a liability for coherent signalling at LF. The fiddly software is all concerned with coping with the wandering soundcard conversion rate. Yes, a small amount of hardware replace
Sounds like an application for one of those Cortex-M development boards with built-in fast multi-channel ADCs, like the one Alberto recently mentioned here. I have a stm32f429-"discovery" board here.
Thanks very much to Domenico IZ7SLZ for informing the group about our LF EbNaut-PSK activities! I am glad that this has raised some interest, and I'm sure that trying Paul's software is well worth th
Is it really necessary to mix down to baseband before doing the A/D conversion? Wouldn't direct sampling with fs = four times the carrier frequency do the trick? I think that an I/Q signal at zero b
No, this doesn't work as the sampling of the I and Q information must be simultaneous. Doing it your way, they are offset by a cycle of Fc In fact, I had this very discussion with G3PLX back in 199
Aha... Thanks Andy. I assume that the second -S2 in your _expression_ of Q is a typo. If changed to -S3 it all makes sense and the mixing with a quadrature LO at Fs/4 becomes clear. It was something
Yep, that S2 was a typo. I'm in the process of building a custom direct conversion Rx for narrowband. So far I've built a follow on digitiser for Softrock or QSD type receivers. Two identical opa
Hello LF and all, here's my "2 cents" about coherent-bpsk transmit point of view. I will briefly describe the setup used by me during the tests and QSO with DF6NM. I have employed an old analog SSB E
Hi Domenico, Thanks for your report. I see you on my OPDS32 grabber, as you say. 2015-09-28 21:00:47 IZ7SLZ 1159km 137502.120Hz 1mHz -46.7dBOp 93% 17.9dB 2015-09-28 20:00:47 IZ7SLZ 1159km 137502.120H
Hallo Stefan, thank you very much for your message. On 10/1/2015 4:29 PM, DK7FC wrote: Hi Domenico, Thanks for your report. I see you on my OPDS32 grabber, as you say. 2015-09-28 21:00:47 IZ7SLZ 115