My first experience of HF data modes was in the 1980s was as a Short wave listener decoding RTTY (Commercial and amateur) using a Microwave Modules decoder fed into an old black and white portable TV. Many years later, as a licenced ham I used a PK232 terminal, mainly on RTTY again, but I also recall dabbling in AMTOR and even monitoring some HF packet.
These days with PC soundcards taking care of most of the decoding all we need is a simple interface between radio and PC and we can transmit and receive so many different digital modes.
In this respect perhaps I am a little lazy as the only Digi Mode I really use at the moment is PSK31. I do from time to time notice other modes in the "waterfall" display, particularly OLIVIA with its distinctive sound. Recent entries by some of my fellow bloggers have inspired me to Download the FLIDGI software and try to see if I could find some OLIVIA contacts.
So far I have limited success I have managed to decode a few OLIVIA QSOs but it seems quite difficult to determine what particular settings the are being used e.g 8/250, 8/500, 16/500 etc- is there a standard setting I wonder? Most times I cannot find the settings in use so can't get a decode. This morning, before leaving for work I even saw a very wide looking signal on 20 metres using 32/1000.
This leads me on to the number of different digi modes available. Just look at all the modes listed on Flidgi. Just as an experiment a couple of evenings ago myself and another local amateur found a quiet spot on a dead 10 metre band and ran through a couple of the modes to see how they worked.
We tried OLIVIA, FELD-HELL and THROB. FELD-HELL in particular was a very interesting mode. Its output on the screen looks almost like a FAX printout. I believe by the way that HELL is a shortened version of the proper name HELLSCHREIBER.
I wonder what the advantages of each of these modes is? It would require some time to familarise yourself with each of these modes and their advantages. Yet in the meantime new modes are being developed- all quite confusing.
Myself the only modes I really hear on HF( I am not counting SSTV and the digital DRM version) these days are PSK, OLIVIA and RTTY, but maybe other modes are in use. Does anyone use HELL on HF now, and what ever happened to AMTOR and PACTOR?
My first experience with digital modes was at the start of the 90s with a TNC2C packetmodem on 11 mtr. It was a very populair mode that time. Later I built a hamcom modem from some electronic components I found in the scrapbox. I picked up again when I obtained my license and still like digimodes. But same as you haven't got enough time to try everything. I still would like to test olivia and digital SSTV, hope to find some time in the future...73, BasReplyDelete
I agree the multiplicity of digital modes is confusing. Fldigi supports something called RSID which is transmitted at the start of every over and can switch receiving software into the correct mode, but hardly anyone uses it.ReplyDelete
There is information on the Fldigi site and also that of MultiPSK about the different modes, which suggests there is not much to choose between most of them, Olivia being the best of the bunch mainly due to the fact it is the most recent.
The wide mode you saw up above 14.100 was probably ROS, which is 2.2kHz wide and unsupported by any other software, and operating in the frequencies normally used by 32/1000 Olivia. The refusal of most of the digital fraternity to accept that there is no place for such a selfish wide mode or at least insist it moves to another frequency has made me somewhat disillusioned with digital modes and with amateur radio in general.