Digital modes timeline for 'ham radio'

[Gi4CZW Cliff]

Reading about "Piccolo" and remembering RTTY I'm interested to know which came first and how one developed from the previous one, as PSK31/amtor etc. etc. There appear to be so many modes, no doubt each with advantages. So is there a suitable book or internet link I should read ? Thanks in advance. Cliff.

[G6Tanuki]

From memory there's something about the history of RTTY in the old "RSGB Teleprinter handbook" and its ARRL equivalent from the 1960s/1970s.

First to come was 'classic' two-tone RTTY [essentially frequency-shift-keying] with two different 'shifts' used - 850Hz or 170Hz. There were different Baud-rates preferred in different countries; indeed, from memory at one time the US amateur licence specified the baud-rate!

This was in the 1950s/60s using lots of immediately-post-WWII surplus gear: Creed or Siemens mechanical teleprinters, often with a paper-tape reader/punch for offline message-preparation and storage. Terminal-units were invariably valve-based [transistors couldn't really handle the +/-80V loop-current used to drive a a mechanical printer's solenoid.
There were a couple of ex-Military terminal-units available surplus which worked surprisingly well given the technology [I still have somewhere the instructions and spring-balance for setting up a Carpenter bipolar relay]

PICCOLO was a UK MFSK standard developed for the Diplomatic Wireless Service [DWS] in the late-1950s and went into service in the very-early-1960s. The guy who did most of it was J.D. Ralphs - there's s a number of IEEE papers on the subject. I have a fond spot for Picolo [and the Racal LA1117 modem].

It still used mechanical printing devioces though.

Have a look here and scroll down to the post by Clive Robinson: https://www.schneier.com/blog/archiv...id_bl_398.html


Googling will reveal details on more-modern protocols like packet-radio. I had a lot of fun in the 1980s with a DRSI PC*PA card and the KA9Q TCP/IP stack.

[Dave757]

Hi,

I remember the Eddystone 830/9 was a specially adapted model for Piccolo, - one to avoid I remember (if you didn't
want it for Piccolo!), in the days when 830's were fairly readily available.

Wish I had my old 830/7 now!

Anybody remember the Racal Kaynard and where that fitted into the picture?

Kind regards

Dave

[G6Tanuki]

Kaynard was a somewhat-smaller successor to Piccolo, if I remember correctly: I dropped out of that part of the game a few decades back.

These days IP (in some form - digital radio, ADSL, mobile phones, BGAN portable satellite terminals) ubiquitously replaces radio as the 'transit' level and for anything at all confidential you just stick a "CATAPAN" at each end.

[Gi4CZW Cliff]

Many thanks for the replies, the Clive Robinson blog most interesting. Now I'm thinking that I posed the question incorrectly, as it is the timeline of digital modes from CW, through RTTY and Piccolo towards the PSK xx's that interested me. Cliff