Saturday, August 07, 2010

Making HF APRS MOR robust

I was surfing around looking at information about robust digital modes, as you do, and stumbled across something called the WINMOR Sound Card TNC. WINMOR is a free, open and documented protocol intended for reliable HF data communications. Originally developed as a low cost alternative to Pactor for emergency communications systems such as Winlink, it has been made available as a virtual TNC for other developers to incorporate in their products. I started to wonder if this is the solution people are looking for to make APRS over HF more reliable, rather than trying to use digital modes such as PSK63 or GMSK that weren't designed for this type of application, as is being tried by G4HYG in APRS Messenger.

The documentation for the software is somewhat over my head, but from what I can deduce the Sound Card TNC (shown above) does not provide an interface like a regular packet TNC. However there is a module called BPQ32 that appears (from the description) to implement a TNC-like interface. I've probably misunderstood something - in which case hopefully someone will point this out to me - but it doesn't seem beyond the bounds of possibility to connect an APRS client like APRSISCE to this TNC and then you would be able to send APRS using the reliable WINMOR protocol with forward error correction (FEC).

The only problem would be finding a place to operate, since SCS's proprietary Robust Packet protocol seems to have already established itself below the FSK300 APRS channel on 30m.


Lynn (D) said...

WINMOR, as I understand it, is being developed as a new transport protocol for the WinLink 2000 "global Radio Email System" ( They've been tweaking and working on it for at least the past two years that I know of.

Winlink also injects their station's positions into APRS using a -10 SSID which is why I've been using -12 for APRSISCE/32 clients regardless of Bob's newly renovated SSID recommendations. I still go by -12 is "Portable units such as laptops, camp sites, etc" (

Unknown said...

You are correct, it has been developed as an alternative that does not require an expensive SCS Pactor TU.

The docs make it look like it would be a good protocol for APRS. It would be interesting to find a way to try it.