 aa777888-2 
Member
Joined: Nov 2001  USA
 Posts: 3621 Feedback: 0% (0) |
Posted: 7/23/2012 5:06:34 PM
THE IMAGE ABOVE IS A PAID ADVERTISEMENT Someone asked how APRS could be used in a net. APRS is basically a short-message net. It can be used to status people into the net, send short messages and, if there is a need, arrange for QSYs for longer messages. In addition there is no reason that both the APRS TNC software and digital mode software can't be run simultaneously. So if someone needs to send a longer message it can be done that way.
Other interesting things about APRS are that messages are acknowledged so you know if they got through and that it can be set up to digipeat. So relaying becomes automatic. Plus the entire mess can be left to operate in an automated fashion.
Now the downsides of HF APRS:
1. APRS is much more complex to set up and understand than simple digital mode keyboard-to-keyboard stuff.
2. The 300 baud signalling has nowhere near the link margin of "regular" digital keyboard modes, not even as good as PSK31.
I just started to get setup to play with some of this using the UZ7HO software and AGWTracker. I've found the UZ7HO software to be very unstable and I don't like it. AGWTRacker works great. I'm going to try the AWGPE TNC instead next. It has worked very well for me on VHF with AWGTracker already.
Here are some interesting links:
Video tutorial: http://www.youtube.com/watch?v=d1Liu1vzrYA
Another video: http://www.youtube.com/watch?v=c89MXcvgNN4
The NET14 website: http://www.bandscommunications.co.uk/
|
|
|
|
KB7DX
Bitten by glowbugs
Team Member
Joined: Oct 2006 AZ, USA
Posts: 5962 Feedback: 100% (6) Link To This Post |
Posted: 7/23/2012 10:14:51 PM
A few of us here played with HF packet some months ago. We found that it isn't nearly as robust as PSK or Olivia. Back in the 90's I was into packet HF and VHF. It was different then as there were many stations on the air to digipeat through. Nowadays the HF packet traffic is sparse save for the "Net 105" on 14.105 USB. The few of us here that tried it had limited success and couldn't come close to the reliability of Olivia unfortunately.
|
|
|
|
|
Posted: 7/23/2012 11:48:43 PM
It's be nice if someone had a "wrapper" for olivia, I know FLdigi comes with FLarq, but it specifically
won't work with olivia. I think PSKmail developers played around with several protocols and determined that for their application PSK250 is what worked best, so I guess there's some trade-off of link margin for speed and ARQ. Would automatic control of olivia be legal in the 14.100+ sub-band? I think so but I've not looked over that. Fldigi's macros are sophisticated enough at this point a store/forward or mailbox front end might be pretty achievable. |
|
|
|
|
Posted: 7/24/2012 6:29:25 AM
Maybe we should try the PSK/GMSK version of the TNC:
|
|
|
ARCHIVED
