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[aprssig] APRS Messenger now has APRS over PSK-63

Stephen H. Smith wa8lmf2 at aol.com
Mon Mar 1 01:42:54 UTC 2010


On 2/28/2010 2:46 PM, Chris Moulding wrote:
> Following Stephen's explanation I've just uploaded a 1800 Hz version 
> of APRS Messenger v2.33 to the webpage:
>
> http://www.crosscountrywireless.net/aprs_messenger.htm
>
> The other audio tones, 700, 1300 and 2100 Hz are also available.
>
> APRS over PSK-63 activity is increasing daily in Europe and the US. 
> It's a quick and cheap (free) way of getting on HF APRS. The amount of 
> feedback I'm getting on the program is helping development. It already 
> has a TCP/IP link to export HF APRS packets to map display on 
> APRSISCE/32 and RadioMobile,  soundcard selection, selectable HF 
> beacon rates, VHF / HF stations heard listboxes and a lot of 
> improvements over the initial version. Over the next few weeks I'll 
> add GPS input to allow mobile HF tracking over PSK-63.
>
> 7


This is way cool!

I have just finished experimenting with using the TCP/IP port 8063 to 
link to other APRS applications.  I can now confirm that the local port 
8063 works with UIview, APRSplus and APRSpoint.

In the old days of the G4IDE PSK31 Server for UIview, one used the PSK 
Server's IP connection just as through it was an Internet APRS server.  
You simply set up your APRS application's server config to log into  
"localhost:portnumber" instead of a "real" .  ("localhost" a.k.a. 
"127.0.0.1" is a "magic" IP address that always means your own computer 
rather than another one on a network.)

I threw together a test setup consisting of two laptops with their sound 
systems cross-connected with 3.5mm patch cords.  I am running the 1300 
Hz version of the latest APRS Messenger (getting ready to deploy it in a 
setup using KAM tones on 10.151.000 LSB) on both machines.    In turn, I 
set the main APRS TCP/IP server login of UIview, APRSplus and APRSpoint 
to "127.0.0.1:8063" and have sent/received messages from all three.

However the port 8063 server apparently can only accept one connection 
at a time. (The local server in UIview will accept multiple clients at 
once.)  Solution:  I have UIview's main "APRS Server Setup" connected to 
APRS Messenger.  In turn, UIview's "local server" is re-sharing the data 
with both APRSpoint and APRSplus.    All three now receive messages sent 
from the other laptop at the same time.

I assume that once APRS Messenger gains the GPS input and capability to 
send posits, that this will work to put APRS posits on the map in any 
(or all) of these programs.    To make the most of the slow PSK 
transmission rate, I would strongly suggest that APRS Messenger use the 
highly-compressed MIc-E transmission format since it is about ONE-THIRD 
the length of a plain-text APRS posit. The downside is that it is not 
human-readable, although ALL APRS mapping applications can decode it.

As I write this message (at about 5:40 PM Pacific Time here in Pasadena, 
California), I can actually hear faint PSK carriers underneath 
(pitch-wise) the conventional AX25 packet tones on my TS-50 monitoring 
30M.    This will be a REAL challenge but may well demonstrate the 
superioriority of PSK63 over FSK packet, since my local noise level 
(from a leaking cable TV trunk line) is absolutely horrendous -- around S9.

Gotta go and connect one of the laptops to my off-air monitoring 
system........


------------------------------------------------------------------------

--

Stephen H. Smith    wa8lmf (at) aol.com
EchoLink Node:      WA8LMF  or 14400    [Think bottom of the 2M band]
Skype:        WA8LMF
Home Page:          http://wa8lmf.net

NEW!    Universal HF/VHF/UHF Antenna Mounting System
   http://wa8lmf.net/mobile/UniversalAntMountSystem.htm

"APRS 101"  Explanation of APRS Path Selection & Digipeating
   http://wa8lmf.net/DigiPaths

Updated "Rev H" APRS            http://wa8lmf.net/aprs
Symbols Set for UI-View,
UIpoint and APRSplus:


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