[drats_users] D-Rats Slow Data is Garbled - Packet doesn't decode

[Mike Heitmann]

Tom,

I have a 2820 that I use for D-RATS all the time and it works fine.

 All D-STAR radios suffer from lack of error correcton for low speed data (there 
isn't any the my knowledge). Any errors along the way will cause what you 
describe.

A couple of things (you probably know this already, thanks for your patience):
1. With the '92AD, make sure the "power save" feature is OFF. If it's on, the 
'92 radio will miss at least part of the data header and slow speed data will 
not work.
2. Make sure the GPS features are turned OFF on both radios - GPS reporting uses 
the low speed data channel too.
3. There is zero error correction for low speed data - any packet loss will make 
it fail. Could something be de-sensing the receive input to one radio or the 
other? I've had that problem with my '92 when it sitting next to the PC.
4. If you have not done so already, try configuring the 2820 to use it's built - 
in GPS to report DPRS position via your local repeater gateway. The radio uses 
the low speed data channel to report position. If that works then the low speed 
data channel is working.
5. Experiment with a terminal emulator connected to the 2820 and the 92. The 
RS92 software has a terminal program built into it that will let you send text 
data, and you can check the boxes for sniff and raw data in the D-RATS -> Radio 
-> Port configuration menus to get d-rats to display the raw data received. Or 
use a terminal emulator program. Until that works reliably, D-RATS will not work 
either.

Hope you get it going,
Mike, N0SO




----- Original Message ----
From: Tom G <tom.w1tg at yahoo.com>
To: drats_users at intrepid.danplanet.com
Sent: Sun, October 31, 2010 8:12:55 PM
Subject: [drats_users] D-Rats Slow Data is Garbled - Packet doesn't decode

I don't think this is a D-Rats issue...more of a Radio hardware thing.  Using 
D-Rats 0.3.2.

I looked through past posts but couldn't find anything similar to my problem.  
Connecting the 2820 to D-Rats and everything works the way it's supposed to 
except the data that's hitting the other radios.

The message packet is garbled and not decoded by the receiving stations.  I 
troubleshot the issue connecting with a hotspot repeater and simplex via another 
D-Star Radio 92AD.  This doesn't appear to be a RF issue but rather the data 
that's going out from the 2820.

I'm seeing the message from the 2820 hit the repeater and simplex radio during 
my testing but there are too many errors for the packet to be displayed properly 
by the RX machines.  I'm viewing the raw message data via remote and local PC 
connections hitting the RX radios and the packet is garbled.

I've confirmed comms via RF with the repeater HotSpot and the 92AD..both chat 
and file xfer all work fine both directions on my other testing radios.  Used 
the same Base station antenna as the 2820...the 92 runs at 100mw with the 
connection just fine.

The 2820 can hear and decode both the HotSpot repeater and the 92 in simplex 
modes just fine.  Neither of them can decode the 2820 packets though.

DV mode and analog on the 2820 work fine also...no issues with audio out or into 
the unit via simplex or repeater modes.  So I'm scratching my head as to what 
could possibly be going on.

The 2820 is relatively new < 1 year and hasn't been modified or abused in any 
way.  It's seen both mobile and base usage and in all other ways appears to 
operate normally except for the data packets being garbled out to the other 
radios on D-Rats.  This is the first time I've tried to operate it via the 
D-Rats software.

I'll restate that it does everything it's supposed to with D-Rats except get a 
clean ungarbled packet out to another radio.  Both the other radios hear and see 
the packet coming from the 2820 but can't decode it.  Because they can't decode 
the packet, the other radios don't see the 2820 station, but the 2820 can hear 
and see the D-Rats radios I'm testing with...it responds to ping and position 
requests but the 2820 packet in response is garbled and shows up as yellow 
highlighted raw text on the good testing radios.

Sorry to go on for such a long post but just trying to give as much info as I 
can to troubleshoot the issue.  


My guesses:
1.  Unknown data setting on the 2820 I don't have correct
2.  The 2820 is somehow defective on the data side.
3.  Level adjustment somewhere on the 2820...

I've also posted the same message to the 2820 Yahoo Group to see if someone 
there maybe familiar with this issue.

Appreciate your thoughts and solutions....

Tom - W1TG


      
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