[OZAPRS] Problem getting Tinytrak 3 going

[Richard Murnane]

Hi Mark,

> No, there's no channel busy light.

In this case, you should turn up your Rx volume (with the squelch  
open) until it comes on, then turn up the squelch. If you still get no  
busy LED on, then you probably have a cable problem and your TT3 will  
transmit blind, so risk collisions and packets getting lost.

> Based on Peter's comment, I turned off smart beaconing, and now it's  
> keying the transmitter, but still nothing showing up on aprs.fi.

It could be just the beacon text packets you're hearing, which as I  
said before won't show a position.

> I can hear my packets going out on the other 2m rig in the car, but  
> perhaps I'm overdriving it. I'll have to check the devation.

It would be helpful if you could check the actual packets being sent  
too.

Also, if you can plug the GPS into a terminal program and see what's  
coming out. You should see $GPRMC sentences:
> RMC - NMEA has its own version of essential gps pvt (position,  
> velocity, time) data. It is called RMC, The Recommended Minimum,  
> which will look similar to:
>
> $GPRMC,123519,A,4807.038,N,01131.000,E,022.4,084.4,230394,003.1,W*6A
>
> Where:
>      RMC          Recommended Minimum sentence C
>      123519       Fix taken at 12:35:19 UTC
>      A            Status A=active or V=Void.
>      4807.038,N   Latitude 48 deg 07.038' N
>      01131.000,E  Longitude 11 deg 31.000' E
>      022.4        Speed over the ground in knots
>      084.4        Track angle in degrees True
>      230394       Date - 23rd of March 1994
>      003.1,W      Magnetic Variation
>      *6A          The checksum data, always begins with *
If the third field is "V" instead of "A", you don't have a lock (but  
then the GPS LED on your tracker would be flashing instead of solid on.)

> Another interesting thing, is that with smart beaconing turned on,  
> but in the absence of either a GPS signal or valid fix (I haven't  
> figured out which yet), the TT seems to fall back to the fixed auto  
> TX interval. So it sends out the status text at 1/5 of that rate,  
> rather than 1/5 of the applicable rate as determined by smart  
> beaconing. It seems that smart beaconing just didn't detect me  
> moving at all.

I would expect that if it doesn't detect you moving that it wold  
beacon at the slow rate, whatever that happens to be. More than that I  
couldn't say :-)

- Richard
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