[aprssig] "Smart" vs. "dumb" trackers

Randy Love rlove31 at gmail.com
Mon Jun 23 10:32:35 CDT 2014


All of the opentracker series distinguish between dead carrier and actual
tones. Software DCD is your friend.
BTW, the OTUSB line run under $50 and have usb readily available for
attaching to a table running your favorite flavor of APRS client.

Randy
WF5X



On Mon, Jun 23, 2014 at 11:11 AM, SARTrack Admin <info at sartrack.co.nz>
wrote:

>
>
> On 23/06/2014 17:03, Stephen H. Smith wrote:
>
>> On 6/23/2014 10:03 AM, SARTrack Admin wrote:
>>
>>> The tinytrak-3 connected to a (cheap) handheld radio will check for an
>>> open
>>> squelch (any noise) before transmitting.
>>>
>>
>> Except that this is not a positive carrier detect; i.e COR. All it does
>> is sense audio energy coming from the radio's audio-out.   It gets
>> fooled by dead carriers or under-deviated voice signals on the channel
>> into thinking the channel is clear.
>>
>
> Correct, but how often do you have 'dead carriers' of voice data on the
> APRS frequency? It basically always is a APRS signal, so it works quite
> well.
>
>
>>
>>> The TinyTrak-4 has even a full decoding capability.
>>> http://www.byonics.com/
>>>
>>
>> But you still need (in addition to the handheld and TT4) :
>>
>
> The original question was about Trackers. Not a full two-way messaging
> system.
>
> Have a look at my original design, using a VX-170 (or Type Approved radio
> in my final design), GPS chip and TinyTrak3 in a small box, and powered
> from the radio. This setup runs for 12 hours, every 30 seconds TX (used on
> a special VHF frequency). You can also use a very cheap Chinese radio on
> the HAM frequencies.
>
> http://www.sartrack.co.nz/Trackers.html
>
> Bart
>
>
> --
>
> SARTrack Developer and CEO
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> aprssig at tapr.org
> http://www.tapr.org/mailman/listinfo/aprssig
>
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