[aprssig] APRS Cron Object Injector

KF4LVZ aprssigZbr6 at acarver.net
Mon Mar 23 12:08:11 CDT 2015


On 2015-03-23 08:51, Jason KG4WSV wrote:
> 
> 
>> On Mar 23, 2015, at 7:52 AM, Steve Dimse <steve at dimse.com> wrote:
>>
>> Most mobiles are free-running microcontrollers without time sync
> 
> The exception to this would be devices with GPS, and even more so those that can timeslot. 
> 
> Not sure how many mobiles use this, though.  We do it with all our balloon trackers, but that and maybe a non-144.39 net where you're shooting for high channel utilization are the only use-cases I can think of. 
> 

Depends on the mobile.  If it's something like a Kenwood D700 then the
squelch hold-off will automatically cause a random delay in the
transmitted packet.  As far as I've been able to tell on the D700 for
example, Kenwood's timing method is X minutes since last transmission
but do not transmit until squelch is closed.  So assuming the timer has
activated in order to trigger a transmission, the radio holds until the
squelch is closed and then transmits.  At that point the timer is reset
to be ready for the next transmission.  If the timer is set to three
minutes, the transmissions will be a minimum of three minutes apart but
more likely longer than that depending on the channel conditions.  I
don't know if the D710 follows the same concept.



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