What I meant by tx only is that most of the vehicles have a dedicated xcvr with an external tnc for tx position on the APRS freq but yes there is squelch detect.
Those vehicles that do have display capability such as the Garmin 350 or AvMap G5/G6, etc. then they can monitor positions.
The TNC's are a mix of anything that works, mostly OT2's and KPC3's.
No, on most days a single DIGI would not work and there is insufficient time to drive to a place, setup a digi, then drive to the net control site. The first net operator has to be at their respective site and set up by 6:30 AM. Setup takes an hour and the drive could be two hours from the overnight. The other one or two net operators could be several hours from their site also. Setup requires putting up at least three masts and isopole antennas for the primary frequencies. The rest of the frequencies are handled by magmounts antennas.
You have to understand, in order to reach a site to cover a good portion of the course, we have to be on a mountain top but the course could very well be in a canyon. Access to the net site is usually gravel and/or dirt Forest Service roads or private roads, not necessarily paved highways.
--- In email@example.com, Tony VE6MVP <tony@...> wrote:
> At 01:46 PM 2013-05-09, k7ybz wrote:
> Your previous posting mention a bicycle event. This sounds quite interesting.
> > The only reason we used the smartbeacon is that a vehicle "might"
> > be stationary for a good portion of the day depending on the course
> > and assignment. Most of the vehicles are TX only but a few have displays.
> Could you be a bit more specific as to make and model of your vehicle
> APRS units? As I'm sure you're aware being able to listen for a
> quiet moment before transmitting would be very nice.
> The folks out here in central Alberta are experimenting with the
> Quiet time setting and ensuring that value is different for each
> adjacent digipeater. The idea being that if two digis hear the same
> packet and then start transmitting at the exact same time they will
> clobber each other out for the listeners along the duplicate coverage zone.
> >We were not intending to set up a DIGI but will not rule that out.
> Can a single digi at a high point cover the entire course for that day?