Re: APRS trackers IDs for all balloons.
James Ewen VE6SRV
Not sure where you got the misunderstanding
I'm not sure what conclusion you think I came to which would cause a misunderstanding. I asked if the chase crews had RF based APRS reception capabilities, and then explained why having RF based APRS is a good thing, and why trying to install infrastructure as described below would probably not be worth the effort involved.
I am not familiar with the local topography of the recovery area as far as elevation goes but how about the possibility of using a temporary mobile digipeater on the non standard APRS frequencies to repeat the APRS packets to an I-Gate. This would require a public accessible high elevation spot for max range.
As I stated in my previous message, the chances of having a recovery vehicle in the right location for reception of payload packets is much higher than attempting to place a temporary digipeater in a location that might happen to be located where it picks up a final landing location of a payload.
The only people that need to have the exact landing coordinates are the people that are physically picking up the payload, and even then, close is usually close enough to get you in visual range. With RF based APRS reception capabilities in the chase and recovery vehicle, those final landing coordinates can be received directly from the payload over RF. If that chase and recovery vehicle has I-gate capabilities, then the bonus delivery of packets to the APRS-IS happens as well.
The work required to deploy a temporary digipeater in an effort to get better reception and delivery of payload packets to an I-gate that is most likely closer to the payload than the temporary digipeater seems to be a fools errand.
The primary concern is local RF reception of packets from the payload. A distant second is the bonus delivery of those payload packets to the APRS-IS.
It makes far more sense to invest the effort to drive the mobile I-gates closer to the payload than to install a temporary digipeater in an attempt to get the landing coordinate packets delivered to an I-gate.
Remember, packets from a flying payload will most likely have a better line of sight to an I-gate than a land based digipeater will have to that same I-gate.
Digipeaters help ground based trackers get heard by giving the packets better LOS to other stations by digipeating from advantageous physical locations. Airborne trackers have much more advantageous locations than ground based digipeaters by virtue of the airborne nature of the tracker. Until the height above average terrain (HAAT) of the airborne tracker is less than the HAAT of the digipeater, the airborne tracker will have a larger RF footprint than the digipeater, and thus greater range. (Barring specific terrain obstructions. A ground based digipeater will probably have a higher gain antenna, and higher RF power, but HAAT trumps gain and power in a hurry at VHF)
These two messages are just my attempt to get people to stop thinking that in order for a packet to exist, that it needs to be handled by a digipeater and /or an I-gate. RF packets can exist in the world without digipeaters and/or I-gates.
While the world may ponder the age old question, "If a tree falls in a forest and no one is around to hear it, does it make a sound?", there is a definitive answer to the question, "If a packet isn't heard by an I-gate or digipeated by a digipeater, did it ever exist?". The answer to the second is a resounding "Yes!".
On Jun 15, 2016, at 12:48, Michael <mw@...> wrote: