[aprssig] FW: APRS Question (Drone tracking of downed balloons)

[Robert Bruninga]

Good info on the drone technology.  Thanks...

But the flight does not have to be but a few minutes.  And can be done
within line of sight.  Just drive to the last received position of the
balloon as it came down, plus a little bit of estimation and a good sense of
altitude (local hill) and launch the drone from there.

With the balloon doing a 1 minute APRS packet, (which is now a constant
position on the ground), it should not take but a few minutes to get that
posit.

Besides, its more toys to play with in the field.

The TinyTrackerTT4 (cut down from a MTT4B 10W tracker) only weighs  60g and
a 9v battery weighs 40g and makes a full function digi with Xcvr.  We use
these for all of our student satellite projects, but we have re-layed out
all the parts onto our own board to make it fit on a 3" square board and
without the 10 Watt amp.

They mention the 1 Watt Microtrack 1000 as having a transceiver, but it uses
the TT3 chip which I don’t thinkn has a packet receiver code? So it cannot
act as a digi?

Bob

-----Original Message-----
From: Stephen H. Smith <wa8lmf2 at aol.com>
Sent: Thursday, June 11, 2020 9:17 PM
To: TAPR APRS Mailing List <aprssig at lists.tapr.org>
Subject: Re: [aprssig] FW: APRS Question (Drone tracking of downed balloons)

On 6/11/2020 2:28 PM, Robert Bruninga wrote:
> Kameron KG7VSN asked a question about using a RC aircraft to act as a
> final digi for a balloon once it has landed.  But I’d take it one step
> further.
>
> Put the APRS digipeater on a drone and also listen for the LAT/LON of
> the balloon.  Then launch the drone once the balloon begins to
> descend.  Program the drone to always go to the balloon position and
> maintain 1000 feet altitude until told otherwise.  (or whatever is the
> legal height for drones…)
>
>

Maximum legal height for civilian-type drones is only 400 feet AGL.  More
importantly, you have to maintain visual contact with the drone at all
times; i.e. you can't send it many miles away from your own control point.

The real question is how would you mount a digi on a drone?
The average consumer drone has next to no additional lifting capacity. Like
a space rocket where 80+ percent of the liftoff weight is fuel, about 2/3rds
of the weight of the typical drone is battery pack. I have been thinking
about putting a Big Red Bee APRS tracker on my Autel EVO which would be less
than an ounce added weight.

But an APRS digi would require a full TX/RX radio, a TNC-like device of some
sort sor and a battery system.  Maybe one of those discontinued Alinco
credit-card-sized QRP 2-meter rigs and a TT4....

Most serious consumer drones (DJI, Autel, Parrot, etc) are powered by
proprietary lithium-ion battery packs with odd voltage outputs. One might
also have to factor in some sort of DC-to-DC converter if you want to steal
power
from the drone's own battery pack.   Note that the maximum run time for most
of
these drones on a fully-charged battery is 15-25 minutes max, even before
you start sucking power from the battery pack for other electronic devices.
Due to the limited flight time, ou would have to launch the chase drone very
close to the end of a balloon flight, just before landing.


Note that the drone already has TWO radio systems on board.  One for flight
control and camera control uplink and engineering data (battery state,
altitude, GPS data, etc) downlink.  A separate radio provides the live HD or
UHD video feed down link.  One would have to thoroughly test the EMI/RFI
issues before putting a third 2M VHF transmitter onboard.

___________________________________________________________
Stephen H. Smith    wa8lmf (at) aol.com
Skype:        WA8LMF
EchoLink:  Node #  14400  [Think bottom of the 2-meter band]
Home Page:          http://wa8lmf.net

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