[OZAPRS] [aprssig] 434 MHz tracking

Terry Neumann tfneumann at internode.on.net
Tue Aug 7 11:03:39 EST 2007

Andrew Rich wrote:

>Um the glider was at 8000 feet and i was on the ground.
>Mind you when I drove it, i got 1.9 km's out of it.
Blimey! An ASK-21 (like the one I usually fly) - 8,000 feet and they 
only went 8 Km away?    That's even more conservative than I am (and 
that's saying something!).

Interesting exercise though.  I've been wanting to do that for years.  
One of our club's more adventurous pilots - who has the aircraft and the 
talent to match his ambitions -  quite often goes up to 300+ Km away 
from our field here at Balaklava.  He always gets back too.   I've 
wanted to stow a tracker in the back of his machine almost since I've 
been working on APRS, but I've wondered about the legalities of putting 
such a device in a situation where I'm not in absolute control of the 
station and  another person (non amateur) could be seen to be so.    The 
other fascinating aspect of putting a VHF tracker in his aircraft is 
that his cross-country flights often are trips to the north from here 
where there there are no other APRS activities, so it would be a good 
test of airborne 2 metre propagation.

There are also airworthiness considerations in fitting such a device, as 
well as a lot of avionics which may not like a burst of 8 watts every 5 
minutes or so on a previously untried frequency.      Theses 
considerations aside, the new Byonics device would make it much easier,  
however a non listening transmit device up to 15,000 feet in altitude 
would be certain to get the wrong sort of attention.  

Incidentally I've had a look at the manuals for the 8 watt device 
currently under discussion.   It seems to me that the power amp on this 
package can be throttled back to give output below 8 watts and almost 
down to zero.   I'd be interested in such a device when anti collision 
options are developed.    However we can expect the price to go up and 
there will be a further delay to incorporate a sensing device 
(receiver?) of some sort.  We could then find the price up to the level 
of a current TT3 / micro handheld package - which is what I am working 
on now for the gliding / motorbike / push bike experiments.   And I do 
like to make as much of my own gear as I can .............



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