[OZAPRS] Hang Glider APRS
Terry Neumann
tfn at rbe.net.au
Wed Apr 19 17:48:17 EST 2006
Andrew Rich wrote:
>Gudday
>
>In contact with the local hang glider club. One guy is going to fly 100
Km's
>cross country.
>
>Now I have to make the decision wether the pocket tracker will make the
>distance.
>
>I measured it with a comms test set - 168 mW.
>
>Anyone had expereince with RF vs Distance from airborne objects ?
>
>
My experience with conventional gliders suggests that this would be
pretty marginal at the power levels offered and the distance expected.
I need to stress that this "experience" is with voice communications
using the dedicated air band radios. These use frequencies in the VHF
air band - most often 122.7 Mhz on AM - and with outputs of around 2 - 5
watts (depending on how these things are measured) we expect distances
of 100 km from airborne aircraft at (say) 2,000 feet back to ground
stations. It's all a function of having sufficient altitude to maintain
a line of sight path. If you get very low, this can be compromised
severely. It seems reasonable to assume that these observations will
also be valid for the 2 metre band which is what I imagine you will be
using.
The efficiency of the antenna needs to be considered as well as it's
proximity to the metal bits of the airframe and how these might enhance
or shield the signal. Hang gliders, like us, circle a lot in thermals
to gain height (hopefully).
It's possible but it really looks like this will be a true experiment at
the power levels proposed. That is to say that it may or may not work
all the time or all the way.
My 10c worth,
Terry
>-----------------------------------------
>Andrew Rich
>Amateur radio callsign VK4TEC
>email: vk4tec at tech-software.net
>web: http://www.tech-software.net
>Brisbane AUSTRALIA
>
>_______________________________________________
>Ozaprs mailing list
>Ozaprs at aprs.net.au
>http://aprs.net.au/mailman/listinfo/ozaprs
>
>
>
>
_______________________________________________
Ozaprs mailing list
Ozaprs at aprs.net.au
http://aprs.net.au/mailman/listinfo/ozaprs
More information about the Ozaprs
mailing list