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-   -   APAR Antenna. For 2 meter Guruís (https://vansairforce.net/community/showthread.php?t=186429)

NYTOM 09-01-2020 05:03 AM

APAR Antenna. For 2 meter Guruís
 
Tried asking this question at the end of another APAR thread but the thread was already dying. Question: trying to install hidden APARS antenna in wingtip.
Tried one of those portable 6í twinlead J-poles secured in the tip but it doesnít seem to work. Thereís a 37Ē dipole out there made for high altitude balloons that would lay right in the wingtip with little fiberglass clips. Could even make one just like it very cheaply. Any thoughts on its effectiveness? Spent a lot of time and $$$ putting this transmitter in years ago durning the build and have been really impressed with the tracking accuracy Vlad has achieved out there in the Wild West in the middle of nowhere , where ADS-B towers donít exist yet. I know I could use a old LORAN antenna but hate to put another object sticking out of the fuselage. Any proven methods?

Thermos 09-01-2020 06:29 AM

Hi Tom,

When you say your j-pole doesn't seem to work do you mean that it doesn't work at all, or that you aren't getting the APRS transmission range you expect?

Wingtip-mounted dipole antennas have some limitations, but a lot of APRS-equipped RVs use them and they seem to work reasonably well. You've probably checked your coax and connectors but if not, I'd do that before changing out antennas. If you have a ham radio friend with an antenna analyzer, you can almost certainly bribe them with food and/or beverages to bring their analyzer to check out your installation. A quick sweep with the analyzer can help pinpoint coax issues or a poor antenna impedance match - both of which will reduce your APRS range.

Hope this helps. Please check back if it doesn't and we'll try some other tricks.

Cheers,

Dave

Carl Froehlich 09-01-2020 02:39 PM

The easiest antenna for the wingtip is to buy (or make) ann Archer antenna and trim to be resonate on the 2 Meter band at your frequency of interest.

As with all wingtip antennas, an Antenna Analyzer is required to get it properly tuned.

Carl

FinnFlyer 09-02-2020 08:42 AM

nanoVNA
 
Look into the nanoVNA.
$40 well spent for an antenna analyzer.

Spend a bit more ($60-80) and get a nanoVNA S-A-A V2 that goes to 3GHz and you can check your transponder and ADS-B antennas with confidence too.

Finn
(Still have to try the DDRR as comm antenna)

petehowell 09-02-2020 06:53 PM

DDRR for APRS
 
DDRR for APRS! I had some fun with materials from home depot a few years back.

Cheap and fun to experiment!

https://vansairforce.com/community/s...highlight=ddrr



Quote:

Originally Posted by FinnFlyer (Post 1459282)
Look into the nanoVNA.
$40 well spent for an antenna analyzer.

Spend a bit more ($60-80) and get a nanoVNA S-A-A V2 that goes to 3GHz and you can check your transponder and ADS-B antennas with confidence too.

Finn
(Still have to try the DDRR as comm antenna)


NYTOM 09-02-2020 07:56 PM

Quote:

Originally Posted by petehowell (Post 1459461)
DDRR for APRS! I some fun with materials from home depot a few years back.

Cheap and fun to experiment!

https://vansairforce.com/community/s...highlight=ddrr

Thatís awesome Pete. It would be fun to build one.


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