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  #1  
Old 09-01-2020, 05:03 AM
NYTOM NYTOM is offline
 
Join Date: Jun 2005
Location: Raleigh, North Carolina
Posts: 1,150
Default 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?
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  #2  
Old 09-01-2020, 06:29 AM
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Thermos Thermos is offline
 
Join Date: Jan 2005
Location: KASH
Posts: 524
Default

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
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Last edited by Thermos : 09-01-2020 at 06:35 AM.
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  #3  
Old 09-01-2020, 02:39 PM
Carl Froehlich's Avatar
Carl Froehlich Carl Froehlich is online now
 
Join Date: Dec 2007
Location: Dogwood Airpark (VA42)
Posts: 2,816
Default

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
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  #4  
Old 09-02-2020, 08:42 AM
FinnFlyer FinnFlyer is offline
 
Join Date: Aug 2018
Location: Bell, FL
Posts: 464
Default 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)
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  #5  
Old 09-02-2020, 06:53 PM
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petehowell petehowell is offline
 
Join Date: Jan 2005
Location: MN
Posts: 2,281
Default 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 View Post
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)
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Pete

Amateur Plane - RV-9A N789PH - 2350+ Hrs
Amateur Radio - KD0CVN
Doggies Delivered - 25+
St. Paul, MN

Last edited by petehowell : 09-02-2020 at 08:54 PM.
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  #6  
Old 09-02-2020, 07:56 PM
NYTOM NYTOM is offline
 
Join Date: Jun 2005
Location: Raleigh, North Carolina
Posts: 1,150
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Quote:
Originally Posted by petehowell View Post
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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