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Old 03-28-2013, 01:12 AM   #11
JimC
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Navcom 1 is the rabbit ears relocated from the tail.
GPSCom 2 is a carbon VHF-5.
No ground plane required for either.

They aren't truly horizontal. The front end is low near the leading edge of the wingtip -- starts just aft of the landing light. The back end is high in the upswept trailing edge. That combined with the fact that Cherokees cruise at a slightly negative aoa means that they are not quite as horizontal as one might expect.

While it is true that for optimum signal they should be mounted vertical because of the polarization, in practice, there is no obviously detectable loss of range or signal clarity from the non-optimal location. It was a deliberate tradeoff that I was willing to make. A couple of extra kts in return for an unnoticeable loss of signal and a cleaner looking plane. I'd like to bury the MB antenna and the ADF boat, but haven't figured out a good way to do it yet.


Right Tip Front 2.jpg  

Last edited by JimC; 03-28-2013 at 01:15 AM.
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Old 03-28-2013, 06:12 AM   #12
RNC
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Assume you're talking about these?

http://www.aircraftspruce.com/catalo...nnasystems.php

Do they need a fiberglass wing tip to work through or do they work through the original plastic ones?


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Old 03-28-2013, 10:00 PM   #13
JimC
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They'll work through the plastic ones. Since the polarization will be wrong, there will be some signal degradation. In my own case, it was not severe. Your mileage may vary.
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Old 03-29-2013, 12:13 AM   #14
Jeff K
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Quote:
Originally Posted by RNC View Post
Assume you're talking about these?

http://www.aircraftspruce.com/catalo...nnasystems.php
BTW, all these are are half wave dipoles. Two ~22" pieces of wire soldered to the center conductor and shield of the coax would make a passable one... better if a balun is used (which is about $1 in coax).


http://www.eaa.org/lightplaneworld/a...nna4ULsREV.pdf

http://www.aeroelectric.com/articles...r_Aircraft.pdf
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Old 12-06-2017, 01:18 AM   #15
YellowLucy
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Default ELT antenna

Quote:
Originally Posted by JimC View Post
Airfoil shaped antenna has about 4% the drag of a circular cross section the same diameter.

I put my ELT antenna inside my dorsal fin and my two navcoms inside my wingtips.

JimC,
What kind of plane do you have? I have a Cherokee 140, and would love to put the ELT whip inside the dorsal fin, but don’t see how to make it fit.
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Old 12-06-2017, 02:26 AM   #16
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I have a Cherokee 150C.
Sounds like your 140 has the Nixon nose dorsal.
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Old 12-06-2017, 02:38 AM   #17
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Quote:
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I have a Cherokee 150C.
Sounds like your 140 has the Nixon nose dorsal.
Yup! Looks like knots2u has an upgrade to the dorsal that might work. They’re quite proud of it though...
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Old 12-06-2017, 02:48 AM   #18
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Isham has one too.

So does pretty much every salvage yard.


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