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Antenna selection?

gfb

Well Known Member
A quick search shows many antenna threads but not one that quite touches on selection. I have no opinions on antenna models or brands, and honestly it seems that antenna manufacturers seem to have many model numbers for antennas that look exactly the same to me :)

I randomly selected some options from ACS, please let me know your thoughts or other recommendations:

GDL UAT Antenna (bottom) RAMI AV-22 (ACS 65)
GTX Transponder Antenna (bottom) RAMI AV-22 (ACS 65)
GTR Com Antenna (bottom) RAMI AV-17 (ACS 179)
GTN Com Antenna (top) RAMI AV-10 (ACS 168)
GTN Nav Antenna (right) Archer SA-001 (ACS 100)
 
I noticed the Delta Pop antennas in another thread. Are people flying with them and happy? I don't know enough about antennas to be able to compare them to the certified types.
 
I noticed the Delta Pop antennas in another thread. Are people flying with them and happy? I don't know enough about antennas to be able to compare them to the certified types.

Exceedingly happy, on performance, service, and price!
 
I just got an antenna from DP as well for a top mounted straight COM antenna. After drilling the holes, i realized that you really really want the company to be around for a long long time making the same antenna for when you need to replace it and not have to drill new holes. Thus, yes, go with DP. :)
 
I just got an antenna from DP as well for a top mounted straight COM antenna. After drilling the holes, i realized that you really really want the company to be around for a long long time making the same antenna for when you need to replace it and not have to drill new holes. Thus, yes, go with DP. :)

I also didn't like the idea of a two-hole com type antenna with a unique mounting pattern.

However, the DP transponder and UAT antennae have a standard mount pattern that is identical to the Comant CI-105, Bendix KA-61 and other certified small blade mounts.
 
dipole stub for UAT

I do notice that you can now buy a specific UAT cut antenna. It looks just like the transponder stainless stub, but is cut shorter than 1090.... for the 978 UAT frequency. I just put on on the bottom of the RV9A for Navworx. It is working fine and was under $25.
 
It's unlikely that you can tell the difference in performance among any of the externally mounted antennas, without megabuck instruments and a test range. Location (to a minor degree) and installation technique make far more difference than antenna selection.

So...

A straight, round section has the highest drag.

A swept round section can get fairly close to a streamline shape in drag.

A streamline section has lowest drag.

I'd buy the cheapest antenna that meets your mounting/appearance requirements. (Unless I find a 'deal' on a used one, I'll be making mine from stainless welding rod & a BNC bulkhead connector.)

Charlie

edit: Just saw that you had multiple antenna types listed. For a transponder/UAT that's likely to be on the belly (in already nasty-turbulent air) and only a few inches long, there's no contest for me. Cheapest every time.
 
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Can't go wrong with a full length DP, Comant or other similar straight com antenna, you should have that for your primary com before you add shortened or bent antennas for #2.

The Archer and similar embedded antennas are ok for nav but many are installed improperly (see a recent thread on this.) I would prefer regular vee or towel-bar antennas although choosing a mounting location can be tricky. It depends on whether you will depend on VOR/LOC at all.

For L-band (DME, transponder, UAT) you have the choice of narrow tuned antennas (rod and ball type) or broadband (most blade types). The rod type works fine; one tuned for 978 UAT is actually longer than one tuned for transponder (1030/1090 MHz). DME antennas are broad enough to cover 978-1213 (note, 978 is actually the low end of the DME band) so can work as transponder or UAT antennas, although some (mainly older) transponders work best with narrow-band antennas.
 
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