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Permalink Reply by Randall Wade Grandpre on February 4, 2015 at 11:58am

  I have an I-com handheld with the rubber duck, it would only x-mitt about 4 miles so had to put an external ant. for entry into class D airspace. The control tower would hear garbled message  and would chastise for poor radio performance. The ext. antenna`s are not that expensive and easily double the x-mitt range.

The recieve range can be deceiving, as the other a/c have higher output x-mitt power. I have heard clear x-mission out to about 100 miles.

I put my external ant. above the baggage area on my 701 as it requires a metal grnd. plane

The rubber ducky needs to be away from metal  for stronger transmissions with the radio ant. inside the a/c.

I

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Permalink Reply by Normand Lambert on February 4, 2015 at 12:11pm

Hi Jerry,

I definitely think you need to install an external antenna. The range with the handheld antenna is OK for short distances but never gets very far. I ordered my external antenna at Aircraft Spruce (part no : 11-05102 - RA MILLER AV-534L COM ANTENNA) and it works very well with my ICOM IA-22 handheld. Never had a problem being heard and the range is very good.

My antenna is mounted topside behind the cockpit over the baggage compartment: as far as possible from the engine and electric noises. You could mount it under the fuselage but be aware that the 701 tail gets REAL CLOSE to the ground on takeoff and that could sign the end of your antenna...

Also, mounting it underneath the plane makes it vulnerable to little hands (kids and thieves)...

I dont see any real advantage to mounting the antenna underneath the plane; never suffered from range problems so far.

Hope this help somewhat.

Regards,

Norm

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Permalink Reply by Tim Juhl on February 5, 2015 at 11:49am

I use a handheld plumbed to an external antenna on my Aeronca Champ.  My comm range is almost as good as a panel mounted radio.  I also have it attached to the intercom so that I can use my headset with it.

On the Champ I just use a bent wire type antenna and that works well.  Most of my transmissions are on or near 122.8 so the narrow bandwidth of the bent wire is fine.  I would suggest, however, that you check out ebay or the like for a broadband fiberglass unit.  Just enter the term "Comant".  Word of warning, some people are still trying to sell LORAN C antennas which often resemble a com antenna.  Funny since LORAN has been shut down for years.

When you figure out how much coax is needed to connect the radio to the antenna you can go online as there are a number of places that will prefabricate cables with whatever type of connector you need.  The antenna and the Sporty's radio both take a BNC.  RG58 is the correct impedance for such an installation. Here is one source: http://www.cablesondemand.com/category/RG58/URvars/Catalog/Library/...

Good luck!

Tim

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Permalink Reply by rob steenweg on February 8, 2015 at 2:24pm

Jerry,

 An external  mounted antenna   would work a lot better than a Rubber ducky, a rubber ducky is a compromise antenna to start with.  Would not mount the antenna on the bottom of the aircraft, when standing on the ground the effective high of the antenna  is very low and the ground will absorb a lot of energy. My experiences with bottom mounted antennas is that some how the antenna connector always seems to be collecting moister etc. I agree Randalls  mounting suggestion on top of the baggage compartment.

Rob Steenweg

Avionics Maintenance Engineer and radio ham (VE1CHW)

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Permalink Reply by Bob Pustell on February 8, 2015 at 3:00pm

I have used handhelds in flight with and without external antenna. External is better, waaaayyyyy better. I agree with the advice to use a modern white fiberglas encased tuned antenna not a bare metal whip antenna. You might as well give that little tiny radio all the help it can get and the better style antenna will help.

Bottom mounted, in theory, works better inflight than a top mounted antenna. It also, in theory, works worse on the ground. In the real world there is no significant difference between top and bottom mounted and top mounted protects the antenna from damage much better.

Be sure to mount your antenna with proper distance from other antenna you might have - ELT, GPS, whatever. They can interfere with each other.

By the way, the one antenna that, for sure, works better on the bottom is transponder. Fortunately, it is such a stubby little thing that having it on the belly does not promote damage or problems.

My two cents

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