Connector installation to Non-TSO'd Comm Antenna

Hi all:

Quick question. I'm installing one of those El Cheapo $19 bent whip comm antennas from AS. One of these: http://www.aircraftspruce.com/catalog/avpages/stainlessantenna.php

So, I understand that you connect the center contact from the coax to the antenna via, what looks like a crimp on connector. There is an illustration in the Aero Electric book that shows this. My question is, what kind of connector is this? Is it indeed a crimp on? Where do you find a connector that can accept a wire as small as the center wire in a coax and still big enough to fit on the antenna?

Thanks

Kelly Johnson

Quick answer is... Yes, it should be a crimp-on connector such as an AMP PIDG in red colour, or similar. The centre conductor of the coax is actually fairly large, close to 22ga, so the red connectors work just fine.

Now I'll throw in an answer to a question you haven't asked. Doing the el-cheapo antenna installation will generally result in el-cheapo results. I've installed literally hundreds of antennas on airplanes in my career and have never had a problem with any of the good ones that were well treated (driving them into the hangar door or snagging a belly-mount antenna on a snowbank doesn't count as proper treatment!). Wish I could say the same for the el-cheapo ones. The last one I installed lasted less than a week. The owner was removing his canopy cover when it was caught be a gust of wind and wrapped around the comm antenna. By the time he had managed to get it unfouled from the antenna, the ceramic insulator on the antenna was busted. He asked me to repair it but after a short discussion I convinced him to put on a used Comant antenna. He's never regretted spending the extra $80 or so that the used antenna cost him, just as I'm sure you wouldn't if you ponied up the extra bucks to do it right the first time.

I have the cheap ant. on my -8A it works great . I have talked to other aircraft over 100 miles away my alt. 3000 agl the other aircraft was 1500 agl.I have received aircraft that were in the pattern over 200 miles away.
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Jim - glad to hear yours is working well. In general, they work well since they're a very simple antenna. However they also generally are far less mechanically robust than something like a Comant, Antenna Specialists, etc which have a 3 or 4-screw mounting base and BNC connector. The only performance problems I've seen with the simple steel whip antennas seem to come from the nuts backing off, allowing the coax connection to come loose. The remainder of the failures have all been basic mechanical failures, typically cracked/broken insulators at the base of the antenna. In helicopter installations this kind of failure is extremely prevalent.

ArVeeNiner said:

Hi all:

Quick question. I'm installing one of those El Cheapo $19 bent whip comm antennas from AS. One of these: http://www.aircraftspruce.com/catalog/avpages/stainlessantenna.php

So, I understand that you connect the center contact from the coax to the antenna via, what looks like a crimp on connector. There is an illustration in the Aero Electric book that shows this. My question is, what kind of connector is this? Is it indeed a crimp on? Where do you find a connector that can accept a wire as small as the center wire in a coax and still big enough to fit on the antenna?

Thanks

Kelly Johnson

Click to expand...

Kelly, I've been using the $57 whip antenna (the one with the ceramic insulators) on my RV-6 since 1999. It too uses a simple connector at the antenna root. I soldered the coax center conductor to the ring terminal and clamped the coax to the airframe an inch or so from the connection to eliminate strain and vibration. The antenna has performed flawlessly with no service problems for 875 hours.

The more expensive antennae are no doubt more robust if abused, but not necessary for good RF performance.

I have one of the cheap ones too, and it has worked fine. At 5,000 ft I've reached approach from 10 miles out. I don't know what the limit of my range is but I'm not sure why I would need more range than that. I did break it off at the first thread once when cleaning the underside of the plane. Just backed into it and it snapped. I bought a replacement at WagAero for about $20. I also have a piece of stainless rod the right diameter (3/16"?) that I will thread, bend and cut to length if I ever break the antenna again. I think I paid $3 for the 36" rod at Lowes.

Thanks for the input everybody. Since I already have it in hand, I'll install the cheap one and see how it goes. I'm putting it in a place that is very accessible if I need to upgrade it.

KJ