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RV8R999

Well Known Member
Just bought a couple of "experimental only" SS comm whip ant from Spruce. No BNC connector attached to the ant only a 1/4" mounting stud and insulator and nut. Checked SteinAir and dont see any type of BNC that has a terminal ring. I guess I can rig one up using some RG400 cable but this seems hokey to me. Does anyone of a P/N for a BNC used for ANT like this? Thanks

Ken
 
I have used a couple of these and made them work fine. I don't know of any BNC connector for them, but you can wire the center of your coax to the antenna and the sheild of the coax to ground using crimp on terminals. Make certian that you have good ground contact at the base of the antenna or it will not tune. Try to keep the leads as short as possible. You will have to tune the antenna by using some type of SWR meter and adjusting the length of the antenna for lowest SWR. You can adjust the length by moving the mounting nuts and/or trimming the antenna itself. This antenna will work just as well as any antenna, no matter how expensive, that is a similar length, but it will require some work.
 
Hey Ken,

I agree with Drew's advice on installing these sort of antennas - I have used them on other airplanes for years, and they can work very well. However, what I found when I tried to install one on my -8 was that it is very hard to shield the connections inside the fuselage so that they don't radiate RF. this was never a problem with older, certified avionics, and airframes, but with the newer digital EFIS's, instruments, and Autopilots (not to mention some Comm's....), you can have all sorts of weird LED effects when you key the mike as reflected RF bounces around inside your RV fuselage. Definitely not a good sign if you are planning on an IFR ship with digital boxes helping you along. Yes, you CAN install one of these inexpensive antennas if you do a perfect job at the connections, but if you are depending on digital electronics, you might find it is less trouble to spend th money on an antenna with a BNC connector. I initially installed one of the cheap ones on the belly of the Val - it got change out long before the airplane was finished (problems discovered during integration testing...) - it now lives on the roof of my hangar, as a receive-only antenna for our base station.

Paul
 
The only way I would install one of these on an RV is to put an aluminum box over the connection end after making a perfect connection to the antenna. Sort of like the boxes you see inside devices with tuners.

The goal would be to stop the RF from leaking out all over the airplane.

One could get creative and build a custom connector out of some pipe fittings that would cap down over the entire connection and shield the unshielded portion of the connection.
 
yeah thats what I thought..They were really cheap so I'll keep them around for an emergency..I actually have two really nice blade comm ant from my other plane but was planning on selling them..guess they are goin on the 8 now. Thanks!

Ken
 
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