SonexBuilders.net

I've had a rather big order of lots of electronic stuff, relays, wires etc. from spruce arrive yesterday so I'm like a child with new toys today :-)
One of the things I had ordered was my com and transponder antenna's, I bought these:
http://www.aircraftspruce.com/catalog/a ... ntenna.php

I chose the 45 degree bent antenna for com and standard transponder antenna.

Now that I have them I am wondering how you connect these to a coax cable, there is no BNC connector or anything, looks like you're supposed screw something on the end but what? (excuse my ignorance if this is a stupid question)

Anybody have any experience with these? I know I have seen them installed on Sonex's before.

I bought the same thing. You have two choices, spend hours searching the inter tubes looking for an adapter to go from the threaded end to a BNC, which I did find on a truckers CB radio website, or just crimp a terminal on the inner coax and another on the shield. The inner connector is attached to the threaded post on the antenna. The shield is grounded to the field plane on the fuselage. My goal was to try to get my used Garmin radio a friend gave me work. It didn't work well. One of the joys of experimental aviation. Trying things on the cheap.

I abandoned the entire setup and bought a new radio and antenna from MGL. Works great.

fastj22 wrote:I bought the same thing. You have two choices, spend hours searching the inter tubes looking for an adapter to go from the threaded end to a BNC, which I did find on a truckers CB radio website, or just crimp a terminal on the inner coax and another on the shield. The inner connector is attached to the threaded post on the antenna. The shield is grounded to the field plane on the fuselage. My goal was to try to get my used Garmin radio a friend gave me work. It didn't work well. One of the joys of experimental aviation. Trying things on the cheap.

I abandoned the entire setup and bought a new radio and antenna from MGL. Works great.

Thanks,
I've got a Flightline FL760 com, I'll try and make it work but might abandon it if it does not work.
In the mean time I found a thread on the subject on yahoo groups as well (after a lot of hassle trying to search something on yahoo):
https://groups.yahoo.com/neo/groups/son ... pics/72069
Looks like at least some have been able to make it work for them.

rizzz wrote:Now that I have them I am wondering how you connect these to a coax cable, there is no BNC connector or anything, looks like you're supposed screw something on the end but what? (excuse my ignorance if this is a stupid question)

My previous Sonex had an antenna connector like you have. I simply opened up the end of the coax enough to be able to separate the center feed from the grounding braid. I then used ring terminals on the wires to make the connection. Finding a ring terminal to fit around the base isn't too difficult but it is a large size. That's OK, you'll have plenty of braid to fill it with. Use a quality crimp tool or solder and use heat shrink to help strengthen the connection against vibration. I used a screw into the top for the center wire connector.

You need to also secure the cable close to the antenna. I did this with a spot of clear silicone attaching the coax to a cleaned and prepped spot on the aluminum floor close to the connector. Worked very well. You also need someone with an SWR meter to check the antenna after the install. Not sure where you plan to mount yours but Myunn has a bent whip on the belly and with that configuration the SWR can read a little high on the ground but in the air it gets better.

Hope this helps,

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
53.2 hours / Status - Flying
http://kitplanes2.com/blog/2013/12/ownerbuilder-2/
http://www.youtube.com/channel/UC49h6Qijc17_Ebfz0CbRFtg

rizzz wrote:I've got a Flightline FL760 com, I'll try and make it work but might abandon it if it does not work.

I have the Flightline FL760 and I really like it. When I first started using it during my phase one I was going in to a local airport one day for fuel. When I called they came back and suggested I switch to Com 2. LOL! I didn't have one of them. The problem was noise getting into the mic. I talked to a rep from a company that sells the Flightline radio and he gave me instructions on how to turn down the mic gain (it's inside the radio). Turns out that putting resistor plugs in the motor and using a much better headset made a world of difference! I now use, and highly recommend, the Clarity Aloft headset. Like many I choked on the price until I got them on my head and in the air.

I even use the built in intercom with good results. My passenger (the wife) was using an older set of Lightspeeds that I have and the combo worked well. I did turn off the Vox for the intercom as I have a panel switch wired to turn it on and off as needed.

Dale
N319WF

daleandee wrote:

rizzz wrote:Not sure where you plan to mount yours but Myunn has a bent whip on the belly and with that configuration the SWR can read a little high on the ground but in the air it gets better.

thanks,

With the com antenna on the belly, where have you mounted the transponder antenna?
I was planning to do com on turtledeck and transponder on the belly.

rizzz wrote:With the com antenna on the belly, where have you mounted the transponder antenna?
I was planning to do com on turtledeck and transponder on the belly.

You rich guys with your transponders ...

8~)

I haven't yet added a transponder as I'm waiting for the money tree to pop another bloom. Dick Fisher had the same set-up (he had the Micro-air radio) and his Comm antenna went in front of the spar box (as mine is) and his transponder antenna was back under the turtle deck behind the rear spar. Worked well for him. Not sure what the spacing requirements are other than "as much as is reasonably possible."

Dale
N319WF

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Here's how I ended up attaching the coax to the antenna:




As you can see I made a doubler to strengthen the attach point, the doubler has a 90 degree bend in it which is where the shielding attaches using a ring terminal.