Marker Beacon and Transponder Antennas

[dahugo]

I am a ham radio operator, so I am pretty sure that almost any antenna outside will receive a marker beacon signal--in other words I dont' have to buy one of the expensive ones, and can probably install a cheapie COM radio antenna underside to receive the marker beacon. Anyone disagree? If so, why?

Also, do the $120 blade antennas for transponders work any better than the $18 stubbie? They're both 1/4 wave so I cannot imagine they do.

Finally, has anyone tried using an NMO mount antennas usually desigend for auto use on an airframe?

[aparchment]

There was just an article on antennas in Kitplanes magazine. In the article Stein says that the stubby transponder and the blade appear to perform the same, so unless you are dying over the aesthetics, get the stubby and save some money.

[captain_john]

A local builder here 'glassed a stripped piece of coax into his lower cowl for his marker beacon. I am thinking of doing the same thing in a wingtip.

I think Dan's site (www.rvproject.com) has some details somewhere on how he did his. I wanna say 40" of stripped coax is the correct length.

As far as the XPDR is concerned, the little stubby one is the one I was planning on.

CJ

[Dan A]

The only real difference between the antennas for the transponder , other than price, is the blade doesn't break off when you wash the plane with a brush!

Dan RV 8 N742DA WA7WLV

[captain_john]

I have been hearing about the little stubbies a lot lately. Seems everyone is saying that they are easily broken if ya hit them with the cleaning brush.

I am gonna give it a try anyways and just be careful when I wash the plane. I will probably do it by hand anyways.

CJ

[cjensen]

I did the ball-on-a-stick antenna. For $12-19, why even worry about it? Just be careful, and if you break it, buy a new one! BTW...the blades will break too if you're not careful when cleaning...ask me how I know.

[dpansier]

It wouldn’t take much to pull a mold off a streamlined transponder antenna and cast a new one. Use the stick and ball antenna and cast it into the mold with West epoxy and West 404. Place two 8-32 screws into the epoxy for mounting the unit to the aircraft.
Search the Internet for hobby molding, lots of info.

Once you have the mold you can make as many as you like, you can give one to all your buddies. <G>

Don
RV-7 Finish Kit

[Rockyjs]

I agree that virtually anything will work for a marker beacon antenna. I'm going to try a ball on the stick transponder antenna for that and see how it works. I'm actually gonna use the fuel vent in the wing root that the rocket guys use, and am using the pre punched fuel vent holes for a marker beacon and transponder antenna.