Vert Stab mounted Nav antenna. Facing FWD or Back?

apkp777 · #1 11-19-2009, 10:58 AM

Hey all,

I see some builders have put their "cat" whisker Nav antenna facing fwd. What's the deal with that? I am trying to install a RAMI nav antenna and it does seem to be a round peg in a square hole. The rudder contacts the antenna when facing aft, facing fwd it looks kind of goofy. Any thoughts on this?

Also, the round insulator puck is too wide for the stab tip. I am assuming everyone has just cut some of sides away to make it fit. Am I correct?

noelf · #2 11-19-2009, 11:25 AM

...in the tail fin of my -6A with the whiskers pointed aft. I am 6'2" and the tips just hit my eyebrow...make that eyebrows, no uni brow here

I checked to be sure the antenna would not interfere with the rudder deflection, and all was ok.

You are correct that the hockey puck is larger that the width of the stab tip. But do not cut into the hockey puck. The hockey puck contains the BALUN that matches the impedance of the cat whisker dipole antenna to the impedance of the 50 ohm coax you will be using.

That said, I chose not to use a hockey puck, but rather constructed the balun out of the coax cable (design and construction articles aplenty on the web and in Nuckolls' book). The balun coax was stuffed into the vertical stab tip, and I constructed a "V" block out of UHMW material to hold the antenna whiskers. VOR reception is quite good, I have no plans to change anything.

But, if I were to do this again, I would mount the whiskers facing forward just to keep them away from my eyes, and I would try to use the hockey puck, but mount it in a vertical orientation (make a bracket) and still use my custom "V" block with some short wire to attach between the hockey puck balun and the SS antenna elements that are attached into the block.

apkp777 · #3 11-19-2009, 12:15 PM

I already fabbed a BALUN. Now I just need to figure out how to mount the antenna. I am considering belly mounting. Any downside that you know of?

Mike S · #4 11-19-2009, 01:06 PM

Quote:

Originally Posted by apkp777

I already fabbed a BALUN. Now I just need to figure out how to mount the antenna. I am considering belly mounting. Any downside that you know of?

Poking the dog in the eye????

boom3 · #5 11-19-2009, 02:02 PM

I made a couple brackets and mounted mine on top with the whiskers facing forward. I put nutplates on the VS for the fiberglass tip so it is removable.