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MB antenna in cowling

F

Flying Scotsman

Well Known Member
I see references in several threads to people putting their marker beacon antennae in the cowling...sounds like a nice solution, anybody have pictures/recommendations as to how to do this? Top or bottom? Glassed in? Etc...

TIA!

Steve
 
Another option would be not to install it at all. From what I understand unless you're shooting Cat II/III ILS's or need an OM for the FAF on a LOC approach when your GS is out (and a GPS can sub for that), you don't need a MB receiver any more.
 
Anywhere

Steve,

I used a 40 inch piece of RG400 coax with the outer braided shield stripped. I epoxied the inner portion to the upper side of my wingtip.

I imagine you could use any convenient place on the lower cowling, as long as it was had minimal shielding from below. You just need to remember to disconnect it before removing the lower cowling.

If I were to put mine in the lower cowling, I would definitely glass over it because of the different environment.

For that matter, a coat hangar in the front of the gear strut would probably work too. Maybe someone could test that :)
 
I used a "boat" style MB antenna. I believe it was from RA Miller?? It is intended to be mounted on the underside of the belly of the aircraft.

I mounted it to one of the engine mount tubes, sort of in-line with the hot air exhaust from the baffle mounted oil cooler. It pretty well has melted the plastic housing of the antenna.

I have only made one approach/ landing at an airport with MB's and an ILS. The MB lights and tones were inop for me. I did not fabricate a ground plane plate for this antenna, so I do not know if that is my issue or I just plane overheated the antenna to the point of failure.

I may try the stripped back RG400 approach next.
 
BNC connector on firewall

I placed a BNC connector on the firewall and glassed in a 40 inch stripped piece of coax right below the hinged lined on the lower cowl.

A quick and easy install.
 
Steve,

I should be able to answer that question in a few days. Just returned from transition training and prepping for first flight. :)

Will let you know.


Mike
 
cfiidon said:
I used a 40 inch piece of RG400 coax with the outer braided shield stripped. I epoxied the inner portion to the upper side of my wingtip.
Don,

Please help me understand....did you run RG400 from your audio panel all the way out to the wing and strip off the last 40", or did you only use a 40" section in the wingtip attached by smaller wires back to the audio panel?

Thanks,

Tony
Click to expand...
Click to expand...
 
tonyjohnson said:
cfiidon said:
I used a 40 inch piece of RG400 coax with the outer braided shield stripped. I epoxied the inner portion to the upper side of my wingtip.
Don,

Please help me understand....did you run RG400 from your audio panel all the way out to the wing and strip off the last 40", or did you only use a 40" section in the wingtip attached by smaller wires back to the audio panel?

Thanks,

Tony
Click to expand...

Tony,

I epoxied the 40 inch stripped section to the wingtip. I have about another 18 inches of "pigtail" with a BNC connector on it. The RG400 will run from the audio panel out to the wingtip and connect there to that pigtail. This facilitates removing the wingtip when necessary.

Don
Click to expand...
Click to expand...
 
thanks

Don,

Thanks for that info.

It seems then that it would take about 20 feet of RG400 cable. I can see why guys would prefer the savings in weight and cost to go with the cowl.
 
I saw a different approach to the cowling mount that I'm planning to use. The guy mounted a rubber ducky antenna to one of the lower mount tubes using Adel clamps. What I like is the antenna does not need to be disconnected to remove the cowling. The antenna he used was a Pryme RD-8. It's about a foot long with a BNC connector on the base. I'll put a bulkhead BNC connector on the firewall and run RG-400 from there to the antenna and radio.
 
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