communications trailer antenna mount in top

[vsp5151]

We have small trailer we are fixing up for an amateur communications trailer. We would like to have two 1/4 wave antennas on top, one for UHF and one for VHF. These would be temporary use antennas typically used after you get to where the trailer is needed until better antennas could be deployed. There is no headliner in trailer, the aluminum top is easily accessible. Would a NMO mount work in this thin aluminum? We even discussed backing the inside of the trailer top with a piece of thin metal just to provide extra strength. Would this mount work or is there a better mount we can use for thin aluminum.

 

[mmckenna]

Adding some rigidity under the aluminum should be pretty easy. Since the area will be dry inside the trailer, regular sheet metal would work fine. You can get that in various gauges from most hardware stores. Trick will be securing it. Not sure I'd trust glue or any other adhesive due to heat coming through the roof. If there's any frame work to support the roof, work with that.

A standard NMO would work just fine. If you wanted to get fancy, they make NMO mounts with an "N" connector on the underside.

 

[SteveC0625]

I used a 3/8” NMO and found a thin fender washer with a 3/8” ID for the underside of the roof. It’s been on our shelter resource trailer for several years with no issues

 

[jeepsandradios]

As others said a NMO mount is fine. I helped with multiple SAR trailers in NY and all have some variant of an NMO. The 3"8" is better in my opinion as its a simple hole. I actually found that a 4x4 outlet box cover plate works perfect on the inside to help with making it rigid. I have used a fender washer in a pinch also.

 

[K4RBT]

They do this in aircraft with its thin skin, it is called a "doubler plate", only problem is they rivet the skin and plate together. If you are near an airport with a FBO, check with them to see if there is another way to mount the plate. For honeycomb panels like on helicopters, it is done differently.