NMO O ring.

[superman2112ms]

What size is the O ring for the NMO mounts. Is it in fact an O ring or a flat rubber washer type? The groove in the mount appears to be for a flat ring. Obviously the old one I am looking at is old dried out and flattened. I just want to go to the hardware store if possible.

 

[jeepsandradios]

its definitely an o ring. Larsen sells a pack of 3 for under $10.00. Do a google search and you will find many locations to get them

 

[KB4MSZ]

Here is EBay

O Ring Replacements for NMO Antenna Mounts - Package of 5 Rings - by W5SWL ® 721405425549 | eBay

 

[a417]

They are usually toroidal in shape. I'm sure cheaper, knockoff ebay specials might have a flat gasket.

 

[N4KVE]

Depends which o-ring you are talking about. The one that goes in the bottom of the antenna is round. But the one that goes around the NMO mount, & sits on the trunk/roof is flat. My friend keeps telling me since I have the round o-ring in the antenna, I don’t need the flat one that’s on the car, but I use both. The flat ones gets crispy after a year, so I pick up a few at the ham fest, & replace them.