NR240CA Roof Rack Mount SWR and Photo.jpg

This is a Diamond NR240CA, be careful I've seen the NR240C being sold and I don't think it's the same thing. This is a wide-band antenna using a similar design to the Comet CA-2x4SR model.

https://www.diamondantenna.net/products/NR240CA

I tested the match on a roof rack mount.

https://forums.mygmrs.com/gallery/image/471-mobile-mount-with-antenna-rear-view/?context=new

Note this is a 5/8 wave design and requires some kind of a ground plane to work. For whatever reason the match was way better than I had expected with that mount. Your installation could be significantly different. Note I have 13.5 feet of RG-316 coax in line with another 10 feet of RG-8X mini coax. The extra loss in the cable helps to reduce the SWR. When I tested the nearly identical CA-2x4SR, on the same mount system, the SWR match was higher. The testing was done using a RigExpert AA-1000 antenna analyzer. So on an equal testing basis the NR240CA seems to do better.

The Diamond NR240CA is significantly more expensive than the Comet CA-2x4SR. However the Diamond has a locking collar design for the fold over feature.

https://www.diamondantenna.net/static/pdfdocs/NR240CA.pdf

The Comet uses a simple spring loaded design where one has to pull up on the antenna until the bottom end is clear of the socket to fold it over. With time the spring looses tension and lifts out of the socket at highway speeds falling over. My old CA-2x4MB antenna has this problem. I had to wrap electrical tape around the fold over area to permanently prevent this from happening again. I like the locking collar design of the Diamond better. 

https://forums.mygmrs.com/gallery/image/473-close-up-of-mobile-mount/?context=new