Join Date: May 2006
Location: Chicago, Illinois, USA
Model: 1997 GL1500 2007 GL1800
So far I am pretty happy with the JMCB. I was kind of forced into it when I ditched the stock radio and therefore lost the intercom ability. I have the DU model and have my intercom back. And yes it does have a 3.5mm aux in so you can hear MP3's or whatever in the headset. The only thing is that it uses a 6 pin cord for the headset. As long as you are using a J&M headset that has CD, ECD, BCD, ICD in the model #, all you have to do is purchase a separate lower cord and you can use the same headset on either bike.
As far as the grounding plate, I don't think it adds any structural stability, it was just a way to attach the antenna to the frame because where the antenna mounts, it is all ABS. When I first added the Hondaline CB to my Aspencade years ago, I thought I would save some money and just buy the replacement antenna instead of the kit. It came with nothing extra, no grounding plate, no coax extension, etc... Just the antenna. I ended up having to buy the coax extension for it and went ahead and bought the grounding plate as well. IMHO, it didn't ground thatmuch betterand I ended up sanding it down a bit around the holes so it would provide a better connection. It wasn't until I went to an auto parts store and picked out an engine grounding strap that I was able to get decent SWR reading. I attached it to the lower antenna bolt and then to a bolt on the frame. It worked better than the grounding plate IMHO. Also hopefully you have the correct coax and aren't just going to use a regular AM/FM extension coax. I did that the first time around and it didn't work very well. Couldn't get the SWR's to come down low enough. I ended up buying the proper Honda CB Antenna extension cable and that worked wonders. You can identify it by the grey covering on the female connector instead of a black female connector. It is part #39169-MZ3-770 and is around $15. I think I still have it and have no use for it if you are interested.
When checking the SWR's, make sure to check it at the antenna connector at the CB transceiver and not at the connection under the seat. It needs to take into consideration the coax along with the antenna to properly tune it...
Honorary Wild Rhino- Thanks Fly!!
97 Aspencade - Pearl White
Darkside Rear Tire- Austone 175R16
Double Darkside Front-Battl-Ax BT-45 130/70-18
2014 starting mileage- 60106
07 GL1800 - Crucible Orange Metallic
Converted to California Sidecar Viper Trike.