Power cable Nuvi 765T

Is this a Garmin cable, or aftermarket?

Assuming you are referring to the newer style GTM 20 without LED's. It is used for an external FM antenna. It accepts a 2.5mm stereo phone plug with the antenna connected to the tip.

Supposedly Garmin sells an accessory antenna, p/n 010-11282-00 and can be seen at https://buy.garmin.com/shop/shop.do?pID=33370, but I have never actually seen one.

Thanks for the response! I do have the GTM 20. I will see if plugging my scanner antenna helps improve reception in known areas where I loose the signal.

Is the jack on the CABLE or on the MOUNT? My nüvi 760 MOUNT has a small jack on the side that's used for an external microphone when using it with the Bluetooth feature.

GPS Satellites transmit their signals in RHCP (Right Hand Circular Polarized) RF array. Your vertical scanner antenna might degrade or completely null that signal out. Most scanners won't cover the GPS frequencies although some will. Good luck on your experimentation !

Military: 1227.6 MHz
Civilian L1: 1575.42 MHz
Civilian L2: 1227.6 MHz
Nuclear burst detection L3: 1381.05 MHz
Civilian L5: 1176.45 MHz (introduced on 2F)

Let us know the out come of the better reception.Several users have posted about the connection on the power cable but not if it was a improvement.

I didn't have much luck with faster / better reception using the additional antenna.

I have to agree with charlesd45. If I go to the diagnostic screen on my Nuvi 765 I can see that when I plugged in my external antenna the signal level went up and the error count went to 0. But I was also able to get the same thing to happen by just moving around the GTM 20 power cable.

I guess with the Nuvi 765 if you want the traffic you must be tethered to the GTM 20. No way of receiving traffic without it. When I unplugged the cable traffic stopped working.

Is the 2.5mm jack on the mount used for bluetooth microphone?

Yes

After the fix for the 7x5's, acquiring satellites was much improved for me, but i had already bought a booster. When the weather is poor the booster may come in handy. Now it sits in the corner, have no need for it. I don't get reception in under ground parking lots, which means my last position doesn't work. Inside of malls doesn't seem to be a problem, or other buildings. I still see posts in here where people have problems with these units. Most of the time I don't have those problems. My screen still stalls here and there and reboots once in a while. You would think that all 7x5's should work or not work the same. Thanks Garmin, for your quality control.