Garmin 300 to 800 AIS upgrade - fitting size

calcman05

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Joined
Feb 3, 2024
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Fluid Motion Model
C-302 SC
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DINGLEHOPPER
I just swapped out my old Garmin AIS 300 for an 800 so I could transmit and receive. It's working great and sending position messages as it should. Unfortunately I'm having trouble getting it connected back to my Garmin VHF200 radio. The VHF antenna is supposed to go into the AIS unit (working) and then from the AIS back to the VHF200 radio. Unfortunately the size of the output connector on the AIS 800 is small, and the cable the connects to the radio is large. Any idea what exact connection formats I'm working with? Seems like I need some adapter.

My old AIS300 only had the large size plugs, so that's why I'm in need of some adapter.

See photos.

Appreciate any insight!!
 

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The AIS800 typically ships with accessories in the box, notably for this purpose a 1.2m interconnect cable which has TNC on one end and the PL-259 on the other.

Options to complete the install would be:
1) Buy an SO-239 coupler and install it between the existing cable to the VHF and the included interconnect cable.

2) Buy a TNC to SO-239 adapter and install it directly onto the AIS800, then connect the existing cable to the VHF.

3) Cut the PL-259 plug off the existing cable and install either a crimp or solder on TNC connector, then just plug it into the AIS800. (Less loss on the system this way)

4) Buy a pre-made cable long enough to replace the existing, which already has TNC to PL-259 as the plug ends.
 
I just swapped out my old Garmin AIS 300 for an 800 so I could transmit and receive. It's working great and sending position messages as it should. Unfortunately I'm having trouble getting it connected back to my Garmin VHF200 radio. The VHF antenna is supposed to go into the AIS unit (working) and then from the AIS back to the VHF200 radio. Unfortunately the size of the output connector on the AIS 800 is small, and the cable the connects to the radio is large. Any idea what exact connection formats I'm working with? Seems like I need some adapter.

My old AIS300 only had the large size plugs, so that's why I'm in need of some adapter.

See photos.

Appreciate any insight!!

Garmin uses a special cable for the VHF splitter to pass through the VHF signal from the antenna to AIS and back to the VHF radio. The Garmin 800 usually comes with this cable. The Cortex unit does not come with one.

I just bought one for a Cortex AIS install I'm doing. Here's the link.
 
I went with the adapter from vetco and it fit perfectly. Thanks everyone for the help!!

 
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