Garmin 200 VHF Radio w/ Garmin 300 AIS Not Receiving

[MechGuy]

On a new to me 2017 31s, I have a Garmin VHF 200 radio connected to a Garmin AIS 300 and found the Garmin VHF not receiving, just static. It may or may not be transmitting, I don't know. I suspect the splitter in the 300 AIS unit is the issue. I'm wondering if I could replace my VHF 200 and 300 AIS box with a Garmin VHF 215 AIS? Thanks.

 

[SJI Sailor]

First I'd try plugging the antenna directly to VHF (not to AIS 300) and see if that solves it. Use a handheld VHF to test (always important to have around, just use channel 68 etc while testing and not 16!)

If it still doesn't work, I'd try a separate VHF emergency antenna (also good to have) to determine whether it's the radio vs antenna.

As for replacing the radio and AIS together ... yes, if the antenna is good, that's an option. I'd personally consider a transceiver (broadcast) unit such as Cortex rather than receive-only in that case. Good luck!

 

[MechGuy]

Thanks for that info SJI Sailor. I’m heading down to the boat and will connect the vhf radio directly to the antenna to see if it will work bypassing the AIS box. The Vesper Cortex is a beautiful system but was hoping to spend less for a solution.

 

[Rocky]

I had a radio issue a while ago....I learned that most VHF issues are due to issues in the Cable or Antenna. So you are on the right path....
In my issue, the cable outer casing had worn through where it came out of the cabin....and the wires had corroded. I replaced my antennas at the same time and all is well....

So check the cable as well...

Rocky

 

[MechGuy]

I confirmed that it’s the Garmin AIS 300 unit. I connected the VHF radio directly to the antenna and it works perfectly. The odd thing is I’m still picking up AIS signals on the chart plotter from surrounding boats in the marina with no antenna plugged into the AIS unit. So now I’m wondering if I can use an external splitter to share the antenna with both?

 

[SJI Sailor]

Good news! The local signals are probably strong enough to pick up on the AIS without an external antenna. Adding a splitter should work fine (I would expect) and personally I'd consider this one made for this exact purpose:

Shakespeare 5257-S Antenna Splitter f/VHF Radio, AIS Receiver & AM/FM Stereo https://a.co/d/7WP1fAZ

However I have another idea ... if you don't have a small emergency VHF backup antenna, get one and attach it to the AIS antenna in, and see how well it performs inside the cabinet. The boats are fairly transparent to VHF frequencies and we don't need long range AIS reception. Best case it costs less and you get a backup antenna, too. Worst case you get a splitter later and still have a backup antenna 🙂

Shakespeare 5911 Classic Emergency VHF Antenna https://a.co/d/7v9iRYb

Just a thought and maybe there is some reason not to try it but it seems reasonable to me.

 

[MechGuy]

Thanks for that info. I suspect the emergency antenna would work sufficiently for close range encounters which would be the main concern. Either one will save me from spending the big bucks for a while. Thanks again.

 

[RandR]

Related question. I have a new to me, 2019 R-31S with a Garmin VHF. I receive AIS well, but I don't transmit. Where is the AIS 300 box located so I can see if I have one.