Bryan - I have had hailers in the past and like them. As above, they make wonderful foghorns. I can also call other vessels that are close & look in distress, marina dock hands, people on shore, etc. for various directions or help. They are also very good to hear responses from people, to hear other fog horns or navigational sounds (bells, horns, etc.)
My hailers in the past have been independent units with a power unit, a send/receive horn outside, and a mike.
When I bought my 2120, I was very limited in space so I looked for a small VHF radio with hailer functions. I bought an ICOM M504 VHF radio that said it had these functions. I added the ICOM specified speaker/receiver horn on the roof.
The fog horn worked well and I could talk into my VHF mike and transmit and adjust the hailer output volume. But I could not receive any incoming sound on the hailer function. After a number of conversations with ICOM, they admitted the advertising was not correct for the M504 as it cannot receive incoming sound. They suggested I buy a more expensive (and bigger) ICOM VHF radio to get all the true "hailer" functions.
I'm okay with the fog horn and voice transmission out only features. In all my boating and many ICOM purchases, this is the first time I've ever had a problem with them so I'm really okay with them and what I have.
As you can see, I have the outside fog/transmit horn aft over my convenient Parker wire run and it works fine calling forward.
Good luck with yours,
..........Pete
