Marine Band - Different Radio Channels

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Marine Band - Different Radio Channels

Postby G4RMT » Wed Mar 22, 2017 10:05 pm

In another topic, I mentioned that Marine band channel implementation is not the same in every country, but I've also discovered that in a random selection of radios, even within a country allocation there are differences and channels simply missing. There are a number of common simplex channels that run across all the specifications and radios I tested, but even allowing for the fact that some radios cannot display the 'A' after the channel number, usually designating simplex use of a normally duplex channel, some strange frequencies still appear.

If anyone is interested - I put the results of my transmit and receive testing of four different radios - 3 Icoms and 1 Dolphin. I did rather assume the Icom radios would all be the same, but they aren't.

If you want to download the Excel spreadsheet - here is a link.
http://www.limelight.org.uk/marine-band-frequency-slots-multiple-radios.xlsx
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Re: Marine Band - Different Radio Channels

Postby Giblets » Sat Mar 25, 2017 11:03 pm

The channels with the A suffix are ones that are used in the USA. On a dedicated marine VHF transceiver one normally has the option to select either the USA group of channels or the International group which is what is used in the UK.
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Re: Marine Band - Different Radio Channels

Postby G4RMT » Sun Mar 26, 2017 12:29 pm

Er, yep - that's where I got the information from - the radios I have here. I probably didn't explain it well, the thing that surprised me is that even on some of the Icoms that have International, US and Canadian programming, some channels are missing, others have jumps, and it's not obvious in manufacturers blurb what channels are in them. "Programmed for international Marine channels" says the info - but if you are into yachting them the UK marina channels would be pretty important - but not every Icom I have here has them. In that spreadsheet you can see which channels are common to all or some band plans, but it's a bit weird how some are just absent.

Most of the US ones have simplex versions of the ones that are duplex in the UK - most use the A to denote this, but not all - some show no 'a' in the display, but are working on simplex. I have two Icoms that in the high 80's will not talk to each other on one channel, but one up or down they will?

I'd not be happy buying a radio that had channels mysteriously missing - you never see a spec that lists what they have in them?

I pulled one of the Icom M5's apart and it has a keyboard programming jumper installed like the H/U-16 series it shares a chassis with, but the H-16 access code doesn't work - so unless I hit on it by accident I can't experiment with programming. As I have two where one has been reprogrammed, it clearly can be done - just not by me.....yet.
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Re: Marine Band - Different Radio Channels

Postby Giblets » Sun Mar 26, 2017 10:49 pm

Just had a look at the spreadsheet and am not too sure which channels you say are missing. Certainly the marina channel 80 is shown but if you are thinking of the old marina channel which was 37 (157.850) this is now M1 which is the channel all sailing clubs use for their comms during races, etc. I am into yachting and all my UK based radios have Ch 80. I sometimes have one of the handhelds set to the USA set in order than I can monitor the boats transmissions on 80A when they are talking to the marinas which receive on 157.025 (80A) but transmit on 161.225 (80) being a duplex channel in the UK.
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Re: Marine Band - Different Radio Channels

Postby G4RMT » Mon Mar 27, 2017 9:33 am

37(M1) and M2 are in one of the Icoms, a modern one, and one of the older ones - but missing from the Dolphin, and the slightly older Icom - very odd, and makes these useless on the marina channels. I had assumed, and never checked, that all the radios had all the channels in the allocation. I've another boxed marine radio on the shelf - I'll power it up and check what it has in it.

It must mean that plenty of people have incomplete radios in their boats - perhaps never even noticing that certain channels are absent!
EDIT
Just checked a Marine-i II TX-150H - brand new, International channels, and it has channels 75 and 76, not present in two Icoms, but doesn't have the marina channels?
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Re: Marine Band - Different Radio Channels

Postby Giblets » Mon Mar 27, 2017 1:36 pm

37(M1) and M2 are not the marina channels now. In fact M2 never was. This falls to duplex Ch80 only in the UK.
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Re: Marine Band - Different Radio Channels

Postby G4RMT » Mon Mar 27, 2017 2:51 pm

It does seem strange that while all the radios have the duplex ch 80 - the other two are not in all of them, but I suppose it's because these are not in the international allocation. Must make buying a radio for use by sailing clubs not quite as simple as it sounds!
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