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Sailon1 · 24-12-2019, 10:26

Greetings,

I am searching for an inexpensive VHF radio with AIS transponder. Ebay has a refurbished Icom RKB M506-21 for less than $400. I've just begun
exploring this topic, and would greatly appreciate any input. The system will
be replacing the VHF radio on board. A few concerns:

1. Will existing masthead VHF antennae be compatible?
2. Screen size and color? I wear reading glasses.
3. Best to mount in the cabin or in the cockpit? Current VHF is in cabin.
4. Recommended brands or non-recommended brands?
5. Other???

Thank you for your input!

continuouswave · 24-12-2019, 12:18

Quote:

Originally Posted by Sailon1

I am searching for an inexpensive VHF radio with AIS transponder

Just to be sure: do you really plan to install a CLASS B AIS Transmitter on your boat?

Or do you just want a VHF Marine Band radio with an integral AIS receiver?

You will not find any VHF Marine Band radios with an integrated AIS Class B transponder at a $400 price point.

At the moment I believe there is only one such device approved for sale in the USA: the NAVICO Simrad RS40B. It sells for about $1,200. The RS40B has connections for transmission lines to two antennas, one for the voice radio and one for the AIS transmitter.

If you want to use a single antenna, you need the NSPL 500 AIS Splitter, a $250 accessory.

Quote:

Originally Posted by Sailon1

Will existing masthead VHF antennae be compatible?

I am confused by your use of "antennae." Do you have more than one antenna on the masthead now?

An AIS transmitter operates at 162-MHz. Generally an antenna already installed for a VHF Marine Band radio will be tuned for 156-MHz. The VSWR bandwidth of such an antenna will be unlikely to be very broad, but depending on the transmission line loss the VSWR may appear to be below 2:1, which will permit the AIS transmitter to operate normally.

CarlF · 24-12-2019, 12:53

Yes. VHF radios usually are AUS receivers but not transponders. Getting just a receiver loses the best parts of AIS. You want ships to see you as much as you want to see them. They’ll also usually answer a radio hail too because they can see your name on their AIS display rather than looking for another small white sailboat.

If your current VHF is working OK just leave it. A handheld VHF is very handy to have in the cockpit too.

I have a Vesper 6000 transponder. A very popular unit that works with any Chartplotter. It can be mounted anywhere. No holes to drill. It connects to my chartplotter and also networks to my phone and iPhone. I also got a Vesper antenna splitter and share the VHF antenna. Early splitters had a lot of problems but the Vesper one is great. It even has its own amplifier to strengthen the signal.

The Vesper has a built in VSWR measure of your antenna and coax quality. If it shows poor, replace them for better VHF and AIS range.

https://www.milltechmarine.com/Vespe...nna_p_359.html

https://www.milltechmarine.com/Vespe...ter_p_225.html

slug · 24-12-2019, 13:17

Quote:

Originally Posted by continuouswave

Just to be sure: do you really plan to install a CLASS B AIS Transmitter on your boat?

Or do you just want a VHF Marine Band radio with an integral AIS receiver?

You will not find any VHF Marine Band radios with an integrated AIS Class B transponder at a $400 price point.

At the moment I believe there is only one such device approved for sale in the USA: the NAVICO Simrad RS40B. It sells for about $1,200. The RS40B has connections for transmission lines to two antennas, one for the voice radio and one for the AIS transmitter.

I
If you want to use a single antenna, you need the NSPL 500 AIS Splitter, a $250 accessory.

I am confused by your use of "antennae." Do you have more than one antenna on the masthead now?

An AIS transmitter operates at 162-MHz. Generally an antenna already installed for a VHF Marine Band radio will be tuned for 156-MHz. The VSWR bandwidth of such an antenna will be unlikely to be very broad, but depending on the transmission line loss the VSWR may appear to be below 2:1, which will permit the AIS transmitter to operate normally.

I’ve used the Simrad ais for years..no problems

Dedicated ant

Ais output to chart plotter

At the time the Simrad was the cheapest transceiver unit

Vortec · 25-12-2019, 19:49

I have a Lowrance Link-8 with built-in AIS receiver witch outputs NMEA 0183 to OpenCPN. It has this advantage that it monitors my budget Matsutek HA108 transceiver. I don't think it is a transponder because then it should respond on request (as my transponder in the little Cessna did).

kev_rm · 25-12-2019, 19:59

Don't be fooled by marketing related to AIS vs. VHS antenna. The difference in antenna optimal dipole configuration of 162 to 156 megahertz is I think less than one inch. (assuming quarter wave)

Quote:

Originally Posted by continuouswave

An AIS transmitter operates at 162-MHz. Generally an antenna already installed for a VHF Marine Band radio will be tuned for 156-MHz. The VSWR bandwidth of such an antenna will be unlikely to be very broad, but depending on the transmission line loss the VSWR may appear to be below 2:1, which will permit the AIS transmitter to operate normally.

continuouswave · 26-12-2019, 07:58

Quote:

Originally Posted by kev_rm

Don't be fooled by marketing related to AIS vs. VHS [sic] antenna. The difference in antenna optimal dipole configuration of 162 to 156 megahertz is I think less than one inch. (assuming quarter wave)

Your thinking is incorrect.

A wavelength at 156-MHz is 75.66-inches

A wavelength at 162-MHz is 72.86-inches

This is a difference in wavelength of 2.8-inches. The typical VHF Marine Band antenna is a half-wavelength radiator.

The VSWR bandwidth of small-diameter whip half-wavelength end-fed antennas with base matching transformers to 50-Ohm is not very wide due to the small diameter of the radiator and the large impedance variation with frequency due to the end fed arrangement. Manufacturers of this type antenna provide a cutting chart to permit the radiator to be cut to the proper length.

continuouswave · 26-12-2019, 08:02

Quote:

Originally Posted by slug

I’ve used the Simrad ais for years...

The SIMRAD RS40B radio has only been available for sale for a few months, so it is unlikely you have "years" of experience with it. You must be talking about a different SIMRAD AIS device, not a CLASS-B AIS Transponder integrated into a VHF Marine Band DSC radio as in the RS40B I mentioned in my remarks you quoted.

thomm225 · 26-12-2019, 08:42

Looks like the Standard Horizon GX2200 VHF/GPS/AIS does the same thing as the unit you found on Ebay and has GPS.

It uses the same antenna as an old VHF Radio

I replaced my 1990's era Standard Horizon Intrepid VHF with a new GX2200 for around $310

Mine is mounted in the cabin by I can see/read it from the cockpit as it's aimed that way mounted in the same place the old one was

I wear reading glasses when needed but don't need them to read the screen on this unit while sailing

Standard Horizon GX2200 Matrix AIS with GPS

https://www.thegpsstore.com/Standard...ite-P5754.aspx

**tkeithlu** · 26-12-2019, 09:10

I'm quite happy with my Chinese Matsutec hp33a, which is available for $300 or less from several sources. The designer included route plotting, so it serves as a backup nav unit as well. It'll even give you GMT to the second for celestial, if that floats your boat. Given that you can buy a fully functional (MMSI, etc.) VHF radio for $100, I'm not sure of the advantage in paying $400 plus to achieve this.

DefinitelyMe · 26-12-2019, 11:01

I also vote for a Matsutec 33A, plus separate VHF. But, you do need a splitter or a second antenna. Yes, despite what VHF enthusiatsts will tell you, both will work fine using whatever antenna you currently have; it just won't be optimised for one or the other.

The Matsutec is a standalone unit that doesn't require a chartplotter to work. The screen is not huge, so if that is a concern for you it might not be a great fit.