AIS Range: Reception Report

[jimh]

Description of AIS Receiving Station

During non-boating season I usually have my VHF Marine Band radio (Standard-Horizon GX2150) with integral AIS receiver and my chart plotter (an ancient first-generation Lowrance HDS-8) on my desk indoors. The radio and chart plotter are interconnected using two NMEA-0183 connections; one for radio to chart plotter and a second for chart plotter to radio.

The two devices consume just little enough power (when the 25-Watt transmitter is not used, which would be illegal anyway) to be powered from a 12-Volt power supply that I build so many years ago I have no idea exactly when, but it was probably in the late 1970's or early 1980's at the latest, making the power supply about 45 to 50-years old. But it still works and can deliver about 3.5-Amperes, which is just enough to run the plotter and radio as long as the radio is in receive-only use.

The antenna for the radio is located in the attic of my cabin in northern Lake Michigan's Grand Traverse Bay, right on the eastern shore of the Leelanau Peninsula. The antenna is a Yagi with a reflector, a loop-driven element, and one director. The main lobe is aimed more or less due east. The gain of this antenna is probably about 5-dB compared to a half-wavelength dipole, or in terms of "marine antenna" gain perhaps 7-dB or more,

The principal use of this set up is to read the mail on VHF Maine Band traffic on Channel 16, to listen to USCG alerts on Channel 22, and to receive NOAA Weather Radio broadcasts. And thanks to the integrated AIS receiver in the radio, the AIS1 and AIS2 channels at 162-MHz are also monitored, allowing me to know of any boats equipped with AIS transmitters in the local area.

With that background on the gear in use, I now turn to the topic of this short article:

AIS Range and Reception Reports

With the radio NMEA-0183 output connected to the chart plotter, the chart display shows AIS targets received by the radio. This is quite interesting because it gives a nice indication of the range at which AIS signals can be received. At the moment the motor vessel CAROLINE MCKEE (a 135-foot length, 36.1-foot beam tug) is being received at a range of 20.6-miles from my location. The tug is northeast of me near Charlevoix, Michigan, probably at the Saint Mary's Cement plant with a barge in the notch. That is quite a satisfactory range.

Simultaneously a second vessel heading southwest in open Lake Michigan at a range of 18.4-miles and bearing 008-degress is also being received. It is another tug, the motor vessel CANDACE ELISE. With the heading almost due north, this signal is off the main lobe of the antenna, so the gain from the Yagi is minimal, if any, and perhaps even a loss compared to an omnidirectional antenna.

I also often hear calls from larger vessels that are approaching Charlevoix to alert other boaters they are proceeding inbound--the channel is not particularly wide and a large vessel may take up most of its width. The Beaver Island Boat Company ferry EMERALD ISLE is often heard making SECURITY calls when it approaches or departs Charlevoix.

When boating season really gets going, the chart plotter and radio are moved to my boat, so I miss having them on the desk. I have to resort to a small handheld radio to keep up with local marine traffic.

[jimh]

Another AIS Reception Report

Checking this morning I found vessel STEELHEAD transmitting with Class-A AIS at a range of 21.8-miles bearing 50-degrees true. This 65.6-foot steel hulled vessel is owned by the State of Michigan and designated as a survey vessel. It has a FCC issued calling of WZH2163, but ironically the license expired in 2016 and was subsequently cancelled in February 2017. Also curious is the MMSI is 338070488, which is apparently not in the ITU ship station list because it probably was not issued by the FCC. Typically ALL MMSI registrations issued by the FCC end in a zero. Typically all ships with an FCC MMSI are listed in the ITU ship list. If those norms hold true in this case, the assumption is the MMSI for STEELHEAD was issued by a private MMSI-issuing agency in the USA.

However, according the website of BoatUS, a private MMSI-issuing agency, the criteria for being able to register a vessel are as quoted below:

BoatUS has been authorized by both the Federal Communications Commission (FCC) and the U.S. Coast Guard to assign MMSI numbers only to vessels that meet the following criteria:

• Used for recreation only
• Not required by law to carry a radio
• Not required by law to have a FCC Ship Station license
• Vessel is under 65' in length
• Do not communicate with or visit foreign ports (i.e. Canada, Bahamas, Mexico, and the Caribbean)

If you do not meet these criteria, you are legally required to obtain a Ship Station License from the FCC. They will concern an MMSI number with a Ship Station License.

I believe you have to meet ALL of the criteria listed to be exempt from using the FCC for registration for an MMSI.

The STEELHEAD length is presumed to be as stated in their AIS broadcast as 65.6-feet, thus this vessel is NOT "under 65-feet." Also, it is not "used for recreation only."

Thus at first glance, the State of Michigan is operating a vessel with an expired and cancelled FCC ship station license, and with an MMSI issued by a private authority for which is not eligible to use. But is is transmitting with a Class-A AIS device, usually only seen on commercial ships.

New Long-distance Record
I just noticed the AIS signal from the ferry EMERALD ISLE coming south toward Charlevoix at a distance of 25.1-miles bearing 035-True. That is the best distance noticed since I started this thread.

[jimh]

As often happens, the really BEST place to find out what federal regulations say is to use a source provided by the federal government. My comments above wherein I cite a non-government website for the regulations regarding what type of boat is eligible for to NOT have a FCC ship station license and could thus also be eligible to have an MMSI issued by a private registration agency.

First, "voluntary ship" status means the vessel has volunteered to equip with a marine radio as there are no regulations that compel the vessel to equip with a marine radio. According to Federal Communications Commission and their website, the actual rules that determine what vessels are eligible to be consider "voluntary" regarding radio equipment say this:

You do not need a license to operate a marine VHF radio, radar, or EPIRBs aboard voluntary ships operating domestically. The term "voluntary ships" refers to ships that are not required by law to carry a radio. Generally, this term applies to recreation or pleasure craft. The term "voluntary ships" does not apply to the following:

1. Cargo ships over 300 gross tons navigating in the open sea;
2. Ships certified by the U.S. Coast Guard to carry more than 6 passengers for hire in the open sea or tidewaters of the U.S.;
3. Power driven ships over 20 meters in length on navigable waterways;
4. Ships of more than 100 gross tons certified by the U.S. Coast Guard to carry at least one passenger on navigable waterways;
5. Tow boats of more than 7.8 meters in length on navigable waterways; and,
6. Uninspected commercial fishing industry vessels required to carry a VHF radio.
7. Ships required to carry an Automatic Identification System (AIS) transceiver by the U.S. Coast Guard regulations enacted pursuant to the Maritime Transportation Security Act of 2000.

Ships are considered as operating domestically when they do not travel to foreign ports or do not transmit radio communications to foreign stations. Sailing in international waters is permitted, so long as the previous conditions are met. If you travel to a foreign port (e.g., Canada, Mexico, Bahamas, British Virgin Islands), a license is required. Additionally, if you travel to a foreign port, you are required to have an operator permit.

Cf.: https://www.fcc.gov/wireless/bureau-div ... o-stations
Read at "Who Needs an FCC License"

The interesting point is the designation of the length of a power-driven vessel that disqualifies it as being a "voluntary ship" in item -3. The length is given in meters, as 20-meters. The equivalent length in feet is then 65.6168-feet.

In the case of the vessel STEELHEAD, its AIS transmission indicates the vessel length is 65.6-feet, which would then be interpreted as being "not over 20-meters." Perhaps that is the actual length, or perhaps that figure was chosen as it was infinitesimally not over 20-meters, which then complies with the length requirement to be consider as a voluntary ship.

Also interesting: on the FCC record of the expired ship station license, the radio service category is "SA" with means voluntarily equipped. The licensee was the State of Michigan, and the category was "government entity."

[porthole]

Do you have any of the virtual ATONS broadcasting AIS from land based stations in your area?

[jimh]

Do you have any of the virtual ATONS broadcasting AIS from land based stations in your area?

I have not seen any virtual Aids to Navigation in my reception area in the northern Leelanau Peninsula. I have seen many instances of AIS virtual ATONS in the Detroit River area.

Cf.: https://continuouswave.com/forum/viewtopic.php?t=229

You were also involved in that discussion.

The problem for me to see any virtual AIS ATONs up here is because of my seasonal presence here. By the time the real ATONs are removed and replaced by virtual AIS ATONs, I am no longer up here to listen for them on my AIS receiver.