GMDSS Shore Station Designs
Mr. John Page the GMDSS instructor at the STAR Center (www.star-center.com), and a good friend of mine asked Malloy Communications to build a small GMDSS (Global Maritime Distress Safety System) shore station. This was to include: MF/HF/SSB/SITOR/DSC, as well as two Ross VHF/DSC radios.
We used the ICOM 710RT. This system is no longer made but I like it better than the new 802. The 710 has the option of mechanical filters down in the IF stages, which cleans up the signal very well before it goes to the audio stage and ultimately to the speaker.
We attached a NECODE DSC-1000, which is no longer made to the SSB. The DSC-1000, was purchased by SEA, they changed some of the programming to meet their specific needs and you now see it on the SEA GMDSS console.
We also put a power meter in line with the SSB. This might surprise you but most GMDSS students (deck officers) are unsure how the RF (radio frequency) energy goes from a radio to the antenna. The power meter allows the student to observe his own transmitted signal. It also is an excellent diagnostic tool to determine if the radio system is still working.
Here is something to think about. Based on my involvement with the GMDSS project in Venezuela before it collapsed due to the political in-stability of the region I would like to suggest the following. These GMDSS shore stations are usually designed by Government officials that have this grand notion that everything must be remoted and interfaced with complicated port radar monitoring systems. We have been involved with this type of project. However let me offer a suggestion. To meet the basic operation of GMDSS one could put up an approved GMDSS VHF/DSC radio, connected to an antenna 100' (30m) in the air. Then for MF (Medium Frequency) let Malloy Communications design an MF antenna for monitoring and transmitting on the DSC distress frequency of 2187.5 KHz along with an approved SSB with DSC. That is it. Place the radios in a location where the normal business is occuring and if the alarm rings, have someone who has had additional training answer the distress call. This would give a country a Sea Area A-1 and A-2 set up. It would be best to have a 1Kw amplifier, but it will work with a straight 100 watt SSB/DSC radio. You should also note that a MF antenna designed for 2187.5 KHz will need about 1 acre of open land in-order to work properly. The small station would look similar to this training GMDSS shore station we installed at the STAR-CENTER (Maritime Training facility), located at Dania Beach, Florida. This station is located on the third floor, and the antenna systems mounted on the roof. Malloy Communications can design the system for your location. I would be interested in your comments.