System

Public address or PA systems have been around for well over a hundred years. While the concept itself is not new, the technologies used in modern PA systems have changed and advanced considerably since the early days.

The basic concept of a PA system is simple: a microphone connects to an amplifier which in turn connects to a loudspeaker mounted in a central location for public delivery of announcements, alerts or other one-way communication.

Traditionally, PA systems are hardwired; the microphone, amplifier and speaker are physically connected with cables or wires. Today, however, PA systems can now be partially or completely wireless, thanks to the technology of radio.

One company that takes wireless PA to the max is Ritron. The company, based in Carmel, Indiana, sports a complete line of fixed mount wireless intercom, callbox and PA systems using two way radio technology. Ritron products are also made in the USA.

Ritron is a leading manufacturer of wireless PA systems. The Ritron Loudmouth Wireless Stand-Alone PA System allows a user to broadcast a message over the loudspeaker wirelessly - not from a traditional microphone, but direct from a two way radio. The wireless system provides safe and secure communications from mobile and handheld radios. Since it is wireless, the PA system can be set up quickly and easily without the expense of a wired installation. It installs almost anywhere and is a perfect solution for public address delivery in locations where the installation of a wired PA system is not practical or even feasible.

The Ritron Loudmouth Wireless Stand-Alone PA System is also easy to integrate with your existing arsenal of two way radios. It comes in two versions: UHF and VHF. The LM-U450 is field programmable to one of 77 UHF frequencies and the LM-V150 is field programmable to one of 26 VHF frequencies, including MURS, and can also receive NOAA weather channels and weather alerts. Using the software, the units are custom programmable to any frequency in their typical respective UHF or VHF range.

Both models feature a choice from 153 digital and analog Privacy Codes and one of 9 Paging Codes for added PA security access. Both models also include a loud, powerful PA horn type speaker capable of --95dB SPL@ 50 ft. Both versions operate on 110VAC and include a rechargeable back-up battery.

The Ritron Loudmouth Wireless Stand-Alone PA System is small and light, but it is sealed in a weather-resistant, industrial grade housing. With this rugged construction, the Loudmouth PA system is ideal for use in a variety of applications and outdoor locations such as schools, parking lots, factories, warehouses, marinas, golf courses, ball fields or nearly anywhere else a public address system is needed.

Sure, the public address system has been around for over a century, but it isn't getting older, it's getting better. With the integration of wireless radio technology, the classic PA system is enjoying new life.

Let's talk about ARTS. No, we're not talking about music, movies, impressionist paintings or the theatre; we're talking about Vertex Standard ARTS. Vertex radios and ARTS?, you ask. What's that all about?

ARTS™, also known as Auto-Range Transpond System, is a type of technology used in two way radios - more specifically, Vertex two way radios. In fact, Vertex Standard built ARTS as a standard feature in all of its portable radios, such as the VX-231, VX 351 and VX 354. That's great, you say. But what is ARTS? What does it do?

The Auto-Range Transpond System (ARTS) is a feature used to detect and alert you when you and another ARTS-equipped radio station are within range of each other. When ARTS is in use, your radio will transmit for one second every 55 seconds in an attempt to handshake with the other radio. If no signal is received or your radio is out of range of the other for more than two minutes, it will emit a beep alert or tone. Once you and the other radio station are within range of each other again, your radio will receive a transmission from the other radio and beep to acknowledge the reconnection.

From an operator's perspective, ARTS is a simple concept and a feature easily explained and understood. But that's only the beginning.

Then there is ARTS II.

ARTS II takes ARTS to a whole new level. It uses MDC 1200 encode/decode for selective signaling. MDC (Motorola Data Communications) transmits data on a radio's voice channel in bursts at a rate of 1200 baud (hence the term MDC 1200). This data includes information about the radio doing the sending, such as its Unit ID, status and pre-defined messages. By utilizing MDC1200 signaling, ARTS II allows each radio user to know exactly which specific radio or radios are in or out of range. ARTS II is a standard feature in the Vertex VX-450 Series portable radios (including the VX-451 and VX-459) and VX 4500 and 4600 Series mobile radios.

Although the technology used to bring ARTS to the world of two way radios is a bit complicated, the concept itself is rather simple and the feature is easy to set up and use. Such a feature can also be a very important tool when you need to stay in touch or monitor employees, team members or other radio operators in your group. The video below demonstrates ARTS and ARTS II in action to help you visualize the potential uses for and value of this feature.

And that's basically all there is to it. Congratulations! You are now a Master of ARTS.

One of the most important things to have with you when you are out on the water (besides something to keep you afloat) is a means of two way communication, such as a radio. If you are a boater, you probably already know how important it is to have a radio on board.

Marine VHF radios are commonly used on seafaring vessels both large and small to communicate ship-to-ship or ship-to-shore for everything from routine contact with ports and marinas to emergency distress calls. These radios operate using VHF frequencies from 156 to 174 MHz.

Marine radios operate very much like your typical land-based two way radio, but with some differences in channels, wattage, range and features. VHF marine channels are different than those used for land based radios and are specifically for use in marine environments. They are allowed to operate between 1 and 25 watts. Because transmissions primarily occur over open water, their range will generally be much greater than land-based radios.

Marine radios also offer many additional features not found on most land-based radios, such as emergency weather alerts and weather-proofing. It is not uncommon for marine radios, particularly handheld units, to be submersible in water and even float.

One important feature often found in a VHF marine radio is Digital Selective Calling, or DSC. DSC is part of the Global Maritime Distress Safety System (GMDSS). A Class-D (DSC) Digital Selective Calling-capable VHF radio has a second receiver to monitor Channel 70 (DSC channel) activity at all times while receiving another channel. DSC allows the user to send a distress signal at the push of a button without using a microphone to exchange position information with other boats or stations. As of March 25, 2011 marine radios are now required by the FCC to be Class-D DSC complaint.

The FCC has set specific requirements for users of marine radios operating within US jurisdiction. The FCC states: Depending on the size, purpose, or destination of a ship, its radio station must meet certain requirements established by law or treaty.

On October 25, 1996, the FCC released a Report and Order in WT Docket No. 96-82, 11 FCC Rcd 14849, FCC 96-421 (pdf), eliminating the individual licensing requirement for voluntary ships operating domestically which are not required by law to carry a radio. Voluntary ships are those that are not required to have a radio. WIth a few exceptions, most recreational vessels are considered voluntary.

According to the FCC, domestic vessels are those that do not travel to foreign ports. If your vessel travels to ports in other countries, you will need to have a license. The FCC rules require certain vessels to be equipped with radio equipment for safety purposes. These rules are set in accordance with international agreements.

Marine radios typically have 88 channels, however not all of those channels are allowed to be used by everyone. Certain channels are reserved for specific types of communications or for specific groups, such as commercial ships and the Coast Guard. For instance, Simplex channels, 3, 21, 23, 61, 64, 81, 82 and 83 CANNOT be legally used in U.S. waters by the general public. Channel 16 and Channel 9 are emergency channels and are reserved specifically for emergency communications. Channel 16 (for voice) and channel 70 (for digital DSC) being monitored 24 hours a day by the US Coast Guard.

In addition to the other requirements, there is one other very important rule to note: Marine radios are specifically intended for marine use. It is illegal to operate a marine radio on land.

There are two basic types of VHS Marine Radios, fixed mount and handheld. Fixed mount radios are installed or mounted in your vessel. Handheld radios are carried with you like any other handheld two way radio or walkie-talkie.

Examples of fixed mount VHF marine radios are the Icom IC-M412 (available in black or white) and the Cobra Marine MR-F80B-D Class-D Fixed Mount Submersible VHF Radio. Examples of handheld marine radios are the Midland Nautico 3VP, and the Icom IC-M36 VHF Marine Radio. Cobra, Icom, Midland and Uniden are all popular brands of marine radios.

When shopping for a marine radio, it is important to note that while antennas are typically included with handheld radios, an antenna is not included with fixed mount marine radios and are purchased separately. This is because the antenna will be mounted somewhere externally on the vessel itself. Marine radio antennas vary in size, length and type and your choice of an antenna may vary depending on where and how it will be mounted on your vessel.

For more information about the basics of choosing and using a marine radio, listen to The Two Way Radio Show Episode 16 - An Introduction to Marine Radios.