Relm Radios

Relm makes amazingly durable radios (watch the video at right).

In addition to offering Relm radios, we offer Relm radio chargers, cables, and batteries. We also offer the Relm mobile extenders and related products.

Before you select a radio solution, develop an understanding of such things as:

• What that system actually needs to accomplish. For example, communication between the home office and field personnel is a very diffent goal from communication between offices.
• User constraints. For example, if mobility is essential and weight is a constraint, then you'll need to limit your selection to a particular weight range.
• What the user environment is. For example, are you setting up a LAN where a large number of obstructions exist?

A simple system design process begins with listing the existing needs, likely future needs, constraints, and conditions of use. Then draw out in block form the major elements and how they relate or connect to each other.

If your design is complicated or is for a critical application, please contact us (or by phone 847-584-1000). We have experts who can help you.

It's part of the electromagnetic spectrum, starting at 3KHz and going up to 3,000GHz. While that may sound like it's a big part of the electromagnetic spectrum, it's really not. At lower frequencies than radio, the spectrum has electric waves. At higher frequencies, it has (in this order) infra-red, visible light, ultra-violet, gamma rays, and cosmic rays. That's the science of it, in a nutshell.

From a practical standpoint, we use this narrow part of the electromagnetic spectrum to transmit signals in a variety of methods. We do this in eight bands, each of which has advantages and disadvantages for a given application. The bands range from VLF (Very Low Frequency, 3 KHz to 30 KHz) all the way up to EHF (Extremely High Frequency, 30 GHz to 300 GHz). Above EHF is a band that isn't yet designated.

Contrary to common misperception, cell phones are not an alternative to radio. The cell phone is a radio application. Yes, it is a different type of radio and radio system from, for example, a station-to-station system like the walkie-talkie. But it's still radio.

Anything wireless, such as a WiFi network, is using radio.

Your alternative to radio is a wired system. That could be POTS (Plain Old Phone System), coaxial cable, Ethernet, or some other system consisting of wires and cables. Typically, those are not point to point. And, of course, none of those are mobile. With wired systems, configuration changes can be expensive and time-consuming, if not outright impossible. So often, radio is the best solution.

Anyone installing a cabled or wired system cannot call the job complete until the system as been tested. That is also true of radio systems. Testing protocols vary, depending on the complexity of the system and what functions are critical. Cost is also a factor, as testing requires resources.

That testing must include the wired equipment that provides the radio to the system. For example, you set up a LAN. You still need to test the Ethernet to the wireless routers.

With a well-designed system, everything should work seamlessly. But "should" and "do" don't always line up, and you don't want to find this out during a critical window such as an emergency. The adage "trust but verify" applies to all communications systems, even to radio-based ones.

Your main technical reference for the actual radio gear is the manufacturer's manual.

For the wired part of radio systems, the National Electrical Code, NFPA 70, provides communications cabling requirements in Chapter 8. Other NEC Articles may also apply, especially those in Chapter 5. The IEEE provides many communications-related standards. If you go to the IEEE Website's Standards library and select "Communications" you will see these. It's a huge list, but only certain ones will apply to your specific application.

But other standards, plus federal regulations, may apply to your specific application. If you aren't sure what those are, please contact us (or by phone 847-584-1000). We have experts who can help you.