A Quick History And Explanation Of Microwave Communication In Telecom Networks


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by Mac Smith

Microwave communication is the sending of signals via radio using a series of microwave towers. It's a form of "line of sight" communication. There must be nothing obstructing transmission of data between these towers. That's why microwave towers are frequently placed on mountaintops. When positioned on a tall peak, a tower has lines of sight to valleys below on all sides and to other mountaintop towers. The increase elevation also reduces the impact of the Earth's curvature on line of sight.

Quick History Tutorial: Microwave Transmission Technology was Developed in the 1940s
The technology used for microwave communication was built in the early 1940's by Western Union. The first microwave message was sent in 1945. It traveled from NY to PA. Following this success, microwave became the most common way to provide service.

With new satellite and cell technologies, microwave has become less widely used in telecom. Fiber optics are more common. But microwave gear is still used at many remote sites where fiber cabling cannot be installed cheaply.

Microwave Communication Can Be Analog or Digital
Microwave communication uses analog and digital formats. While digital is the most advanced form, both are useful.

Analog Microwave Communication may be most economical
Analog microwave communication may be cheapest at your tower sites. Why? It's paid for and in service. If you have older microwave equipment, it's most likely analog. To avoid having to retrain your staff, you may want to stick with the analog microwave gear you have. Because you know this equipment, you won't face new problems.

Decrease System Poll Time with Digital Microwave
Digital microwave comms use more advanced, more reliable technology. It is much easier to find equipment to support this transmission method because it's newer. Because it has a higher bandwidth, you can transmit more data using more verbose protocols. The increased speeds will also decrease the time it takes to poll your microwave site equipment. This more reliable format provides for more reliable reporting with advanced communication equipment, while also allowing you to bring in your LAN connection when it becomes available at the site.

You must monitor your microwave systems
Whether you use digital or analog, you have to monitor your microwave communication equipment. You need to know that your data transmission equipment is online. Don't let your customers be the first to tell you about a network outage.

You also have other concerns not directly related to microwave. Consider the risk of copper theft. Most microwave sites are very remote. Sure, a typical equipment failure is a problem, but fixing it quickly minimizes the revenue impact. A copper theft event is a much bigger problem. First, it probably takes a long time to fix. Second, replacing (and paying labor costs to reinstall) copper is expensive. This is equally true for any other kind of theft or vandalism. You lose revenue AND skyrocket costs at the same time.

Also think about the required aircraft obstruction lighting for your towers. To avoid FCC/FAA fines for non-compliance, you have to keep your lights online. Any lighting failure must be reported promptly to minimize your risk of fines and liability.

It's problems like these that necessitate a remote monitoring system to instantly notify you of microwave transmission failures.

Deploy an RTU at Your Site to Protect Your Critical Microwave Communications
A network alarm monitoring system is composed of a fleet of remote telemetry units, or "RTUs", which collect alarms from your microwave communication equipment and forward them to your alarm master. These remotes are a critical piece of your monitoring system because they provide your alarm master with the information it needs to notify you of an outage via email or text message.

No matter what RTU you choose, you'll be in better shape than if you use "embedded" monitoring built into your microwave system. It's never good to let equipment monitor itself (what happens when it fails?), but there's another problem, too. Embedded systems are big trouble when it's time to upgrade your transport.

Imagine that your LAN has expanded or you're upgrading to new microwave hardware. What happens to your monitoring? Will you purchase a brand new monitoring system for every site? Will you keep your old transport gear powered up purely for its telemetry? These are painful options. Dedicated RTU hardware eliminates this problem.

Don't think that this can't happen to you. I spend a lot of time speaking with network owners on the phone and at seminars, and this is a very common theme. Many people are forced into a hunt for monitoring when they upgrade their microwave transport network. Don't wait until you're in a tight spot. Set up your monitoring system on your terms and on your timetable.

What should I look for in a RTU for microwave transmission sites?
There are plenty of RTU manufacturers out there, but most of them won't be appropriate for your microwave facilities. Some will be built for corporate IT environments in air-conditioned data centers, not remote industrial mountaintop sites. Others won't have the right transport or protocol you need. Here's a quick RTU tutorial for microwave transmission sites:

  1. Power Input Voltage:

    What power voltage is available at your microwave transmission site? Hint: It's probably not 110 VAC, making "IT" RTUs a poor choice. Look for an RTU with native -48 VDC, +24 VDC, or whatever you need it to support.
  2. Form Factor:

    Do you have rack space available? Is it 19" or 23" wide? If the rack is full at a site, can you mount on a wall? What about DIN rails inside a small cabinet. Can you mount this RTU on a DIN rail? You need an RTU that you can physically accommodate.
  3. Inputs:

    How many contact closures do you have to monitor? How many battery voltages? Will a single temperature sensor work, or do you need to mount several at different locations? You need monitoring hardware that can cover all the critical equipment and environmental conditions at your microwave site.
  4. Outputs:

    Do you have gear that can be controlled with a contact closure? If so, you'll want a control relay output on your RTU to cover each one. Do you have gear that gets jammed up and needs a routine power cycle? Higher-amp relays (ex. 10A) can remotely toggle power to force a reboot. Find an remote alarm device with the right outputs
  5. Transport:

    Do you have older analog microwave transmission gear that requires a 202 or FSK modem? Do you need a serial connection? Do you have IP overhead channels on your digital microwave? All of these potential scenarios need a different RTU transport.
  6. Protocol:

    Dictated by your transport and alarm master, you need to choose a compatible protocol. You might need something older like E2A, TBOS, TL1, or TRIP. You might need something newer like SNMP or DNP3. Make sure your RTU supports the necessary protocols.

Can I honestly expect to find an RTU that covers all my requirements?
If you know where to look, you can find the RTU you need. You may simply need to adjust your thinking just a bit.

First, look for a manufacturer who has done this before. What microwave transmission sites have deployed their gear already? Are the end-users happy with the results? Can you call them yourself to hear their thoughts, or do you just have to take the manufacturer's word for it?

Second, remember that some element of your specification may not be available 100% off-the-shelf. You can probably find a 90% match, but one part may be missing. That's when you need a manufacturer who will adjust their design to be a perfect 100% fit to your spec. You'll get a totally proven design, just in a config that meets your needs. You also shouldn't need to order very many units to quality. Anything more than qty 10 should not involve any NRE fees.

What about a central monitoring console?
Good RTUs are important, and they can generally handle themselves if you have fewer than 12 RTUs in your fleet. With a small number of facilities, you can just have your RTUs send you SMS text messages or emails when there's a problem with microwave transmission or anything else.

With more than 12 sites, you really need some kind of central alarm collector to help you manage alarms throughout your network. Just like RTUs, however, there are good master stations and bad master stations. Here's what to look for:

  • Protocol compatibility is key. Your master should be able to interpret whatever protocol your RTUs and other gear use. A very common protocol is SNMP, but DNP or Modbus are also popular in microwave environments. If you have your choice, an efficient protocol (bits instead of verbose text) is better to reduce bandwidth overhead.
  • Get a proven design. That's a cliche for a reason. Your network is important. People are depending on you. Don't be a guinea pig testing out your manufacturer's new equipment. Custom/tweaked designs are OK. Just make sure that the individual elements being packaged together have all been proven in the lab and in the field.
  • Watch out for licensing headaches. If you're buying a master station, buy a master station. Don't purchase something at a seemingly low price, then get nickeled and dimed every time you need to add a new monitored device. Paying for individual protocols one time is fine. That's a large design decision. Paying for each device you add is just silly. You own your network. Don't let your monitoring manufacturer take away your control.
  • Don't buy more master station than you need. If you have 20 sites, you probably need a master station. What you definitely don't need is an enterprise-scale master that can handle thousands upon thousands of locations. You'll be paying for a lot of capacity you'll never, ever use. Look for a master that has a few levels of capacity & price to choose from. You'll get to choose the capacity you need right now.
  • Consider your upgrade path. If you have big growth in the future, you can upgrade to your manufacturer's next size up. Because you'll be sticking with the same manufacturer, your migration and training expenses should be minimal. The protocols and interface should basically be the same. Ask prospective vendors whether they offer upgrade discounts. If you do grow within the next few years, can you upgrade for free? It's a really good sign if your vendor believes that their products are useful enough to help their clients expand.

What about training my team to use the monitoring system?
A monitoring system is a significant equipment investment, and it only has value if your team can set it up and use it properly. This is where many vendor offerings fall flat. Sure, they may have halfway decent hardware and software, but they just it throw it over the fence when you buy it.

What will really serve you best is a variety of training formats. Your primary users will probably want classroom training (or at least videos that simulate a classroom environment). During installation and routine updates, a good tech support line will help you with your questions. Solid documentation (print and online) will help you when you just need a simple reference guide.

You'll know you're dealing with a full-service, high-quality vendor when you get all that for free. Even classroom training should be free if you're willing to travel to a training center. If you need training at your offices, that should also be available for a reasonable price.

Classroom training for RTUs usually takes only about a day. They're fairly simple when compared with master stations, so there isn't as much material to cover. Comprehensive master station training takes 3-4 days, because master stations have so many functions. You need to understand not only day-to-day monitoring, but also the initial configuration process.

Classroom training is a good idea for a few reasons. First, you get live attention from the instructor (you won't get that from a YouTube video). Second, you can ask questions in real-time. Also, most people don't consider that their classmates at training will be a big resource. It's rare to interact with colleagues from half-a-dozen other companies at once. They'll all have similar kinds of experience, so they can probably offer real-world insights about monitoring that your instructors (with all their product knowledge) cannot.

Avoid the trap of microwave-integrated monitoring systems
Many transport manufacturers provide some kind of monitoring function. In the case of microwave systems, you frequently get a few contact closures and a bit of overhead bandwidth to transmit alarm data. This can seem like a good idea (and it's certainly better than nothing at all), but consider the negative impacts of a monitoring system that's integrated with (and, therefore, totally reliant on) your microwave transmission equipment:

  • Capacity and functions are generally limited. Your microwave manufacturer is good at what they do, but they're not experts in remote monitoring. They give you just enough so they can honesty put "equipped with monitoring" on their feature list. Will microwave-integrated monitoring have the intelligent features you need to efficiently manage your network? Can it track analog values like temperature? Can it track generator fuel consumption over time?
  • With integrated monitoring, you're letting your microwave equipment monitor itself. Independent monitoring via an RTU is superior for reliability. An RTU can have backup transport (ex. cellular) to route around a microwave failure.
  • When you want to upgrade your microwave transmission gear, your monitoring will vanish overnight. At best, you have to move all alarm points over to a new system. At worst, you'll have to purchase a fleet of RTUs overnight.

Protect Your Microwave Transmission Reliability with a Dedicated Remote Telemetry Unit Now


The KDA 864 RTU is one remote that can help you protect your important microwave communication equipment.

The KDA 864 provides you with 64 alarm points and 8 control points in a single 19-inch rack unit. It also supports 202 modems for use with microwave base bands 0-4, as well as FSK modems on 4-8 and 8-12 base bands. With support for DCP, E2A, TBOS, TL1, TRIP, or TBOS, the KDA 864 will protect your microwave communication to keep your network online. If you need more capacity, you can connect up to four KDA's to form a larger alarm unit.

Don't let a major outage destroy your service reliability. In today's business climate, that's something you simply can't afford. Deploy a KDA remote in your microwave network today, and start collecting the alarm data you need to provide the high-quality service your customers demand.

Dozens of NetGuardian models are available for remote monitoring. They all do more or less the same thing (monitoring and control automation), but have different capacities and different transports, form factors, etc. Consider some of these RTU candidates for monitoring your microwave transmission at modern sites:

  • NetGuardian 216T/240T

    Any NetGuardian with the "T" designation in its model number has native T1 compatibility. This is a huge advantage at digital microwave sites, which often have T1 overhead channels. As you'll know instantly if you've ever worked with T1, it is not IP LAN. You need translation equipment to connect Ethernet devices to T1. That's where the NetGuardian 216T/240T (one has 16 discrete inputs, the other has 40) come in. Not only will they route alarm data over T1, but they also break out LAN to a 10/100 switch on the back panel. This gives instant connectivity to all LAN-based devices at your remote site. The NetGuardian 216T is also frequently less expensive than the an equivalent one-function device that only performs translation and has no monitoring functions. That's the definition of a "no-brainer" solution.
  • NetGuardian 832A

    If you already have LAN available at your microwave transmission facility, your RTU options open way up. You're not looking for any special transport or protocol, so you can focus exclusively on an RTU's core functions. The NetGuardian 832A is a good place to start, because it will show you what's possible. It has 32 discrete inputs for monitoring contact-closure alarms from your equipment, door sensors, motion sensors, etc. It has 8 analog inputs for monitoring temperature, battery voltages, humidities, etc. in more detail. The 832A can also perform control functions with 8 control relay ouputs, and it has 8 terminal server serial ports for accessing legacy serial equipment via LAN.

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Related Products:
KDA 864

Related Topics:
Microwave Data
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