More data

When you look at more complex MIBs you may see all kinds of things you want to read. This is a simple example, and more complex equipment (with SNMP support) will usually have all kinds of information for you.

If a new piece of equipment going in at the transmitter site has an Ethernet port for Web browsing support, it may very well have SNMP support as well. If so, your wiring is complete the moment you plug in that RJ-45 cable. You can read the information via your IP network wherever there is an SNMP manager; and conversely, if you have an SNMP manager, it can read agents all over your IP network.

Now let's take a look at some real world examples of SNMP usage.

A year ago, Clear Channel New York began a new transmitter facility build for WLTW and WWPR. For this project we acquired two Nautel NV20s (one for each station) and we decided to repurpose two BE FM10Bs (which had been WWPRs transmitters) so that one became an alternate for WWPR, and the other became an alternate for WLTW. The NV20s provide complete metering and control via the Advanced User Interface that is accessed via Ethernet. We also have nine Harris Z10s, which have complete metering and control available via a serial connection (which we use). However, the BE transmitters date from the early 1990s, and only had legacy GPIO connections on their internal terminal blocks.

Figure 1: The BE transmitter before

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For this project, I really wanted to try to update the BE transmitters so that they were accessible via the same network as the Nautel transmitters. We chose the Mini Control Silver from Audemat to accomplish this. To simplify the installation, I decided to install the MCS for each station inside the transmitter itself. (See Figure 1, the before shot, and Figure 2, the after shot).

Figure 2: The BE transmitter after

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The Mini Control Silver is kind of the baby brother of the Relio (which is built by SeaLevel, and programmed by Audemat). Our new transmitter facility uses Relio for remote control, and each of these devices acts as an SNMP manager, communicating with the MCS (inside the transmitter), which acts as an SNMP agent in this case.

The MCS has eight analog inputs, eight status inputs, and eight relays, so I was able to connect to everything I needed inside the FM10B -- the standard meters, on/off controls, and overload reset. It's powered from a source inside the transmitter.

- continued on page 4