This Analyzer Fits in Your Pocket

Also, read about one engineer’s experience with a handy sample rate converter
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Also, read about one engineer’s experience with a handy sample rate converter
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RFExplorer is shown with Touchstone Spectrum Analyzer Software. Greg Muir, principal engineer with Wolfram Engineering in Great Falls, Mont., sends a link to a cute unit. It’s called RF Explorer, a hand-held spectrum analyzer about the size of a pack of cigarettes.

It was designed for AV professionals to troubleshoot wireless audio equipment, through it’s too bad there are not more frequency bands useful to the broadcast engineer.

There are six models that range from $129 to just under $400. You can find out more at


Brad Arnold is chief engineer for Goforth Media Broadcasting in Mobile, Ala. He wrote to say he is impressed with the versatility, usefulness and quality of the Behringer Ultramatch SRC2496 A/D Sample Rate Converter.

At Goforth Media, Brad is responsible for an FM and two AM stations. The AMs are WBHY Christian talk and WLPR with a southern gospel format. Both AMs get their program feeds from a digital subcarrier riding on the FM and picked up on FMeXtra digital receivers. Brad’s backup feed is a Tieline box, running over telco lines, with one AM on channel one and the other on channel two.

The two audio processors are Orban Optimod 9200s. An audio/music dealer was offering the Ultramatch on sale for $199; Brad had some experience with this device and felt this was an offer he couldn’t let pass so he ordered the unit.

Brad’s intention was to insert it between the receivers, the Tieline and the Optimods. The FMeXtra receivers come with two digital outputs, optical and AES, and an analog output, which he was using. The Optimods also have digital inputs, both optical and AES, and of course, the analog in.

You can feed the Optimod with analog and digital inputs, and there is a reason for doing this. When a digital input is selected on the Optimod, and analog is also present, the unit automatically will divert to analog should the digital signal disappear. One reason Brad’s digital signal could drop out is if his microwave STL should fade out, or if the digital output of the main control room were to act up, or a loss of AC power occurred at the FM site.

Since Brad has the Tieline analog connected to the analog inputs on the Optimod, he gets an instant transfer over to the Tieline feed, should the digital drop out.

Brad writes, “But, now for the good part.” He takes the digital out of the receivers and feeds it directly into the digital input of the Ultramatch. The digital out of the Ultramatch feeds into the digital input of the Optimod 9200s. Brad sends the AES signal into both 9200s through an AES splitter. One Optimod selects the LEFT channel, and the other selects the RIGHT.

The day Brad installed this arrangement, he was listening to the southern gospel music on his off-air receiver while he hooked up the SRC quickly. When he powered up the Behringer Sample Rate Converter, he could immediately hear the difference in the quality of the audio. The bass and highs were more pronounced; the mid-frequencies were clearer.

It’s Brad’s opinion that the Optimod responds better to the digital signal as compared to the analog. Brad highly recommends using the 2496 in any analog audio chain where a digital conversion is needed.

Readers may ask, “Why didn’t Brad just use the digital out of the receiver, instead of inserting the Ultramatch?” Brad inserted the Ultramatch to have an easy-to-access level control, a front-panel headphone jack and a visible level meter to assist in troubleshooting when audio is lost. He had no idea it would also improve the audio and do it for under $200.


Bryan Urban of Austin Community College referenced our tip in the Sept. 1 column, in which we referenced putting white dots on USB connector orientation and cautioned you to watch the orientation in case the connector is mounted upside down or vertically. The white dot is to help ensure that staff members don’t force connectors, ruining the socket and the plug.

Bryan suggests placing a white dot on the device you are plugging into, as well. Good suggestion. This way you match white dot to white dot to get proper orientation before inserting the USB plug. Bryan notes that this isn’t a new idea; camera lenses have been marked this way for years.


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This fake owl was an inexpensive solution to a persistent problem for KBRT. After no issues over 2-1/2 years, the 11 GHz microwave link from the studio of Crawford Broadcasting’s KBRT(AM) in Costa Mesa to its mountaintop transmitter site began experiencing receive frame errors.

Packets were being lost in both directions between audio codecs and there were short audio dropouts on the air. This would occur every night, almost like clockwork, at about 11:30 p.m. It would last between two and 30 seconds, with several short (half- to one-second) audio dropouts occurring during that time.

Because the issue always happened at night and was so predictable, it was likely biological in nature.

Director of Engineering Cris Alexander considered buying and placing a game camera on the studio roof to see if that could capture what was happening, but that idea was nixed as it wouldn’t solve the problem.

Figuring the issue was likely at the studio where the rooftop would provide birds with a place to land and do other things that birds do, Cris figured a better approach would be to invest in an $18 plastic owl from Home Depot and place it in front of the antenna.

As soon as the owl was installed, two hawks got very upset and carried on for hours. But the nightly receive frame errors magically disappeared.

If you are faced with bird issues — or for that matter, any kind of rodent, insect or pest problem — bookmark for a variety of humane solutions that work.

Contribute to Workbench. You’ll help your fellow engineers and qualify for SBE recertification credit. Send Workbench tips to Fax to (603) 472-4944.

Author John Bisset has spent 46 years in the broadcasting industry and is still learning. He handles West Coast sales for the Telos Alliance. He is SBE certified and is a past recipient of the SBE’s Educator of the Year Award.


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Holiday Lights for Your Racks

Most satellite receivers are located inside dark equipment racks. I've had numerous suggestions from engineers who have used "rope lights" inside a rack to illuminate the equipment