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Simplify Satellite Audio, Control Wiring

Marc Mann of San Diego read our tip to keep A/C condensate drain line traps clean to prevent flooding and finds it timely.

Marc Mann of San Diego read our tip to keep A/C condensate drain line traps clean to prevent flooding and finds it timely. But where A/C evaporator units are located above mission-critical equipment — where water dripping could spell disaster — Marc suggests the following.

Many manufacturers offer a small float switch that installs directly at the condensate pan outlet. It typically is wired into the A/C control board circuit to shut the system down should it detect an overflow condition. It can also trigger a remote alarm should one desire.

Installation is fairly easy for anyone who has repaired an irrigation sprinkler system; the drains are constructed of PVC. The Safe-T-Switch Model S62 detects downstream clogs and interrupts the thermostat circuit to shut the system off before flooding occurs. The Safe-T-Switch is compact to fit in tight places; the potted contacts are ideal for use in a wet environment. The reed/magnet float switch resets automatically after the drain is cleared.

If you have a maintenance contract with an A/C and heating company, have them install one of these during your annual or semi-annual visit; this way you may save the cost of a call-out charge.

(click thumbnail)Fig. 1: A handy way to handle DB connectors.In addition, the technician typically fills out a preventive maintenance checklist during his visit. Ask the tech during his next visit if he specifically “blew out” all the traps and have him note that service on his report.

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Cumulus Youngstown Market Engineer Wes Boyd, a frequent Workbench contributor, asks if I’ve seen the latest little gizmos from Broadcast Tools.

These contact fan-out connectors sure make Starguide hookups and changes easier and faster.

The Connect O’Adapter converts DB-15 and DB-37 connectors to removable screw terminals. Joe Jarjoara, chief engineer for Qantum Communications of Cape Cod, Mass., can be seen in Fig. 1 holding the DB-15 adapter. The screw terminals simplify the wiring hookup, and the connector can separate so you don’t have to remove all the wires if the receiver is removed for service.

Fig. 2 shows the Connect O’ Pad, which Joe uses on his StarGuide receiver. The COP provides an effective way to connect audio wiring and adjust the audio outputs on your StarGuide II and III receivers via the built-in trim pots.

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(click thumbnail)Fig. 2: The Connect O’Pad provides an easy connection for audio and includes trim pots for volStu Engelke is engineering manager for Salem Media of New York City. Stu writes that he always finds something of use in Workbench; now it’s his turn to share some useful information in the form of some great Web sites.

The first helps to keep you informed: This site displays the top 10 headlines from whatever sites you choose. It’s a great way to keep up with whatever interests you without having to pore over several Web sites. Lifehacker, which we’ve mentioned previously, is one of the choices.

If you like the word “free,” this next site is for you. Go to and type “46 best ever” into the Search field. You’ll be taken to a list of “The 46 Best-Ever Freeware Utilities.” There are a lot of great freeware products; many are as good, or even better, than their commercial alternatives. Get the lowdown on the latest here.

(click thumbnail)Fig. 3: This site offers “The 46 Best-Ever Freeware Utilities.”And the interval at which Windows XP resets the clock via the Internet can be changed to whatever you like. As mentioned previously, this is a registry hack. You’ll find out how to implement the reset at

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Les Proctor of KNEB(AM/FM) in Nebraska agrees that most audio transformers will not pass an FM stereo composite signal but says there is always an exception.

When KNEB(FM) bought a Harris FM-20K transmitter in 1981, there was a noise problem due to a ground loop between the transmitter composite input and the STL output. Les solved the problem with an old Westinghouse 111C telephone repeat coil. This transformer not only eliminated the ground loop but also successfully passed the composite stereo signal and a 75 kHz subcarrier!

Les says that the transformer continued to work fine years later when a 57 kHz RDS subcarrier was added to the mix. Les writes that there are transformers manufactured and marketed specifically for ground loop elimination with composite signals.

John Huntley, engineering manager with the Cumulus stations in the Rockford, Ill., market, says General Radio used to make such a version, but the 111Cs seem to be easier to find as the phone company moves further and further away from copper radio loops.

Thanks, gentlemen, for the tip. Now it’s time to scrounge around some old phone closets!