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Learn How to Add a Pad to a Punch Block

Also, protect your tower from frozen catastrophe

Fig. 1: Andy starts his project by assembling the 6 dB pads.

Fig. 2: Solder the pads to wire to punch easily on the blocks. Andy Soule is market engineering manager for Townsquare Media’s Brewer, Maine, cluster. A syndicated show on Andy’s country station recently changed distributors; after the change, the staff heard distortion during the program. The audio sounded fine in the XDS receiver, but Andy determined the levels were too hot for the console.

He determined he needed a 6 dB pad to “pad down,” or drop, the level. Andy had heard tales of pre-made pads that snap on in place of a bridge clip on a punch block. That would have been perfect, but a quick Web search only came up with some out-of-stock options (and an $80 price tag).

Andy needed to make his own, but he wasn’t sure of an elegant way to insert the pad in the line. He was at the parts store picking up the resistors when he found a bottle of GC Electronics’ Insulating Coating. Andy flashed back to a magazine article that had piqued his interest years ago. It described how to assemble a small circuit, then dip it in an insulated coating, so it is like a single component.

The result is not pretty, but it is a lot smaller than if he had used tape or perf board. Some industry veterans may remember that “secret” RC time constants and certain IC assemblies were potted or sealed this way in some of the early audio processors.

Fig. 3: The pad assembly is small enough that it can be dipped directly into the container. By adding wires to the pads, Andy can punch down the wires and tuck them out of the way, making the assembly neat. And yes, as you can see in Fig. 5, Andy did label the assemblies so the next guy will have one less reason to curse his name.

Andy’s going to try this approach again, making the silence sensors for his Sine Systems remote control, using the simple circuit in the back of their RFC1 manual. He also tells us that he didn’t spill a single drop of sealant on his copy of Radio World, visible in the photos.

Thanks, Andy, for a compact solution for engineers to consider.

Fig. 4: Andy sealed the pads and a portion of the interconnect wire. Andy Soule can be reached at [email protected].


Falling ice is always dangerous but when it comes off a 1,600-foot television tower, it can be deadly.

Here’s a link to a video showing how destructive this ice can be. The car damage toward the end of the video is just amazing. Check it out:

Fig. 5: The pad assembly is labeled and complete. The falling ice video is a good reminder of why you should have some kind of ice bridge to protect the transmission and lighting lines passing to the tower from your transmitter building.

I’ve heard engineers discount ice bridges citing their expense; but even sections of chain link fencing mounted a foot or so above the transmission line will sacrifice itself rather than the lines being downed by falling ice.

Of course, the heavier metal ice bridge works best — consider it your insurance policy.

Good ideas come in all flavors. We want yours!Contribute to Workbench to help your fellow engineers and qualify for SBE recertification credit. Send tips to [email protected]. Fax to (603) 472-4944.

Author John Bisset has spent 45 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.