Station acquisitions can tax the most seasoned engineer.
Either you’re given a building and told to work with it, or your predecessor(s) did it differently. In either case, you may need to think creatively for solutions.
(click thumbnail)Fig. 1: You can isolate a studio speaker using springs.Faced with the need to build new studios in a building where box-like studio rooms existed but were not well isolated, Dirk Nadon and his engineering team at the Nassau New Hampshire cluster came up with some innovations.
Inspection of the row of box-like rooms disclosed little in the way of isolation. They discussed adding insulating wall foam sheets and flooring; but the biggest concern was that of bass coupling between the studios once speakers were cranked up.
With that problem in mind, Dirk and the team canvassed various hardware stores. Their goal was to find a set of springs that would support the studio speakers and serve to isolate their vibration from the deck above each studio.
The springs had to be heavy enough to handle the weight of the speaker and not lose all tension when the speaker was hung from it. Fig. 1a shows the spring assembly up close. An eyebolt is screwed into the deck. A reusable locking chain link connects the spring to the eyebolt.
A small link chain runs down through a hole in the ceiling tile, and mounts to the speaker with another reusable locking chain link and eyebolt. Figure 1 shows the finished speaker mounting.
Dirk showed me another helpful tip: labeling the rear of your equipment racks. No big deal, you say? In a facility with multiple stations and a multitude of equipment racks all in a row, having the rear of the rack labeled helps when troubleshooting an emergency.
(click thumbnail)Fig. 1a: A close-up.To simplify the group’s operation, Dirk has a separate rack for each station. Most of these racks house the identical equipment. Without the labels, it would be easy to find yourself looking at the same equipment, but in the wrong rack. The labels make it quick and easy to identify — and the identifying labels are based on frequency, not the ever changing call sign, as seen in Fig. 2.
By the way, the rack shown is a 32-inch deep model made by Middle Atlantic, part WRK-44-32.
With the increased requirement for additional depth for some equipment, planning for a deeper rack will avoid headaches later.
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George Levites wrote to object to the use of steel wool to seal cable entry points in a transmitter.
His worry is that small strands or pieces of this stuff can be blown around the transmitter enclosure via the rig’s cooling fans or blowers.
George added a case in point: At a transmitter site where he worked years ago, it was the company’s practice to have a commercial cleaning crew come in one night a month, after sign-off, to clean and wax the composition tile floors.
For a few days after each cleaning, the staff noticed frequent HV trips. They examined the transmitter and found numerous mini dust bunnies that were largely composed of steel wool strands. This debris came from the steel wool pads the cleaners used on their floor polishing machines. The large exhaust fan that was used to cool the transmitter literally was drawing this material into the transmitter.
(click thumbnail)Fig. 2: You can identify racks with the frequency, which, unlike call letters, is less likely to change.George suggests you use expanding foam-in-a-can and RTV sealants instead. Also, household scrubbing pads woven out of stainless steel would work well; they are coarser than regular steel wool and are not brittle. Good points!
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Gary Sharpe worked as an engineer in broadcasting for some 33 years, most of the time as chief engineer of one or more radio stations. Gary reads Workbench regularly and writes, “Frankly, it is the first thing I turn to after reading Paul McLane’s editorial. If you were closer to the front of the magazine than he is, I’d be reading your column first.”
Gary appreciated the May 23 item about finding odd critters inside one’s transmitter and about sealing up all the openings in the rig.
He suggests taking this a step further: Seal up all the holes, the spaces between front-panel plates, the edges around the doors and such. You will gain further benefit.
For example, you can seal the door edges with duct tape. Just pull it off when you need to open up the door and replace the tape when the door is closed for the last time that maintenance session.
Not only will you prevent insects and other tiny critters from getting into your transmitter, but all of the air passing through the transmitter now must go through the air filter and not bypass it. Sealing rigs this way makes for a much cleaner transmitter interior for a much longer time.