AM, Marti and Making Sound Waves - Radio World

AM, Marti and Making Sound Waves

Readers write in to keep us straight!
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AM REVITALIZATION

I thoroughly enjoyed, if that’s the best word choice, the excellent article on “Our Last Best Chance to Revitalize AM,” in your Jan. 6 issue.

The one missing piece of this discussion is on the receiving end. AM tuners in many current generation receivers are, in a word (and here the word choice is correct), terrible! Go back and pull out a radio from the ’70s or earlier and they will almost always prove superior to today’s radios. That’s, again using a single word choice, unacceptable! What to do? The industry can’t force manufacturers to build better AM tuners but it can certainly speak up until it’s heard.

Another point of contention is the FCC language on just about anything electronic that it cannot generate harmful RF noise. Does anyone remember the last time that was enforced? Didn’t think so!

The bottom line is broadcasters, working together with the FCC, are working to find ways to increase their transmitter power, location and FM translators where possible.

Let’s not forget the receiver end of that discussion.

Bill Wertz
President
Wertz Media
Seattle

MARTI

Nice job on the Jan. 6 RW piece about George Marti.

One of the stations where I worked as C.E. had a Marti M-30B like the one in the photo, but also an older one with no model number. It was either a first generation or a prototype of the M-300 unit. Its cabinet was the same size and shape, made from aluminum painted gray, and had a much larger meter with the meter cover external to the case (sticking out instead of recessed). Otherwise, the schematic, tube compliment, etc. was nearly the same. That used a peculiar PA tube as well.

We ran those units every weekend, right up until 2009. I must have had both of those transmitter on my bench a dozen times over my 20-year tenure at that station. Almost every problem we had with those was operator-related and had nothing to do with the equipment. The fan in the lid was the most failure-prone part of the unit.

Ah, those were the days when broadcast equipment was built by real men, for professional broadcast use! Broadcast equipment was held to a higher standard than what was available to the general public. These days, we make radio happen with a bunch of equipment that is no more reliable than the consumer-grade rubbish found at any Best Buy. George Marti really put out reliable stuff, even if it did look a bit primitive.

Paul Shinn
Chief Engineer
KVML(AM)/KKBN(FM)/KZSQ(FM)
Clarke Broadcasting
Sonora, Calif.

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iStockphoto/45RPMUNDERSTANDING WAVES

Regarding “Digital Deciphered” Dec. 16, 2015 issue:

“The waves themselves are known as Hertzian Waves, in honor …” it seems that Jim is getting electromagnetic waves confused with air pressure variations that our ears respond to. Ears do not respond to electromagnetic radiation.

“… energy at frequencies just above 50,000 Hz becomes so energetic that electrons jump off the wires …” This is just so wrong. It is not how electromagnetic radiation is generated.

Noel Maginnity
Carterton, New Zealand

Jim Withers’ reponse:

I would ask the reader to forgive my “shorthand.” Since the focus of the article was about the differences in analog waves and digital pulses, I did not adequately explain the differences between sound waves and waves of the electromagnetic spectrum.

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