HFU HF Underground
Technical Topics => Part 15 AM and FM Station Operation => Topic started by: ThaDood on August 05, 2024, 1809 UTC
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https://www.radioworld.com/columns-and-views/readers-forum/letter-richard-fry-on-part-15-am-coverage-area This subject has come-up more than once on the Part 15 sites.
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20 years ago I hated the guy, but over time I grew to respect him. He always stuck to actual facts and presented them whether you liked it or not. I was actually disappointed to hear he had passed away in February.
The chart of his shown in Radio World clearly acknowledges the fact that up to a mile and a half is range is technically possibe when conforming to the 3 meter antenna/ground lead restrictions. Years ago he posted his correspondence with the FCC chief engineer who confirmed that the "200 foot rule" was bogus
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Something that had only occurred to me recently is that in every one of his many varied calculations over the years concerning potential part 15 AM range, a- He ALWAYS based it on a Class E transmitter.. Which has a greater potential than any Rangemaster or Procaster would.
I find that interesting, because other than the now discontinued SStran AMT5000, or or maybe a home scratch built unit, but there are no manufactured Class E Part 15 transmitters in existence and haven't been since the early 1970s.
So why did he always base his calculations on Class E Transmitters? The only reason I can think of was to make the range potential of the common part 15 to appear greater than what it actually is.
This from the guy often labeled as an enemy of part 15 AM
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So why did he always base his calculations on Class E Transmitters? The only reason I can think of was to make the range potential of the common part 15 to appear greater than what it actually is.
If what you say is true Rich (that he always based his calculations on Class E transmitters), the other reason I can think of would be to illustrate the maximum possible range that could be achieved with a compliant Part 15 transmitter. You're never going to have a transmitter with a final stage that is 100% efficient, so using a class E transmitter represents the maximum efficiency that can be practically achieved. That seems like a more likely explanation to me.
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If what you say is true Rich (that he always based his calculations on Class E transmitters), the other reason I can think of would be to illustrate the maximum possible range that could be achieved with a compliant Part 15 transmitter. You're never going to have a transmitter with a final stage that is 100% efficient, so using a class E transmitter represents the maximum efficiency that can be practically achieved. That seems like a more likely explanation to me.
Well when I finally noticed that he calculated Class E in the Radio World example I went looking at his numerous other calculations at part15.org, mbcf.biards.net and RadioDiscussions.com and saw that every one of them calculated a Class E transmitter. It really surprised me that I had never noticed before.
Anyway, your probably correct in your assessment of why he did it, but at the same time.. There were no part 15:Class E Transmitters in existence (still aren't)other than the SSTran 5000 which was a kit.
I just find it to be so curious.