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Post by Deleted on Jun 20, 2017 0:59:45 GMT
Full Time Stations
AM broadcasting under the part 15 rules is a full-time authorization, a privilege not enjoyed by daytime licensed stations who dream about those illusive words: nighttime authority.
But when the sun falls the ionosphere falls along with it and develops a hell of reflected sky-waves that crowd part 15 signals into the rough.
A long time ago in a thread at part15_us I asked, "Why can't part 15 stations raise their power at night to give us a fair chance of matching our daytime signal.
Member PhilB explained why that isn't likely to happen, but that thread has vanished into a far away constellation.
Now I'm back to wondering about the same question.
Why can't we raise power at night?
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Post by jimhenry2000 on Jun 20, 2017 1:48:32 GMT
I agree with your question. Full Time StationsAM broadcasting under the part 15 rules is a full-time authorization, a privilege not enjoyed by daytime licensed stations who dream about those illusive words: nighttime authority. But when the sun falls the ionosphere falls along with it and develops a hell of reflected sky-waves that crowd part 15 signals into the rough. A long time ago in a thread at part15_us I asked, "Why can't part 15 stations raise their power at night to give us a fair chance of matching our daytime signal. Member PhilB explained why that isn't likely to happen, but that thread has vanished into a far away constellation. Now I'm back to wondering about the same question. Why can't we raise power at night? |
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Post by End80 on Jun 20, 2017 19:43:06 GMT
You can raise power at night if your transmitter has a means to do so, or you could simply extend on your antenna system at night and probably get the same effect.
It's very difficult to read the part 15 rules in the dark.
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Post by End80 on Jun 20, 2017 19:51:59 GMT
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Post by Deleted on Jun 20, 2017 20:52:06 GMT
Spirals from the Past
Richard Powers you found the original!
As I recall when that conversation took place we were very lofty and technical, so how come now it gets sillier and goofier?
What I thought, which finally got explained, was that as skip-waves got stronger our part 15 signals got weaker. I still think so.
All those schooled engineers with their definite knowledge of physics and mathematics.
Einstein made a mistake, maybe our resident engineers are wrong sometimes.
I may not be an engineer but am sometimes right. Doesn't that prove the point?
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Post by Boomer on Jun 21, 2017 2:58:01 GMT
It seems your transmitter's signal would be there just the same, but mired and mixed in a soup of other broadcasters from distant places at high signal strengths.
The foreign signals are equivalent to having a higher noise floor, so they reduce the effective range of your station.
I'd have to agree that in this fog of other stations, it would be hard for a field strength meter to tell how much signal you were putting out.
Maybe more signal should be allowed at night, it doesn't seem it would hurt anything in the face of the other super power stations on the frequency. Traveler's service stations use 100 times more power than P-15, and I've never heard a complaint of interference at night, or that any one those stations had to turn off at dusk. That implies they don't cause unacceptable interference to licensed broadcasters.
I also think that forms of carrier-current and loop antennas are good at reaching audience at night. The stations I've heard use the low end of the band, and with the closed loop antenna, the signal levels tend to be very high close to the loop, but drops off fast with distance. It's more of a targeted transmission, with high signal levels in the coverage area.
Carrier current is like a station that doesn't compete in the antenna station territory.
Boomer
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