Amplitude-Modulated microwave stations
 

Hi:

Are there any AM stations in the microwave-frequency spectrum?

Can they tolerate a higher range of musical pitches than the
medium-wave and long-wave stations?

I haven't found a reason not to have an AM station with a frequency as
high as that of the average FM station.

I do understand that the average FM station needs a higher frequency
than the average AM station because FM needs more bandwidth. High
frequency band means more bandwidth is available. Right?


Any assistance is appreciated.



Thanks in advance,


Radium

Behold, Radium scribbled:

Are there any AM stations in the microwave-frequency spectrum?

The highest frequency commonly used for AM voice communication is VHF
aircraft. The rest are military.

Can they tolerate a higher range of musical pitches than the medium-wave
and long-wave stations?

Only because they are less crowded.

I haven't found a reason not to have an AM station with a frequency as
high as that of the average FM station.

Here's one for you - who could receive it?

I do understand that the average FM station needs a higher frequency
than the average AM station because FM needs more bandwidth. High
frequency band means more bandwidth is available. Right?

That was true when dinosaurs roamed the earth and the FM band was created.
While less crowded than shortwave, V/UHF is filling up fairly fast.


--
Gregg
*It's probably useful, even if it can't be SPICE'd*

Gregg ) writes:
Behold, Radium scribbled:
Can they tolerate a higher range of musical pitches than the medium-wave
and long-wave stations?

Only because they are less crowded.

The LW broadcast band is quite narrow, but I don't see why a low-power LW
station couldn't also broadcast in stereo, just as they do for MW. Sure
would be more user-friendly than IBOC.

I haven't found a reason not to have an AM station with a frequency as
high as that of the average FM station.

Here's one for you - who could receive it?

Anybody w/an ICOM, Ten-Tec, etc.

I do understand that the average FM station needs a higher frequency
than the average AM station because FM needs more bandwidth.

That was true when dinosaurs roamed the earth and the FM band was created.

It was true since there was no method of digitally transmitting FM. That
does not need more bandwidth. You should be able to get quite a good narrow-
-band FM signal into a 10kHz channel using digital transmitters esp. since
it should be easier to do so at lower frequencies w/out creating artefacts.
So to turn your question around: why not have frequency-modulated mediumwave
mono stations? Static is eliminated, as well as the need for linear power
amplifiers, which are less efficient than class C. And most AM receivers can
use slope detection to demodulate the signal somewhat. FM also has a higher
capture ratio, which would result in less interference at night.

Gregg wrote:

Behold, Radium scribbled:

Are there any AM stations in the microwave-frequency spectrum?

The highest frequency commonly used for AM voice communication is VHF
aircraft. The rest are military.

UHF aircraft voice communications operate from 225 to 400 MHz (mostly
military).



I haven't found a reason not to have an AM station with a frequency as
high as that of the average FM station.

Here's one for you - who could receive it?


I've got at least 4 receivers capable of AM above 1 GHz (1,000 MHz) and
all are at least 10 years old.

Dave

Maximo Lachman wrote:



use slope detection to demodulate the signal somewhat. FM also has a higher
capture ratio, which would result in less interference at night.

That would be a LOWER capture ratio.

Behold, Dave Holford scribbled:



Gregg wrote:

Behold, Radium scribbled:

Are there any AM stations in the microwave-frequency spectrum?

The highest frequency commonly used for AM voice communication is VHF
aircraft. The rest are military.

UHF aircraft voice communications operate from 225 to 400 MHz (mostly
military).

I knew those, but the "scanners for the masses" don't normally go there.

I haven't found a reason not to have an AM station with a frequency
as high as that of the average FM station.

Here's one for you - who could receive it?


I've got at least 4 receivers capable of AM above 1 GHz (1,000 MHz) and
all are at least 10 years old.

Same as above.

I was thinking he meant a broadcast for the masses, what most broadcasters
aim for. Sorry if I misunderstood.

--
Gregg
*It's probably useful, even if it can't be SPICE'd*