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Long Wave digital-only AM IBOC broadcasting?

J

JasonW

Guest
Hello All,

I was wondering...is it illegal to broadcast in the Long Wave band (150 kHz - 530 kHz) in the US? I know that the FCC allows 1 watt unlicensed "LowFER" beacons on 160 kHz - 190 kHz under the Part 15 rules. Also, the Long Wave band in the US is rather sparsely populated by aviation Non-Directional Beacons (NDBs), but they are narrowband (only 5 kHz for the relatively few "Talking NDBs" with voice weather advisories--most are even narrower morse-only Continuous Wave), and in any given area most Long Wave frequencies are unused.

Since AM IBOC requires much less radiated power than analog AM to get a listenable signal out to a given distance, and because there are currently no North American analog Long Wave radio stations to "IBUZ-out" with interference, digital-only AM IBOC could find its niche here.

With the lower IBOC power requirements, there would be no need for gigantic Long Wave towers--the NDB-style 100' - 200' towers or telephone pole-supported Marconi "Tee" wire antennas would work just fine.

An all-digital AM IBOC Long Wave service could be used for low-power local broadcasting or for longer-range regional broadcasting.

What do you all think? -- Jason
 
> Hello All,
>
> I was wondering...is it illegal to broadcast in the Long
> Wave band (150 kHz - 530 kHz) in the US? I know that the
> FCC allows 1 watt unlicensed "LowFER" beacons on 160 kHz -
> 190 kHz under the Part 15 rules. Also, the Long Wave band
> in the US is rather sparsely populated by aviation
> Non-Directional Beacons (NDBs), but they are narrowband
> (only 5 kHz for the relatively few "Talking NDBs" with voice
> weather advisories--most are even narrower morse-only
> Continuous Wave), and in any given area most Long Wave
> frequencies are unused.

........I believe the services you mentioned are the only ones authorized
to broadcast in the 150-530 kHz band.
>
> Since AM IBOC requires much less radiated power than analog
> AM to get a listenable signal out to a given distance, and
> because there are currently no North American analog Long
> Wave radio stations to "IBUZ-out" with interference,
> digital-only AM IBOC could find its niche here.
>
> With the lower IBOC power requirements, there would be no
> need for gigantic Long Wave towers--the NDB-style 100' -
> 200' towers or telephone pole-supported Marconi "Tee" wire
> antennas would work just fine.

........The "gigantic" towers you refer to were likely government-operated
and provided military communications via ground wave over vast areas. This is now done by satellites. The governemt has taken down many longwave towers.
>
> An all-digital AM IBOC Long Wave service could be used for
> low-power local broadcasting or for longer-range regional
> broadcasting.
>
> What do you all think? -- Jason
>
 
> ........I believe the services you mentioned are the only
> ones authorized
> to broadcast in the 150-530 kHz band.

Hmm...would it be hard for iBiquity to get an experimental license for limited-duration test broadcasts on Long Wave?

520 kHz is still part of the Long Wave band, but since it is so close to the "official" bottom edge of the AM broadcast band, many AM receivers can tune that low (most of mine do), and it would be very easy to modify (or maybe only adjust) an AM IBOC transmitter to operate at 520 kHz. Moreover, since 520 kHz is legally *not* part of the AM broadcast band, it should be easier to get an experimental license for digital-only test transmissions at this frequency.

> ........The "gigantic" towers you refer to were likely
> government-operated
> and provided military communications via ground wave over
> vast areas. This is now done by satellites. The governemt
> has taken down many longwave towers.

I was referring to the huge (1000' - 2000') Long Wave towers still used in Europe. If an all-digital Long Wave service were ever authorized in the US, it would be possible to slant-wire feed or shunt-feed existing US TV and FM towers that are 1000' - 2000' tall. But really, the AM station-size towers and Marconi "Tee" wire antennas used by Long Wave Non-Directional Beacons (NDBs) would work just fine for digital-only Long Wave broadcasting. -- Jason
 
> It sounds like a great place to try DRM too.

Ye read me mind! :) -- Jason
 
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