Low-power digital-only AM IBOC & FM IBOC question

[JasonW]

Hello All,

It looks like the digital signal component of the hybrid analog/digital IBOC system will always be somewhat hampered because of the need to avoid having it interfere with the analog signal component.

However, many communities across the US have no local radio stations at all. In places such as these, low-power digital-only IBOC stations could be set up. Using AM frequencies near the bottom of the band (say, 540 kHz - 620 kHz) would help prevent unwanted skywave interference. Top-loaded monopole antennas (Non-Directional Beacon [NDB] loaded monopoles or Marconi "Tee" wire antennas would work nicely) and 250 watts output at these low frequencies could easily cover most smaller communities with strong signals. On the FM side, 10 watt - 200 watt transmitters could do the job in most cases.

Has anyone ever tried this under a Part 5 experimental license? I know that iBiquity is after the "big fish" of major market stations, but starting at the grassroots in smaller communities could bring digital-only IBOC to fruition sooner. I'm against AM IBOC in its current form because of its night-time skywave interference problems (skywave should be preserved for emergency communications), but if it could be implemented locally at lower power (and/or lower frequencies) so as to avoid this, I'd have no problems with it.


-- Jason

 

[vsa]

Don't forget that 250 watts at 540-620 kHz still makes for a huge signal. 25 to 50 watts would probably do the job for what you're talking about.

However, Kahn Communications' CAM-D does what you want to accomplish while also having full analog compatability.

I don't understand why this invention is being written-off in such a cavalier fashion.

 

[autopaint-1]

Because with the Cam D, there is no FM equivelent and with Cam D you can not turn off the analogue carrier. Also, Leonard Kahn has done more to turn away the majority of US radio station owners than any one man. One least note; Where are the Cam D receivers? I keep hearing that it's a great system but you can't find a radio, anywhere. I don't want to hear about software radios. The average American isn't a radio experimenter. So far Cam D is great only by those promoting it. Where are the stations? I don't want to hear about a 1 Kw station in a small market. IBOC is THE system and it's really too late for the other wanna be's to make a dent. The industry learned its lesson with AM stereo (another advancement Mr Kahn helped destroy thanks to HIS system and HIS lawsuits.

 

[vsa]

AUTOPAINT-! WROTE: "Because with the Cam D, there is no FM equivelent and with Cam D you can not turn off the analogue carrier."

CAM-D would work well with an FM partner such as FMeXtra. Kahn has also said that an analog carrier-turn-off option would not be very difficult to add in the future. It's doing analog and digital simultaneously and with comptability that is the challenge.

AUTOPAINT-! WROTE: "Leonard Kahn has done more to turn away the majority of US radio station owners than any one man."

Leaonard Kahn demonstrated the first AM stereo broadcasts in 1960 on XETRA 690, a station that is now being jammed by KSPN 710's HD exciter in Los Angeles from sunrise to sunset. Kahn is a radio genius. AM stereo did not die because of him. Some people needed a scapegoat. I suppose you'll blame HD Radio's demise on Leonard Kahn as well.

AUTOPAINT-! WROTE: "One least note; Where are the Cam D receivers?"
HD Radio took about 14 years after its beginnings in 1990 to come out with its first receiver. A little patience for CAM-D please. Meanwhile, CAM-D's benefits for analog broadcasting are substantial and real all by themselves.

 

[autopaint-1]

"CAM-D would work well with an FM partner such as FMeXtra. Kahn has also said that an analog carrier-turn-off option would not be very difficult to add in the future. It's doing analog and digital simultaneously and with comptability that is the challenge."


Neither system is being taken seriously by the broadast industry. I've talked with the powers in the industry. IBOC is it as far as digital broadcasting is concerned. Also, they will not use a system which will require modifications of a major nature to make it work. If Kahns system doesn't allow the immediate removal of the analogue component forget it. When I first learned of IBOC I asked about Kahns system and was met with shaking heads and negative comments.

"Leaonard Kahn demonstrated the first AM stereo broadcasts in 1960 on XETRA 690, a station that is now being jammed by KSPN 710's HD exciter in Los Angeles from sunrise to sunset. Kahn is a radio genius. AM stereo did not die because of him. Some people needed a scapegoat. I suppose you'll blame HD Radio's demise on Leonard Kahn as well."

The point is that Kahns system was not accepted when the commision finally adapted a stereo standard and he did more to turn off everyone in the industry than any single person.


CAM-D would work well with an FM partner such as FMeXtra. Kahn has also said that an analog carrier-turn-off option would not be very difficult to add in the future. It's doing analog and digital simultaneously and with comptability that is the challenge.

AUTOPAINT-! WROTE: "Leonard Kahn has done more to turn away the majority of US radio station owners than any one man."

Leaonard Kahn demonstrated the first AM stereo broadcasts in 1960 on XETRA 690, a station that is now being jammed by KSPN 710's HD exciter in Los Angeles from sunrise to sunset. Kahn is a radio genius. AM stereo did not die because of him. Some people needed a scapegoat. I suppose you'll blame HD Radio's demise on Leonard Kahn as well.


"HD Radio took about 14 years after its beginnings in 1990 to come out with its first receiver. A little patience for CAM-D please. Meanwhile, CAM-D's benefits for analog broadcasting are substantial and real all by themselves."

It's not 1995 any longer. His system is too, little too late.