Getting back to what I was saying earlier, the plan really doesn't address AM revitalization. It simply gives some a way out of a dead end the FCC itself created. And in the process, it creates a new problem of clutter on the FM band.
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NEW FCC AM Revitalization rules and proposals. Why the excitement?
- Thread starter EngineeringDog
- Start date
Getting back to what I was saying earlier, the plan really doesn't address AM revitalization. It simply gives some a way out of a dead end the FCC itself created. And in the process, it creates a new problem of clutter on the FM band.
My argument would be with the ever increasing noise floor, the last thing a station would want is their carrier level intentionally going up and down. I heard that very thing recently on a station in Richmond VA, who was obviously running MDCL. Very audible noise floor going up and down during a talk show, where the host was leaving pregnant pauses. AM has noise problems anyway, why make the noise problem that much more obvious to the listener?
That isn't what I've heard. On two separate stations that run MDCL, you can hear the system working in changing noise floor during talk. If you're around something particularly noisy like computer monitors, switching power supplies, florescent bulb replacements, the noise is very pronounced and noticeable to a listener who doesn't know any difference between the weird noise station and another on the dial that doesn't bother with MDCL.
Are you running it on Vashon Steve? If so, how much documented power savings has the station seen? My guess is theoretical and actual savings don't line up. Then add in the risk of sending more AM listeners away from your station, and the juice (pardon the pun), may not be worth the squeeze.
Are you running it on Vashon Steve? If so, how much documented power savings has the station seen? My guess is theoretical and actual savings don't line up. Then add in the risk of sending more AM listeners away from your station, and the juice (pardon the pun), may not be worth the squeeze.
Yes I have a client running MDCL on two 50kw stations, I agree it's questionable if MDCL helps anything below 25kw. For the client running MDCL they do see the power saving in several thousands of dollars a year, enough to pay for the upgrade of the DX50 and convince them to add it to a second.
I would have to start a new thread to really debate this but I have seen it implemented twice in the Puget sound area with no side effects except power savings.
I would have to start a new thread to really debate this but I have seen it implemented twice in the Puget sound area with no side effects except power savings.
D
Darth_vader
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Heard any of the WWCRs recently?
I already have my suspicions on that point. I should not be able to drive as many miles across town as I do
and still hear them if they're operating at their posted wattage.
Depends on where they're installed.
I know of a couple of 10-watters that have scary coverage ranges. I've seen both installations and they're legal.
Years ago (maybe an old Broadcast Engineering mag), I read a story about a wind-powered station that was also in the 10-watt-range, but you wouldn't have known it by their coverage.
Height usually trumps power in FM broadcasting. A very low power transmitter, with enough antenna height can rival many Class A stations while listening on your car radio. Where the rubber meets the road is in building penetration. Most houses are good for a 10 db loss, maybe more. A steel and metal office building is even worse. At just 200 feet, a 250 watt translator is usable for about 15 miles in your car. Reception inside a building, especially on a terrible radio like most people have, is an entirely different story.
Stucco is about the same as a steel-and-concrete office building -- a good 20 dB or more depending on the frequency and the distance from the outside wall.
And what might be a hidden item is the insulation attached underneath the stucco. It is usually foil wrapped on the exterior. I am assuming there is probably more loss of signal from that than from just plain old stucco.
I have a west facing indoor antenna (Mohu Metro) that I can attach to the inside of a double pane window or pin to my cork board just a foot away. I suffer more signal loss, particularly from the hi-VHF's, from the solid wall than I do from the window location. I need to remove my sun screen from the window and see if the signal improves. It is fabric but very tightly woven.
One of our translators is 250 watts at about 350 feet on relatively flat terrain. It gets out 25-30 miles. The last 10 or so is a bit weak, but still better than 1000 watts AM at night.
Foil, chicken wire, anything metal will affect the attenuation through the walls. If that metal is connected somehow to ground, add another 20 dB at some frequencies.
At my old Phoenix apartment, the metal lath on the building attenuated everything above about 3 MHz at least 30 dB, and below it roughly 10-15 dB. AM radio was usable, but shortwave and TV were problematic. I had to position my TV antenna below the top of the window to get anything, and shortwave actually worked better with the antenna 15 feet or more inside the apartment. The apartment was about 4 miles SE of the South Mountain tower farm, which was why I had no issues with FM. In fact, I still needed an FM trap on the TV antenna despite the high attenuation.
The house I'm living in now (30 miles ENE of South Mountain, at 1500' elevation, near Usery Mountain) is also stucco/chicken-wire, but apparently is not grounded. Attenuation at VHF and up is not that bad, but AM & SW reception are all but nonexistent -- even the few Phoenix stations that put usable signals into this part of town. Outside antennas cannot be above the roof line due to FAA regulations/city ordinance -- I'm within the Falcon Field airport protected zone.
In my experience during the DTV transition where people living with neighborhood HOA are forbidden from using outdoor antennas, attenuation through the roof or walls isn't as big a deal as noise created by consumer products and noisy utility service. If the noise floor is higher or equal-to the field strength at the destination, you're fighting a losing battle.
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