The idea being making the translator a primary service so the associated AM can be shut off
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AM Radio - Directional Transmitter Antenna Systems - Still Needed?
- Thread starter kfbkfb
- Start date
In theory considering a co-channel situation; there would be a distance where neither will be available because the received packets are considered by the receiver as out of order, so nothing is decoded. Once you got into the stronger field and more aligned packets are received from the stronger station, the radio will begin decoding (playing) that stream.
Won't happen
I think there are so many cases of AMs being downgraded to low power at night that at some point the FCC will realize that it would be best to let them have FM permanence if they have a translator, allowing the band to clear out. Anyone at the Commission is aware that both of our geographic neighbors have pretty much emptied the AM band and around the world AM is being eliminated or reduced in population; they should realize that reviving the band is not possible or probable.
K
kenglish
Guest
Maybe clearing out the smaller stations, and replacing them with lower- power FM's (with coverage similar to the AM's day power/pattern) would work. They wouldn't be "translators", just a new class of FM.
Keep the high- powered AM Clears, so as to have wide-spread coverage for news and emergencies, and for the DX'ers 😉.
Same for the Regionals. You could even re-allocate a few cleared-out channels to a regional status, as needed.
Keep the high- powered AM Clears, so as to have wide-spread coverage for news and emergencies, and for the DX'ers 😉.
Same for the Regionals. You could even re-allocate a few cleared-out channels to a regional status, as needed.
The first step is to eliminate daytimers. They may have been useful and viable long ago, but not now. If they can be replaced by the equivalent of protected translators, they can serve small to medium markets entirely and also provide useful service to groups of immigrants who tend to concentrate in smaller geographic areas. And, of course, they can be general market stations for a particular part of a big market, too.
Those Robin Mathis 50 kw day and 250 watt night stations and their ilk qualify as "daytimer" as well
Then, look at solutions for highly directional stations that just don't cover much of the market at night or have been grown out of by post-WW II urban sprawl. Those are, in many ways, daytimers too.
Mexico solved the problem and moved over 600 out of about 800 AMs to FM by changing the separation between stations; they realized that the current NARBA standard was based on the technology of the 40's and 50's and tighter assignments can be made. That standard is almost universal in much of the rest of the world. It would, though, require many stations to move to different frequencies to optimally use the band.
The question is whether there are investors willing to back such a plan. We are so far into being a smartphone based society that major changes in FM allocations may be, like AM stereo, too little and too late.
I keep seeing comments here and there (on RD as well as some FB groups and other forums) that the "FM band is full", yet even in my metro when I tune my digital FM radio across the band there are plenty of empty frequencies. I think there would be enough in my area to cover many, if not most, of the AM stations in the metro.
The problem with that analysis is that stations are "protected" for a distance from their transmitter based on their FCC class. So, while a spot may be seemingly empty to your, were you to put on a station from your location, its signal would most likely interfere some miles away with a co-channel station's protected coverage area, or overlap an adjacent channel's area making for interference in it's guaranteed coverage space.
As David says, there are several factors that reserve certain channels/frequencies. Those reasons could include co, or adjacent channels at distance, including Canadian or Mexican treaties to prevent potential interference across borders. For example, in the North, there a symbolic line called 'Line A'. This line was the agreed line on the U.S. side where certain channels were limited to a particular field strength or allowing channel use North of line A: Frequency Coordination with Canada Below 470 MHz This is part of the Canadian/US treaties.
'Line A' could also include limitation of field strength across the line, which means the station may be below Line A, but coverage can't cross the line.
K
kenglish
Guest
In the Salt Lake City market, there are no channels that are not occupied by licensed stations, or are first-adjacent to licensed stations.
Not one.
Those websites that show nearby stations and give you a list of channels that can be used for your mini-FM car transmitter just come back with a shrug and "Sorry, Dude!"
Even the pirates and boosters/translators are walking on each other. Trying to fill the "empty" channels would just make the FM band in to another AM.
Not one.
Those websites that show nearby stations and give you a list of channels that can be used for your mini-FM car transmitter just come back with a shrug and "Sorry, Dude!"
Even the pirates and boosters/translators are walking on each other. Trying to fill the "empty" channels would just make the FM band in to another AM.
Another FM translator option:
1 analog FM signal + (IIRC) up to 8 HD subchannels from 1 FM + HD translator.
Change the rules so that HD1 doesn't have to be a repeat of the analog FM signal, this configuration would comply with existing (USA) FM spectrum requirements and allow 9 AM to FM "translations" in 1 FM + HD translator.
Kirk Bayne
1 analog FM signal + (IIRC) up to 8 HD subchannels from 1 FM + HD translator.
Change the rules so that HD1 doesn't have to be a repeat of the analog FM signal, this configuration would comply with existing (USA) FM spectrum requirements and allow 9 AM to FM "translations" in 1 FM + HD translator.
Kirk Bayne
The HD radio subcarriers in the hybrid mode could only carry 100-150 kbps of data. 9 subchannels would sound awful.
What is a mini-FM car transmitter? Is that anything like the Christmas light displays and my church's Sunday morning services?
K
kenglish
Guest
They are those little-bitty legal ones that people use to listen to music from their phones and such thru the radio speakers.
The ones used for Christmas light displays and drive-in Church are not always legal.
There's no vacant FM band channel here for any of them. Some people just use the 87.5 to 87.9 frequencies.
I generally used 87.5 or 87.7 which usually worked pretty well except in areas with TV stations or Franken FMs on channel 6. But that isn't a problem much any more except for a Franken FM in Memphis that will be going away soon.
I'm not sure that it's ever been field-tested, and I'm skeptical, because just about everything else related to HD radio hasn't panned out very well. But supposedly HD works with multiple transmitters phase-locked together as a single-frequency network. I've often wondered if an AM broadcaster could effectively cover a market using a number of small transmitters (say 100 watts) spaced at strategic locations throughout the market using shortened antennas (yes - they're inefficient, but it doesn't matter in this case). This would be in place of a single 10KW transmitter. Think multiple TIS stations, only with higher power. The distance from any single listener to the nearest transmitter would be short, and the 1/R-squared rule still applies. If you could cover a market with, say 10 of these 100 watt facilities the total contribution to skywave interference would be way less than a single 5kw facility, and you have the option of placing the transmitters where the people are in a market - something that's not always easy with a single site and a directional antenna.
Would it work? Would the FCC allow it? I'm curious as to what other's opinions are.
Dave B.
Perhaps the 100W AM transmitter antenna system could use existing cell phone towers.
KDTD - Wikipedia
Kirk Bayne
Not sure if they still provide them, but with some of their aftermarket satellite radio install kits, they used to include a small FM transmitter to get satellite radio audio into an existing factory car radio receiver. If one bothered, you could change the frequency of the little transmitter to a frequency that didn't interfere with a station on your car presets. Problem was, the little transmitter default frequency was something like 88.5Mhz. Most consumers just left the default frequency set.
A few years ago there were a series of complaints sent to the Commission, where essentially Mom was taking the kids to school while listening to her local NPR station. When she pulled the family minivan near Bob the carpenter's pickup, who was listening to Howard Stern, Mom's kids get treated to Stern's show.
Synchronous AM boosters have been around for a while, but never really worked well. Even if you lock the main site and booster oscillators to GPS, there is still enough natural shifting propagation delay to make the audio UN-listenable. In a mobile listening environment, it's even worse. Given the lack of Bit Error Correction allowed in an MA3 bit stream, I believe you'd find a similar problem trying to use fixed geographically spaced transmitters with a mobile audience. Between the natural propagation changes in the MW band, add-in terrestrial noise sources constantly moving with the vehicle, and I'm willing to bet the experience wouldn't be worth the effort.
I believe it was in the Denver area, where a similar model to what you mentioned was tested for DTV. Several small DTV transmitters were spread over several miles with directional antennas all locked to GPS. The test results were very encouraging, but TV viewing usually isn't intended for a mobile viewing environment. The downside was the significant design involved, much of that would have to include some trial and error field (expensive) engineering. The upside was the ability to reduce coverage holes caused by terrain. Now of course, Internet streaming to mobile devices (smart phones) has pretty well killed any interest in pursuing portable TV watching.
Cell phone/PCS companies want nothing to do with broadcasters, and would fight that idea to the death.
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