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HD Radio

A

acheron1982

Hey - Need some education here.

Just bought a new car and it has HD radio so I'm able to listen to HD radio stations for the first time. I've been switching back and forth between 97.1-2 and 99.7-2 since alt music is my personal taste. So how come can I get 97.1-2 all the way to Villa Rica but I can only pull 99.7-2 to about six flags hill on the west side. How does HD Radio signal work? Are there coverage area maps similar to FM signals on Radio Locator?
 
I know that HD radio signals are only allowed to run at a fraction of their analog parent signal due to the fact that the power increase on digital will trample all over the analog dial. Correct me if I am wrong. It's something to do with sideband interference. It's like when your analog tuner locks onto .2 before/after the actual frequency. I don't believe the HD signals will ever be allowed to be turned up full blast until the analog spectrum gets completely turned off. I enjoy my HD radio. I've only had the Insignia family of portable HD radios (now discontinued). I've noticed the HD radio service goes out almost equally as far out as the broadcast DTV signals from Atlanta. There's a great deal of naysayers on this topic on the HD radio board. I like listiening to radio in digital. I think it's the future and where FM should go. I do feel like the only thing keeping it going are the translators and AM stations that need these HD subchannels to rebroadcast the AM signals and the translators to have something to rebroadcast off of. It really hasn't caught on as quickly as I had hoped. It seems almost stagnant if you ask me. It will require the FCC to mandate putting these tuners in all future radios like they did with FM tuners.
 
I have had an HD portable radio for a few years. In Stockbridge I have been unable to get 97.1 in HD until recently. I get 92.9,94.1,94.9,96.1,96.7,97.1,98.5,99.7,100.5,101.5,103.3,104.1,104.7,105.3,107.9 in HD on a regular basis. Sometimes 107.5.
 
The engineer types can correct me if I am wrong in how I word this.

The FCC allowed HD to double (or was it 1.5 times) the power of the HD transmitter. Most of the Atlanta stations had already made capX investments at the lower wattage. I asked the question on this board at the time if the stations would upgrade their HD power to reflect the new FCC maximum. The response i got was that the stations will upgrade in the natural order of things such as equipment replacement, transmitter move, or when corporate thinks it is important.

That being said, I have noticed in the last year or so a few of the HD stations have better signals. I have the same old reciever in my car that I've had for 10 years, so I know it is not the receiver. So, maybe some of the stations have upgraded their power.

(did I explain this correctly?)
 
BarryATL said:
The engineer types can correct me if I am wrong in how I word this.

The FCC allowed HD to double (or was it 1.5 times) the power of the HD transmitter. Most of the Atlanta stations had already made capX investments at the lower wattage. I asked the question on this board at the time if the stations would upgrade their HD power to reflect the new FCC maximum. The response i got was that the stations will upgrade in the natural order of things such as equipment replacement, transmitter move, or when corporate thinks it is important.

That being said, I have noticed in the last year or so a few of the HD stations have better signals. I have the same old reciever in my car that I've had for 10 years, so I know it is not the receiver. So, maybe some of the stations have upgraded their power.

(did I explain this correctly?)
Click to expand...

As memory serves, the old limit was !% of analog power. That was extended to 4% and as much as 10% if interference conditions allow.
 
Barry has it essentially correct. Those stations using separate transmitters and antennas for analog and HD have the easiest upgrade. They need only turn the 'loud' knob on the transmitter, or upgrade it to the higher power. For stations using a common antenna but separate transmitters the cost is higher. The combining system wastes 90 percent of the HD power, thus the increase in transmitter power is substantially larger. In some instances, the equipment which combines the two must also be upgraded. For those who use a single transmitter to produce both analog anf HD, the cost is highest. The transmitter must be modified, or in many cases replaced. It's confusing, because it's a juggling act.
 
If that is the case, how in the word am I actually able to pick up the HD stations for 97.1 all the way to Villa Rica. Remember, 97.1 tower is clear on the northeast side of the metro near the Mall of Georgia. Meanwhile, 99.7 tower sits in downtown and only gets to Six Flags Parkway on the west side (the HD stations anyway). Still not making all that much sense if in fact they are allotted only a small fraction of the analog signal. I also note the audio on the 97.1 HD station is awful and seems to be lower (volume wise) than all the other stations (analog and HD).
 
I occasionally have to drive to Birmingham for work and have never had an issue listening to either station in HD out to the state line. Both are spotty by then.
There is a really good HD3 station at 88.5 I just noticed a few days ago. There used to be a good Americana HD2 on 96.7 but that signal is pretty weak in the areas I travel.
 
acheron82 said:
If that is the case, how in the word am I actually able to pick up the HD stations for 97.1 all the way to Villa Rica. Remember, 97.1 tower is clear on the northeast side of the metro near the Mall of Georgia. Meanwhile, 99.7 tower sits in downtown and only gets to Six Flags Parkway on the west side (the HD stations anyway). Still not making all that much sense if in fact they are allotted only a small fraction of the analog signal. I also note the audio on the 97.1 HD station is awful and seems to be lower (volume wise) than all the other stations (analog and HD).
Click to expand...


Height Above Average Terrain (HAAT) is very important in FM broadcasting. The old “rule of thumb” for a regular FM station usable coverage is line of site plus 25 to 35%. That is why in the class B markets stations often take a severe hit in transmitter power to get their antennas on the tallest building or tower in the market that will give them the most folks in the line of sight from the tower. An example of this is New York City. A lot of the class B’s are on the Empire State Building at 6 KW and 415 meters (1339 ft.) in height when they could be 50 KW at 500 ft. 97.1 is a full class C* 98 KW at 1585 feet HAAT. 99.7 is a C0 at 96.6 KW (100 KW beam tilt) @ 1115 feet HAAT. 400 + feet will make a big difference in line of sight which with HD’s lower power is about all one can expect.

* According to several postings on this board by folks who are usually correct, The 97.1 tower needs some very expensive repairs and some short sight person at Cox has WSRV moving to a much shorter 212 Meter tower and being downgraded to a C1. IMHO will lose 60 db coverage in Bartow and Douglas counties which I believe both have PPM units, and more importantly 97.1 will lose a lot of adjacent and secondary channel protection which is required for HD radio.
IMHO this down grade is similar to Forty years ago. The directional night time AM stations in Atlanta did not upgrade their nighttime signals, while most of Atlanta’s growth took place outside their nighttime coverage. Cox should have lots of cash, but if repairing or replacing the existing tower is impossible, then moving to the WWEV tower:
http://radio-locator.com/cgi-bin/finder?call=WWEV&x=15&y=4&sr=Y&s=C
or the 106.7 tower would work better.
http://radio-locator.com/cgi-bin/finder?sr=Y&s=C&call=Wyay&nav=&x=0&y=0
than were they are going.
Fifty years ago FM was like HD is now not enough receivers to really pay off. FM really did not take off until the automobile companies started putting FM radios in just about car on the road in the late 1970’s. If the existing HD system ever takes off, first and second adjacent channel protection will be very important. Full class C’s have the best protection.
 
I know of only 3 ATL AM stations that have been able to successfully significantly upgrade their night signals in the last 40 years or so (there may be others):

1) WRNG/WCNN, which went from being a daytimer as late as 1979 to 10kW-DA, but with a null over Cobb and a hard null over Gwinnett
2) WPLO/WKHX-AM/WDWD, which went in the early 80s from 5kW-DA with an east-west figure-8 pattern from North Druid Hills to 4500W-DA with a southeasterly hand-puppet pattern out of Powder Springs, increasing north suburban night coverage
3) WGST moved from 920 to 640 in the late 80s; they increased their day power from 5kW to 50kW, but their night power remained the same at 1kW. They have a directional (N-S) night signal now, but a very mild one. They do get the coverage bump from moving down the dial.

My point is, I don't think that many ATL AM stations could have upgraded their night signals even if they had wanted to. Most ATL AMs were already hemmed in at night, between competing local/regional channel stations as well as Class As on the clears, mostly to the north. Someone could have pulled a WOWO and bought a smaller market class A clear for the purpose of putting the class A license on an Atlanta station, but nobody has (plus you'd have to find a cochannel class A station to buy for the purpose of downgrading). WRNG had to build 8 towers in a Peachtree Corners floodplain to get the pattern they needed.

What I would like to know is how many ATL AM stations had to slash their night signals because they lost the land for their tower array and had to find a single stick somewhere, and had to cut their power as a result.

A lot of this is similar to what happened to TV, where Atlanta was only allocated 4 VHF channels (same as Birmingham, I believe) because the population was a lot smaller at the time, while bigger metros got the theoretical VHF max of 7 channels.
 
There has been little opportunity for night signal improvement since the 40's. AM used to be a much higher priority, especially night service, and there was no way those who had the good signals would allow more competition.
Most night service added since then has ugly directional patterns which were marginal even back in those days of lower RFI and physically smaller cities of license.
There are only a rare few decent HD stations in Atlanta. I have really enjoyed the classic rock on 88.5's HD3. I'm surprised that a bunch of college students could program a format with music made long before they were born. They go really deep into the album cuts and play stuff I haven't heard for years. The weird thing is they keep saying it is testing so maybe it is just someone's dad and their iPod.
The HD2 at 88.5 is a college format and could probably attract some listening. WABE has two good HD stations, one all news/talk and one classical. Most of the other stations are similar to their analog hosts and don't interest me although I do like the noticeable lack of noise on HD.
 
I know I'm beating the dead horse here but I honestly believe something is up with 99.7. I live in Alpharetta (travel to Carrollton a lot) and even in Alpharetta, the HD signal on 99.7-1 goes in and out.... In Alpharetta. No other HD stations is having this trouble. I checked 88.5, 94.1 and even 105.7 which is weaker and I'm not noticing the problem that I hear with 99.7-1. 97.1 and 106.7 are impressive signals. Actually, I would argue 100.5 is pretty impressive considering it's low wattage compared to how far I get it. That aside, while 97.1 HD station gets out pretty far (about as far as the regular FM signal), I do notice that the sound quality is about 50% lower on the HD stations. I actually have to turn the volume up in my car a good bit to hear it.
 
I've also noticed that WRDA gets a pretty good HD signal from Canton all the way out here to Loganville and it is only 16.5 kW with a long distance. I cannot receive any HD from WNNX. The remaining HDs come in pretty clear but not much further east of Loganville. There also have been many software updates in HD radios over the last 10 years. I noticed that my old Gigaware (RadioShack) iPhone tuner will not receive any of the Cox stations' HD2/3 signals. It typically rejects them and forces the tuner back to HD1. The newer tuner in my Insignia portable receives these just fine.
 
acheron82 said:
I know I'm beating the dead horse here but I honestly believe something is up with 99.7. I live in Alpharetta (travel to Carrollton a lot) and even in Alpharetta, the HD signal on 99.7-1 goes in and out.... In Alpharetta. No other HD stations is having this trouble. I checked 88.5, 94.1 and even 105.7 which is weaker and I'm not noticing the problem that I hear with 99.7-1. 97.1 and 106.7 are impressive signals. Actually, I would argue 100.5 is pretty impressive considering it's low wattage compared to how far I get it. That aside, while 97.1 HD station gets out pretty far (about as far as the regular FM signal), I do notice that the sound quality is about 50% lower on the HD stations. I actually have to turn the volume up in my car a good bit to hear it.
Click to expand...

I think they fixed it. Noticed the same problem of 99.7 cutting in and out and it was back to normal on my ride home.

RadioDoogie said:
I cannot receive any HD from WNNX.
Click to expand...

WNNX turned off their HD last year in trade for a power increase up to 13.5kw.
 
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jabba17 said:
I know of only 3 ATL AM stations that have been able to successfully significantly upgrade their night signals in the last 40 years or so (there may be others):

1) WRNG/WCNN, which went from being a daytimer as late as 1979 to 10kW-DA, but with a null over Cobb and a hard null over Gwinnett
2) WPLO/WKHX-AM/WDWD, which went in the early 80s from 5kW-DA with an east-west figure-8 pattern from North Druid Hills to 4500W-DA with a southeasterly hand-puppet pattern out of Powder Springs, increasing north suburban night coverage
3) WGST moved from 920 to 640 in the late 80s; they increased their day power from 5kW to 50kW, but their night power remained the same at 1kW. They have a directional (N-S) night signal now, but a very mild one. They do get the coverage bump from moving down the dial.

My point is, I don't think that many ATL AM stations could have upgraded their night signals even if they had wanted to. Most ATL AMs were already hemmed in at night, between competing local/regional channel stations as well as Class As on the clears, mostly to the north. Someone could have pulled a WOWO and bought a smaller market class A clear for the purpose of putting the class A license on an Atlanta station, but nobody has (plus you'd have to find a cochannel class A station to buy for the purpose of downgrading). WRNG had to build 8 towers in a Peachtree Corners floodplain to get the pattern they needed. .
Click to expand...


Two examples of stations that IMHO had someone could had done something with in the mid to late 1970’s right after 80-90 took effect and there was revenue for AM stations in Atlanta:

#1 1010 should have looked at some kind of deal going east similar to WINS 1010’s pattern in NYC.
http://radio-locator.com/cgi-bin/patg?id=WINS-AM&h=N

1010 had to deal with the Canada. They came up with a 4 tower pattern that seems to work well enough and relevant format that the station still shows up in the ratings almost 50 years, all news (April 18th 1965). A quick check of the FFC site shows no class A or B in South Carolina. Billy Graham’s 1010 in Black Mountain (Ashville NC) was only 500 Watts at night easterly. A night time signal south of Charlotte NC would most likely gotten by the FCC. . I think an 8 tower pattern like WCNN’s night time pattern:

http://radio-locator.com/cgi-bin/patg?id=WCNN-AM&h=N

only at 50 KW and pointed ESE from somewhere near Cartersville and a possible change of City of License would have worked fine in 1980.


#2 1060 WKNG (had 500 watts pre-sunrise in the 1980’s) with no Class A or B on 1060 in either of the Carolinians and 1080 in Marietta should have worked a swap.
 
secondchoice said:
Two examples of stations that IMHO had someone could had done something with in the mid to late 1970’s right after 80-90 took effect and there was revenue for AM stations in Atlanta:

#1 1010 should have looked at some kind of deal going east similar to WINS 1010’s pattern in NYC.
http://radio-locator.com/cgi-bin/patg?id=WINS-AM&h=N

1010 had to deal with the Canada. They came up with a 4 tower pattern that seems to work well enough and relevant format that the station still shows up in the ratings almost 50 years, all news (April 18th 1965). A quick check of the FFC site shows no class A or B in South Carolina. Billy Graham’s 1010 in Black Mountain (Ashville NC) was only 500 Watts at night easterly. A night time signal south of Charlotte NC would most likely gotten by the FCC. . I think an 8 tower pattern like WCNN’s night time pattern:
Click to expand...

While possible, a night operation like WINS' with enough power to cover what was then the metro survey area would likely have interfered with the 10 kw non directional operation on 1010 in the Dominican Republic, a NARBA signatory. If aimed to the SW like WCNN, it would have had issues with the several night allocations in México (The way the KLAT in Houston protects México).
 
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