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New Radio-Locator Maps
- Thread starter Ai4i
- Start date
R
rbrucecarter5
Guest
The only thing I notice about them is that they are WAY too conservative. Probably reflect the arbitrary dBu contours that mean nothing to actual listeners. Anybody with decent equipment does much better.
I drive a few kilometers northeast of the third largest metropolitan skyline in the United States and hear three stations southwest of downtown,
two with 60dbu and one with a 70dbu contour, as all monaural picket fencing, but as soon as I leave that area, even going away from the stations,
they all change to nice, clean:
Even some official omnis look very different on the new maps,
such as WXDJ.
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rbrucecarter5
Guest
Here is an example: http://radio-locator.com/cgi-bin/patg?id=KBPA-FM You can see the leftmost loop around Houston - all along that loop I could get almost perfect stereo - very few dropout with no tropo, no skip - 24/7/365. It is a monster signal. But a local LPFM covers the frequency now. Most of the Houston / Dallas stations hang in until a co-channel takes over the frequency along I-45. This is true on multiple frequencies, a 50 to 60 mile zone where they swap a bit, until one is dominant. All much larger circles than the radio-locator maps indicate. The same is true for AM. This little station http://radio-locator.com/cgi-bin/patg?id=KPET-AM comes in all the way to Ft. Worth. Where this one http://radio-locator.com/cgi-bin/patg?id=KGNC-AM&h=D is close to accurate, although it does slightly better with a listenable signal in NE suburbs of Dallas. This one http://radio-locator.com/cgi-bin/patg?id=KCRS-AM&h=D is fairly accurate, although the null towards San Antonio is more severe than the map indicates, with KTSA becoming dominant by Garden City and not Sterling City as the map indicates. On the whole, I think their AM maps are better than FM, with the FM being much too conservative.
G
Groove1670
Guest
Keep in mind these maps are based on calculations for FM radio receivers some 30, 40, 50, 60 years ago. Radios are much better now. Such factors as Co-channel and ducting are most likely to impact a signal. Conditions can also vary with terrain and height.
Forget the Local, Distant, Fringe stuff.
They represent signal strengths of 1mv/m, 316uv/m, and 100uv/m, whether measured by a vacuum tube FIM from before WWII or by the latest digital measuring equipment.
My only question was why the maps have changed as they have, much less rounded, more jagged edges, and very recently.
The stations have not changed their signal contours, someone doing the calculations has.
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rbrucecarter5
Guest
There is really good software out there that more accurately predicts coverage, obviously they are not using it.
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They are using the same predicted contours as the FCC uses for allocations and regulatory purposes.
You can get a more precise view of an FM station's usable signal using Longly-Rice calculations which take into account much more granular topographical data, but the maps are very complex and take a while to render.
For AM coverage, more accuracy would require actual field strength readings, such as a directional proof.
Going back to FM it has been amply shown by evaluation of hundreds of thousands of ratings diaries that 80% of indoor listening occurs in the 70 dbu contour and fully 95% in the 65 dbu contour. When you make observations based on car radio reception, you are ignoring the locations where the majority of radio listening occurs.
The calculations of field strength have not changed, ever. A 70 dbu signal is still a 70 dbu signal. The device used to receive the signal is not part of the calculation of predicted service contours.
And radios may be more selective due to receiver design, but they do not seem to be more sensitive. Analysis of ratings for in-home and at-work confirm that there is no change in the areas where stations get most of their listening.
To the contrary, the radio-locator maps are overly generous in estimating "local" or "primary" coverage. For fixed location indoor listening, the useful contour is about 20% inside the innermost contour on radio locator... as mentioned before, 95% of the in-home and at-work listening takes place inside the 65 dbu contour, while the strongest one radio-locator uses is 60 dbu... well beyond the useful contour for the locations where most listening takes place.
Your standard for "listenable" is not realistic. You have the DXer's tolerance for noise and multipath and other artifacts, as well as the inability to realize that listeners won't keep coming back to a station that comes in OK one day and not at all the next.
My daughter suffers through all kinds of multipath, drop-outs, etc. to listen to her favorite FM in the car. I remember doing the same as a DXing kid 35+ years ago. But I just can't do it anymore. I'm faster to turn the radio off because of crap signals than anyone. And my daughter suffers through crap reception only because we're in the radio shadow of Pikes Peak and other intervening terrain.
It is like that in many growing markets with all of the rimshot FMs. Even a smaller market like Charleston has a lot of these. Our ESPN sports signal is on 98.9 FM, a rimshot, and a lot of people complain they can't listen or have to listen on AM because the signal is northeast of the city and barely brings in 60 dbu to less than half of the Charleston area (and not the most populated areas).
Even on a clock radio, it is tough to get a signal in a lot of the region.
Even on a clock radio, it is tough to get a signal in a lot of the region.
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rbrucecarter5
Guest
People listen to crappy compressed audio with crappy earbuds, because they like their selected style of music. My home town of Midland was absolutely filled with DXer's in the 60's and 70's, because local radio was censored. People were eating static and fades to listen to KOMA, WLS at night, and weak AM signals from other nearby towns during the day. Enough people were putting up deep fringe antennas for Dallas FM - from classical fans wanting WRR to kids wanting better rock stations to the equivalent of soccer moms wanting the soft rock station. Enough people that the local cable company accommodated them by putting the stations on cable. It is about the MUSIC - not the signal strength. People will revolt against bad local radio any way they can. In the 60's and 70's, that was DX. Now, it is satellite, streaming, Pandora, music players, or whatever it takes to get away from really bad local radio. I have personally installed close to a dozen Pioneer Supertuner 3D aftermarket radios for people wanting KCOL, and living closer to Beaumont than I am. I have also acted as a buyer for other people wanting KCOL at home, I know what to buy and how to put up antennas. I won't get rich doing it, but I am making some money on the side helping people out. It's not just KCOL, some people wanted help with NGEN before 91.7 signed on, there are some people that ask about KLBJ - I have to tell them no. There are some people wanting one or another foreign language format that is a long way from their house. Others want the classic country station and they are way Southwest of town. It is pretty much a mixture of different formats wanted by various people, and willing to spend some bucks on vintage tuners / receivers and antennas to get it. I can only imagine what the numbers are for people on satellite, streaming, or whatever other technique that don't need help. Station owners can put whatever weird formats they want on local stations, there will always be malcontents like me that rebel against it. Whether it was me - waiting patiently in Midland for a pathetic mono country station on 97.9 in Odessa to sign off so I could hear KZEW, or the kids I met in Lubbock struggling 12 years ago to get KMKI in Lubbock, or my sister in law wanting oldies, or that guy in the gas station who wanted some foreign language station and somehow recognized my name as somebody who could help, or my lawn guy that hears a station really from Mexico and wants to buy my radio - I give him a CCrane catalog which he gratefully takes, and shows up in two weeks with a CCrane-EP while he does yard work to 620 AM, to the guy at work wanting KTRH deep inside a building and now has a box loop, to all the people I hear about listening to home town teams on AM at night, to the Katrina refugees listening to WWL in the Astrodome - DX is alive and people doing it are all over, because local radio fails to reach a lot of people.
Have the doctors given her anything?
Seriously (or Siriusly) though, after having nothing but perfect reception and no heavy processing for so many years,
I find that one little "tst" or "psp" is just too much for me, and I always used to listen to out-of-market stations.
It is smart to reign their signal in from the fish and the gators,
escpecially with such a small, low-gain antenna,
but I cannot believe those lines can really be so jagged
They are likely not smoothing the data points.
And WXDJ is directional for protection purposes... had to do that when it moved towards the north a bit. Note the null to central FL.
It looks like they are not.
I must have missed that one.
The only other place I can recall Tropix, Studio, Joy, WFTL-FM ever being was on the old 1400 stick in Fort Lauderdale.
If they use 360 radials, every 1 degree, rather than the 8 every 45 degrees required, the results are jagged if the terrain is quite irregular. Small numbers of radials require interpolation, or the results are polygonal. If the terrain is flat or nearly flat, large numbers of radials will not appear jagged.
Usually, if the HAAT is quite large, it will appear smoother. If the HAAT is lower, it will appear more jagged, as the differences in HAAT in a particular direction are greater compared to the overall average HAAT, unless the HAAT is less than 30 meters in all or many directions, the lowest HAAT for which service contours are generally predicted.
Usually, if the HAAT is quite large, it will appear smoother. If the HAAT is lower, it will appear more jagged, as the differences in HAAT in a particular direction are greater compared to the overall average HAAT, unless the HAAT is less than 30 meters in all or many directions, the lowest HAAT for which service contours are generally predicted.
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And if only Radio-Locator was free for everyone without limits... 
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