How reliable is Radio-Locator?

[Schroedingers Cat]

I have written on this topic on the 1050 Frequency of the Week regarding why WEPN and KYW were allowed so close together.

AM stations have what is called a Nighttime Interference Free (NIF) Contour. This is calculated based on cochannel and now more recently first adjacent channel interference from othre stations. It is the contour where the desired to undesired signal is supposed to be 20:1 (26 dB) 90 percent of the time. In reality, you should be able to hear stations somewhat beyond that contour, except that some stations are operating with day facilities or in excess of PSSA and PSA powers at night. Often just one cochannel station operating with day facilities can greatly increase the effective NIF contour of other stations. Even Class A stations often have a calculated NIF in the 2 mV/m range from adjacent channel interference, even before IBOC, and even though they are supposed to be protected to the 0.5 mV/m groundwave and 0.5 mV/m 50% protected skywave of cochannel stations at night.

Don't expect many stations to have listenable signals beyond the inner contour at night. DX and intermittent service, yes. Severe auroral conditions, yes, like daytime.

Class B ( Former Class II and Class III) stations in the CONUS usually have an NIF in excess of 2.5 mV/m, which is the inner contour on the day and night R-L Maps. Many newer stations are as high or higher than 25 mV/m (Class Cs/IVs are usually around this). I read somehwere where there is a station with close to a 100 mV/m NIF (this means that the 10% interfering skywave calculation is around 5 mV/m, typical of a cochannel 50 kW station around 250 miles away).

The 2.5 mV/m thus actually represents the best protected stations when all stations are operating with licensed patterns and powers at night. Usually these are the older Class I-III (Class A and B) stations. These would be usually the former Class III-A stations, and the Class II-B and II-As, along with the Class Is/As.

In summary, don't expect good service outside the inner AM contour at night, except DX, intermittent, and severe auroral condition groundwave service. In many cases, it's less than that.

 

[spunker88]

No, not exactly. For one thing, there are no 100 kw Canadian "border blasters" in existence. The CRTC limits wattage of Canadian AMs to 50 kw, just as is the case here in the US. Secondly, few Canadian AMs target a US audience and those that may do so are not able to advertise it (CKWW Windsor comes to mind).

Lastly, R-L seems to catch the big 50 kw Canadian signals pretty well, though some that they still list are now off the air. It's the smaller regional and local stations that they come up short with.

Perhaps you're thinking of Mexican AMs, a lot of which are not captured by R-L. Although those would be the ones from interior Mexico; the "border blasters" are usually represented. As an example, look at listings for San Diego and note that XETRA and others from Tijuana are included; even the maps seem as accurate as those for US stations.

I call them border blasters even though they are not. Every time I get tropo the same 50-100kw stations from Ottawa, etc come booming in to Upstate NY with strong signals.

 

[Schroedingers Cat]

Went over the time limit for changes.

An exception may be Class As, if not interfered with by adjacent IBOC sidebands.

 

[Schroedingers Cat]

Which, again, comes back to one of the problems with radio-locator: it's using data from the FCC's CDBS database for a purpose for which that data was never intended.

The purpose of the Canadian data in CDBS is to tell US broadcasters what they need to be protecting at or across the border. It is not intended to be an accurate reflection of what is, or is not, actually on the air outside the borders of the United States.

I can't stress that point highly enough. The FCC doesn't care what callsign a Canadian station is using or if it's been silent for 20 years. If it's required to be protected, its technical data appears in CDBS.

The authoritative source for data on what is (or is supposed to be) actually on the air in Canada is, unsurprisingly, Canadian - Industry Canada's BASERAD database. Unlike CDBS, there's no online search tool that provides direct access to BASERAD. The very useful (and free!) RECNet search tools do, however, provide a way to search the Canadian database.

http://cdbs.recnet.net:8080/fmq.php?

You have to select "in Canada Database" from the pull-down menu to get the Canadian information.

The Canadian database contains US listings as well, but again, those are there to tell Canadian broadcasters what they have to protect, and so it's not an accurate depiction of what's really on the air in the US, either.

The border situations with new stations are often complex, involving the directional patterns of FM stations on both sides of the border. Follow what is happening in Windsor, ON, for instance. Many alternate (400 kHz from Detroit Area allotments) channels are being authorized.

The Canadian database often shows US AM directional data for US stations that no longer operate, which is neat to look at. I'll ask this question again. Does anyone have a really old database using the AMDATA.DAT format that would show what the really old directional antenna parameters were? I have some going back to the late 1990s, but I mean even older than that.

The US and Canada FM and TV databases usually only show "Border Zone" stations within about 200 miles of the border in the other country.

 

[Tincap]

From what I've seen, Radio-Locator's reception maps are very hit-or-miss: some examples include WKBE-FM actually reaching to southern Rensselaer and Albany counties despite being outside the blue contour, and WQSH-FM reaching quite a bit beyond the blue in the north and south (first-adjacents get in the way in the east and west). However, WAJZ-FM is very spot-on and is a true fringe signal (barely receivable) in the blue contour

As for the empty frequency finder, it's failed me a couple of times (such as picking up WLZW Utica in parts of Albany and Rensselaer counties on 98.7 FM, which RL says is an empty frequency IIRC) and thinking 100.3 is an empty frequency when it's not (WKBE-FM reaches much further than the map implies)... so I don't usually trust that either

There are many variables to consider when looking at the coverage map. I live weeeeell beyond the fringe contour of Albany's WPYX, but have received it on numerous occasions, here north of the St. Lawrence River.

On a semi-related note, why is fmscan.org so fail these days?...

~BG

 

[pianoplayer88key]

So I guess I'm not the only one who has noticed inaccuracies on Radio-Locator. I'll list a few examples...

They list XEKT Tecate, BCN, Mexico, as being on 1380 kHz, but it's actually on 1390. I believe it interferes with KLTX Long Beach somewhere, but where I'm located XEKT dominates the frequency during the day, although KLTX can be heard at night.

Also, I'm about 33% beyond the fringe of 960 KIXW Apple Valley, CA, but at noon can receive a trace of their signal on my Tecsun PL-606 ultralight using the stock loopstick.

I think they severely underestimate the ground conductivity for Baja California. For example, take a look at the 1kW non-directional day pattern for 560 KBLU Yuma, AZ, and you'll see what I mean.
Also in August last year I took a few radios, including the Tecsun PL-380 (606 wasn't out then), to Cameron Corners, CA, for some midday DXing one day. There, I heard a listenable signal from 1160 XEQIN San Quintin, Baja California, in spite of being about 2-2.4x past the 0.15mV/m fringe blue contour. Also, XEPRS, which is directional 24/7 with their night pattern (although it's listed as non-directional daytime), is listenable, in spite of being 3 or more times farther than the 0.5mV/m night distant purple contour.

On the other hand, there are places where I should be able to receive a signal quite well, but it's barely there. For example, my grandma is within or near the red local 2mV/m contours of 1230 KYPA, 1260 KGIL, 1280 KFRN, 1330 KWKW, 1460 KTYM, 1480 KVNR, 1580 KBLA and 1650 KFOX - they range from barely detectable to audible-but-very-noisy. It probably doesn't help that she is 1/3 mile from
23kW 1300 KAZN and 50kW 1430 KMRB. V-Soft lists KMRB as having, in her zip code, the not-so-flea-powered daytime field strength of 3,149.9 mV/m!

As for FM, I can hear several stations from L.A. like 91.5 KUSC, 101.1 KRTH for example, even though I'm outside their fringe contours. Also I can sometimes hear 103.3 KVYB Santa Barbara, CA, from 212 miles away, and when I'm several thousand feet up in the mountains north of L.A. or San Bernardino, a lot of the San Diego and Tijuana FMs come blasting in.


About the comment that a 100kW FM can stay in for 3 hours while traveling cross-country... I definitely believe the accuracy of that, but it's not good enough for me. (Some of the big L.A. stations I'm sure could stay in for 5 hours maybe if you did it right, though.) On a summer day, I like to be able to tune in a station at, say, 7am, then at 7pm that same day still be able to hear it, without ever losing it in the middle of the day. That must explain why I like 50kW stations below 600 kHz using Franklin antennas (actually the only Franklin in use is 1530 KFBK, with 1500 KSTP's day antenna being very close) in areas with a ground conductivity at least 15-30.
A while ago I read an article in which a traveler was able to hear a powerful station two days (i think) after he had left its COL. He received KKZN Thornton, CO, 827 miles away in Pocahontas, IL, at 3:45pm in April last year - described the signal as armchair copy in the headphones with his Tecsun PL-600 and 2-foot box loop antenna. I do believe that is WELL beyond KKZN's "fringe" contour. Also on a couple occasions I've faintly heard 700 KALL, 626 miles away, with a 11" loop antenna, in spite of being 2x past the fringe contour and 32 miles from 77kW 690 XEWW (formerly XETRA).

Also there are signals they don't seem to list, but I have heard them. Anyone know how to get info / maps for 774 JOUB Akita, Japan, 657 Pyongyang, North Korea, 972 HLCA Dangjin, South Korea, and 594 JOAK Tokyo, Japan? (The last one was heard even though I'm less than 8 miles from 5kW IBOC 600 KOGO.)

 

[LibertyNT]

you know,
regular skip could explain a lot of those far daytime logging's.

 

[radioman148]

Which, again, comes back to one of the problems with radio-locator: it's using data from the FCC's CDBS database for a purpose for which that data was never intended.

The purpose of the Canadian data in CDBS is to tell US broadcasters what they need to be protecting at or across the border. It is not intended to be an accurate reflection of what is, or is not, actually on the air outside the borders of the United States.

I can't stress that point highly enough. The FCC doesn't care what callsign a Canadian station is using or if it's been silent for 20 years. If it's required to be protected, its technical data appears in CDBS.

The authoritative source for data on what is (or is supposed to be) actually on the air in Canada is, unsurprisingly, Canadian - Industry Canada's BASERAD database. Unlike CDBS, there's no online search tool that provides direct access to BASERAD. The very useful (and free!) RECNet search tools do, however, provide a way to search the Canadian database.

http://cdbs.recnet.net:8080/fmq.php?

You have to select "in Canada Database" from the pull-down menu to get the Canadian information.

The Canadian database contains US listings as well, but again, those are there to tell Canadian broadcasters what they have to protect, and so it's not an accurate depiction of what's really on the air in the US, either.

The border situations with new stations are often complex, involving the directional patterns of FM stations on both sides of the border. Follow what is happening in Windsor, ON, for instance. Many alternate (400 kHz from Detroit Area allotments) channels are being authorized.

The Canadian database often shows US AM directional data for US stations that no longer operate, which is neat to look at. I'll ask this question again. Does anyone have a really old database using the AMDATA.DAT format that would show what the really old directional antenna parameters were? I have some going back to the late 1990s, but I mean even older than that.

The US and Canada FM and TV databases usually only show "Border Zone" stations within about 200 miles of the border in the other country.

I also have some AMDATA.DAT databases from the 90s. I too would love to see some older ones.

 

[Schroedingers Cat]

The databases used to be on magnetic tape through a distributor in Virginia as I recall. The tapes were very expensive, like $300 for a monthly tape. I don't know if that had AM, FM, and TV or just a single database. It froze out the engineer tinkerers who wanted to investigate what was possible without paying thousands of dollars in consulting fees. The bigger picture would have been more viable facilities before rules became more restrictive. The consultants could have made a lot of money on the final application and construction stages.

I don't know what year they began the AMDATA.DAT format or similar databases for FM and TV. At some point in the past, they must have changed from paper records to computer databases, so I don't know if they really old ones would even be available.

Some things that I and some others on radio-info have been interested in are the patterns of such stations as WJJD 1160 at the Dempster and Greenwood location, and WISN 1150. WAWA 1590 had an 4 tower pattern, as did CHLO on 680.

There are quite a number of stations that became directional around 1940, changing frrequncies in 1941, often with the same tower configuration, and the upgrades from 1000 to 5000 watts day and or night, beginning in the 1940s and reaching a peak in the 1950s and 1960s. There were compromises made, such as DA-1 stations who wanted to upgrade ti 5000 watts daytime and stay at 1000 watts nighttime and not buy two new phasors. Did they make the day pattern more restrictive, also making the nighttime pattern more restrictive than in had to be? It seems like it was usually the stations coowned with TV stations had the money for 5000 watts fulltime and/or two phasors, and really nice transmitter buildings, back in the old days.

 

[dx1ng]

I find that Radio-Locator is useful, but as others have stated, it has it's limitations.

Some have mentioned that the contours are too conservative or else quite inaccurate. Keep in mind, on AM, the "Fringe" contour represents a 150 uv/m signal. For the average consumer, this is weak and unusable, and no stations would consider that to be part of it's service area, but for a DXer it would be quite readable (if there were no interfering stations) and such a station would often be considered a "pest". Keep in mind, for daytime allocation studies, stations often have to predict where their 25 uv/m signal contour would be. The station would be at 25uv/m strength much farther from the station than the 150 uv/m, and DXers with good equipment can pick up such a weak signal. In short, the fringe contour is not the end of a station's signal...the better your radio & antenna, the weaker the signal and farther from the tower you can pick it up.

AM contour maps are based on the often inaccurate FCC conductivity maps. Radio-Locator does the best it can with the data it's given. FM contour maps are based primarily on the height of the antenna relative to the terrain elevation in the first 10 miles or so from the antenna. Depending on the terrain beyond the 10 mile mark, these maps can be very innaccurate. I prefer to look at the actually FM signal pattern anyway, which can be seen on the fcc site.

In general formats listed can be very out of date. You really can't rely on them. Also, often Radio-Locator will indicate that a station has no website, when they do. I ran into that a lot last year. Also, I find Canada radio listings useless, and has been discussed by others in this thread.

However, despite its limitations, I turn to Radio-Locator first while FM DXing. I also use the FCC AM Query website, and lately I have found Wikipedia to be surprisingly helpful.

 

[Schroedingers Cat]

Wikipedia is very hit and miss on station histories. Often there is a rich history, and yet the only things on Wikipedia are from the current owner and format. Call letter history is often limited to the FCC listings of call letter changes. It does give the link to Radio Locator and AM FM TV Query. The patterns shown for AM Query are often the actual radiated and measured patterns from proof of perfomance measurements. Groundwave maps are more circular than the patterns and do not show the true pattern, just predicted coverage contours. One suggestion would be that they would show predicted 0.5 mV/m 50% and 10% skywaves of Class As and powerful Class Bs, even though Class Bs are not skywave protected.

 

[radioman148]

Schroedinger--

You mentioned WJJDs tower being located at Dempster & Greenwood. Do you know what year they moved to their current location on Ballard rd?
Also did they have a directional array at the Dempster Greenwood location?

Thanks

 

[Schroedingers Cat]

We discussed that on a thread in the Engineering section. We were unable to come to any definite conclusion except that if it was 50 kW, it must have been directional. Others said it was unlikely that it was a drop wire like WTAM/WKYC had for a while. The pictures you see from Mooseheart that had two towers were the hammock or T antenna. It was omni 20 kW there and apparently at Dempster and Greenwood, before becoming 50 kW in the late 1940s. My relatives in that area remembered the "tower" there. It moved to Ballard Rd. around 1963 with two towers, and went fulltime with the four tower rhombus (equal sided parallelogram) arrangement around 1980. Up the road a few miles, WEAW/WKTA had possibly a top loaded parallelogram but was moved across the road as simple monopoles as I recall and is now a trapezoid "near parallelogram" arrangement. I think the trapezoid allowed some null filling, like the new WMVP dogleg.

 

[radioman148]

We discussed that on a thread in the Engineering section. We were unable to come to any definite conclusion except that if it was 50 kW, it must have been directional. Others said it was unlikely that it was a drop wire like WTAM/WKYC had for a while. The pictures you see from Mooseheart that had two towers were the hammock or T antenna. It was omni 20 kW there and apparently at Dempster and Greenwood, before becoming 50 kW in the late 1940s. My relatives in that area remembered the "tower" there. It moved to Ballard Rd. around 1963 with two towers, and went fulltime with the four tower rhombus (equal sided parallelogram) arrangement around 1980. Up the road a few miles, WEAW/WKTA had possibly a top loaded parallelogram but was moved across the road as simple monopoles as I recall and is now a trapezoid "near parallelogram" arrangement. I think the trapezoid allowed some null filling, like the new WMVP dogleg.

OK, so when I began listening to WJJD in the late 50s when they were Top 40 they were transmitting from Dempster and Greenwood with a DA--right?

 

[Schroedingers Cat]

The present day pattern for WYLL on Ballard Rd. has nulls toward Milwaukee and Salt Lake City which are approximately 20 kW "ERP" based on Class B minimum efficiency, the same pattern as WJJD had in 1963 from what we can figure. It looks like they were ND with 20 kW from Mooseheart and Dempster/Greenwood, until they went to 50 kW with a DA pattern very similar to the pattern from Ballard Rd., from NW of Dempster and Greenwood. They apparently went 50 kW in about 1947, so I would say yes to your question. I wish I had known all this in 1962 when I was first there. I would have looked for the towers. Perhaps the second tower was shorter and/or was taken down first. They built a shopping center there. Maybe the remaining tower was used as an auxiliary for a while or had other services mounted on it.

I didn't get out to look at the Ballard Rd. site until the late 1970s. The ground was all torn up from installing the two new towers and ground system one time I was out there around 1980.

I did have my Hearever Rocket Radio (Germanium Diode) with me, and with it hooked up to the telephone dial stop, WJJD was wall to wall. I was in about fourth grade in 1962. Later on at night, since it was November, it was off and I could hear WGN, a station I had already DXed in Michigan (on a Delco Car Radio and Magnavox Stereo Theater AM-FM-TV-Phonograph). I didn't know about WJJD's Limited Time Hours then. I heard WGN ID, but WBBM must have been there too. If you plug 60068 into Doug Vernier's Zip Code Signal site, it shows both WGN and WBBM at about 100 mV/m, consistent with later calculations I made from the groundwave graphs in around the late 1960s when I first saw them in the NAB Handbook. I calculated WJJD as around 400 mV/m at the receiver location.

According to Glen Clark, who designed the new WMVP array, the Chicago area has conducitvity very close to M-3 values. I think they made actual measurements for the I-As back in the day, and that was used for the M-3 Map. If you notice, the 15 mS/m patch that runs toward St. Louis starts near Mokena where the WLS tower is located.

 

[w9wi]

The present day pattern for WYLL on Ballard Rd. has nulls toward Milwaukee and Salt Lake City which are approximately 20 kW "ERP" based on Class B minimum efficiency, the same pattern as WJJD had in 1963 from what we can figure....

Interesting that they would *still* have a 20kw-equivalent null toward Milwaukee. One would think that would have become unnecessary when WISN moved from 1150 to 1130 in, was it 1965 I think? Since they had to modify the array anyway when they went from limited time to unlimited time, I would think they would have taken that null out.

 

[radioman148]

The present day pattern for WYLL on Ballard Rd. has nulls toward Milwaukee and Salt Lake City which are approximately 20 kW "ERP" based on Class B minimum efficiency, the same pattern as WJJD had in 1963 from what we can figure. It looks like they were ND with 20 kW from Mooseheart and Dempster/Greenwood, until they went to 50 kW with a DA pattern very similar to the pattern from Ballard Rd., from NW of Dempster and Greenwood. They apparently went 50 kW in about 1947, so I would say yes to your question. I wish I had known all this in 1962 when I was first there. I would have looked for the towers. Perhaps the second tower was shorter and/or was taken down first. They built a shopping center there. Maybe the remaining tower was used as an auxiliary for a while or had other services mounted on it.

I didn't get out to look at the Ballard Rd. site until the late 1970s. The ground was all torn up from installing the two new towers and ground system one time I was out there around 1980.

I did have my Hearever Rocket Radio (Germanium Diode) with me, and with it hooked up to the telephone dial stop, WJJD was wall to wall. I was in about fourth grade in 1962. Later on at night, since it was November, it was off and I could hear WGN, a station I had already DXed in Michigan (on a Delco Car Radio and Magnavox Stereo Theater AM-FM-TV-Phonograph). I didn't know about WJJD's Limited Time Hours then. I heard WGN ID, but WBBM must have been there too. If you plug 60068 into Doug Vernier's Zip Code Signal site, it shows both WGN and WBBM at about 100 mV/m, consistent with later calculations I made from the groundwave graphs in around the late 1960s when I first saw them in the NAB Handbook. I calculated WJJD as around 400 mV/m at the receiver location.

According to Glen Clark, who designed the new WMVP array, the Chicago area has conducitvity very close to M-3 values. I think they made actual measurements for the I-As back in the day, and that was used for the M-3 Map. If you notice, the 15 mS/m patch that runs toward St. Louis starts near Mokena where the WLS tower is located.

Thanks!

I listened to WJJD alot in the late 50s when they were basically the only Chicago station playing Top 40 music. Now I realize they were coming from the Dempster Greenwood location at that time.

 

[Schroedingers Cat]

The present day pattern for WYLL on Ballard Rd. has nulls toward Milwaukee and Salt Lake City which are approximately 20 kW "ERP" based on Class B minimum efficiency, the same pattern as WJJD had in 1963 from what we can figure....

Interesting that they would *still* have a 20kw-equivalent null toward Milwaukee. One would think that would have become unnecessary when WISN moved from 1150 to 1130 in, was it 1965 I think? Since they had to modify the array anyway when they went from limited time to unlimited time, I would think they would have taken that null out.

Since the maximum goes SE toward Chicago, it allows a concentration of the signal, and a little better service on the South Side, and Indiana "Suburbs". Now there's WHBY 1150 Kimberly, which is probably why they didn't consolidate near Joliet.

WLS has always been weak in the Northern Suburbs of Chicago. There's a recent STA application for WMVP to use the WLS tower during work on the WMVP array that alludes to the WLS tower being too far south for service to the Northern Suburbs. WYLL's night array between Joliet and the WLS site also puts a weak signal over northern Chicago, also due to the narrow main lobe. It's surprising that WCFL didn't do better in the ratings back in the day, being the only station that puts a 25 mV/m M-3 predicted signal over all of Chicago, day and night, from the west central TL and concentration of signal to the east. WSCR? Not quite. 25 mV/m misses the SE corner of Chicago.

 

[BobOnTheJob]

Trying to answer the question of the reliability of Radio-Locator maps, I need to know something first : Is WINK 1200 Pine Island Center,FL operating with their long term 10KW facility or with their 50KW CP? On the south end of Sarasota, they are about as gone as you can get in the day...perhaps too weak to ID. If they are still at 10KW, the map is in agreement. If they are at 50KW, the map suggests a quite listenable signal on a sensitive portable or car radio...in which case, the map would be quite inaccurate.

 

[swfl]

Trying to answer the question of the reliability of Radio-Locator maps, I need to know something first : Is WINK 1200 Pine Island Center,FL operating with their long term 10KW facility or with their 50KW CP? On the south end of Sarasota, they are about as gone as you can get in the day...perhaps too weak to ID. If they are still at 10KW, the map is in agreement. If they are at 50KW, the map suggests a quite listenable signal on a sensitive portable or car radio...in which case, the map would be quite inaccurate.

WINK 1200AM is still operating at 10,000 watts as of right now. There is a CP to increase to 50,000 watts which has been around for some time now. It appears to still be active but I am not sure of just what the current status of that is. Hopefully one of the SW Florida radio people who are in the know can help you out more.