Acceptable registrations in the queue through March 16 at 11:00a ET have now been activated. Enjoy! -M.W.

Terms of Use have been amended effective October 6, 2019. Make sure you are aware of the new rules! Please visit this thread for details: https://www.mibuzzboard.com/phpBB3/view ... 16&t=48619

Some Longley-Rice maps are available for FM stations at rabbitears.info!

The technical side of broadcasting. Think IBOC is a sham? Talk about it here! How about HDTV? Post DX reports here as well.
User avatar
MWmetalhead
Site Admin
Posts: 11872
Joined: Sun Oct 31, 2004 11:23 am

Some Longley-Rice maps are available for FM stations at rabbitears.info!

Post by MWmetalhead » Mon Aug 16, 2021 9:02 pm

There's a catch, though!

Instead of searching by call sign, one must instead search by FCC Facility ID.

Here is an L-R map for 97.9 WJLB:

https://rabbitears.info/contour.php?app ... beb7&map=Y



User avatar
Ben Zonia
Posts: 2143
Joined: Sat Jun 03, 2006 10:35 pm
Location: Honor

Re: Some Longley-Rice maps are available for FM stations at rabbitears.info!

Post by Ben Zonia » Mon Aug 16, 2021 9:59 pm

If you see the red dots way out past the NE corner of Flint to near Mayville, I can tell you for a fact there's a sweet spot out that way. A friend of mine, who lived in the same subdivision as the late Dave Barber, near Frances Rd. and Bray Rd., could get a crystal clear picture from WKBD-TV 50 (ANALOG of course back then). I thought it was a tropo effect, but he said it was always clear. In my area, it was usually all snow and rarely much better, though several miles closer, outside a nearby red dot area. When CKLW-TV 9 was on Riverside Dr., those red dot areas could get it quite well 60 miles or so away. From my location, just barely.

Note also the green area near Rattalee Lake Rd. and Bridge Lake Rd., where WJRT had it's inter city microwave relay tower to relay ABC programming between the WXYZ-TV Studios on 10 Mile Rd., and the WJRT-TV Studios on Lapeer Rd. You could also get a clear signal there from WILX-TV, and even a decent signal from WOOD-TV, especially during tropo events, used when WJRT-TV had the NBC Game of the Week, while WNEM-TV, once NBC, had Tiger Baseball. Some early applications for WJRT-TV specified this as a transmitter location back in the 1950s. While the FCC wouldn't grant Goodwill Stations, the otherwise Superior Applicant, a CP until they changed the TL to Chesaning, within the Counties in the Flint Saginaw Bay City Market, even though they probably would have had good signal throughout FSBC from Clarkston. On the other hand, the Chesaning location provided service to near Houghton Lake and even fringe near Grade B ABC service near Grand Rapids in the brief period before WZZM-TV 13 finally worked out their own competitive applicant problems.


"I had a job for a while as an announcer at WWV but I finally quit, because I couldn't stand the hours."

-Author Unknown

User avatar
Ben Zonia
Posts: 2143
Joined: Sat Jun 03, 2006 10:35 pm
Location: Honor

Re: Some Longley-Rice maps are available for FM stations at rabbitears.info!

Post by Ben Zonia » Tue Aug 17, 2021 10:32 am

I found the TV Longley Rice Maps. But not the Radio.

It's easy enough to find the Facility ID Number.

Do you have to register and sign in to access it?


"I had a job for a while as an announcer at WWV but I finally quit, because I couldn't stand the hours."

-Author Unknown

bmw
Posts: 6725
Joined: Sun Dec 05, 2004 1:02 am

Re: Some Longley-Rice maps are available for FM stations at rabbitears.info!

Post by bmw » Tue Aug 17, 2021 3:38 pm

Actually Facility ID is completely unnecessary, as is registering an account. All you need is the station's call letters.

https://www.rabbitears.info/fmq.php?req ... &call=WLEW

For example - there is a link for WLEW - just replace those WLEW letters with whatever station you want. There will then be a direct link to a Longley-Rice coverage map towards the bottom of the listing.



User avatar
Ben Zonia
Posts: 2143
Joined: Sat Jun 03, 2006 10:35 pm
Location: Honor

Re: Some Longley-Rice maps are available for FM stations at rabbitears.info!

Post by Ben Zonia » Tue Aug 17, 2021 4:50 pm

And it shows the areas far beyond the 60 dBu where WLEW-FM is receivable in the car.

Thanks for the links.


"I had a job for a while as an announcer at WWV but I finally quit, because I couldn't stand the hours."

-Author Unknown

Marcus
Posts: 340
Joined: Fri Jan 21, 2005 1:08 pm
Location: Sarnia, Ontario

Re: Some Longley-Rice maps are available for FM stations at rabbitears.info!

Post by Marcus » Tue Aug 17, 2021 7:51 pm

https://rabbitears.info/fmq.php

This link allows you to search by city and state. One thing that's worth noting is that you won't get the whole metro area in one list. For example if you are looking for WCSX you either have to enter those call letters or put in Birmingham, MI. I also have not been able to get the Canadian FM L-R maps so far.



User avatar
MWmetalhead
Site Admin
Posts: 11872
Joined: Sun Oct 31, 2004 11:23 am

Re: Some Longley-Rice maps are available for FM stations at rabbitears.info!

Post by MWmetalhead » Wed Aug 18, 2021 6:36 pm

Many, many thanks to both bmw and Marcus for the tips! :)



Inundated
Posts: 47
Joined: Fri Nov 23, 2018 6:56 pm

Re: Some Longley-Rice maps are available for FM stations at rabbitears.info!

Post by Inundated » Thu Aug 19, 2021 2:37 am

It works great for the most part, but I wonder if there are L-R maps for FM translators. I don't see a link for one on the query return for a translator here.

ETA: There is a link for another translator here, just not the first one I mentioned.



paul8539
Posts: 1108
Joined: Fri Dec 10, 2004 5:20 pm

Re: Some Longley-Rice maps are available for FM stations at rabbitears.info!

Post by paul8539 » Thu Aug 19, 2021 3:13 pm

BEN ZONIA:

The two locations that you mentioned are up in the hills, the high ground. You can get better signals on high ground.



User avatar
MWmetalhead
Site Admin
Posts: 11872
Joined: Sun Oct 31, 2004 11:23 am

Re: Some Longley-Rice maps are available for FM stations at rabbitears.info!

Post by MWmetalhead » Thu Aug 19, 2021 6:50 pm

After spot checking about 10 to 12 different FM stations, I can say the rabbitears.info maps tend to underestimate actual signal strength, especially if we're talking outdoor or mobile reception.



Kennelly Heaviside
Posts: 145
Joined: Fri Jun 11, 2021 12:06 am

Re: Some Longley-Rice maps are available for FM stations at rabbitears.info!

Post by Kennelly Heaviside » Thu Aug 19, 2021 8:58 pm

MWmetalhead wrote:
Thu Aug 19, 2021 6:50 pm
After spot checking about 10 to 12 different FM stations, I can say the rabbitears.info maps tend to underestimate actual signal strength, especially if we're talking outdoor or mobile reception.
I'm not sure this is exactly accurate. I would certainly agree that reception is POSSIBLE far beyond the limits of the red dots/squares. But the red dots/squares represent a field strength of ABOVE 40 dBu, which is 100 microvolts per meter. This is quite a bit more than is necessary to receive a signal.

In the old days of FM, when stations were few and far between, many stations put the 50 uV/m, 34 dBu F(50,50) contour on their coverage maps. Even 10 watt eduationals could be heard 25 miles or so and had such a map, putting the 34 dBu into the middle of the next county. You literally used to be able to hear full power stations which were not duplicated cochannel or on strong first adjacent channels anywhere in the state, all over the state.

Late at night, FM stations, particularly in smaller markets, used to sign off the air at 10 PM or 11 PM or Midnight. You could then hear unduplicated 3 kW Class As all over the state in many cases, with a good receiver and/or antenna combination. Technics introduced a tuner going on 40 years ago with a digital signal strength meter in 2 dB steps. Stations such as WMBI-FM 90.1, WJML-FM 98.9, WFMR 96.5, and WLPX 97.3 were not duplicated cochnnel and could be heard 200-250 miles away bouncing around 2 dB, 1.2 microvolts to 6 dB, 2 microvolts with an outdoor high gain antenna.

One 50 kW Class B station could be heard quite steadily about 180 miles away with an Archer/Antennacraft FM-10, probably 75% of the time most of the year, at around 14 dB, 5 microvolts on the Technics Tuner, until the signal was duplicated by new Docket 80-90 type drop ins.

So I agree that the signals are RECEIVABLE outside the red areas in the absence of interference, but I would doubt that you would measure above 40 dBu, 100 microvolts per meter, with a Potomac FIM-71, if you have a few thousand to throw around for a used one. But now, there is so much interference from new stations as a result of Docket 80-90, new Canadian stations, and new low power stations and translators, etc., that it is unlikely you will hear much outside those red areas. And of course, it also all depends also on propagation conditions.


Kennelly Heaviside. The best Technical Consultant no money can buy.

Post Reply Previous topicNext topic