Friday, January 11, 2019

The KKOB-770 Synchronous Operation In Santa Fe

Returning back to Arizona from Denver after Thanksgiving, I decided to stay in Santa Fe, New Mexico. This was a perfect opportunity to check out the status of the KKOB-770 synchronous transmitter site in Santa Fe.

KKOB-770, as most of you know, is Albuquerque's 50 KW blowtorch outlet, "The Talk Monster". A single tower does duty during the daylight hours. At night, a second tower is switched on, the signal covering most of the western U.S. with a westerly-facing cardioid pattern. The nighttime notch at the base of the cardioid falls over Santa Fe.

KKOB maintains a 230 watt synchronized transmitter just one mile west-northwest of downtown Santa Fe, adjacent to the John Griego Vietnam Veterans Memorial Park. A single tower is visible just a couple of hundred yards or so from the parking lot of the park. The tower is a 231 ft. (70 meter) high affair, with an effective height of 65 electrical degrees.

The purpose of this operation is to fill in KKOB's nighttime pattern in the Santa Fe area. Santa Fe is 56 airline miles from Albuquerque.

Driving past the location at mid-afternoon about 2 PM, it was evident that the tower was transmitting during the daytime hours. Driving along the road past the park's parking lot, and closest to the tower at about 200 yards, I had the car radio tuned to 770 KHz. Weird signal fluttering occured for several hundred yards along the road as the Santa Fe and Albuquerque signals combined. For several seconds, the phasing of the two signals completely nulled, resulting in no signal at all.

It was a strange listening experience, as Albuquerque's KKOB-770, at 50KW, normally puts out a respectable signal to this area in the daytime.

The following synchronous operations are authorized through FCC license in the U.S. The FCC terms them as "Experimental":
Call          Frequency     Power     Location
---------     ---------     -----     -----------------
(D)WI2XAC      740.000       500      Ponce, PR
(N)WI2XAC      740.000       100      Ponce, PR
(U)KKOB        770.000       230      Santa Fe, NM
(D)KM2XVL     1220.000       170      Huntsville, TX
(N)KM2XVL     1220.000        11      Huntsville, TX
(U)WBZT       1230.000       800      Pompano Beach, FL
(U)KCOH       1230.000       410      Houston, TX
(U)KDTD       1340.000       200      Kansas City, KS

I've been wanting to check out this operation for awhile.

Click image for a larger version.

KKOB-770 Santa Fe. 230 watts synchronous operation.

KKOB-770 Santa Fe. 230 watts synchronous operation.

KKOB-770 Albuquerque. 50,000 watts. Single tower daytime, both towers at night.

Sunday, December 16, 2018

Late 2018 IBOC Report, KNX-1070, KSL-1160

We talked at some length a few years ago about IBOC, or so-called HD radio. At the time, iBiquity Digital Corporation was the sole licensed vendor for the U.S. That has changed.


Old news by now, in October, 2015, Dedicated To Sound, Inc. (a.k.a. DTS) purchased the rights to this HD Radio technology from iBiquity and is now the new sole owner.

DTS announced thusly:

"DTS is excited to announce it has entered into a definitive agreement to acquire iBiquity Digital Corporation, the developer of digital HD Radio technology for AM/FM audio and data broadcasting for approximately $172 million. DTS expects to finance the transaction through a combination of cash on hand and debt."

iBiquity was the exclusive developer and licensor of HD Radio technology, the sole FCC-approved method for upgrading AM/FM broadcasting from analog to digital. iBiquity’s partners included leading automakers, consumer electronics and broadcast equipment manufacturers, radio broadcasters, semiconductor and electronic component manufacturers and retailers.

The market that has shown some success is the automobile HD Radio market. The home market has not. Said DTS, "This transaction extends our strategy of delivering a personalized, immersive and compelling experience across the network-connected entertainment value chain, and complements our existing suite of technology and content delivery solutions while enabling us to strengthen our position in the large automotive OEM market. Consumers have come to expect a higher quality sound experience in their car, and we believe there is a tremendous opportunity for DTS to capitalize on the upgrade to HD Radio technology as cars are increasingly equipped with screens and advanced entertainment systems.”

iBiquity had successfully driven penetration of HD Radio technology in the North American automotive OEM market. HD Radio technology was built into approximately 35% of cars sold in the U.S. in 2014, and DTS expects the majority of North American vehicles to come equipped with HD Radio technology over time.


The IBOC acronym stands for "In Band On Channel". Currently in the U.S., a hybridized version of the digital signal is imposed on the analog signal and the result transmitted. This is supposed to be an interim or transitional method. Stations that are licensed through the FCC for the digital add-on and have entered into contract with iBiquity and now DTS may transmit the hybrid signal. Current FCC records show a total of 237 stations are authorized to transmit IBOC hybridized digital. Many of those who made the initial licensing effort to get a digital signal on the air have terminated transmission due to resultant nighttime skywave interference problems on the broadcast band.

The misnomer here, at least for the hybridized version, is the term "On Channel". The 15 KHz digital sidebands either side of the main carrier bleed fully beyond the adjacent AM channel center and into the adjacent station's far sideband. Let me state this is another way: They have positioned the digital sideband information on the adjacent channel! No filter, on any receiver, regardless of bandwidth, can reject it. However, testing has shown some receiver's passbands are better than others. In order to provide room for these expanded sidebands superimposing digital information on top of analog audio, stations also have had to narrow their audio response to an absolute 5 KHz maximum, further reducing standard analog audio quality. Adherence to strict technical standards is now an absolute imperative, both in the transmitter, modulation technique, and antenna or you have an even worse interference problem. And we all know radio stations often fail in this area of strict adherence. This, currently, is what the FCC calls "Hybrid" digital operation, the precursor to going fully digital at some future date.


On the AM broadcast band, where this will all end up is anybody's guess. Will it ever go entirely digital? I suspect not, at least for the foreseeable future. The number of facilities registered to transmit hybridized IBOC digital has remained fairly stable over the last couple of years. In 2009 as IBOC was ramping up, 289 facilities were registered with the FCC. That number reached 293 a year later in 2010. Since the peaks of the initial few years, however, the overall decline has been sure but steady.

TopazDesigns runs a nice U.S. AM and Canadian AM station search site. Within it is also a page kept current with the latest IBOC stations on the air. Their current count as of this date shows only 117 transmitting, and only 35 at night. As is evident, interest has waned for digital on the mediumwave band.

Here in the far American West, there are some big boys still transmitting IBOC. Notably, the strongest received in southwestern Arizona at night is Salt Lake City's 50 KW KSL-1160, followed by Los Angeles's 50 KW KNX-1070.

Adjacent to KNX-1070 on its upper side is 50 KW KRLD-1080 in Dallas, Texas. A two tower array with 4.8 dB gain in my direction pushes a respectable 150 KW effective radiated power (ERP) at me. KRLD-1080 is essentially impossible to hear when KNX-1070 is faded up to full strength as digital hash blankets 1080 KHz. Careful nulling of the radio's loopstick does help, but the two stations are nearly 180 degrees opposed to each other.

I mentioned that some radios are better than others in reducing adjacent-channel hash, not withstanding the nulling technique. In my stable of super portables, the Sangean ATS-909X does the best job, followed by the Tecsun PL-880 and the C.Crane EP Radio Pro. The difference in the Sangean is fairly remarkable, I believe owing to the Silicon Labs Si4734/35 DSP chip being used down-chain in the I.F., and the outstanding fidelity of the audio section.

The worst IBOC offender here is Utah's KSL-1160 at 506 miles distant. I am in its sweet spot, propagation-wise. Its 455 ft., half wavelength (+) single tower with gain of 2.31 dB pumps about 85 KW ERP at my direction. KNX-1070 has an almost identical tower, however at only 237 miles distant I am in its skip zone and thankfully much of its signal is wasted overhead in the E-layer on its way to New Mexico and beyond.

My best chance at reception on 1170 KHz, adjacent to KSL-1160 is Tulsa, Oklahoma's 50 KW KFAQ-1170. But it's a long way off at 1057 miles and it takes some tremendous power to overcome KSL's signal. As luck would have it, the three tower array's main lobe is pointed directly at me in western Arizona. With respectable 5.56 dB gain, it pushes an astounding 179 KW ERP at me. KFAQ-1170 should boom in here at night, but caught in KSL-1160's digital hash on 1170 KHz, it barely makes a dent unless KSL is in deep fade. If KFAQ fades up as KSL fades down it makes an appearance. WBAP-820, a 50 KW station also in Dallas and clear of an IBOC hash problem, is in regularly. So is 50 KW WOAI-1200 in San Antonio.

Shown in the graphic is KSL's received signal in my SDRPlay RSP1a SDR receiver's waterfall. As you can see, the sidebands creep well into the adjacent channels 1150 and 1170 KHz. My guess is they are pushing the 5 KHz audio bandwidth, causing needless and excessive digital hash, that, or over-compressing the audio, or both.

We will see in the future where digital will go in the U.S. mediumwave band.

Click image for larger version.

KSL-1160 Salt Lake City, Utah

Wednesday, November 7, 2018

US Ground Conductivity Map v2 2018

It came to my attention some time ago that the map sets are not working correctly. It turned out it was a Google Maps problem. Non-casual Google Map creators are now required to register and obtain a pass key to allow map use. I have done that.

The first change and correction is to the US Ground Conductivity Map. The download link is at the upper right. The new version is v2, 2018.

The US and Canadian Pattern Reference Maps (current 2016 version) are effected as well. They will be updated soon.


Friday, October 12, 2018

Mediumwave Web Tricks

I use a number of tricks to quickly locate information on mediumwave stations. You might call them shortcuts, or easy ways to get to certain station web site data we might be interested in - and without having to re-navigate each site again looking for what we want. Why not just go directly there? Follow along and I'll show you how.

Here's some one-click examples of what we can get, simply by copying and pasting a link into your browser:

     1. Station broadcast format. Data provided by Arbitron.
     2. General station data. Data provided by
     3. Station's application list. Data provided by
     4. Station's contour map. Data provided by
     5. General station profile information. Data provided by
     6. General station data. Data provided by
     7. Contour maps. Data provided by
     8. Satellite .JPG image of transmitter site. Data provided by

Let's go through them, one by one.

1. Get Station Broadcast Format From Arbitron

US and Canadian mediumwave stations file station information, including format, web stream location and other details with Arbitron quarterly. You just have to know where it is.

Here's the link for KLAA for summer 2018. Change the call sign to one of your liking and copy and paste the URL in your browser. We will do this throughout this post.

Substitute call letters of your choice, including Canadian stations. For the surveyID= field, use the current season we are in. i.e., use WI18 for winter 2018, SP18 for spring 2018, SU18 for summer 2018, FA18 for fall 2018. Next year, in 2019, use "19".

Only one season will work, the current season. You can't get historical data. Note, however, that in nearly all cases, Arbitron will show that the station's data is not current for the current season. They are drawing the data off of the previous season's submission. It is indeed current, as the station has not submitted changes.

2. Get General Station Data From The FCC

Here's the link, again for KLAA.

Substitute call letters of your choice, including Canadian, Mexican, or any foreign station that has filed with the FCC.

3. Get A Station's Application List From The FCC

Again, for KLAA. Substitute call letters of your choice, including Canadian, Mexican, or any foreign station that has filed with the FCC.

4. Get Public Profile For Station From The FCC

Substitute call letters of your choice. It appears to be U.S. stations only. Station KBMB used here.

5. Get Daytime Contour Map For A Station From The FCC

Substitute call letters of your choice. It appears to be U.S. stations only. Station KBMB used here.

6. Get General Station Data From Radio-Locator

Substitute call letters of your choice, including Canadian. Here we must also enter the frequency in KHz. KLAA, 830 example used.

7. Get Contour Map For A Station From Radio-Locator

Here's the link for the daytime contour map for KLAA. Change to h=D.

Substitute call letters of your choice, including Canadian. Use the letter "D" at the end.

Here's the link for the nighttime contour map for KLAA. Change to h=N.

Substitute call letters of your choice, including Canadian. Use the letter "N" at the end.

Some stations are in the Unlimited category, like KOA-850 in Denver, for example. Here's the link for the unlimited contour map for KOA. Change to h=U.

Substitute call letters of your choice, including Canadian. Use the letter "U" at the end.

8. Get A Satellite .JPG Image Of A Station's Transmitter Site

Google maps has a function that will create a small .JPG image for you of the satellite ground view of a latitude-longitude coordinate.

This one is a little more difficult. You must know the latitude and longitude of the station transmitter site, but you can get that from the FCC General Station Data link (section #2) above. Replace the latitude (33.92861111) and longitude (-117.61583333) with one of your choice. Remember to use a negative longitude if you are in the western hemisphere, and a negative latitude if you are in the southern hemisphere.

Maximum zoom is 17. Lower the zoom if you need to.

The maptype= parameter can be "hybrid" (terrain with some satellite ground annotation), "satellite", "roadmap" (a road map), or "terrain".

.JPG size is either 640x640 or 320x320. Using scale=2 will double the size. format= can be jpg, png, or gif.

Here's the link for KNMX-540, Las Vegas, New Mexico:,-105.17138889&zoom=17&size=640x640&maptype=hybrid&scale=2&sensor=false&format=jpg

KNMX-540 Static Map from Google

One more handy bit of code to get V-Soft signal data.

Easy Way To V-Soft Signal Data

Now let's write a little HTML to get some V-Soft data.

Get a nice signal strength chart by zip code or station call sign from V-Soft. If you've ever wanted to know what the mediumwave signal strengths are in your zip code from various stations nearby, you can.

Copy the following code into any text editor (like Notepad), and save it as an .HTML file. No changes are necessary.

<form action="" id="findzips" method="post" name="findzips">
<input id="zip" name="zip" size="20" type="text" value="123456" /><input type="Submit" /> ZIP CODE</form>
<form action="" id="findstations" method="post" name="findstations">
<input id="call" name="call" size="20" type="text" value="KLAA" /><input type="Submit" /> CALL SIGN</form>

Then click the file. Enter either your zip code (or any zip code), or a station's call letters. Click the Submit button. You will be re-directed to the site and see a nice table of signal strengths.

Hope you enjoy these web tricks.