[QCWA Everglades Chapter #69] A look into some radio history....

Sun Apr 27 11:03:42 EDT 2014

Good posting Bill and a great tutorial on propagation;  my ex father in 
law, W9ALH,  SK now,  was the chief engineer at WLS in Chicago for many 
years and gave me a few tours of the transmitter facility located in 
Tinley Park, IL just outside of the city.  They were in the process of 
changing the analogue Collins transmitters to a new Harris "digital" 
setup and I was allowed to watch and bring them coffee.  Not being an 
employee, they told me to keep my hands off their new gear!  It was a 
real treat for me and I was duly impressed with the tuning house with 
coils the size of 55 gallon drums.  I still have his original Drake 4 
line twins and use them occasionally.

73 de W4DL    Mike
Tallahassee & Pompano Beach, FL USA

On 4/27/2014 9:37 AM, Bill wrote:
> Not all this will come through. I can send the original html posting 
> if you would like. Notify me personally please.
> Bill W2CQ
>
>
> For some of you receiving this ''radio history'', it is a look-back at 
> where you once spent time earning your living......for most, however, 
> it is an historic lesson...........If you were a 'kid' during those 
> ''MusicRadio'' days it is nostalgia......
>
> Why Did WABC Have Such a Great Signal?
>
> It did seem like you could hear WABC everywhere. During the day you 
> could receive the station 200 miles away without any problem. At 
> night, it covered over 38 states like a blanket. When people speak of 
> WABC reaching 8 million people a week during its peak, they're 
> referring to only the New York City Metropolitan area. But, if you 
> take into account listeners from out of the local area, that number 
> was even greater. There is 1971 aircheck of Dan Ingram where he 
> comments "I just got some terrible news... I read the ratings and WABC 
> is only the 13th ranked station....... in Pittsburgh Pennsylvania!"
>
> Wow! What a signal. How was that possible?
>
> AM broadcast radio stations generate two kinds of radio waves: 
> Groundwave and Skywave. How effectively they accomplish this during 
> the day and night governs how far they reach.
>
> Musicradio WABC did both amazingly well.
>
> Here's how:
>
> WABC's Groundwave Signal
>
> Groundwave signals hug the surface of the earth. To some extent a 
> groundwave signal bends with the curvature of the earth. This effect 
> is greater as radio waves get longer. This is why AM radio stations on 
> the low end of the AM Broadcast band have greater daytime range given 
> the same power level as stations on the higher end of the AM broadcast 
> band. One example is comparing New York City radio stations WQEW and 
> WABC. Since WQEW is much higher in frequency at 1560 kHz. vs. WABC at 
> 770 kHz., its local range is much less even though both stations 
> operate at the same power level of 50,000 watts.
>
> In engineering terms, WABC at 770 kHz. was (and still is) New York's 
> biggest station. Like WNBC and WCBS, it had a non-directional 50,000 
> watt signal; but it had the advantage of a half-wave tower -- which 
> most engineers consider an ideal height.
>
> WABC's Fantastic Half Wave Tower!
>
> By virtue of its lower dial position and longer waves, WNBC at 660 
> kHz. should have owned the "biggest signal" distinction; but it shared 
> its tower with WCBS at 880 kHz., and the original plan to 
> "sectionalize" the tower to make it electrically equivalent to a half 
> wave on 660 never worked. To this day the WFAN signal on 660 radiates 
> from a tower considerably short of its ideal efficiency of a half 
> wave. While WCBS was at about a half wave, its higher frequency and 
> shorter waves produced a less powerful groundwave signal than WABC. 
> The only other New York 50kw station in the lower part of the band, 
> WOR, was highly directional (first using two, then three towers to 
> produce an irregular signal pattern designed to protect other stations 
> on its frequency, 710 kHz).
>
> So WABC was the biggest station in the biggest market. It was the only 
> New York station on the lower section of the AM dial with a half wave 
> tower! In fact to this day, it still has the biggest signal.
>
> AM antenna design and all the other variables involved in transmission 
> choices are something of a black art as well as an interesting 
> science. For the strongest groundwave coverage, electrical lengths in 
> excess of 1/2 wave (180 degrees) are desirable. In fact, 5/8 (225 
> degrees) is considered optimum, because it produces the maximum 
> possible groundwave (or horizontal lobe) from a single vertical 
> radiator. It also produces a small lobe at a high angle up toward the 
> sky, which can be a problem in some regions because it reflects back 
> on top of the groundwave. This is sometimes responsible for the 
> distortion heard at night on local AM radio stations.
>
> Of course, you have to remember that the wavelengths get longer and 
> longer as you get to the lower part of the AM broadcast band. As a 
> result, the length of a tower to achieve 5/8 wave, or even 1/2 wave, 
> gets extremely large. A 5/8 wave tower for a station such as WFAN at 
> 660 kHz. would be tremendous.
>
> Most AM stations use radiators well under 1/2 wave. WMCA at 570 kHz. 
> is just 67 degrees. The old WINS (at 1010 kHz.) towers were 
> approximately 78 degrees, and the new ones are 141 degrees.. All four 
> of the Chicago" clear channel stations" ( WMAQ at 670 kHz, WGN at 720 
> kHz, WBBM at 780 kHz. and WLS at 890 kHz.) are more than 180 by a few 
> degrees. WSM (at 650 kHz.) in Nashville and WLW (at 700 kHz.) in 
> Cincinnati are in the 190's. WWKB (formerly WKBW at 1520 kHz.) in 
> Buffalo is 225 degrees.
>
> WABC's transmitter position might be considered less than ideal, since 
> it doesn't sit on salt water like so many other New York stations; but 
> it's a lot better than the original Bound Brook site, and actually 
> gets a decent angle on Long Island. This is because Manhattan and Long 
> Island have extremely bad ground conductivity, which is one reason 
> WQEW (formerly WQXR at 1560 kHz.), which transmits from Maspeth Long 
> Island, has such a hard time in New Jersey. WCBS and WFAN have better 
> angles on Long Island, but don't do nearly as well as WABC in New Jersey.
>
> Interesting fact: at one time, a common tower for WABC, WNBC and WCBS 
> was on the drawing board, but it turned out there was no way all three 
> -- which are relatively close to each other on the AM band -- could 
> share one tower without severely compromising their audio quality to 
> avoid interfering with each other. But the plan grew out of what we 
> might call "tower envy" for WABC's superior system.
>
> To see WABC's daytime coverage, click here for the The WABC Signal 
> Coverage Map .
>
> WABC's Skywave Signal
>
> While groundwave signals "hug" the surface of the earth, skywave 
> signals work by "bouncing" off of the ionosphere. During the day this 
> particular layer of the atmosphere absorbs radio signals. But at 
> night, it acts as a reflector bouncing medium wave radio signals back 
> to earth. This bounce or "skip" allows these signals to travel great 
> distances. And, in WABC's case, it was a non directional signal. In 
> effect, given the right "conditions" its signal could go anywhere..... 
> and it frequently did!
>
> At night, WABC reached incredible distances. It was a class 1-B Clear 
> Channel station. This meant that at night, there was only one other 
> North American radio station on 770 kHz. That station was KOB in 
> Albuquerque, New Mexico (Today, KOB is KKOB and there are other 
> stations on 770 kHz. at night due to changes in F.C.C. regulations). 
> As a result of this clear channel status, you could pick up WABC's 
> nighttime skywave signal across most of the eastern half of the United 
> States, Canada and at times, Europe. There were even reports of 
> reception in Hawaii, Australia and South America.
>
> Many clear channel stations (examples include WBT in Charlotte NC, 
> WTIC in Hartford CT, WBZ in Boston MA) have directional nighttime 
> patterns. This gives them a terrific signal in some directions and 
> virtually no signal in other directions. Such was not the case with WABC.
>
> Ham radio operators (yes, I'm one) will tell you that good conditions 
> include things like time of year (fall and winter are the best), 
> sunspot cycle (every eleven years it starts over), and stray 
> atmospheric disturbances. That is why on some nights WABC might have 
> come in like it was your local AM radio station while on other nights 
> you could not hear it at all. And, of course, radio stations on 
> adjacent "channels" could splash over and interfere. In WABC's case 
> the adjacent stations were (and still are) WJR in Detroit MI at 760 
> kHz, and WBBM in Chicago IL at 780 kHz. If either of these stations 
> were local to you then WABC's skywave signal was more difficult to 
> pick up.
>
> WABC's Call Letter and Frequency History
>
> 1921: WJZ at 833 kHz. starts broadcasting from Newark, NJ. The station 
> is owned by Westinghouse and has an output power of 3000 Watts.
>
> 1923: WJZ is purchased by RCA, moved to New York City and its 
> frequency is changed to 660 kHz.
>
> 1926: WJZ becomes the key station of the "Radio Corporation Chain" a 
> network of seven east coast radio stations. A new entity called the 
> "National Broadcasting Company" is created.
>
> 1927: NBC creates the "Blue Network" of radio stations with WJZ as the 
> key station.
>
> 1928: WJZ is moved to 760 kHz. NBC moves its other New York City radio 
> station, WEAF (flagship station of NBC's "Red Network") from 610 kHz 
> to WJZ's former frequency of 660 kHz. WEAF eventually becomes WNBC and 
> is now WFAN.
>
> 1935: WJZ increases its power to 50,000 watts.
>
> 1936: WJZ's transmitter site is moved to Bound Brook, NJ and operates 
> from a 640 foot tower.
>
> 1941: WJZ shifts frequency to 770 kHz.
>
> 1943: WJZ, along with NBC's "Blue Network Company" is sold by RCA/NBC 
> to Edward J. Noble and Associates.
>
> 1944: WJZ's transmitter is moved to Lodi, New Jersey and returns to 
> 50,000 watts from a non directional 648 ft. tower (the station had 
> been operating at 25,000 watts from a brief intermediate transmitter 
> site in Kearny NJ).
>
> 1944: WJZ's licensee name is changed from the "Blue Network Company, 
> Inc." to "The American Broadcasting Company, Inc."
>
> March 1, 1953: WJZ's call letters are changed to WABC which stand for 
> the "American Broadcasting Company".
>
> 1953-Today: WABC continues with the same call letters and transmitter 
> location.
>
> And, just to make it a little more confusing...
>
> The call letters "WABC" were originally used by a totally different 
> New York radio station.
>
> The A. H. Grebe Company was a manufacturer of radio equipment and 
> owned a number of radio stations including WAHG in New York City. WAHG 
> became WABC which stood for the "Atlantic Broadcasting Company". It 
> operated on several frequencies, 950 kHz (1924), 920 kHz (1927), 970 
> kHz (also 1927), 860 kHz (1928), and 880 kHz (1941). Eventually, WCBS 
> became the station on 880 kHz. References to the call letters "WABC" 
> before 1953 are referring to this completely different radio station.
>
> Jim Hawkins has the best written and most comprehensive page about the 
> WABC transmitter facilities. This is a MUST visit if you would like 
> more information about the WABC transmitter facilities (both past and 
> present). You can start at his page dedicated the the WABC 
> transmitting facilities from 1966 at:
>
> JIM HAWKINS' WABC RADIO 77 Transmitter Page
> http://hawkins.pair.com/wabc.shtml
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