Looking up one of WOR's three
|Accessed||times since February 2, 2003|
|WOR Announcement of increase to 50,000 Watts|
My own memories of WOR
As a kid, WOR was THE place to tune for school closings announced by John
Gambling on a snowy day. When it snowed, my siblings and I would listen to Mr. Gambling as he read school after
school. It was like winning a day-off lottery. I also remember John Gambling Sr. with a live band in the studio.
Visit the official WOR 710 web site for its current, diverse programming.
|WOR pre 1932 Control and
Source: Belden Photographers of Newark
Supplied by Tom Ray - WOR
|WOR Tower 1924 on top of
Bamberger Station in
Newark, NJ. Note transmitter
house, shown in image above,
appears bottom center in this
Source: Radio News, January 1932
Note: This photo was printed reversed
in the magazine so that the
"Bambergers" and "WOR" sign would
|WOR Site as it appeared at Carteret, NJ in 1935. The two Blaw-Knox towers
were 350' high. This system was an array of three vertical antennas consisting of the towers and the center wire suspended by
the wire between the towers. The Carteret location was chosen to be in line with NY City, Trenton and Philadelpha. The three verticals were in phase to create lobes in the the direction of those cities. The weak end signals, were in the direction of the nearby NJ shore on the southeast side and the northwest PA mountains in the low populated Pocono area. See below.
Source of photo: "electronics" September 1935
Source of information: "Commnication & Broadcast Engineering" February 1935
|While at Carteret, the WOR transmitter was in line
with New York, Philadelphia and Trenton and
it's directional lobes were aligned to those cities.
Source: "Commnication & Broadcast Engineering"
|Mercury Vapor Rectifiers
These photos were used in am Isolantite Ceramic Insulator advertisement
which used WOR AM. The advertisement says that the photos are
from a recently built Western Electric Transmitter. The tower photo
was from the same advertisement, which appeared on Pg. 45 of "electronics"
September 1935. There waas no indication as to what part of the transmitter
the amplifier section was in, but it is obvious that they are high power, water
cooled tubes. (All images were computer enhanced.)
WOR Transmitter Building
|Auxiliary equipment racks
contain satellite receivers,
analog and digital audio
processing and IBOC
|Many paths from the studios at 1440 Broadway. Input feeds rack, including satellite
|Digital (top) and analog processors
Optimod 6200 (top) and 9200.
The digital processor feeds the IBOC
|Ibiquity IBOC Exciter..|
|The IBOC software runs on a Linux OS platform. The unit can be controlled remotely via dial-in modem. It also has a TCP/IP port. The IBOC exciter box has a GPS receiver to synchronize all IBOC transmitters for quick tuning and lock-in from one HD station to another.|
|Left: Continental 317C-1 on left, Harris DX-50 Main
transmitter at the far end and RF Switching cabinet on
Right: View from opposite end showing RF Switching
and auxiliary equipment racks behind it.
|The Continental 317C-1 is a Doherty linear tube transmitter.
It serves as a standby transmitter and is used once per week
for the Joe Franklin show on Sunday morning, midnight to 5:00 AM.
Joe Franklin not only still has his radio show, but his own restaurant
and, in a way, his own transmitter!
|Door open on 317C-1 Driver cabinet
IBOC Junction Box
IBOC Junction Box on top
|Exciter (blue) relay to switch from internal
to IBOC is mounted between the two
|The IBOC system is connected into the Harris DX-50 with fail-safe mechanisms installed. The connection from the internal exciter to the first driver was replaced by a relay, which switches to the IBOC exciter. The Audio is also switched from pure analog processor the output of the IBOC exciter. If the IBOC system fails, it is detected and the relay switches from the IBOC exciter to the internal RF and the analog processor.|
|RF output switching cabinet connecting with
the phasor behind it.
|Inside the RF switching cabinet.
It feeds the three towers, switches between the
two transmitters and switches the dummy load.
It allows single tower operation with any of the
three towers. Switching to low power
non-directional allows maintenance on other
towers and the phasor. It controls the common
point input to the phasor and
the 3 outputs of the phasor.
|The phasor front panel.|
|Inside the phasor looking in through the back
door. The IBOC carriers could be
heard "ringing" the coils as a hissing sound
along with the analog audio in this cabinet.
New coils were installed in 1998.
|The tower array is in a dogleg (weak triangular)
configuration. Each tower has detuning skirts for
1010 (upper) and 1190 KHz. Click on the images
for a better view of the skirts. At the bases are
detuning networks for 1010, 1190 and 620 KHz.
|Tower base showing Austin
transformer, "Johnny Balls"
to divert lightning strikes.
|Kerry demonstrated the WOR-HD with this receiver to me. First he tuned in some other AM stations, which, of course sounded like the usual narrow bandwidth AM. Then he tuned in WOR. Initially it sounded like the other stations, but within about 2 seconds it opened up with a very clear, High Fidelity sound. The transition sounded as if the radio had been in a box and the lid had been taken off. I was told that with the initial IBOC exciter software the sound was good, but, with each new exciter software update, the audio has continued to improve. One cannot make a final judgment as this system is continuing to evolve and improve.|
The IBOC AM Hybrid signal consists of
In the IBOC AM all digital mode,
|The WOR-HD spectrum shows the carrier in the center, the two "valleys" on either side are the secondary digital regions and the first set of peaks show the primary digital carrier regions. The red outline show the NRSC Mask, which bounds the legal limits of the overall hybrid signal.|
|300KW 3 phase
|Kerry Richards, Chief Engineer (Left) and
Thomas R. Ray, III, CSRE, and
Corporate Director of Engineering
Read Tom's article in Radio World
as described by Tom Ray
Emphasis and formatting added by Jim Hawkins
If the main transmitter is operating in analog mode, the audio chain is:
This switching is remote controllable.
The chain for the main TX is as follows:
The analog audio modulation is set, with IBOC carriers off, to -98%/+120%. This modulation does not change. The primary and secondary carriers then modulate the transmitter to produce sidebands where the primary IBOC carriers are -28dB referenced to carrier level [-28 dBc], while the secondary IBOC carriers are -38dB referenced to carrier [-38 dBc]. Total digital carrier power is approximately 1500 Watts for a 50KW station.
If you keep in mind that the AM signal as we typically know it (the modulated envelope) is actually a phenomenon of the modulation vectors interacting with the sidebands and the carrier, it appears that the AM carrier actually disappears at -100% modulation. In fact, the carrier never pinches off or diminishes in amplitude and is a constant (as proven on a spectrum analyzer), and the IBOC sidebands are in addition to the analog modulation. This may appear to a conventional AM detector as overmodulation in the negative direction, but this is not the case. Basically, we are adding 1500Watts to the sideband power on WOR.
© 2003 by James P. Hawkins
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