Transmitter Page

WLW 1997 Tour Video

New 2013 WLW Tour by K7AGE
A detailed technical and historical presentation by
Geoff Mendenhall - W8GNM and Jay Adrick - K8CJY
This is a very professionally done, 1/2 hour documentary.

WLW, Cincinnati, Ohio, was the first United States commercial 50 KW station and the only standard broadcast station to ever broadcast at a power of 500KW from 1934 to 1939! It was also the first to make use of a directional antenna system for skywave radiation control. (WSUN and WFLA, St. Petersburg, FL. shared the first directional antenna system.)
It was called
The Nation's Station and was started by Powel Crosley, a grand innovator of products and services from radios to automobiles.

Map Location

In the foreground is a cooling pool which was once used for the 500 KW transmitter. The leftmost building is the transmitter plant building and the house to the right was, at one time, the transmitter plant of WSAI, but now is the residence of the CE and his family. The base of the WLW tower is visible on the right.
The transmitter plant houses five operational 50KW transmitters and all of the original cabinets of the original "superpower" 500KW transmitter. The newest transmitter is a Harris 3DX, which is completely solid state.

To the left: The WLW antenna is an 747 foot Blaw-Knox vertical radiator. The middle of the tower was made wider (35' square) for additional structural strength. It has been in use since 1933 and supports a total stress load of 450 tons, including 135 tons of structure steel (900,000 lbs)!

 Global Hit Locator
Since 10/13/2012


Western Electric 7A
Fired up on New Years Eve

70 year old Western Electric 7A
transmitter is used by WLW between 10:45 and
12:15 1/1/00 to celebrate Y2K. See this transmitter

Message from WLW CE, Paul Jellison about
the event.

I spent the evening at the 700 WLW site babysitting for the dreaded y2k "crash" as suspected it was a whimper of a situation. Since I was a captive audience I decided to amuse myself. My idea was to operate into the millennium operating WLW on the original 1927 model Western Electric 7a 50 kW transmitter. This is the original 50 kW transmitter that WLW signed on with in 1928. It has been maintained and updated quite well through the years. It is still water
cooled and operates very quietly compared to a blower cooled transmitter. After replacing a tube in the RF exciter that had failed sometime in the last month or so, the transmitter came up just fine. I put it on the air at 10:45 PM the 31st of 1999 and operated it till 12:15 am January 01,01,2000. Using a modern audio processor(Orban 9100) to modulate the rig with. It sounded fine and the news department mentioned the fact that we were operating on it in their news casts. I seemed fitting that the transmitter that carried information from the depression era, W.W.II, Korea, Vietnam, man landing on the moon, Kennedy's assassination, FDR's passing, and Nixons impeachment usher the station into the year 2000. The transmitter was taken offline as a main transmitter in 1975 when a Continental 317c1 was installed to operate in main service.



My sincere gratitude goes to Engineering Manager, Paul Jellison - WD8KMX, who spent hours giving me a tour of the site. I am also grateful to Jacor VP of Engineering, Al Kenyon, for responding to my Usenet posting, giving me the go-ahead for this tour; and for additional technical information! I am also very greatful to Mr. Randy Michaels, CEO of Jacor, Inc. for his influence in the preservation of this site. Thanks also to Pete Tauriello, Shadow Traffic reporter for WINS 1010, NY, for telling me that WADO also used a Blaw-Knox tower. (The WADO tower has been replaced on 10/17/1999.) Thanks to J.T. Anderton, VP/Managing Director of Duncan's American Radio, for his informative piece on Blaw-Knox towers and other WLW information. John Byrns sent me a good portion of the technical operation details of the 500KW transmitter. Thankyou, John, for your important information. Thanks, also to Barry Mishkind and John Price who wrote articles on WLW (See other WLW related pages at the bottom).

Additional information may be added to this page as time goes on.
Corrections or additional facts are welcome, especially from anyone who is or has been associated with WLW or have experience with this equipment. Please visit the section
"MORE WLW/POWEL CROSLEY RELATED PAGES" for other related links.

These photos were taken by both my wife, Gretchen, and myself at the WLW transmitter site in Mason, OH on August 14, 1997. For photo buffs, I used a Cannon AE-1 35 mm camera with a 35-135 mm zoom and my wife, Gretchen, used a Canon G-III semi-automatic with 40 mm lens. For flash shots, we both used Kodak Gold 100 film. I used one roll of the new Kodak Gold MAX film pushed to 1600 speed, which came in handy for natural light shots.

This is a private, non-profit page created by Jim Hawkins - WA2WHV, who is not affiliated with WLW.

For inquiries about this page, please visit my FAQ page.

WLW 700 KHZ, Cincinnati, Ohio

The transmitter plant is located on Tylersville Road off I-75 just beyond the now defunct VOA Bethany Site about 23 miles north of Cincinnati. The single, omnidirectional, double diamond-shaped halfwave tower is now 747 feet high. It weighs 135 tons and was built by Blaw-Knox.

WYGY FM, owned by Chancellor broadcasting, has antennas on the top of the WLW tower. The WYGY transmitter facility is in a separate building, which we did not visit. They use a Continental and Harris 20 KW transmitter in main and standby service.


500,000 WATTS FROM WLW - "Whata-Lotta-Watts"

A 1930s picture of the 500KW transmitter. More of these pictures can be seen in the brochure gallery page.
Courtesy WLW, All Rights Reserved

Boilerplate attached to one of the rear doors of the 500KW transmitter. The rig is credited as RCA Serial #1, but was actually a joint effort. RCA was responsible for the overall design of the transmitter, GE was
responsible for the RF section and Westinghouse was responsible for the control systems.

Before the 500 KW transmitter was walled off in 1975 into a shallow room, it was visible from a broad area in the plant. It is now more difficult to photograph. The room is also used as a temporary storage area for equipment and other station property. The transmitter itself is physically huge, composed of chambers with windowed doors on top of a catwalk. Below the catwalk are other panels with metering and controls. On either side of the transmitter, one can walk up steps to the catwalk or straight ahead to the rear of the cabinet, where there are steps back down to the floor. The back of the transmitter is deceiving. It looks like an ordinary wall with double doors which resemble closet doors. On the other side of the hallway are windows to the back of the building. The total height of the transmitter is 15 ft tall by 54 feet wide (about 2 1/2 times my height)!

Wide view of 500KW transmitter showing catwalk. (Equipment stacked on catwalk was removed.)

Open door view of water-cooled transmitting tubes in one of the chambers. These tubes are 5 feet high. The bottom of the tubes are metal sheaths, through which the cooling water was run and then pumped outdoors to fountains in a cooling pond in front of the plant.

View of two cabinets showing tubes.

Panel below catwalk.

Panel below catwalk shows what appear to be water cooling valve controls.

General view of transmitter. (Some retouch work was done to eliminate equipment store on the catwalk and floor.)

(See Simplified Schematic)

The transmitter was designed with redundancy and cutback (reduced power mode) in mind, giving the transmitter more continuity of service. The final amplifier was divided into 3 separate modules, each using four RCA type UV-862 tubes in push-pull parallel making up a total of 12 output tubes. The outputs of the three modules were combined in series in such a way, that if one of the 3 RF modules failed, the transmitter could continue to operate using the other modules. This idea was a very important step in transmitter design as modern solid-state transmitters are designed entirely in this a modular fashion as is described in my WABC Digital AM Transmitter Page Digital Modulation Section. Modern transmitter with modular design are composed, typically of 1KW modules with lower power modules used for shallow slopes of modulation.

In the same fashion, the 8 tubes in the modulator were actually 2 modules composed of 4 tubes in push-pull parellel, each with a separate modulation transformer, making it possible for the transmitter to continue to be modulated at a reduced level if one of the modules failed.

The power supply section (on the rightmost end of the transmitter) used six mercury vapor rectifiers each rated to handle 450 amperes. These tubes can be seen in a 1930s photo on my WLW brochure page.

The operating Constants recorded in the log for the 500 KW transmitter on May 2, 1934 were:

PA voltage of 11.7 Kilovolts with a PA current of 65 Amperes, which yields a DC input power of 747.5 KW.

Antenna current was 72 Amperes

The site was and still is fed with two 33,000 volt lines to its own substation on the property, which steps it down to 2,400 volts going into the plant, then converted to 480 volts within the plant. Water was distilled and circulated through Pyrex tubing to keep high voltages isolated. The 500KW rig was driven by a Western Electric 50 KW rig, still used as a standby. WLW attempted to obtain a superpower license again in the 60's with plans to upgrade the 500KW to 625KW with modern tubes. The request was rejected.

Here I'm standing in front of the big, 15 foot tall transmitter.

Here I'm dwarfed by a modulation transformer for the big transmitter (in the basement). I'm 6 ft tall. This is one of two of these transformers that were originally used, each weighing 35,700 lbs, filled with 725 gallons of oil. The oil has been drained from this transformer due to PCBs.

View of link coupled output coils with Faraday shield and tank circuit capacitor (looks like a baking rack) in the back. Tuning is accomplished by changing the inductance of the coil. Loading is accomplished by moving the outer coil closer or farther away from the inner coil. This is all mechnically coupled to controls in the front of the transmitter.

Part of the switching and relay system for the 500KW transmitter (in the basement).



Dramatic shot of the famous Blaw-Knox, diamond shaped tower, looking up to the center of the tower. The "WLW" sign on the tower is approximately 11' X 35' wide. Please see the note from Mr. J.T. Anderton, who kindly supplied additional information on this tower and WLW.

Full view of pond once used to cool the transmitter tubes. Water was sprayed into the air as fountains. Frogs and other life now make their home in this pond.

View through wall around base of tower showing insulators which support 900,000 lbs!

A Note From J. T. Anderton

VP/Managing Director of Duncan's American Radio

In addition to a lifelong interest in AM tower sites and coverage, I have been fortunate to have had the opportunity to do more than two years of research in the internal technical file room of the FCC, to gather technical data for my series of coverage map atlases, published by Duncan's American Radio. In addition, I visited more than 2,500 stations in all parts of the country during an 11-year stint as a regional manager for the NAB. I have also photographed more than 1,000 tower sites over the past 20 years. I have talked with radio people and engineers in all parts of the country, and also have had the chance to cross-check the heresay and folklore at the FCC. Given that these towers are so unique, I'm fairly confident that if there are more, I would have come across them by now.

I didn't go into this detail to brag, just to establish that I might be a reasonably reliable source.

Here are the Blaw-Knox diamond cantilever towers still standing (to the best of my knowledge), along with their electrical radiating length (each would be a few feet higher above ground, allowing for base insulators, aiviation beacons, etc.):

WSM, Nashville (650) 800'
WLW, Cincinnati (700) 739'
WBT, Charlotte, NC (1110) 3 in directional array, 428' each
WFEA, Manchester, NH (1370) Taller of two towers in directional array,
350'(second tower is 199')
WBNS, Columbus (1460)

WHO in Des Moines had one until the late 1940's, when it was replaced at the same site by the existing uniform cross-section tower. The bottom two-thirds of the old WHO tower was moved to the rear of an Iowa State Police station in Des Moines for use as a communications tower.

These towers are a special part of radio history. I have visited all of them, and they do make quite a visual impression. Most uniform cross-section towers all but disappear visually against many skyscapes, but not these. Their mass stands out against any color of sky, often resulting in strong visual images. The WLW tower, with the call letters lighted in white at the mid-way point, makes a strong visual impression, especially at twilight.

All five of the 50-kw transmitters ever used by WLW are still in place at Mason. All five are licensed and capable of full-power operation, including the original water-cooled 1927 Western Electric. This unit was the first 50-kw transmitter to be licensed in the United States. In the 1980's, the engineering staff of then-owner Jacor Communications restored this transmitter to it original operating condition, using parts left on hand by the engineers of longtime owner Crosley Broadcasting.

Randy has a strong sense of the importance of the WLW Mason site in radio history.

I hasten to add that WLW is no relic. It is a living, breathing, 100% local, full-service, ratings and revenue dominant AM radio station (a rarity in this era). According to our Duncan revenue estimates, it is the highest billing radio station outside of the largest markets.

J T Anderton
Duncan's American Radio


This was originally the Temple, Cincinnati Lodge No. 5, B.P.O. Elks, designed by the Architect, Harry Hake Sr. (my father-in-law's boss). It later housed WLW studios and was named "Crosley Square," which is inscribed over the front door. I took this photograph on August 13, 1997.


  • March 2, 1922- A broadcast station license for the call letters WLW was issued by the Radio Division of the Bureau of Navigation, U.S. Department of Commerce to the Crosley Manufacturing Company authorizing 20 watts of power on 833 kilocycles. The company, which manufactured "The Harko" radio receiving set, was owned by Powel Crosley Jr. who was to be WLW's sole announcer and technician.

  • August 18, 1922- WLW moved from Crosley's home to his new factory building at 1625 Blue Rock St. at B & O right-of-way and was authorized to increase power to 200 watts.

  • September 1, 1922- WLW began using a newly-installed Western Electric 1-A transmitter, raising the power to 500 watts and changing the operating frequency to 970 kilocycles. For an antenna, the station used two 125 ft. toweers, supporting a 140 foot 12 wire "T"-type antenna.

  • June 7, 1923- WLW began sharing time on 970 kilocycles with a new Cincinnati station, WSAI. The air slogan used was "Queen City of the West".

  • Early 1924- WLW used the air motto "The Station With A Soul", moving to new quarters at 519 Alfred Street, Cincinnati and raising power to 1000 watts.

  • May 1924- WLW changed frequency to 700 kilocycles, but was later shifted to 710 kilocycles to make room for WBAV of Columbos, Ohio. WBAV was re-assigned elsewhere on the dial, later that year.

  • January 1925- Remodeled, spacious studios were opened at the Crosley factory. WLW was then granted permission to raise power from 1000 watts to 5000 watts.

  • January 27, 1925- WLW installed a new 5 KW transmitter at Harrison, Ohio where two 200 foot tall towers were erected. Also, that month, WLW's studio location was moved to 3401 Colerain Ave. WLW presented its inaugural from the new studio on 710 kilocycles with 5000 watts of power at 8:00PM that day.

  • June 1, 1927- The new Federal Radio Commission assigned WLW to operate on 700 kilocycles, dividing time with WMAF at Dartmouoth, Massachusetts and KFBU at Laramie, Wyoming.

  • September 4, 1927- WLW became affiliated with the NBC Blue Network.
  • May 5, 1928- WLW was granted a construction permit to raise power to 25,000 watts regularly and to 50,000 watts experimentally by the FRC.

  • October 4, 1928- WLW closed the Harrison, Ohio transmitting plant, moving the operation to Mason, Ohio, adjacent to the WSAI site there. A new Western Electric 50,000 watt transmitter was installed in a new building built by WLW there. The antenna was a "longwire", running north to south, suspended between two 300 foot towers, 600 feet apart.

  • October 4, 1928-- WLW became the first United States commercial 50 KW station. By the end of that year, four other stations attained the 50 KW power level -- WEAF New York City, WGY Schenactady NY, WBAP Fort Worth TX and KDKA Pittsburgh PA. 1928, thus, became the year of the beginning of regular 50 KW broadcasts.
  • Early 1933- WLW began construction of a new, first-of-its-kind 500,000 watt facility at Mason, Ohio with the approval of the FRC. A new $400,000 RCA 500 KW transmitter was installed at the site and a new 831 foot, 136 ton, half wave, Blaw-Knox double diamond-shaped vertical antenna was erected for $46,000. A 75 feet square, concrete lined pond was built in front of the building for transmitter cooling. Water was pumped through specially designed, water cooled tubes, then out through fountains which sprayed the water into the air and into the pond.
  • January 1, 1934- The FRC authorized WLW to use 500,000 watts on an experimental basis using the call W8XO.

  • April 17, 1934- The FRC issued a license to operate at 500,000 watts during regular hours under the WLW call letters.

  • Wednesday, May 2, 1934- WLW began experimental 500 KW broadcasting as Mrs. Franklin D. Roosevelt threw the switch at the White House desk in Washington D. C. Some saw the WLW call letters as signifying "Whatta Lotta Watts".

  • December 21, 1934- WLW was required to cut back to 50,000 watts during the nighttime hours due to interference caused to CFRB at Toronto, Ontario, about 375 miles away.
  • October 1, 1935- New downtown Cincinnati studios were opened in the Union Central Building Annex. WLW's main studios, including the showplace "Studio A" with its massive pipe organ (dubbed the "Moon River Organ"), remained at 1329 Arlington St. The organ is now located at the Shady Nook Restaurant in Millville, Ohio.

  • October 18, 1935- WLW's 831 tower was struck by an aircraft at the 600 foot level, leaving the tower mechanically undamaged!

  • Early 1938- WLW used the air slogan "The Nation's Station".

  • February 28, 1939- WLW reverted back to 50,000 watts of power, ending the superpower experiments, except for the W8XO experimental license, allowing 500 KW operation between 12 midnight until 1:00 AM, which remained in effect until December 29, 1942.

  • September 1945- The Crosley Corporation was sold by the Powel Crosley interests to "The Aviation Corporation", a major industrial manufacturer.

  • Today- WLW "Seven-Hundred W-L-W" is Ohio's second oldest continuously licensed AM broadcast station. It operates on 700 KHZ with 50 KW of power from studios located 1111 St. Gregory St., Cincinnati. The transmitter site remains on Tylerville Rd., Mason, Ohio. Licencee is Jacor Broadcasting of Cincinnati, Inc. with Randy Michaels being the CEO. Randy is known to be quite knowledgable in the technical end of the business. It is a "Full
    Service/News/Talk/Sports" station, with a country music program for truckers after midnight. It runs 24 hours a day and is an affiliate of the ABC Information Network.

This short synopsis was written, using historical information obtained from Broadcast Pro-File and some other sources. I have left out many names, location changes, frequency changes, power changes and numerous other changes and details in the history of WLW. More detailed information can be obtained from Broadcast Pro-File at:

    Broadcast Pro-File
    28243 Royal Road
    Castaic, CA 91384-3028

For more details on this or other radio station histories, you can write to them for a free catalog of historical radio station documents for very reasonable prices.


Please click on this button if you wish to view 17 rarely seen, historic photos scanned from an early brochure from WLW, provided here with permission from WLW. You can view the gallery, which takes longer to load; or the slide show, which sequences through each individual picture.


Slide Show

Antique Radio Classified Covers WLW
to Celebrate its 100th Issue of November 1992

This Antique Radio Classified cover illustration is from 1930s brochure for the Crosley Corporation radio station WLW. The cover design is reminiscent of the beautiful Art Deco style of its time.

This is probably my favorite issue of ARC with two, interesting related articles entitled: WLW - "The Nation's Station" by Dorothy A. Schecter (pg 4), and "Radio Broadcasting in 1925" by Philip Whitney (pg 8).

© Copyright 1997 by John V. Terrey. Reprinted with permission of Antique Radio Classified where it appeared as the cover of the November 1992 issue. For a free sample issue write to: A.R.C., Box 2, Carlisle, MA 01741.

"Seven-Hundred W-L-W" Today

WLW Billboard, which was located at Colerain Ave. and W. Galbraith Rd., Cincinnati, OH when this photo was taken in 1997. The light reminded motorists that they could tune in to WLW to hear the news. Note, the antenna on top of the billboard above the light.

Click the icon to hear the news jingle and intro aircheck recorded the morning ot 8/18/97 at 7:00AM after the storms that moved through Cincinnati the previous day. (Recorded with small mike next to tiny SW-100 speaker!)


The dish at the upper right of the lookout tower is the 950 MHZ primary input link.

The lookout tower was for the armed guards that watched the facility during WWII. There was a spotlight on top an intercom, heat and power. They could watch over the compound, and remember it extended to the 2 towers across the road and the demonstration farm they had in operation. The 4 lane road out front was then a gravel lane. There was serious concern about security at this site. They even had motion sensors and climb detectors on the fences around the perimeter. This site predated the USIA, later to become the springboard for the Voice of America just down the road with short-wave operation. There were several Rhombic antennas and Short-wave transmitters here on site.With calls of WLWO the O standing for overseas. Or the rumor has it. W8XAL was a propagation test transmitter on 6030 kHz and maybe other frequencies. W8XO was the 500 KW am test callsign. The WLW transmitter was used for coded communications during the war. I had an old friend since passed that used to tell me about listening at night with his sweetheart and they would break into programming with some nonsensical string of words. He said it would begin with the word pelican spoken 3 times then they read some text and a closing. No one of authority has ever acknowledged or explained. But since WLW could be heard in Europe and the Pacific its use was not hard to figure out. Hitler himself referred to Crosley as the liar of Cincinnati. Thus the security. He was aware of this operation. Also WLW experimented with very narrow shift FSK rtty on the Clear Channel channels. But I think that was after the war.
There were receiving loops for WSM, WGN and others. I have found limited documentation here and some old TTY paper with communications with WSM in Nashville.
Paul Jellison.

Receiving and audio processing equipment racks receive incoming signal from either the 950 MHZ link or a backup T1 line, process, amplify and pass the signal onto the transmitter modulator input.

Closup of leftmost rack.

Closup of middle rack. Second box to bottom is the Unity-AM audio processor which allows engineers to create their own presets for optimal audio processing. Another popular unit of this type is called the Optimod-AM.


"The 3DX50 BETA [Destinytm] test transmitter has been (and continues to be) in regular, full time, service at WLW since the middle of March 2000. It is being used as the main transmitter with the DX-50 as the backup. It has been very reliable and has experienced lightning hits without damage." According to Geoffrey Mendenhall, V.P. of Harris Advanced Product Development

Harris DX-50, 50KW transmitter with digital modulation. This is the main transmitter. It is completely solid state, small, quiet, cool and relatively maintenance free. A detailed description of the DX-50 with photos can be found on my WABC Digital AM Transmitter Page
Digital Modulation Section.

Heavily modified Western Electric A-7 50KW Transmitter. This was the transmitter, that was used to drive the 500KW monster. It is water cooled and is fully operational. This transmitter uses a pair of 4CW25000 modulator tubes. This transmitter was operated netween 10:45 and 12:15
in celebration of the Y2K change!

Crosley 50 KW transmitter originally called a "Cathenode" (Cathode/Anode) built on site by R.J. Rockwell. DC coupled back in the 50s. Audio was performance certified by McIntosh as a very Hi-FI transmitter, but very inefficient. It was changed to a high-level, plate modulated transmitter in the late 60s. In the mid 70s, it was converted from a water-cooled to an air-cooled transmitter.

Continental Electronics 317-C1 50KW Screen Modulated, modified Terman Doherty Transmitter, installed in 1975. Basically a Doherty amplifier with modulated screens. A very reliable transmitter. Paul Jellison told me that WGSP Atlanta and KOA Denver is using this transmitter. PA tubes are 4CX35000 (one is visible sitting on the desk). W.H. Doherty was responsible for early successful linear amplifier designs in the 1930s.

Wide view of transmitter room, a heaven for lovers of old and new transmitter equipment. The Western Electric and Crosley are lined up in the background with a transmitter console in the middle of the room. The DX-50 is visible along the right side and I am standing in front of the Continental TX. There are a number of projects going on in the room which adds a bit of untidyness.

Control console for the Western Electric Transmitter.


View into back of RF final cabinet. Note the water pipes running to and from the final tube.

Closup of neutralizing capacitors.

Closup of final tube.


Continental Electronics Transmitter with PA cabinet door open.


The WLW site is more than just a transmitter site. A great deal of experimenting and building of equipment goes on at the site for both the AM and the television station, WKRC. It seems to have a lab atmosphere with a number of new projects in the works, including a new backup tower, which is to commence construction sometime in October. Paul Jellison, lives with his wife Dee and two sons in the house next door to the transmitter plant. Paul is an Engineering Manager for Jacor, Inc. His official duties for Jacor are to oversee engineering matters for all stations in the Cincinnati area and is the CE of WLW as well. That includes 4 AM signals and 4 FM signals. He has built radio stations from the ground up, from studios to transmitters to towers.


Coax running to the tower is 3 1/8 Heliax and it is pressurized with Nitrogen Gas.

Looking up at the tower along a guy wire.

The tower height was decreased from its original 831 feet to 747 feet. The original height produced a groundwave/skywave cancellation ring which went through Columbus, Indianapolis, Lexington and Louisville. Lowering the mast pushed this ring out farther, away from those population centers. Also, back around 1934, two directional "supressor" towers were constructed across Tylersville Rd. to the south-southwest to reduce skywave radiation toward the Canadian border. CFRB was complaining of interference, so WLW reduced its power to 50KW until the "supressor" towers were in place. As previously stated, this was the first use of skywave directional control for broadcasting.

Al Kenyon on how WYGY FM antenna (mounted on the WLW tower) is coupled
As posted on rec.radio.broadcasting

The WLW tower has a three bay antenna for WYGY 96.5, Chancellor's "Young Country" on the mast at the top of the tower. The feed line goes through an ERI isocoupler before continuing to the tower to avoid shorting out the tower. An isocoupler is essentially a large can (about the size of a 55 gallon drum) with two antennas inside, one of which is mounted on a fiberglass window. The transmission line continues from the antenna on the fiberglass window to the tower, thus the ISO in isocoupler. Many years ago an insulated quarter-wave section was used to get on the tower. (A short across one end of a quarter-wavelength line appears to be an open at the other end.) There was concern that the line section affected the tower's AM radiation.



Accessed times since August 24, 1997.

E-mail questions to Jim Hawkins