WFLI Western Electric transmitter article by Stanley B. Adams

Note: This article stands as written in 2006, some things may have changed. SBA
-Formatting of text and insertion of pictures by Betty Benns
-Pictures by Stanley B. Adams
(left) WJSV – original location of WFLI’s Western Electric 407-A, (right) WTOP recent picture of same original location of the WE 407-A



In late July of 2006, Dave Hultsman (of Continental Electronics) and myself scheduled ourselves a long weekend in the city of Chattanooga. Being but a half day drive for both of us, we finally were able to accomplish something that we had both been talking about for a long time. And, this was to see the fully set up Western Electric 407-A 50 kW transmitter at WFLI, Lookout Mountain. The transmitter pedigree began way back to 1939-40 with WJSV, later WTOP as the original owner. This transmitter is probably the last fully constructed, albeit non-operational, 407 in existence today; and it is entirely possible with the help of a few good engineers that this behemoth could resume an ‘on-air’ status. Being the fanatical historians of communication technology that we are, we knew that this would be a unique trip.


With the approval and urging of Barry Mishkind, we intend to make our visit accessible to all who read his paper and to display pictures and manuals on several of our historical web sites. It bears mentioning here that our friend Powell Way desires a well round of thanks for informing us of this transmitter and its location. Without that ‘golden nugget’, this story could not be written. And without the gracious kindness and time allotted by Jeff Gregory who is now the chief engineer of WFLI, our trip would have been just a bust. But I did learn that Dave loves Waffle House, it must be the old ‘road dog’ in him.



To begin with the beginning, we must go back to the end of WW 2. The country was beginning to ‘right itself’ after a long and arduous war and the Depression that preceded said war. Many young men and women were interested in setting themselves up in the business of a free country and to see what type of success they could muster. The chief characters were the Benns and Brennan family all of Birmingham. The Brennan family consisted of a talented group of brothers; Bill Brennan was the business man (with a Masters of Science from Harvard and I am told that all of the Brennan boys had engineering degrees, except for Daniel), Cyril Brennan was a talented and hard working engineer, and Dan Brennan was the Voice and programming man of the family. From the Benns side, it is reported that Ira Lee Benns obtained an engineering degree from Auburn, the first female to so graduate. She was part of the original corporation that filed for and obtained the construction permit for WVOK in Birmingham. Her son William (Billy) obtained a Masters of Science from Auburn University. And it was due to this and the hired talents of so many good and dedicated people that this family consortium was able to build their own stations from the ground up. Application work, directional array work and even the building of their own towers make this family station group an entirely ‘in house group’. It was during this post war years that American broadcasting made a huge jump in number of stations and in the quality of its’ programming and while many thought that TV was always threatening the future of radio broadcasting, the fact that TV was so radically different in technology and in financial investment that many of our entrepreneurs found their success in radio. So this talented group ‘worked in’ WVOK in Birmingham; then came WBAM in Montgomery, WAPE in Jacksonville, and WFLI in Chattanooga, There was also an application for Dan Brennan for a station in Bibb City, Georgia. All these stations had a little bit of difference in ownership, but shared engineers, air talent, music lists, and whatever else was needed (cf, : Wiki Encyclopedia listing for WAPE and correspondence with several engineers). Channel 8 in Montgomery/Selma owe their beginnings to the Brennan family. The Benns family helped to bring UHF TV to the Chattanooga market in 1985 and was later sold to the Meredith group, and Mrs. Benns, the surviving partner, owns a LPTV in the general area. During the late 1950’s there were several modifications to the AM table of allocations.

The chief being the ability to apply for regional day time service for those Class A Clear channel frequencies. Since sky-wave was not of significance in the day time, and by the use of sophisticated directional systems, stations could be built on these newly allocated channels. The Benns/Brennan combine made their living doing this type of work and also in the owning of stations on such frequencies. The only 24 hour station of this group was owned by William (Billy Benns) in the Chattanooga/Lookout Mt area. Separate directional arrays allowed 50 kW to be ultimately used in the daytime and a grand total of 2.5 kW’s be used at night. The other group stations would remain as day timers. WFLI began with 10 kW in the daytime and used the WE 407 in a low plate voltage mode, and the evening power was 1 kW that was produced by a homemade 1 kW transmitter.

Brennan transmitter

The Brennan homemade transmitter (2013)

During this time, Billy was living in the Richmond/DC area, and running a station in Richmond, doing consulting work and being a close friend to the general engineering fraternity of the area. It was during this time (1960-1) that he heard from Clyde Hunt, vice president of engineering for WTOP, requesting that someone come and get the Western Electric Monster and to GET IT OUT QUICK. Being the determined fellow that he was and with a number of personnel from the Benns/Brennan stations they came to load and ship about 12 tons of transmission hardware. Wayne Woollard, retired engineer, who cut those early broadcast teeth with WAPE in Jacksonville, was one of the roustabouts called in to disassemble, label, wrap and ship a number of truck loads of the old WE 407-A serial number 101 to Chattanooga. WFLI was Billy’s station, and all chipped in to help. Wayne Wollard recalls, “I was up there from Jacksonville the first time when they were dynamiting the rocks for the guy anchors for the directional. Billy lived in Washington, and had owned a station in Richmond Virginia. He was close to the crew at WTOP, and when they decided to upgrade to another transmitter, Billy bought the WTOP Transmitter, “in Place!” And there was some sort of stipulation about having it out of the building in a very short time. Billy and Wayne were both pilots and Billy owned a Cessna”182”. This plane at some later date would crash and he lived through that crash to keep on working. It was Billy, Ike Lee of WAPE and Wayne Wollard who became the trained engineers supervising the dismantling of this extensive transmission system, for a system it was. From power distribution to spare parts, this transmitter was quite a marvel. Pictures are included to see the original layout at WTOP and then at WFLI. It may also be noted that the WJSV license allowed operation of this 407 in August of 1940 and the same was later replaced by an RCA BTA-50G in October of 1960.


702A Oscillators in Second Exciter Cabinet of 5 kW section   5Kw Final 6696A  in Driver section

(left) 702A Oscillators in Second Exciter Cabinet of 5 kW section, (right) 5Kw Final 6696A  in Driver section


As we begin the description of the transmitter, let us remember that Western Electric was very much the prime mover in the design of transmission equipment during the preceding years and even after the time period under discussion. With the backing of Bell Systems and the electrical and electronic support of General Electric and the Westinghouse there was certainly no lack of engineers to tackle the tremendous issues involved with high power transmission systems. WE had been in the business long before as they designed the famous 107A in 1928. Their early focus was on point to point transmission of telephony and telegraphic signals. WLW was the first station in the United States that went to 50,000 watts of programming power (take their 106A and add the high power cabinets and you would have the 107A). The 107A was constructed based upon earlier work with transmitters at New Deal Beach, NJ. KSL was also not long in acquiring a 107A and it is interesting to note that KSL found the 407A to be much improved in over all dependability. WHAS, Louisville, was the first station in the country to receive the 407A and the testimony as contained in the WE publicity folder about the Doherty Amplifier indicates that this unit was very stable in addition to the power savings as found by using the newly developed Doherty circuit. The transmitter consisted of a total of five cabinets. The first cabinet contained two of the 702-A quartz oscillator units with the three stage low RF system and a three stage low level AF system. Rectification shelves were also included in the first cabinet. The second cabinet consisted of the modulated RF stage. Two 232B water cooled tubes supplied the modulated 5,000 watts that formed the basis of excitation to the 50 kW section. Here the transmission line could be connected and the transmitter operated at a reduced power level if problems sufficient enough required the elimination of the high powered circuits; this, in essence was the current WE 5 kW transmitter. Cabinets three and four contained the carrier and peak power tubes as required for full power Doherty operation. Two 298 water cooled tubes were used, with a heat dissipation of approximately 85 kW’s. Cabinet five was a power and control systems cabinet. However, the full power systems were built in an open arrangement of three divisions. The AC division consisted of a power control cabinet built by Westinghouse and power transformers designed to operate off of 460v 3 phase service. Plate power was regulated by a motor controlled auto transformer with surge protection and supplied a nominal 16 to 18 kV. The second division was in the rear of the lower power stage cabinets and consisted of rectifying elements for the 5 kW driver and a third division was developed around the power requirements of the 50 kW stage. The phasor with the tuning cabinets were a part of external station architecture and not related to the basic cabinet line-ups. Please note the original power tube pictures. Total power on average modulation was in the neighborhood of 135 kW. How about that power bill folks?

Now, as we return to the WFLI and the Billy Benns approach, we start with the movement of the 12 tons of equipment from Washington, D.C. to Chattanooga, TN. As the equipment was installed at WFLI, it was installed as Western Electric would have done. Each cabinet and the external divided power components were properly placed and a custom wiring harness connected all of the appropriate points together. Underneath the power tubes of the 5 kW driver and the 50 kW cabinet are still found the Pyrex tubing that separates the high voltage from coupling into the distilled water supply. There is a December 1992 video documentary, howbeit only ten minutes, where Jeff Gregory shows the entire transmitter, and the water cooled tubes were still in use at that time. The ‘pole pigs’ (three of them) sit side by side on a concrete slab next to the station incoming power transformer where the supplied electricity came to become a 460 volt delta/wye type of configuration. Billy was a very skilled owner/engineer and he also had the skills of a very unique Chief and that was Joseph Poteet. Joe, being the day to day engineer, found that he would have to make a great number of modifications as the years rolled by to keep the transmitter on the air as parts and tubes began to be unavailable. As you walk into the station lobby from the outside, there is a framed picture of Joseph F. Poteet. He is wearing a suit and tie and is proudly standing by the transmitter. This is the Joe Poteet that many of the older members of the WFLI staff remember fondly. But the truth be known, we are told that he was often wearing his “bibs” when he worked. Joe, Mr. Jet-Fly (the top 40 name for the station), Poteet was a competent and able employee of Mr. Benns and kept the transmitter operating for many years. He started with the 10 kW/1kW daytime pattern and helped to move to the 50 kW/2.5 kW upgrade. There is a Collins 820-F Power Rock which served as the nighttime/auxiliary transmitter. It is still there just waiting for someone to use it. Mr. Poteet made this station his personal life until he retired about 1992 and during those last few years and on part-time basis he helped Jeff Gregory to modernize some of the circuits in the old Western Electric and to simplify operation. This would bring another half-dozen years to this classic. It seems that a number of over trip relays were by-passed as being unnecessary and that the tubes were changed out to reflect the growing need for reliable replacements. A pair of 833 tubes was used to drive a Machlett 6696 water cooled final in the 5 kW amplifier and were easily able to supply the power as a stand-alone or for the drive necessary for the high power cabinet.

WE407A Original 298A final     6696A Repacement for 298A

(left) WE407A Original 298A final, (right) 6696A Repacement for 298A

Jeff tells us that during this time he removed a lot of the mechanical devices that would limit the negative peaks so as to simplify the power circuits and to also allow the transmitter to just operate simply, without counting on high positive modulation for listenership. He felt that if the old ‘gal’ would just gladly sing every morning that he would be content to just allow her to operate as best as ‘she’ could. Machlett 6696 tubes were used to replace the carrier and peak tube in the 50 kW section and additional forced air was added to both power sections of the transmitter. With the Western Pole Pigs that were provided plate voltage was between 17 and 18 kV. Slightly higher than the tube charts recommended; Mr. Brennan found that if the plate voltage was raised to around 18 kV that the tubes would achieve an extra level of efficient operation and that is how he used these tubes at most of the other stations that were owned by this group. Superior engineering and experimentation to say the least; and some claim that the ghost of Mr. Poteet still walks the transmitter aisle taking a look at all the meters helped to keep the station on the air so long. The work of Jeff Gregory, after the retirement of Mr. Poteet, allowed this classic to remain on the air for an additional six years until Mrs. Ying Benns finally purchased a Harris DX-50. Jeff mentioned that it was extremely hard to have to turn the ‘old girl’ off and that for him engineering came to an entirely different level. (An important note: WFLI had purchased a duplicate 407A to be used as parts and for whatever else; this too, was an historical radio. It came from the famous station of the Mid-West plains, KOMA, Oklahoma City. This transmitter is stored in an adjacent building to the station and perhaps it will serve as a story in its’ own right in the future.) Mr. Benns passed away in 1999 at the age of 81, he was a member of the American Federation of Communication Consulting Engineers. Joseph Poteet passed away in 2003 at the age of 75, he was a Korean War veteran and member of the Signal Corps. Jeff is no slouch in his own right and modified the old transmitter to help simplify the daily power change procedure and to simplify the fault search when the transmitter would kick off the air. We are indebted to Jeff for much of the story and for his grand attitude in showing us around. It is to the memory of all good engineers (licensed or not; degreed or not), that the American broadcasting medium owes a debt far beyond payment. For it is not in the license or the degrees that greatness is found, it is in the willingness to roll up the sleeves, go to work and to make those things happen to benefit of all of mankind.

All rights to pictures and text are reserved, duplication and other use may be permitted upon notification to the author,


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