In 1911, Thomas Appleby co-founded the Philadelphia School of Wireless Telegraphy, which constructed a radio station that used the callsign of "PW". In 1912, Appleby moved on to the post of operator at a new American Marconi station, "HE", which had been built atop the Wanamaker's department store headquarters in Philadelphia, Pennsylvania. HE provided two-way communication, by radiotelegraph, with "HI", a sister station located at Wanamaker's New York City store, 90 miles (125 kilometers) away, which was managed, in Appleby's words, "by my buddy Dave Sarnoff". In 1912 Appleby celebrated his 26th birthday, while Sarnoff turned 21.
 
Thomas Appleby Memoirs, circa 1960, pages 15-17:

WANAMAKER CALLS.

     One evening early in 1912 while I was still at PW, I received a telephone call from Jack Irwin who had been sent from New York by the Marconi Wireless Co., to open their new powerful spark station "HE" (later called "WHE") atop the Wanamaker store in Philadelphia.
     At "HE" was the very latest in wireless, a powerful Marconi transmitter with huge rotary spark-gap and an antenna 1000 feet long stretched from Market to Chestnut streets, supported by two 125 foot towers on the roof of the store. The receiver was of the latest selective type equipped with a Fleming valve detector that could receive from New York, right through the other local transmissions on slightly different wave lengths, and entirely cut out the transmissions from the Government station at the Philadelphia Navy Yard.
     Station "HE" employed a fairly long wave length. Here was one of the choicest jobs on the Atlantic seaboard and every wireless operator in the country would have given his right eye to land such a berth.
     On the phone Jack Irwin said "Tom, how would you like to have the job?" I couldn't believe my ears so startling was the impact of that question. The best I can remember was mumbling something to the effect that I would like it if he was satisfied. Anyhow I agreed to report on the job the next morning and in the meantime Jack made all arrangements as he was leaving that night for an assignment on the West Coast. I have never had the pleasure of seeing him since.
     I really never had handled a genuine Marconi set until I reported that morning, but having the fundamentals in mind it was not too difficult to get underway and commence communications with the corresponding station "HI" (later called "WHI") on the roof of the Wanamaker store in New York.
     The New York and Philadelphia Marconi-Wanamaker stations were two of the most powerful commercials stations of their day and employed a break-in system by means of which the operators could, while transmitting, hear each other whenever the key was depressed at the receiving station. No other station in the United States had such an arrangement which greatly facilitated the handling of transmissions because if, due to interference or otherwise, you missed a word you would immediately press the key and ask for a repetition of the missing part without waiting until the end of the message.
     Jack Irwin was the operator at the shore station that received the famous CQD distress signal sent out by Jack Binns aboard the S. S. Republic when she sank in the north Atlantic in 1909. That was the first recorded use of the famous distress signal which has often been interpreted by the layman to mean "Come Quick Distress."
     The job at Wanamakers was very interesting and especially so due to the large number of visitors daily touring the store that the guides brought by every few hours. The Marconi station was one of the greatest points of interest because the transmitter was housed in a room with a large glass window, and double walls in an effort to deaden the terrific sound of the rotary spark whenever dots and dashes were made by the operator. We would generally wait until the crowd got nicely settled around the window, the guide would nod his head and then we would cut loose with a message, sometimes faked, just to give the crowd a thrill. At a touch of the key a pistol like shot and the brilliant blue white flash of the spark would cause the crowd to jump, clasp their hands over their ears and then slyly glance at us with a sheepish grin.

SPARKS GETS A GIRL.

     At the Wanamaker station in Philadelphia a cute little trick daily brought up messages from her department requesting that certain goods be sent over from the New York store. Before many days I found myself looking forward to her visits. There were many others who came up with similar messages but this one in particular seemed to interest me. Up to that time I hadn't had much time to devote to girls and was still quite busy, but somehow or other I finagled a date and that evening home at the dinner table I mentioned her. My mother for some time past had been trying to get me to visit a friend of hers who had a daughter that mother was certain I would like to meet, but being sort of stubborn in such matters I never would go. When I described my new girl friend my mother asked her name and I told her "Laura Graves" mother threw up her hands and said "Why that's the girl I have been trying to get you to meet." Needless to say we were married about six months later and spent thirty-six lovely years together, being blessed with a handsome son and two beautiful daughters, before she died.

Pages 19-20 (station drawing from the January, 1911 Modern Electrics, page 569): Wanamaker's NYC

DAVID SARNOFF AT WANAMAKERS, N. Y.

     At the New York Wanamaker store my buddy was Dave Sarnoff, now General, U. S. Army, and after being President of the Radio Corporation of America for many years, was elected Chairman of its board of directors.

DETECTING A FIRE 90 MILES AWAY

     One day while Dave was transmitting a message to me I recognized a peculiar flaring of his spark signal just as mine had sounded some time previously when the paraffin oil in my high voltage condensers caught fire. I stopped the transmission and said to Dave "your condensers are on fire." He replied "stand by" and went into the transmitter room to investigate. Returning a few minutes later he radioed "you were right, but how did you know?"

WANAMAKER STATIONS SPEEDIEST IN THE WORLD

     The Wanamaker-Marconi stations were two of the speediest wireless stations in the World in 1912. Not only did the operators transmit by hand at a speed in excess of 30 words per minute but they used a modified form of the Phillips telegraph code in which many words were represented by one, two or three letters. The word "the" was reduced to a single "t", "that" to "tt", the "Supreme Court of the United States" became "SCOTUS", etc. This gave us a tremendous advantage over other stations spelling out their words in full at 10 and 15 words per minute.
     The government operators at the radio station at the Philadelphia Navy Yard would not believe that we were actually transmitting at such speeds and stopping each other whenever necessary for corrections until one day their Chief came up to visit me and I handed him an extra pair of head-phones and signaled New York to go ahead with a message. The Chief's eyes fairly bulged as he heard the incoming message, with no break-in for a correction and what amazed him even more to see me writing out the message directly in full on a typewriter. They always wrote them in long hand. But he was convinced and then admitted the purpose of his visit.
     Government restrictions over radio in those days were not as severe regarding procedure as they have been since that time and we saved much time by often limiting our call to a single letter such as "I" for the New York station and "E" for the Philadelphia station, our ok for satisfactory reception of a message was often also an "I". Other stations would make the call letters three times, the signal "DE" meaning "from" and then their own call letters whenever they called a station. The station answering would do the same thing and add "GA" (go ahead). In the meantime we would have handled two or three complete messages. To hear a single "E" (one dot) and then the message in Phillips code, followed by a single "I" (two dots) in acknowledgement, was more than the Navy boys could savvy, but at least no one ever accused us of hogging the air with unnecessary signals.