QST, January, 1923, pages 61-62:
9ZAF is the station of Dr. Wm. D. Reynolds, Jr., of Denver, Colo. 9ZAF, ex 9WH and 9JE, is one of the pioneer amateur stations of the west. It was the first station to send out daily news bulletins by phone in this territory and later as KLZ was the first commercial broadcasting station in the Rocky Mountain Region.
The transmitter was constructed by the operators at 9ZAF and is a composite phone and telegraph set. It uses two 250-watt tubes and a 50-watt voice amplifier for phone. On C.W. it uses a single 250-watt tube or two in parallel. The hookup is a modified Meissner circuit giving an antenna current of six amperes. When used as phone a 50-watt voice amplifier is used in conjunction with the Heising system of modulation.
The antenna is an "L" type double cage eighty feet high and ninety feet long. Each cage is made up of a top strand of steel cable supporting the five strands of copper cable. This top steel strand supports the weight of the rings and the heavy copper wires with practically no sag. A small cage lead-in is brought from each horizontal cage and joined together making a Y about 15 feet below. From this junction a single 8-inch cage passes direct to the transmitter. A large fan counterpoise composed of twenty No. 14 bare copper wires runs over the house to the back yard. The counterpoise is used exclusively.
The towers are 60 feet high with a 20 foot pole on top making a total height of 80 feet. They are constructed of 1 5/8 inch pine braced with 1x2 braces. They taper from a four foot base to a one foot top. The towers were built in three twenty foot sections which were bolted together on the ground and raised in one piece by means of a thirty foot "gin" pole.
For receiving a Grebe CR-8 and a Kennedy 220 are used on a single wire aerial 85 feet long and 30 feet high'
9ZAF is the gateway to the west coast and handles west coast traffic from Canada to the Gulf. The operating staff of the station consists of three men all of whom hold commercial licenses. They are from left to right, Thompson (TH), Carpenter (DX), and Dr. W. D. Reynolds (DR). 9ZAF has been reported on C.W. from every district and on voice as KLZ from 50 states and provinces of the U. S., Canada, Mexico, and Apia, Samoa, which is more distant than England.