The KFI Transmitter Site
Photos and Descriptions by Marvin Collins
(Posted by Steve Blodgett)

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There is a spiral staircase going up through 
the round structure, at the lower right corner, 
that leads to the front door of the KFI transmitter 
building.  Notice the call letters in the tile above 
the door.  The entire building was covered with
ceramic tile at one time but was cemented 
over years ago.
The upstairs front door of the KFI transmitter 
building.  Note the KFI call letters in the custom
tiles above the door.  This building was 
constructed about 1930.
 

A close up view of the KFI tiles over
the front door of the KFI transmitter building.
One of the tiles that surrounds the front 
door of the KFI transmitter building.  
Does the pattern represent a tower with
radio energy radiating from it?
 
The tuning network box and the base
of the auxiliary KFI tower
The base of the main tower 
which includes the antenna 
tuning unit house.
 
The base insulator and lighting transformers
at the base of the 750 foot KFI main tower
The output power meter on the 
Harris DX 50 transmitter showing 
the output power of fifty thousand
 Watts that is transmitted 
through the tower and
its equipment.
 
The currently on air KFI "T matching"
network for the main tower.
The spare T matching network 
for the KFI main tower
 

The Onan 175 KVA diesel generator
at the KFI transmitter site.
 

Audio and monitoring equipment racks
in the KFI transmitter room.

 
The Harris DX 50 fifty thousand
Watt main transmitter.
Status indicators on the Harris DX50
50 KW transmitter used by KFI.
 

Front panel meters and controls
on the Harris DX 50
Fifty thousand Watt KFI transmitter.
 
The Continental 317C fifty thousand Watt
standby transmitter.
The final tubes in the Continental 317C
transmitter.  These tubes are Eimac 4CX25000
tubes operating as a modified Doherty amplifier.
One tube is the Carrier tube and the other is 
the "Peak" tube.
 
The driver stages in the 
Continental 317C transmitter.
Power supply components in the
 Continental 317C transmitter.  The upper part
 of the cabinet contains the high voltage
 rectifiers.  The lower part of the cabinet 
contains the filter capacitors.
 
The Continental Electronics 50 KW
air cooled dummy load
in the KFI transmitter building.
Wescom T1 equipment used for the main
studio to transmitter audio link for KFI.
The SCE power vault at the KFI transmitter site.
Shortly after I became Chief Engineer at KFI a rat
caused a primary to secondary arc in this vault.  
The resulting power surge destroyed standby 
generator transfer relay in an explosive manner.
 KFI was off the air for six hours that day.
The shop at the KFI transmitter building.
The lathe in the KFI transmitter shop dates
back to 1931 when KFI started transmitting
at 50 KW of power.
A Well Equipped Shop
Grinder and Milling Machine (left)
The good ol' drill press (right)
The cabinetry (far right) in the
shop at the  KFI transmitter building
dates back to 1931  when the
building was constructed.
The label from the original KFI 50 KW dummy antenna
before dismantling in 1979.  The original dummy was in
use from 1931 until 1979.  I was glad to be able to heave
the old dummy antenna out the second story door of the
transmitter building.  It never did work very well.  It would
seem to fail just when needed most.   In 1979 KFI purchased
a new Continental 317C transmitter and dummy antenna
that is still working great.

Here's the label that was removed from the
 power control unit of the original RCA 50C
 water cooled 50,000 Watt  transmitter.  That
 transmitter was removed in 1959,  seventeen years
 before I started at KFI.  I must have found  the label in
 a junk box somewhere and forgot that I had it.
 

 
The December 10, 1941 Miscellaneous Equipment
Log.  At the bottom of this old log page there is an
interesting note about a U.S. Army guard accidentally
shooting a hole in the ceiling of the shop in the 
KFI transmitter building.
The small hole on the left could be the one
that was the result of the accidental discharge
of the rifle belonging the Army guard, who was
stationed at the KFI transmitter site during
World War II.  The accidental discharge of the
rifle occured at 7:35 a.m. on December 10, 1941.
This is the celing of the shop in the 
KFI transmitter building.

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