KMI, Dixon Radio, CA

KMI was the west coast radiotelephone station of AT&T.  It's sister stations on the east coast were WOO and WOM.  They provided voice telephone service to ships at sea, first via AM and later via SSB.

KMI was established in 1921 with its receive site at Point Reyes, just to the west of the RCA receive site.  Transmitters were inland at Dixon, CA.

The station also had a point to point component providing trans-Pacific voice circuits as well as ship to shore service.

The 1939 "Berne book" lists KMI as having five AM HF channels.  



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Early KMI operators at Grant Street in San Francisco.  This photo shows the position at which overseas poin to point telephone calls are controlled.  James Twomey Jr. (left) is the technical operator, controls circuits to Australia and Asia.  Charles F. Reason, chief technical operator, controls the Hawaii circuit.  The panel between the two men is the transmission measuring set.  At extreme right is a 13-A oscillator for testing.

Voice privacy rack, Grant Street.

Voice privacy rack, Grant Street.

Test board, Grant Street.

Terminal equipment, Grant Street.

Left electronic bay, Point Reyes, 1946.

Power supply partly installed, Point Reyes.

Power supply fully installed, Point Reyes, 1946.

Early photo, KMI receive building, Point Reyes.

Receive building, Point Reyes, proudly flying the company flag, 1946.

Early sign at the entry to the receive site at Pt. Reyes.

This beautiful sign was at the entry of KMI in its last years.  This sign has been oreserved and is in storage.

Wide view of the early Pt. Reyes receive site.  At this time the receive antennas were exclusively rhombics.

This survey map is from AT&T Long Lines dated 1930 shows the layout of the trans-Pacific rhombic antennas at the KMI site.

Another view of the early antenna filed at the KMI receive site.

Double sideband point to point receivers and terminal equipment at Pt. Reyes.

KMI LCRI receivers at Pt. Reyes.

Point to point LD receivers in foreground, frequency monitoring position in background.

Here's a more recent photo of the Intercept position.  It was used mainly for monitoring interference on AT&Ts frequencies one suspects that special assignments from government agencies may have been carried out. The intercept receivers included the ubiquitous 51S-1, R-390A with spectrum scope and Eddystone and RACAL units. You'd be smiling too if you were sitting in front of an array of equipment like this - backed up by a selection of log periodic and rhombic antennas!.

MRHS operatives have discovered one of the LD receivers shown in the earlier photo on a storage container.  We hope the owner will eventually donate this receiver for restoration and display.

LD receiver front panel.

LD receiver front panel.

KMI operator at control racks in Pt. Reyes, 1966.

KMI operators at control racks in Pt. Reyes, 1966.

KMI operator consults call sign listing.

Evocative photo of KMI operator's headset resting on a chart showing the azmuths of carious KMI receiving antennas.

KMI operators consult a call sign list.  Note the Collins 51S-1 receivers in the rack.

KMI operators consult a call sign list.  Note the Collins 51S-1 receivers in the rack.

MRHS member Richard Dillman took this photo on a visit to KMI in 1972.   Calls were received on the Collins 51S-1 receivers. The operator identified the channel of the incoming call by watching for a flashing neon light on the speaker associated with that frequency. The best antenna was then selected and contact was made with the ship.

Equipment frame at KMI receive site, Point Reyes.

KMI operating console as it was during the last phase of station operations.  The operator merely had to touch the map at the location of the ship and the correct antenna would be switched into service.

Closer view of the most recent KMI operating console.

One of the last KMI operators lounges casually before his operating console.  The touch map is above his head.  In the last years he probably had plenty of time for lounging as the number of calls placed via KMI dropped off.

Early photo of the KMI transmitting station at Dixon, California.

A more recent photo of the KMI transmitting building shows a neat, squared away installation, typical of the best of AT&T.

After the closure of KMI the Dixon transmitter site was acquired by Globe Wireless.  Here MRHS members tour the site.

Early KMI transmitters out of service.

KMI HF-80 transmitters partly disassembeled with the antenna switching matrix in the background.

Back at the receive site, destruction was taking place.  All of the towers for the large log periodic antennas were taken down.

The towere were assembled at a single location for pick up by the scrappers.

Modern additions to the main KMI receive building were removed.  But the MRHS was able to convince the Point Reyes National Seashore that the building itslef is historic and should be preserved.

MRHS Transmitter Supervisor Steve Hawes salvages useful items from one of the downed log periodics.

MRHS Chief Operator Richard Dillman and Transmitter Supervisor Steve Hawes delicately remove useful parts from one of the downed antennas.

MRHS Transmitter Supervisor Steve Hawes climbs one of the apex poles of a log periodic antenna to salvage a matching network.

Now the good news: The MRHS was able to persuade the Point Reyes National Seashore that some of the antennas should be saved.  These include a TCI-540 omni, a TCI-530 onmi (twin of the one at KPH) and two rhombics.  The signals from these have been brought back to the KPH receive site via existing underground coaxial cable.  Here Steve Hawes works on the matching network for the TCI-540.

This photo gives an idea of the wonderful complexity of the TCI-540 antenna.

KMI TCI-530 antenna.

The Heliax from the antennas appear behind one of the frames on the KMI receive building, terminated in N connectors.

The interior of the KMI frame room as it appears today.

The last operating room of KMI, where the map console once existed, now houses the last KMI sign.

The advent of female operators at KMI resulted in the installation of this rather garishly decorated rest room.