Radio Compass Station NLG

It all began with a plank of wood.  The plank was from a shipping case.  Stenceled upon it was the address: "Radio Compass Station NLG, Point Reyes".  That was a challenge if ever there was one.  Since Point Reyes is the home of the KPH receive site we thought we knew the radio history of the area.  But NLG was new to us.  Luckily our library contains an ITU book from the 1930s covering radionavigation stations.  And there it was, NLG Point Reyes, complete with the latitude and longitude.  The coordinates were plugged into a GPS and the little arrow was followed to... Well, see below for what was found.

A strict procedure applied to the process for obtaining a radio bearing from a radio compass station.  All communications took place on 800m (375kc).  Stations that were part of a harbor entrance group, as NLG was, had a single control station that communicated with the ship.  The ship began the process by calling the compass station on 800m and sending QTE? (what is my bearing?).  The call was answered by the compass station or control station which, when ready to take a bearing, sent K (invitation to transmit).  The ship then sent its call repeatedly for 50 seconds with the dashes considerably prolonged.  Signals such as V or MO were not authorized for bearing purposes.  The radio compass station then sent the bearing, or multiple bearings in the case of a harbor entrance group of stations, to the ship.  These were plotted on a chart to fix the ship's position with appropriate corrections to correct for angular distortion at ranges over 50 miles if a Mercator chart was used.  Accurate bearing were generally available out to a range of 150 miles. ("The Radio Manual", George E. Sterling, 1928 pp 505-507)


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NLG

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NLG

Richard Dillman writes: The arrow on the GPS pointed west along the road from the KPH receive site.  Then, at a little road I hadn't noticed before, it swung to the right.  I followed the road and found... NLG.  Or its remains at least.

NLG

 NLG
NLG

There it was, perched on a hill overlooking the Pacific.  A path through beautiful wildflowers led to the little operations build which once contained the radio compass (direction finder) and a transmitter and receiver for communicating with the ships requesting bearings.  Radio compass stations like this were once deployed around the approaches to all major harbors.  Along the foggy San Francisco coastline, accurate bearings were particularly important.

NLG

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NLG

The lower part of the building has windows providing a spectacular view of the Pacific.  The upper area contained the radio compass loop that was controlled with a wheel and indicator above a chart in the lower area.

NLG

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NLG

On a second visit to the site it was clear that the building is continuing to deteriorate.

NLG

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NLG

Here's the view to the west from inside the building.  The radio equipment was of course long gone.  The building had been used as a residence including a very lucky ham radio operator.

NLG

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NLG

An overall view of the lower room looking away from the windows.  The steps lead to the upper room that housed the radio compass antenna.

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NLG

A small writing desk is tucked in under the stairs.

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NLG

The upper room is very small so it was hard to get a good overall view.  Here's one corner showing a matress.

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NLG

Here's a view of the opposite corner of the upper room.

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NLG

The path back down the hill viewed from inside the main room.

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NLG

How many radiomen hung their coats on these hooks?

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NLG

NLG was equipped with a classic flat top antenna for communications with ships on the designated radio compass frequency in the MF band.  I was able to locate the remains of the mast bases and of the guy anchor posts such as this one.

NLG

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NLG

Here's the remains of the base of one of the MF antenna masts.

Early photo of NLG and surrounding buildings