[GreenKeys] Point to Point vs. Marine

[Richard Dillman]

On Sat, Dec 25, 2021 at 1:29 PM Richard Knoppow <1oldlens1 at ix.netcom.com>
wrote:

    I think we need to distinguish between the marine radio
> operation of KPH and the RCA Communications point to point
> service which was also run from Bolinas Point. The marine service
> through KPH was telegraph with later some RTTY to ships at sea
> while the RCA Communications service ran some large number of
> circuits to Pacific Rim countries. KPH was connected via wire
> telegraph. Richard Dillman could supply details. The messages to
> be sent and received from ships would be relayed by telegraph. I
> suspect these circuits were machine code both ways and later
> Teletype.
>

<snip>

Quite correct, the distinction between the marine service and the point to
point service is important to keep in mind.

The American Marconi Company came to the coast of Marin county north of San
Francisco to build the point to point transmit station at Bolinas.  The
corresponding receive station was built at Marshall(s).  The station was
placed in service in February 1914.  The transmitter was the standard
Marconi rotary gap rated at about 230kW.  The call sign was KET.

https://www.radiomarine.org/point-to-point/bolinas-high-power

In 1920 RCA replaced the Marconi transmitter with two Alexanderson
alternators on about 26kc (high for an alternator but necessary at Bolinas
due to the short antenna) with 200kW output each.  The KET call sign was
retained.    They were so proud of the alternators that they placed a
bronze plaque on the transmitter building.

https://www.radiomarine.org/radio-archaeology/alexanderson

RCA was formed, as we know, to absorb the interests of American Marconi and
thereby prevent that company from obtaining monopoly use of the
Alexanderson alternator.  It's true that the Alexanderson alternators were
dead reliable.  But the reason that alternator installations were
discontinued was the advent of HF as a revenue generating technology.

The the point to point service, from the beginning until its demise in
1973, no actual operating was done at the transmit or receive stations.
This was controlled at the CRO (Central Radio Office) in San Francisco (or
the corresponding city for other stations).  Outgoing messages were
transferred to Wheatstone tape at the CRO and sent by wire line to key the
appropriate transmitter (the alternator or, later, the HF transmitter aimed
at a particular city).  Incoming messages were received on diversity
receivers (one of which we have restored) and activated tone keyers at the
receive site.  These tones were sent to the CRO by wire line where they
were recorded on ink recorders.  Later, then FSK replaced Morse, the same
process was followed using Baudot.  Unique to the point to point service,
on HF each frequency had its own call sign rather than an overall station
call sign.

In contrast, in the marine service all operations were (and are) handled at
the receive site.  Outgoing messages were received by land line Morse
(later by teleprinter) from the CRO and placed in the message rack for
transmission.  When a calling ship had traffic traffic on hand the operator
retrieved the message from the rack and sent it manually, remotely keying
the transmitters in Bolinas.  Incoming messages were also received manually
and typed on a mill or, later, into a message handling system.  Delivery
was through the CRO by teleprinter or bicycle messenger except in the case
of a sea letter message.  These were mailed by station personnel (I have
one in my collection).  These days they are delivered via email.

WX and PX was received at the receive station on punched 5 level tape.  A
Baudot to Morse converter was used to key the KPH transmitters from the 5
level tape.  Today we send PX and WX obtained via the Internet.

Our order wire between Bolinas and Point Reyes is a land line teletype
circuit which we think may be one of the few remaining, certainly in this
application.

We are unaware that point to point service handled voice telephone circuits
although the station did provide broadcast service for the OWI during WWI,
one transmitter having the call KRCA.  The AT&T station next to RCA handled
point to point voice circuits as did the station at Half Moon Bay/Palo Alto
(marine call KFS).

VY 73,

RD


Richard Dillman
Maritime Radio Historical Society
https://www.radiomarine.org
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