From the
APCO Bulletin, July 1946
Resume' of California's
Joint Meeting, CPRA (Southern California) and NCPCOA (Northern
California) APCO Chapters
APRIL 26 AND 27, 1946, LOS ANGELES
POLICE ACADEMY
Meeting was called to order on April 26, at 1:30 P.M. by William
E. Whiting, President, California Police Radio Association.
President Whiting introduced our host, Lieut. W. H. Durham,
Commander of Communications Division, Los Angeles Police
Department, who made a short welcoming address.
[ routine meeting details omitted ]
The Los Angeles Police had a display of equipment used by the
Accident Investigation Division.
The Friday afternoon meeting was devoted entirely to technical
discussion by the various manufacturers' representatives, who
covered all types of equipment and frequencies now in use, or
contemplated for future use in emergency service. There were
approximately 150 persons in attendance.
The meeting adjourned to the Exhibition Hall at 5:30 P. M.
The Friday evening meeting was devoted to a banquet and social
get together, which will be explained more fully later.
Saturday, April 27, at 9:30 A.M., the Business Meeting was called
to order by President William Whiting, who introduced Mr. J. Don
Hossack, President of NCPCOA, and then turned the meeting over to
him for any business requiring attention at the joint session.
Various introductions were made.
Mr. Hossack discussed the need for a standing joint committee
regarding new frequency allocations which would need action from
both Associations in matter of releases in order to prevent
interference between the two areas. He stated this need was
especially true in regard to State Agencies, due to the fact
their area covered the entire State and involved both
Associations. Mr. Hossack stated that Northern California has a
Committee to pass on frequency allocations, as well as power and
antenna structures for new applicants. Mr. Whiting pointed out
that CPRA has a like Committee, and that fullest cooperation
would be extended.
Mr. Anderson, of San Bernardino County Sheriff Office, opened
discussion regarding the possibility of the F.C.C. licensing
police repeater frequencies on 72-76 inc. on a permanent basis
instead of experimental basis as at present.
A motion embodying this request was carried unanimously.
Demonstration
of 72-76 and 152-162 Mcs Equipment
Meeting adjourned at 11 A.M., at
which time manufacturers started demonstrations of Ultra High
Frequency communications from mobile units to a fixed receiving
point.
Equipment was demonstrated on three bands: 30 to 40; 72
to 76; and 152 to 162 mc. bands.
This line was used for all demonstrations by switching at
both ends simultaneously from equipment on one frequency band to
another. All equipment was remotely controlled from the Police
Academy over this line. A radio link was set up from the Police
Academy to Control KGPL, for dispatching information over KGPL on
1730 kc. to cars in the test run.
The test run was made over a selected route, known
through years of local operation to be very difficult to transmit
into the receiving point used. In fact, some of the
manufacturers' representatives state that at some spots “not
even a crow could fly out." Although the maximum distance
from the cars to the receiving point was approximately eight
miles, the intervening terrain provided at least one, and some
cases two ranges of hills, upward to 2,000 feet in altitude
directly between the cars and the receiving point.
The
152 mc. tests were also run from inside the City Hall
garage, sub-basement below ground level. The City Hall is
a 28-story, reinforced steel and concrete structure,
located approximately one mile air line from the
transmitter point. No trouble in intelligible reception
was experienced in this case. In addition, tests were run
through the Second and Third Street Tunnels, which are
rather narrow, and approximately 1,000 feet in length,
without wires or metallic objects running through them.
Communication was good, with the exception of
approximately the middle of the Third Street tunnel. The
tunnels run approximately at right angles to the
direction of the receiving point. As a result of this
test, our conclusion would be that 72 to 76 and 152 to
162 mc. bands are definitely usable in this area for
police work and compare favorably with anything we have
on 30 to 40 mc., as related to rugged terrain and
built-up areas.
In
every case directly behind steep hills, where the two
higher frequencies were not usable, 30 to 40 inc. band
was also not usable. |
"The TEST CAR - Note contrast between the 30-40mc
antenna and that of the 156" |
Each test
was made as nearly as possible at the same location and same time
on each frequency.
It was noted that the noise level, including diathermy on
152-162 inc. was down considerably in relation to signal
strength, as compared with 30 to 40 mc. band. It was also
observed that none of the bands were clear from diathermy
interference.
These tests were run through the Highland Park, Eagle Rock and
Hollywood areas of Los Angeles. The "receiving only"
tests were concluded at 1:15 P. M., at which time we had
intermission for lunch at the Academy Cafe.
Two-way demonstrations on 152-162 mc. were resumed at 2:15 P.M.
Test runs were made with a group of APCO members, in the cars
behind several of the hills covered in the receiving test runs,
and also in the sub-basement of the City Hall.
Communications were excellent through the City Hall, tunnels, and
behind the hills, with only a few limited dead spots. The land
station equipment, used in these two-way tests, was a 250-watt FM
transmitter, operating on 156.525 mc. It was located at KGPL, and
was remotely operated over the same line as were the receivers.
Tests were concluded about 5:30 P.M., at which time the meeting
was adjourned.
During the tests there were approximately 150 in attendance.
The following day more extensive two-way tests were conducted by
Lieutenant H. B. Calvert of the Pasadena Police Department and
Fred Crowder, Radio Technician Foreman of the Los Angeles Police
Department to further determine what could be expected on 156 mc.
They drove out Highway 66 toward San Bernardino, California,
which is located approximately 60 miles north-east of Los
Angeles. Communications were excellent and no .change of speaker
volume could be noticed for about 30 miles, air line, after which
some background noise was noted. It was usable for the next five
miles, at which time signals abruptly dropped completely below
audibility.
The return trip was made by a different route, Highway 99,
through the City of Pomona, where there were some intervening
hills, and the range was restricted to 20 miles, probably due to
the terrain.
The same afternoon, another test was made in the Harbor Area of
Los Angeles, approximately 25 miles, air line, from the
transmitter point to the mobile unit. Tests were run alongside
shipyards, where a large number of steel structures and various
electrical devices, such as arc welders, were in operation.
Communication was solid, with no background noise through this
area, which is considered exceptional.
These tests were run for the sole purpose of determining and
comparing what communications can be expected on the various high
frequency bands now allocated for police use as compared to long
experience on 30 to 40 mc., and not to compare various
manufacturers' equipment.
In fairness to all manufacturers concerned, we have eliminated
the names of any participating manufacturers or names of
equipment used. Some manufacturers were unable to participate due
to the short notice prior to the meeting, and others not having
necessary equipment available, and some because of labor
disputes.
All tests were made under the direction of Fred Crowder, Radio
Technician Foreman, of the Los Angeles Police Department, who was
assisted by K. V. Keeley, Chief of the Fire and Police Signal
Division of the Los Angeles Building and Safety Department,
Captain Chester W. Howard, of the Los Angeles Fire Department and
the technical staff of the Radio Technical Division of the Los
Angeles Police Department.
On Friday evening at 7 P.M., approximately 200 Association
members, wives and guests, enjoyed a banquet and social gathering
at the Police Academy Auditorium. The auditorium is a room 80 x
100 feet with a large stage. Banquet tables were placed in the
center of the room, with the exhibits arranged along the walls.
Entertainment was provided during the evening by the Los Angeles
Police Department Band, under the direction of Captain: Harry
Signor; a Spanish orchestra and soloist; and dancers from the Bob
Cole Studios
Master of Ceremonies, Captain Charles Ellison, of the Los Angeles
Sheriff's office, made introductions throughout the evening.
Deputy Chief Bernard R. Caldwell, representing the Chief of
Police of Los Angeles, gave a welcoming address to the visitors.
Under-Sheriff A. C. Jewell, representing Sheriff Biscailuz, Los
Angeles County, also gave a welcoming address.
The speaker of the evening was Dr .Lee DeForest, often
called the father of the radio, and credited with the invention
of the three element vacuum tube. As he rose to speak, the entire
group stood in tribute. He spoke briefly of the history of radio,
and the things we might expect in the future.
Over 30 door prizes, donated by the various manufacturers and
jobbers were given away during the evening. The lucky numbers
were drawn by Dr .DeForest, and the prizes consisted of
everything from a coffee maker to a complete portable Navy
transmitter and receiver.
On Saturday morning, during the business session, the visiting
ladies, numbering approximately 30, met in the office of the
Commander of Communications Division and were then taken on a
tour of Hollywood,...
At 6:30 P.M., the CPRA held open house for members of NCPCOA, at
the Rosslyn Hotel, where the various members congregated for a
more informal discussion of their various problems. This meeting
adjourned in the wee small hours of the morning, with everyone
feeling that the entire meeting had been the best one eve~ held.
Our two Associations are indebted for the financial success of
this meeting to those manufacturers and jobbers previously
listed.
The success of the entire meeting was due to the hard work of the
Convention Committee, composed of:
Lieut. W. H. Durham, Los Angeles Police, Chairman
Capt. Chas. Ellison, Los Angeles Sheriff's Office.
Fred Crowder, Radio Technician Foreman, Los Angeles Police.
K. V. Keeley, Chief, Police and Fire Signal Division, Los
Angeles.
Keith Furry, Supt, Communications Bureau, Glendale Police
Lieut. Robert Amsbury, Whittier Police
H. C. Culver, California Highway Patrol, Los Angeles.
H. B.
Calvert,
Secretary, CPRA
Ralph Moore~
Secretary, NCPCOA
