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.
|Equipment used on all three bands was FM with approximately the same power output. The receivers used in this test were installed at the transmitter location of KGPL, on a hill, approximately 300 feet above average city ground level. All antennae were mounted on thirty-foot telephone poles. There are several surrounding hills within a distance of one to two miles which are higher than the hill on which the receivers were mounted.||
KGPL Transmitter 1946
|Receivers were installed at this point as the location of the Police Academy is down in a ravine, among the hills and is a very poor radio location. Through the cooperation of Captain Chester W. Howard of the Los Angeles Fire Department, a line of approximately 10,000 feet was laid over the hills from the receiver point to the auditorium of the Police Academy, where a large group could be accommodated.||
Same Location, 2002
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.
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
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"
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.