We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
APRIL, 1926 A PORTABLE B BATTERY TRANSMITTER 679
Antenna Current Filament Voltmeter Plate Current Meter
Radio Broadcast Photograph
FIG. 2
A rear view of the transmitter showing location of component parts. The inductance coils are strapped to two dowel rods and kept away from metallic objects
40 30 15 8
500 400 320 130
WATTS
20
12 4.8 1.4
SIGNAL STRENGTH
R6 R6 R4 R3
At this point, local interference prevented going lower in power, but the meters on the transmitter could not read much lower anyway!
On December 1 6th at 8:18 p. m., 2 gy connected with 9 dcg, Frederick G. Braig, Rockford, 111., and with an input of 1.8 watts (10 mils, at 180 volts) he said signals were audible all over the room.
At 10:05 p. m. on the night of December 17th, communication was established with 9 ccq, Vere Davis, at Braymer, Missouri and the first of a long series of tests was carried out. That night 2 gy was using a Sea Gull 201 -a tube as follows:
19 13 7
4 1
290 200 120 75 40
5.5 2.6
.84
.3
.04
SIGNAL STRENGTH
R3 R3 R2 R2 Rl
A message was given to 9 ccq at .3 watts which he received perfectly. Arrangements were made by wire to communicate nightly on low power. He was using three 201-A tubes with 250 volts of B batteries, no meters or any other means of indicating resonance in the antenna.
Beginning December 21, a nightly schedule was maintained with 9 ccq except when weather conditions prevented, until January 5th when it was necessary to test the transmitter in the field. During this time communication was held many times with other stations with a maximum input at 2 gy of 20 watts. Schedules with 9 cm, Edward N. Fridgen, L'Anse, Michigan and 9 ecc proved conclusively that battery operated sets could be depended upon for consistent work.
INSTALLING THE PORTABLE TRANSMITTER
AT PATCHOGUE, Long Island, 40 miles from Garden City, the transmitter was installed in a hotel room with the antenna against a metal building
and parallel with a metal roof not more than 20 feet from the ground. Strong signals were received at 2 gy in the daytime and at night until 10:00 p. m. when interference and the skip distance made further communication impossible on 40 meters. At 80 meters, however, communication was easily accomplished. During the International Tests, the receiver and transmitter, set up in a farmhouse miles from anywhere, provided the only means of communication with Test Headquarters.
Now all of this low power work was done without special arrangements. After communication had been established, the power could be reduced, and often 2 gy got into communication directly on low power. The antenna system was amusing — a single wire poorly insulated, neither vertical nor horizontal and only about 35 feet long. The single wire counterpoise ran in a direction opposite to the antenna and likewise was not insulated. Antenna currents were never over .3 amperes.
All of which shows that on 40 meters,
Grid Leak
Soft Copper Wire ^Antenna Coil Counterpoise // Dowel Rod
o Broadcast Photograph
FIG. 3
Another view behind the front panel giving an idea of how simple the whole transmitter is
/