Remler "Infradyne"
Remler Division, Grey & Danielson Mfg. Co.,
260 First St.,
San Francisco, California USA

    The 1928 Infradyne is a ten-tube receiver in which radio frequency amplification at broadcast frequencies is combined with amplification at the relatively high intermediate frequency of 3500 kc. which is approximately equivalent to a wavelength of 86 meters. In the intermediate stages the "sum frequency" is amplified. The "sum frequency" is, as its name indicates, the sum of the received frequency and a locally generated frequency. Through the use of the sum frequency selectivity, quiet amplification and freedom from repeat settings on the oscillator tuning dial are obtained.
    The 1928 Infradyne is particularly distinguished for the fidelity of its reproduction. For mellowness of tone, for volume without distortion, it can not be surpassed. Selectivity, which has not been made so great that side-bands are cut and reproduction is spoiled, is ample for present day conditions. In locations immediately adjacent to high-power broadcasting stations fewer distant stations will necessarily be received during the operation of the local stations than would be received were the receiver situated in a slightly less congested locality although no trouble will at any time be experienced in completely separating local stations.
      The 1928 Infradyne combines excellent selectivity and really enjoyable, life-like reproduction with ease of operation, compactness and attractiveness of appearance. The Infradyne is truly a universal set which appeals alike to the man who requires the utmost simplicity of operation and the man who enjoys clear reception of distant stations. It is housed in a beautiful, sheet-copper cabinet finished in two-tone brown crystalline enamel which will harmonize perfectly with the finest of surroundings.
    The 1928 Infradyne is provided with a switch having three positions, "Off," "Local" and "Distance." A turn of this switch to "Local" brings onto operation a single-dial control, five-tube tuned radio frequency receiver. When the switch is in the "Distance" position the complete Infradyne is available.
    There are but two major tuning dials, one of which operates the condenser tuning the radio frequency amplifier circuits and the other of which operates the condenser tuning the local oscillator circuit. When the panel switch is in the "Local" position and five tubes only are in use only the tuning dial controlling the radio frequency amplifier circuits is employed. Each of the two tuning dials rotates through a full 360 degrees in covering the broadcast band and ample dial separation of stations is had at all parts of the scale. An adjustment is provided so that the dials can easily be made to read quite closely together, with a maximum deviation at the far ends of the scale of perhaps five or ten degrees. Illumination of the dials is provided and during the time that five tubes only are in use only the tuning dial employed will be illuminated. In addition to the tuning dial controls, volume and sensitivity controls and a filament rheostat are located on the panel. These controls are all of the semi-fixed type. The volume control is a rheostat in the filament circuit for the first two radio frequency tubes and its adjustment determines the gain in the radio frequency amplifier. The sensitivity rheostat controls the gain in the intermediate amplifier. The panel rheostat is adjusted so that the panel voltmeter reads "3" and is not further used. An "Antenna Compensator" control is provided. The antenna compensator is a device which nullifies the detuning effect of the antenna system, making the use of variable trimmer controls for the radio frequency amplifier unnecessary and hence simplifying tuning. It permits the immediate adaptation of the receiver to the particular antenna system used and does not need to be used for ordinary tuning, once it has been correctly adjusted. Variable coupling between the primary and secondary circuits of the transformers used in the radio frequency amplifier is employed and the degree of coupling is automatically controlled through a cam located on the shaft of the tuning condenser. The result is that maximum -and uniform gain is obtained at all wavelengths in the broadcast band.
    The radio frequency amplifier is a completely shielded, wired and balanced unit ready for installation in the receiver without special attention. Switches are provided which can be adjusted at the time of installation for the degree of selectivity and stability of operation best suiting the operator and local conditions. Five CX 301A tubes, four CX 299's and one power tube, which may be either a CX 112 or a CX 371, are used. These comprise two radio frequency amplifiers functioning at the frequency of transmission, a first detector or mixer tube, an oscillator, three intermediate amplifiers functioning at the fixed frequency of 3500 kc., a second detector and two audio amplifiers. A six-volt filament supply is required and this should preferably be a storage battery of 100 ampere-hour or more capacity. Plate voltages of 221/2, 67'/z, 90 and either 135 or 180 are necessary. The plate supply may consist of "B" batteries of the heavy duty dry-cell type or the storage type or a suitable "B" eliminator may be used. The Infradyne is critical as regards filament and plate voltages and the peculiar requirements of the set must be kept in mind in choosing power supply devices. The receiver draws a total filament current of two amperes when the ten tubes are in use and a total current of 1'/z amperes when five tubes only are being used. The maximum drain on the plate current supply device, assuming the use in the second audio stage of a CX 371 tube operated at a plate voltage of 180, will be in the neighborhood of 40 milliamperes. Detailed information regarding the use of "A" and "B" eliminators with the Infradyne will be supplied upon application.
    The Infradyne is, as has been implied in the above discussion, intended for use with an antenna. One about 40 feet in length will generally be found about right. In localities far from broadcasting stations longer antennas can successfully be used and in localities which are congested as regards broadcast conditions short antennas of the inside variety can be used with surprisingly good results.
    Parts for the 1928 Infradyne are available in kit form. Six blue prints and a complete and detailed instruction book are supplied with the No. 750 Foundation Kit. Construction of the set is simple and virtually resolves itself into the assembly of the component parts and the installation of a wiring cable laid out by the builder in accordance with full instructions furnished.

                                              Remler "Service For Set Builders" Bulletin No. 2, March 1, 1928

Tube Line Up:
01A......1ST. RF Amplifier
01A......2nd. RF Amplifier
01A......1st. Detector
99........Heterodyne Oscillator
99........1st. I. F. Amplifier
99........2nd. I. F. Amplifier
99........3rd. I. F. Amplifier
01A.....2nd. Detector
01A.....Audio Driver
71A......Audio Output

Power Source:
A Battery.....+6 Volts
B Battery.....+22 .5 Volts
B Battery.....+67.5 Volts
B Battery.....+90 Volts
B Battery.....+135 Volts
C Battery.....-4.5 Volts
C Battery.....-22.5 Volts

Frequency Range:
BC Band...550 kHz to 1500 kHz
I.F.Frequency....2.3 MHz

Height...10.75 inches
Width...32 inches
Depth...15 inches

Schematic & Information

Bulliten No. 5 
March 1, 1928

Bulliten No. 8 
April 1, 1928

New Parts Catalog 
January 1, 1928

Extra Parts Catalog 
Effective January 1, 1927

Reprint from the Citizans Radio Call Book
September 1928

Catalog Sheet No. 2
October 1, 1928

This web page was last updated: December 15, 2016