Inhaltsverzeichnis
R-648 / AN/ARR-41
Manufactured by Collins Radio Co., Cedar Rapids.
The R-648 / AN/ARR-41 is a lightweight shortwave receiver technically based on the legendary R-390 dual / triple conversion receiver. The set was used in airplanes and its construction was improved to reduce weight.
Technical data
- Frequency range: LW, SW (190-550 kHz, 2.0-25 MHz)
- Frequency display: mechanical digital display, 100 Hz
- Frequency memory: none
Power supply
- Batteries:28 V DC (airplane on-board voltage)
Dimensions
- 330 x 178 x 432 mm, weight 17 kg
Accessories
Operation
A lightweight version of the Collins receiver R-390 was developed for use in aircraft.
The set is housed in a 43.2 x 17.8 x 33 cm aluminium case. The controls and also the connectors, the BNC antenna connector and the 6.3 mm jack socket as well as the fuse holders are located on the front.
The set is powered by 27.5 V DC from the aircraft electrical system.
The receiver covers the range from 190 - 550 kHz (the aeronautical beacon band commonly used in the USA) and the shortwave range from 2 to 25 MHz in 4 bands. The reception frequency can be read directly from a mechanical counter (mechanical digital), which is similar to an odometer. The long wave and the four short wave bands (2 - 3,999 / 4 - 7,999 / 8 - 15,999 / 16 - 24,999 MHz) are set with the left-hand rotary knob BANDSWITCH and the kilohertz digits from 000 - 999 with the right-hand rotary knob below the frequency display, 200 Hz dial lines give a maximum frequency readout accuracy of up to 100 Hz. A crystal calibrator, which is activated in the CAL position of the operating switch, allows the frequency display of the receiver to be readjusted.
For reception, the POWER main switch is now set to the ON position and the operating mode switch to the VOICE position. The frequency is now set using the MHz and kHz rotary knobs. The preselector is tuned by means of numerous synchronisation discs moved by gear wheels; this mechanical tracking preselector gives the receiver an excellent mirror frequency rejection and large-signal stability.
The desired frequency, for example 6.165 kHz, is now set on the mechanical counter; a „Dial Lock“ button allows the main tuning to be mechanically locked. The IF bandwidth is also selected via the operating mode switch; in the SH(ar)P position, instead of the 6 kHz IF filter, a narrow 1.4 kHz filter is used. A BFO active in the CW position allows reception of CW and, to a limited extent, SSB transmissions.
The power supply of the receiver is demanding and requires a sufficiently powerful 28 V power supply. The R-648 does not have a loudspeaker, headphones can be plugged into the 6.3 mm jack socket.
Technical principle
Components
The set is equipped with 17 tubes.
