Inhaltsverzeichnis
R - 220 / URR
Manufactured by Motorola for the U.S. Signal Corps.
The R-220 is a heavyweight VHF receiver, not only its weight of 80 lbs make the set manufactured by Motorola a real boat anchor.
Technical data
- Frequency range: 20 - 230 MHz in seven bands
- Frequency display: analogue dial, approx. 50 kHz
- Frequency memory: none
Power supply
- Mains operation: 115 V
Dimensions
- 483 x 265 x 375 mm, weight 40 kg
Accessories
Operation
At around the same time as the Collins R-390, Motorola developed the R-220, a heavyweight VHF receiver. The 40 kg set is housed in a 19 inch rack case and measures 48.3 x 26.5 x 37.5 cm. It is operated with the American standard mains voltage of 115 V.
The receiver covers the VHF range from 20 - 230 MHz in 7 bands. The coarse and fine tuning scales are mechanically coupled to each other, the reading accuracy on the frequency dial is around 50 kHz. A crystal calibrator, which is activated with the CALIBRATE switch, allows the receiver to be calibrated.
The antenna trimmer and the crystal calibrator switch are located to the right of the frequency coarse and fine tuning dials in the top left-hand corner of the front panel. The instrument can be switched to display the signal level or the AF output level using the switch next to it. The AUDIO GAIN 1 and 2 volume controls and the headphone sockets are located directly below.
In the bottom row of controls, below the large band switch and tuning knob from the left, are the RF gain control, which is also used as a squelch control in squelch modes, the IF and AF bandwidth controls, the switch for the noise limiter, the BFO and the operating mode switch: in position MGC the receiver is operated with manual control of the RF gain and in position AGC with automatic gain control, in positions AM - Squelch and FM - Squelch the squelch is active, the receiver is muted until the signal level exceeds an certain signal level.
For reception, the OPERATION main switch is set to the FM squelch position. For reception of most frequency-modulated VHF stations, the SELECTIVITY 50 kHz and AUDIO RESPONSE WIDE settings can be used.
After selecting the appropriate frequency band, the frequency is set using the TUNING knob. In the CARRIER position of the measuring instrument switch, the signal strength is displayed and the antenna can be optimally adjusted using the antenna trimmer, allowing you to search for stations in the FM broadcast band below 108 MHz, for example.
To receive, for example, aeronautical radio stations in the 108 - 136 MHz range, you must switch to AM mode.
Technical principle
Components
The set is tube-equipped.
