AMELCO R-390A/URR RADIO RECEIVER (RARE) COLLINS PATENT À NICE

Radio receiver R-390A/URR manufactured by AMELCO under Collins Radio's patent, s/n 637. Here is an historic piece of equipment that has become rare to find in good working conditions. The R-390A/URR provides reception of continuous-wave (CW), modulated-continuous-wave (MCW), frequency-shift keyed (FSK), and single-sideband (SSB) signals. A double sideband signal, either AM or phase-modulated (PM), occupying up to a total of 12 kHz of spectrum for voice transmission may also be received Radio Receiver R-390A/URR is a super heterodyne type with multiple frequency conversion covering a frequency range of 0.5 to 32 MHz. Double conversion is used when operating from 8.0 to 32 MHz, and triple conversion when operating from 0.5 to 8.0 MHz. Linear tuning provides constant frequency spread throughout the entire range. Tuning is accomplished by positioning powdered-iron cores in the RF and IF coils, at a rate controlled by a mechanical arrangement of gears, shafts, and cams. The operating frequency is read from a counter-type indicator. A built-in crystal-controlled oscillator provides frequency calibration. The output of the LOCAL AUDIO provides either 500 mW power to a 600 ohm load or 1 mW for a headset, while the output of the LINE AUDIO provides a 10 mW output Into a 600 ohm balanced line. A BREAK-IN relay is also provided to disconnect the antenna when an associated transmitter is keyed. List of tubes: 6DC6, 6AK5W, 6AK5W, 6C4, 6C4, 6C4, 6BA6W,6BA6W, 6BA6W, 6BA6W, 6BA6W, 6BA6W, 6AK6, 6AK6, 6AK6, 5814A, 5814A, 5814A, 5814A, 5814A, 5814A, 5814A, 26Z5W, 26Z5W, 3TF7, 0A2.                                         Original characteristics : Frequency range 0.5 to 32 MHz Types of signals received CW, MCW, FSK, SSB, and AM Frequency indication Read from digital Indicator Method of calibration Built-In crystal-controlled oscillator Calibration accuracy Less Than 300 Hz Calibration points Every 100 kHz Sensitivity (signal plus noise to noise ratio) AM sensitivity CW sensitivity 5 μV at 10dB rise 1 μV at 10dB rise       Modifications : 1-    220V mains filter (Schaffner) has been added 2-    On state surge current limiter (Keystone Thermometrics ICL) 3-    SO-239 antenna socket 4-    Audio transformer to use a 4 or 8 Ohm speaker (instead of the regular 600 Ohm speaker) 5-    All tubes have been replaced by N.O.S. USA imported What you see on the photos is what you get. It will be carefully packed in a 3 layer card box. This receiver is in working order, nevertheless, due to its age (~50 years), no warranty is provided whatsoever. It is a heavy piece of equipment: 35kg.