281 Ch= R-1A

General Motors Radio Corp.

Données
Forum
Images
Collections

  • Année
  • 1931
  • Catégorie
  • Adaptateur ou convertisseur de fréquences (OC/MF/VHF/UFH)
  • Radiomuseum.org ID
  • 42778

Cliquez sur la vignette du schéma pour le demander en tant que document gratuit.

 Spécifications techniques

  • No. de tubes
  • 2
  • Lampes / Tubes
  • 36 37
  • Principe général
  • Convertisseur / adaptateur HF (pas convertisseur tension); FI/IF 535 kHz
  • Gammes d'ondes
  • PO uniquement
  • Tension / type courant
  • Appareil tous courants (CA / CC) / 110 Volt
  • Haut-parleur
  • - - Pas de sortie basse fréquence
  • Matière
  • Boitier métallique
  • De Radiomuseum.org
  • Modèle: 281 Ch= R-1A - General Motors Radio Corp.
  • Forme
  • Formes diverses décrites en notes
  • Remarques

  • This converter had an output frequency of 535 kHz.

    This operational explanation came from Ebay Item number: 111073448105.

    "This 1931 device has probably caused more confusion as to its real purpose than any other radio item. Most importantly, the 281 is not a radio receiver - it is a converter. A converter receives an incoming radio signal at that signal's frequency and then converts that frequency to another frequency by heterodyning the signal with a local oscillator. This intermediate frequency can then be connected to the antenna input of a radio receiver and amplified and detected, resulting in better selectivity, stability and sensitivity. The GM 281 is a heterodyning-type converter which was designed to be connected to any receiver to provide several different functions. First, as a converter, when used with a TRF (Tuned Radio Frequency - a non-superheterodyne) receiver, that receiver would then become a superheterodyne - providing the advantages of better sensitivity and selectivity. If used with a superhet receiver, that radio would then become a double-conversion superhet - advantages were better image rejection. An added advantage to the 281 installation was that it allowed for remote control of any receiver it was used with, providing remote tuning and remote volume control. Finally, it was also a floor-type ash stand. The IF frequency was 535Kc - so the receiver used with the 281 had to be tuned to 535Kc in order for the combination to work together. The 281 AC plug was to provide the 6.3vac heater voltage for the two tubes in the converter but B+ (high voltage) had to be supplied by the receiver (connecting wires were from the metal "coupler unit" which was mounted in the receiver cabinet.) A 25' cable allowed the 281 to be placed anyw in the room, preferably next to the "over-stuffed" easy chair and the pipe. Today, many GM 281 converters are encountered with the cables removed and the seller trying to convince the buyer that the 281 is a radio receiver - it isn't. Neither was it ever intended to be set up in GM automobile dealerships for customer entertainment. The erroneous auto-related story variations are endless. The 281 was designed for home use and was to provide the user a way to upgrade his older TRF console radio into a remotely controlled superheterodyne radio. "

  • Prix de mise sur le marché
  • 49.00 $
  • Source extérieure
  • Ernst Erb
  • Source du schéma
  • Rider's Perpetual, Volume 3 = 1933 and before

 Collections | Musées | Littérature

 Forum