Regency AR-136 Flight Monitoradio

A friend salvaged this from the Boxborough town dump. 

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It’s an aviation band receiver (108 to 136 Megacycles, amplitude modulation), one of several models of Monitoradio sold by Regency. They were forerunners of the scanner. They had receivers that covered the VHF Lo or VHF Hi public service bands, or, as we see with the AR-136, the aviation band.

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These receivers used vacuum tubes. This one is missing the power transformer, and the 6X4 rectifier has been replaced by something hidden under many layers of black electrical tape, presumably a couple of diodes.

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The three-gang tuning capacitor indicates that it had a tuned RF stage. The phone jacks mounted to the back are a modification made by a previous owner. If you look closely at the right of the first tuning gang, you’ll see what must be the RF amp: a 6CW4 nuvistor.

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Here’s the tube line-up, with my guess as to their function:

  • 6CW4 - RF amp
  • 6BC5 - mixer
  • 6EA8 - oscillator
  • 6BJ6 - 1st IF
  • 6BJ6 - 2nd IF
  • 6AL5 - detector
  • 12AX7 - AF preamp
  • 6AK6 - AF power amp
  • 6X4 - B+ rectifier

It’s interesting that they use a 6AL5 as a detector. I bet the tube lineup and the chassis were designed for Regency’s FM models, where the 6AL5 would be used as a discriminator or ratio detector.

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There’s an extra tube shield taped to the electrolytic filter capacitor. 

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Here’s the front panel, out of the case.

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It’s been modified with the two phone jacks and a UHF female connector ...

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… apparently by Hubley, Inc., whoever that might have been. Google doesn’t know them.

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The wires feed the added phone jacks.

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The first 6BJ6 has gone to air. Note the cloudy appearance of the getter.

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There’s at least one repair visible under the chassis, but on the whole it looks fairly untouched, if you ignore the missing power transformer.

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The brown-wire air-cored inductors are chokes in the B+ feed.

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Some more RF chokes, feeding B+ to the IF stages.

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The big Mallory electrolytic looks like it’s oozing some crud.

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I guess these are the mounting brackets that used to hold the front panel in place, along with the four original feet for the case.

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The top of the case shows residue from strapping tape that at one point was used to hold the chassis in the cabinet.

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The speaker is gone. Whoever modified the receiver also covered up the speaker opening with an aluminum plate.

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The bottom has strapping tape reside, too.

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The other side.

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There’s a bit of rust inside the cabinet.

© Steve Byan 2011-2016