Murphy B40

Today my Murphy B40 came alive.

I’ve got this good old radio as a good bargain on Saturday 12th of june 2010, on the radio flee-market of our own radio club NOV (Noord-Oost Veluwe) from clubmember and radiofriend Daan PD0RAA, who needed some more room in his shack. This old lady was stowed away in the corner of my shack and I’ve decided today to try it. Connecting the mains, turning it on and see the warming lights of the tuning band scales of this old naval comminication receiver. Some noise in the headphone, some more noise when rotating switces, connecting the antenna wires, and CW signals, AM-reception, it’s still working! This baby is more than 50 years old, and still able to do the job! I am the proud owner of a real working “boat-anchor-radio”

I know this B40 Model from the seventies, studying electronics and telecommunications, where the B40 was in the schools’ shack.

Technical info:
AM:   4 uV for 20 dB signal to noise ratio
CW:   2 uV for 20dBsignal to noise ratio

Wide  +/- 4 KHz at 6 dB, Narrow  +/- 1,5 KHz at 6 dB, X-tal filter       0,5 KHz at 6 dB.

Harmonic suppression: at 23 MHz better than 40 dB, at 1,05 MHz better than 95 dB.

L.F. power output: 2,5 Watt

Power supply: 115/230 V 40/60 Hz, 80 Watt.

Dimensions: 43x43x34 cm, gewicht ca 50Kilo

De B40 is een enkelsuper met MF op 500 KHz, Frequentiebereik van 640 KHz tot 30,5 MHz. De ontvanger heeft 14 buizen. 2 trappen HF versterking, Mixer en oscillator met 2 separate buizen, 3 trappen MF versterking, detector en limiter, 2 trappen LF versterking, gelijkrichting en BFO.

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