The desperate months...

Early 1942 found the US in a sad situation, both from a strategic standpoint and from the standpoint of tools required to be effective on the battlefield. Most of the equipment that they possessed was from the 1930s, and technology was rapidly passing us by. Because of the need to understand the electronic threat against us, we followed the example of the British - who after all had been doing it for two years - and pressed into service what we had. This bay shows the basics of that capability, reflecting a photograph of an installation in a ferret aircraft of the time, shown below:

Early signal collection equipment. This included the BC-1031/32 panadapters, Hallicrafters S-27 and SX-28 receivers, and a rudimentary pulse analysis capability formed by a period oscilloscope and an HP audio oscillator.

At upper left in the photo below is an audio oscillator that was used to characterize pulse repetition rates. Initially this HP oscillator was bought and used in its original gray wrinkle finish, but as time went on, a specialized model was produced that was shock mounted and cabled specifically for countermeasures work - the O-10/APA-6 shown here. At the far right is the Dumont oscilloscope used to display Lissajous figures, using the receiver output and the oscillator output as x and y inputs.

Early signal collection equipment

On the next shelf down is a BC-1032 panoramic adapter designed to be used with the Hallicrafters S-27/S-36 receiver to its right. This particular receiver was labeled an S-36M, the modification being an SO-239 connector on the left side of the set to feed the panadapter. It is unusual in another sense as well - for a brief period Hallicrafters had not had time to stamp a tuning dial faceplate with the new S-36 designation on it, so this one and a limited number of others had the new circuitry and the old S-27 faceplate.

At the lower left is the well known Hallicrafters SX-28 HF receiver, used to complete the frequency coverage for ELINT work. Both of these receivers were later reworked and repackaged into aircraft configurations as the AN/ARR-5 and AN/ARR-7 shown here .

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