Manufacturer: Hallicrafter (USA)
Model: SP-44 SKYRIDER, S#6761
Vintage: 1947
Purpose: Spectrum Analyzer
Condition: Working
Comments:
This "scope" is basically a spectrum analyzer, with 450-470kHz center frequency and showing the spectrum -100kHz to +100kHz of the center frequency. This was a great tool for ham operators to observe the quality of the carrier signal and other stations close to their station, possibly causing interference.
It is almost identical to a PT-200 by Panoramic Radio Products Inc., also known as a "Panadapter".
It is safe to assume that Hallicrafter wanted to sell analyzers themselves with their transmitters and receivers in a package, so they re-branded the PT-200. It is not clear if Hallicrafter even made the sp-44 themselves or had them made by the Panoramic Radio Products Inc.
I can't explain the function and circuit better than the manual can do. Please read through the manual if you are interested in further details. The manual of the PT-200 is also available. Note that the resistance table on page 38 contains an error. V8 (2AP1-A) is listed twice in the table. The first occurrence should state V6 (VR105) instead. I have to assume the resistance values are correct for VR105.
This particular unit is working fine and close to calibration. It is fun to play with it.
Model: SP-44 SKYRIDER, S#6761
Vintage: 1947
Purpose: Spectrum Analyzer
Condition: Working
Comments:
This "scope" is basically a spectrum analyzer, with 450-470kHz center frequency and showing the spectrum -100kHz to +100kHz of the center frequency. This was a great tool for ham operators to observe the quality of the carrier signal and other stations close to their station, possibly causing interference.
It is almost identical to a PT-200 by Panoramic Radio Products Inc., also known as a "Panadapter".
It is safe to assume that Hallicrafter wanted to sell analyzers themselves with their transmitters and receivers in a package, so they re-branded the PT-200. It is not clear if Hallicrafter even made the sp-44 themselves or had them made by the Panoramic Radio Products Inc.
I can't explain the function and circuit better than the manual can do. Please read through the manual if you are interested in further details. The manual of the PT-200 is also available. Note that the resistance table on page 38 contains an error. V8 (2AP1-A) is listed twice in the table. The first occurrence should state V6 (VR105) instead. I have to assume the resistance values are correct for VR105.
This particular unit is working fine and close to calibration. It is fun to play with it.
Documentation:
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| pt-200_manual.pdf |