491
The Tektronix 491 is a spectrum analyzer introduced in August 1966.
Due to severe performance limitations, it was replaced by the completely redesigned 492 in 1980.
Manuals
- Tektronix 491 manual @ KO4BB
- Tektronix 491 Band C Oscillator Replacement Modification (PDF, OCR)
- Tektronix 491 Mod WA (PDF, needs OCR)
- Media:Tek 491 fcp nov 1966.pdf