The Tektronix 1L40 is a spectrum analyzer plug-in for 500-series scopes. It covers the frequency range from 1.5 GHz to 40 GHz.
The front-end mixer of the 1L40 is a removable module. By default the 1L40 comes with a coaxial mixer, Tek part number 119-0096-00, which works up to 12.4 GHz. The 119-0096-00 contains a 1N415D detector diode.
Type 1L40 was produced for only 3 years, making it the shortest-lived letter-series plug-in.
- 12.4 GHz to 18 GHz requires the 119-0097-00.
- 18 GHz to 26.5 GHz requires the 119-0098-00.
- 26.5 GHz to 40 GHz requires the 119-0099-00.
Note that the 1L40's display of RF signals is actually back-to-front: lower frequencies are to the right, and higher to the left. This is because the 1st LO is above the input signal frequency yet the display shows the IF sweep from low to high left-to-right, so the displayed spectrum is inverted.
The 1L40 is also capable of displaying signals in its IF range of 150-250MHz, because its input is unfiltered so everything passes straight through to the second mixer. In this case, however, the display is left-to-right.
Signals displayed straight through the plugin's 150-250MHz IF. Dispersion 5MHz/div, centre frequency 200MHz. The peak on the left is the local DAB radio multiplex on channel 6B, 183.648MHz. The hump to the right of that is the local DVB-T multiplex 'Mux 8' on channel 7. Photo taken in Warsaw, Poland, January 2018.