World smallest spectrum analyzer

I think it's the smallest for sure. In regards to the spectrum analyzer, let's say it's more a band-scope...

Is it practical? No, it's just for fun since I have never seen a conversion of a Handycam CCD-F370E crt viewfinder into a spectrum analyzer, I've seen only simple oscilloscopes and small TV screens but never a total use of the two deflection coils in separate from the main viewfinder circuit.

 

 The only part left in place for the crt viewfinder was the beam/HV side, the two coils for the deflection were disconnected and connected to the circuit bellow:

In fact the hardest part was to find the correct settings for the yoke coils.
 Didn't included in the diagram is the RF part. For testing I used a normal receiver circuit and the signal level is taken from the audio and not trough a real logarithmic power meter. The vco was a simple varicap driven oscillator and feed with the sweep ramp signal, no blanking was used.

The video:

Here's during testing with a wide "video bandwidth" :

The beep/eared, and seen, is the Arduino VNA sweeping trough the band and the audio is from the receiver used as fronted.

The normal mess for the prototype, bellow the circuit with the sweep, vertical and horizontal yoke coil drivers:

Keep in mind that if you duplicate the circuit do swap the driver 2n3904/6 transistors with more powerful ones since they will get hot fast.

Out of curiosity I just realized that I disassemble this mini crt in 2012 and it had been getting dust to this day.

Have a nice day!