Hello Polymath

I wonder if anyone has successfully converted a
thrown-away cell-phone into a spectrum analyser?

We would seem to have all the necessary components
in there for free - keyboard, graphical display,
post-demodulation DSP, Frequency Synthesizer,
RF good up to 1 GHz (2G5Hz if an ex-WCDMA unit)

Here would seem to be an opportunity to equip
all Radio Hams with a reasonably state-of-the-art
piece of test gear, that when coupled with an
IF generator would give us all a network analyser
into the bargain!

If you have web access, I have built a scalar network analyser from one of
the commonly available TV transmitters
http://www.g6lvb.com/Articles/NetAn/index.htm.

These TV transmitters use the SP5055 2.6GHz I2C frequency synthesisers and
are easily programmed from a PIC. You could build yourself a spectrum
analyser using the synthesiser as the sweep oscillator as I did.

If you successfully reverse engineer a cellphone enough to be able to use
any of the parts you describe I am sure that there would be a great deal of
interest if you published the information for any particular model.

73, Howard G6LVB