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Old August 14th 05, 06:25 PM
Polymath
 
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Default Spectrum Analyser from Cell Phones?

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!

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Old August 14th 05, 06:30 PM
Dave Holford
 
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Polymath wrote:

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!


Many years ago it was done with junked Video Tape Recorders and, from
what I saw and read, very successfully too.

Dave

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Old August 14th 05, 07:17 PM
Spike
 
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Dave Holford wrote:
Polymouth wrote:

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!


Many years ago it was done with junked Video Tape Recorders and, from
what I saw and read, very successfully too.


Don't hold your breath, as there seems to be a raft of projects ahead
of this one: his own XRC machine, an ATU made from discarded CDs, a
DSP project using an FT-707, and of course, the mathematical basis for
the Big-K approach to DSP to be proved, peer-reviewed, and then
published.

from
Aero Spike
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Old August 15th 05, 12:24 AM
Wankel Rotary
 
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Spike wrote:

Don't hold your breath, as there seems to be a raft of projects ahead
of this one: his own XRC machine, an ATU made from discarded CDs, a
DSP project using an FT-707, and of course, the mathematical basis for
the Big-K approach to DSP to be proved, peer-reviewed, and then
published.


You also forget the gauntlet he laid down in the newsgroups to design a
transceiver that was roughly based upon re-inventing the wheel.

When people took his suggestion somewhat seriously, he backed away, and,
as it the case with all Bean-powered projects, let the subject die.
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Old August 15th 05, 12:40 AM
Wankel Rotary
 
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Default

Polymath wrote:

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!


Bargain - of course - that's after the Radio Amateur has equipped his
shack with a very expensive SMD rework station....

Would it not be wiser to suggest the building of an interface so the
shack PC could be used to do such a task as spectrum analysis?

Beanie/Polymath - Once a dumbass, always a dumbass.


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Old August 15th 05, 08:15 AM
Spike
 
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Default

Wankel Rotary wrote:

Spike wrote:

Don't hold your breath, as there seems to be a raft of projects ahead
of this one: his own XRC machine, an ATU made from discarded CDs, a
DSP project using an FT-707, and of course, the mathematical basis for
the Big-K approach to DSP to be proved, peer-reviewed, and then
published.


You also forget the gauntlet he laid down in the newsgroups to design a
transceiver that was roughly based upon re-inventing the wheel.

When people took his suggestion somewhat seriously, he backed away, and,
as it the case with all Bean-powered projects, let the subject die.


His philosophy seems to boil down to "Don't do as I do, do as I say" -
the motto of the hypocrite.

from
Aero Spike
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Old August 16th 05, 12:54 PM
Howard Long
 
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Default

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


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Old August 16th 05, 03:04 PM
Tim Shoppa
 
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Default

Many years ago it was done with junked Video
Tape Recorders and, from what I saw and read,
very successfully too.


If this is the same project that I remember, it's based mostly around
the TV tuner module from an old VCR.

The TV tuners work real nicely as they have a well-defined interface to
the VCO control voltage, mixer in, and mixer out. The VCO is also the
"right range" (VHF-Lo, VHF-Hi, UHF covers a lot of frequency!) at least
for 50MHz up to the top of the UHF TV band. I don't know what they did
for frequencies below 50MHz.

The TV tuner module is also nicely interface to (a handful of easily
soldered-to pins.)

Cellphones don't really have a well-defined module like the TV tuner in
them. They aren't broadband in the same way. Their synthesizers are
not broadband either.

Tim.

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Old August 16th 05, 09:23 PM
G1LVN \(for it is he\)
 
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"Howard Long" wrote in message
...
Hello Polymath

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.


Sweep oscillator on the X axis of an old junk oscilloscope and the IF stage
of an old multiband radio always did the job for me, mind you that was until
I went to university of course when we found a new use for the spectrum
analyser - listening to Radio 1 in the lab mainly.



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