Posts Tagged ‘EM sniffer’
Sniffer sounds from Martin Howse
Martin Howse has been working in Berlin on the sniffers for the Electromagnetic Fountain.
He has sent me nine audio samples from 4 different detectors where he mainly focused on placing a mobile phone close to different antenna/detector pairs while making incoming and outcoming calls.
You’ll find links to the sounds below as well as location details and notes that he enclosed with the sounds.
**location
Backyard (hinterhof) studio in berlin, Mitte – plenty of 50 Hz power
lines, laptop in 30 m2 room and wireless router at other end of
room. Around 20 wireless networks close by in the yard. Also worth
noting is that the studio is very close to the huge Alexanderplatz TV
and radio transmitter (Fernsehturm).
**samples
This is using a detector based on the AD8307 chip which is looking at a
low/mid range of frequencies (DC to approx 500 MHz). I’m using it here
with the largest printed antenna which is kind of A4 sized (all the
printed antennas are the green ones for which I sent you the link
before) and is for 400 to 1000 MHz. As in most of the recordings the
mobile phone (standard Nokia on o2.de network – see below) is moved
around 1 to 3m from the detector. In this case the signal is not
amplified much (all recorded to minidisk and then transferred to
laptop).
As above but with a bare wire antenna of maybe 1m length.
Using a detector based on the AD8313 chip which demodulates (roughly) in
wide band, high frequency range of 100 Mhz to 3.5 GHz. This is used with
a medium-sized printed antenna for 900 Mhz to 3 GHz. This one needs a
bit of amplification but the phone signal is very strong and clear even
4m away from the device.
As above but coming from 10m outside street door into studio with phone
ringing and then talking on the phone.
Using a detector based on the AD8318 which demodulates (again in rough
terms) a very high range of frequencies from 1 MHz to 8 GHz. Used with
smallest printed antenna (maybe 6 cm long) for 2-11 GHz. Amplification
is needed and the phone is quite close (maybe 1/2 to 1m) to get a
signal.
As above but with a laptop (external wireless card, bittorrent
downloading) providing this strong noisy signal up to 5m away. The
regular beating is from the wireless router which is then turned off
towards the end of the sample and turned on again. The other signals I
have no idea!
This is my own designed sniffer (from the Maxwell workshop but altered
with filter removed for a stronger signal). Here it is used with a tiny
coil (enclosed in plastic) – the one for this recording is 10
microhenries (Mh). Little amplification and a good signal from 2 to 3
metres away
As above but using a wire coil around 1m diameter and made from 2 km
thin copper wire. Power lines 50 Hz overwhelms all signals. Phone is
maybe 2cm away to be heard.
As above but with a chain of six 1mH tiny coils arranged in a circle.
**conclusions
The “ownsniff” detector (with small coils) covers a good, general range
and the other three focus well on more defined parts of the spectrum,
with 8313 working well for GSM900/1800 network devices (mobile phones),
and the 8318 for wireless networked devices (2.4 GHz and UMTS/3G –
around 2 GHz (untested)). These detectors are particularly sensitive
even at around a two metre distance and with only one phone. It may be
necessary to avoid overloading the detectors.
**further notes
The standard Nokia phone (o2.de network) used is a dual band GSM900/1800
model (operating at both 900 MHz and 1800 MHz). These frequencies are
common throughout Europe. The high frequency signals are detected by the
devices and demodulated – what we here is the lower, now audible
frequencies (for GSM900 apparently 217 Hz) which pulse the higher
(carrier) frequency, and the overall envelope of the signal (a rough
analogy would be to standing outside a room with a cocktail party
happening inside – we can’t hear the individual voices or listen to the
conversations but we have an idea of how many people there are, when
they start and stop talking, and how loud they are).
Detectors for the Electromagnetic Fountain
I’ve had several conversations with Martin Howse about the best solution for the detectors used in the Electromagnetic Fountain, and he has agreed to take on the job of designing and building for me. Great!
One of the projects Martin is working on is to develop a software defined radio system for electromagnetic detection. This system could provide a precise analysis of signal detection and allow for more sophistication with regards to the fountain than my own suggestion. However, given the factors involved in production (time, cost, my own lack of knowledge of working with PCs/OS software) this idea was dropped. Perhaps we can pick it up later. So, the original plan to interpret the sound emitted from 3 types of detectors for the control of the fountain valves, pumps and lights is the one we will go for.
SNIFFER 1: Basic little black version as built in Maxwell City workshop, Atelier Nord, Oslo 2007.
SNIFFER 2: Improved version of the Coil sniffer also built during Maxwell City ….
SNIFFER 3: A 100MHz-2.5GHz model similar to the Zap Checker Enhanced sniffer I purchased on the net, possibly with an antenna something like these.
All detectors would have to be shielded from the fountain’s own electromagnetic radiation.
The idea of having antennas that the public can pull out of the fountain base and wave around in the air has been vetoed – more difficult/expensive to implement, and would possibly be too fragile and subjected to vandalism.
The Electromagnetic Fountain 