I will keep you updated. It is not receive only. I found that it would be much cheaper to build a special purpose antenna to overcome the requirements of a power amplifier apart from increasing the penetration into homes with lot of brick masonry.
It should not be a big deal to design one for detecting ISM band emissions but will be a bit tricky due to the DSS modulation scheme which tend to scatter the available energy over the entire band. I do not think that there is any receiver that employs pure passive tuning(which is a theoretical possibility and limited by the availability of high Q resonators and narrow band tunable very low noise amplifiers).
I am in the process of building one (stacked and phased collinear antenna) using inexpensive materials, for an would be secure community network. If you are interested let me know.
You don't really need an omni directional antenna, you could always use a switched parabolic antenna, or even a rotating one. We are talking about ability to identify a potential listener and not talking about some rf glitch caused by a solar flare!.
If you are thinking of using an yet another el-cheapo card as a detector for the local oscillator emission it may not work. If you ever knew about how a receiver works(direct conversion,superhet etc) you will understand what I mean. You do need dedicated h/w for doing it. Also you should remember there is no limit on the receiver antenna gain by FCC. With the current advances in DSP, RF device technologies, electronically controlled phased array antennas and liquid nitrogen cooled rf lna's, nothing is impossible. I could build you one, if you could pay me $$$$$ even out of off the shelf components!.
It is still possible to detect a client in RFMON mode by using a very high gain antenna combined with some DSP to identify a possible listening of a 802.11 receiver since there is no FCC regulation for a receiving antenna gain:)
you could use mac address filtering and all other provisions of security(such as 128Bit WEP with shared authentication only) and use IPSEC to encrypt the entire traffic. If not you could just create an ssh tunnel. Time to get a linux tablet PC?
Actually the zapping could be made much easier if you could use additional high gain receivers(or switch a single receiver between multiple antennas) to locate the intruder by triangulation and immediately activate a focussed beam of high energy RF (high gain electronically controlled phased array Antenna?) to cripple the receiver without impairing ongoing sessions with other authorized clients.
I forgot to mention that once you've identified a rogue receiver, you could then stop the transmission in the particular transmission or just transmit false data. It would be even better if you could start switching the WEP keys in sync with the legitimate clients (or) encrypt the traffic on the fly. If not you can also think of sending a shutdown signal to legitimate clients and then zap a high energy RF pulse to the direction of maximum signal strength to burn out the frontend of the rogue client, it would then become easy to spot the intruder visually with the smoking card!. Then continue regular transmission once the offending oscillator signal is absent.
What about a high gain receive antenna hooked up to a highly sensitive RF receiver trying to identify local oscilltor emissions out of the listening client card. In simple terms, what about a detector similar to "radar detector detector"? Also any RF_MON mode client card is going to be actively scanning the different channels(leading to differing oscilltor frequencies). If you know your legitimate clients are not operating in that channel, and if you have a really focused antenna, you could even catch the intruder by moving the antenna for max signal strength of the oscillator emission.
I feel most of the EDA(Electronic Design Automation) vendors would use it, since a lot of EDA software(esp. chip design s/w from Cadence, Synopsys etc.) run primarily on Solaris. I also see some web developers would find it convenient since there are significant solaris based web servers out there.
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I will keep you updated. It is not receive only.
I found that it would be much cheaper to build
a special purpose antenna to overcome the requirements of a power amplifier apart from
increasing the penetration into homes with lot
of brick masonry.
It should not be a big deal to design one for
detecting ISM band emissions but will be a bit
tricky due to the DSS modulation scheme which
tend to scatter the available energy over the
entire band. I do not think that there is any
receiver that employs pure passive tuning(which
is a theoretical possibility and limited by the
availability of high Q resonators and narrow band
tunable very low noise amplifiers).
I am in the process of building one (stacked and phased collinear antenna) using inexpensive
materials, for an would be secure community
network. If you are interested let me know.
You don't really need an omni directional antenna,
you could always use a switched parabolic antenna,
or even a rotating one. We are talking about ability to identify a potential listener and not
talking about some rf glitch caused by a solar flare!.
If you are thinking of using an yet another el-cheapo card as a detector for the local oscillator emission it may not work. If you
ever knew about how a receiver works(direct
conversion,superhet etc) you will understand
what I mean. You do need dedicated h/w for
doing it. Also you should remember there is
no limit on the receiver antenna gain by FCC.
With the current advances in DSP, RF device
technologies, electronically controlled phased array antennas and liquid nitrogen cooled rf lna's, nothing is impossible. I could build you
one, if you could pay me $$$$$ even out of off
the shelf components!.
It is still possible to detect a client in RFMON
mode by using a very high gain antenna combined
with some DSP to identify a possible listening
of a 802.11 receiver since there is no FCC regulation for a receiving antenna gain:)
you could use mac address filtering and all other
provisions of security(such as 128Bit WEP with
shared authentication only) and use IPSEC to
encrypt the entire traffic. If not you could
just create an ssh tunnel. Time to get a linux
tablet PC?
Actually the zapping could be made much
easier if you could use additional high
gain receivers(or switch a single receiver
between multiple antennas) to locate the
intruder by triangulation and immediately
activate a focussed beam of high energy RF
(high gain electronically controlled phased
array Antenna?) to cripple the receiver
without impairing ongoing sessions with
other authorized clients.
I forgot to mention that once you've identified
a rogue receiver, you could then stop the transmission in the particular transmission or
just transmit false data. It would be even better
if you could start switching the WEP keys in sync
with the legitimate clients (or) encrypt the traffic on the fly. If not you can also think
of sending a shutdown signal to legitimate clients
and then zap a high energy RF pulse to the direction of maximum signal strength to burn out
the frontend of the rogue client, it would then
become easy to spot the intruder visually with
the smoking card!. Then continue regular transmission once the offending oscillator signal
is absent.
What about a high gain receive antenna hooked
up to a highly sensitive RF receiver trying to
identify local oscilltor emissions out of the
listening client card. In simple terms, what
about a detector similar to "radar detector detector"? Also any RF_MON mode client card
is going to be actively scanning the different
channels(leading to differing oscilltor frequencies). If you know your legitimate clients are not operating in that channel, and if you have a really focused antenna, you could even catch the intruder by moving the antenna for max signal strength of the oscillator emission.
I feel most of the EDA(Electronic Design Automation) vendors would use it, since a lot
of EDA software(esp. chip design s/w from
Cadence, Synopsys etc.) run primarily on Solaris.
I also see some web developers would find it
convenient since there are significant solaris
based web servers out there.