Cinemas jamming mobile phone signals #cinemajammers
The US’s National Association of Theater Owners wants the FCC’s permission to block mobile reception inside cinemas. To be honest I thought this already happened in some places… maybe I’d mentally linked it to office buildings with Faraday cage wall structures to prevent eavesdropping on wireless data transfer; I don’t know how common these are in general, but would guess that more sensitive workplaces have had these for a long time.
Of course, the problem with not being able to dial emergency services may be significant, although one would hope that the cinema staff would be able to use a land line to do that if alerted. What might be a more worrying problem is the audience not being able to receive messages/calls–imagine a situation where some urgent or critical news (e.g. “Come home, your house is on fire”) can’t be communicated to someone simply because he or she is in the cinema. Yes, before cellular phones (and pagers) that wouldn’t have been an issue anyway, but it is now.
#EVILTWIN #securityattack – Evil Twin attack
“A Fake WiFi access point is a wireless access point that has been installed on a secure network without explicit authorization from a local network administrator, whether added by a well-meaning employee or by a malicious attacker.” – Wikipedia
Using this method it is possible to retrieve the WPA/2 passphrase in clear-text within minutes. No need of cracking or any extra hardware other than a Wireless adapter.
In some cases you don’t even need an adapter. When ? that we will discuss
#fresnelzone FRESNEL ZONE
resnel zones are used by propagation theory to calculate reflections and diffraction loss between a transmitter and receiver. Fresnel zones are numbered and are called ‘F1’, ‘F2’, ‘F3’ etc.
There are an infinite number of Fresnel zones, however, only the first 3 have any real effect on radio propagation.
In Radio Mobile Fresnel zones ove a radio path can be analysed in ‘Radio Link‘ and ‘RMpath‘
What is a Fresnel zone and why is it important?
Fist, what is it? A Fresnel zone is a cylindrical ellipse drawn between transmitter and receiver. The size of the ellipse is determined by the frequency of operation and the distance between the two sites.
Earth Bulge #Earthbulge
Earth bulge is a term used in telecommunications. It refers to the circular segment of earth profile which blocks off long distance communications.
Fade Margin #fademargin
Fade Margin is an expression for how much margin – in dB – there is between the received signal strength level and the receiver sensitivity of the radio.