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Most cities in the U.S. have local TV stations with "Super Doppler xyz Ultra-Weather Radar !!" or something like that. These radars are usually mounted on a tower and their main lobe is well above the ground [ to avoid what is known as "ground clutter" ].
Noticed that the frequency band 5.35 ???¡é?¡é?????¡é?€?? 5.47 Ghz has been allocated for some weather radars.
This sits right between the UNII 2 and 2 e bands.
Has anyone ever had any problems with interference from these systems ? [ frequency drift, faulty equipment etc on the radar side ]

http://books.google.com/books?id=DSHSqWQXm3oC&pg=PA9&lpg=PA9&dq=5.25+-+5.925+Ghz+weather+radar&source=bl&ots=o_NQIMOI2P&sig=Yj6R6FYSF-H6QWrG_c3tVKXo_tU&hl=en&ei=11ZWS63LII21tgets6SzBA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAcQ6AEwAA#v=onepage&q=5.25%20-%205.925%20Ghz%20weather%20radar&f=false

Bye the way, Matthew Gast's excellent book gives 5.25 Ghz to 5.925 Ghz for weather radars. In fact it is meant for all types, including weather. The latter being in the 5.35 - 5.7 Ghz range.


Dave

No problems FROM them.

But about a year or so before I started at my current employer, the Airport paid them a visit.

Seems we were interfering with their radar. :-//

One of the problems with radar systems is that they have to be incredibly sensitive. When we send a pulse out towards a target [ say an airliner 30 miles from the airport ], a lot of things happen. Firstly, just like an 802.11 signal, it suffers free space path loss. When it reaches the target, it is not usually received and re-transmitted [ although some systems do this, such as IFF Identication Friend or Foe http://en.wikipedia.org/wiki/Identification_friend_or_foe ]

The radar signal bounces off the target and is scattered and reflected. This reflected signal is attenuated by the target surface [ stealth aircraft use special radar-absorbing paint http://en.wikipedia.org/wiki/Radar-absorbent_material ] and some of it gets sent back to the radar transmitter/receiver. The poor old signal now has to suffer more free-space path loss on the way back. By the time it gets back to the receiver, it has been severely attenuated.

Of course we can use high power levels to help compensate for this, but the received signal is still very, very small, and highly susceptible to 802.11 interference under the right circumstances.

The US Space Command uses very long range radars to track satellites in space and also detect the presence of incoming missiles.
http://www.peterson.af.mil/library/factsheets/index.asp

NASA used radar to fire pulses at the belly of the Space Shuttle when it passed over a tracking station like Cooper???¡é?¡é?????¡é???¡és Island in Bermuda. This gave range and altitude data.

Dave