Weather radar Ops - Afghanistan
 

Read somewhere that you need to keep your weather radar ON while flying over Afghanistan. Probably to let the people on ground know that you are a civil airliner and mean no harm. Can someone give me a reference.

They must have some very special gear out there as I wasn't award that weather radar could be received on the ground. Furthermore, how would you differentiate between friend or foe, civil or military?

I suspect that the writer may have confused weather radar with secondary radar, which can be used to identify aircraft.

Most airline SOPs have the wx radar on with tilt down when crossing warzones. AFAIK idea is that the electronic gear on things like warships will see the band and pulse repetition frequency and know that its a civil airliner wx radar and thus not shoot you down.

Presumably enemy military pilots are sporting enough not to do the same with their wx radar? ;)

Surely Weather Radar can be picked up on the ground. Otherwise I would not get ground returns when I tilt it down.

Normally I would tilt it so that the ground reurns are just at the edge of the selected range on my display - say 40 miles for example.

The radar will be receiving signal from much further away than 40 miles. If I just select 80miles on radar range without adjusting tilt then 40-80 miles will just show ground returns.

I believe military radars can i.d. planes by comparing spool speeds inside target aircraft engines so I expect detecting a wx radar would be straightforward. Knowing that it not an enemy aircraft sending psudo Wx radar signals might be a bit trickier.

Wx-radar
 

Have a look at this thread: http://www.pprune.org/tech-log/34479...ification.html - and topic #4 - Notam issured by U.S.A for the Mid-East Region, so I would think it would be the same for Afganistan

LazyLLz

Standard procedure anywhere the US Navy is liable to be around!

It always fascinated me approaching Norfolk Virginia, how strange squiggles used to appear on the weather radar, sometimes when we needed it to circumvent the Norfolk Cbs. :ooh:

@lazyLLz
Thank you very much

@HEATHROW DIRECTOR
Sir, you need to read more about ESM. Or watch more James Bond movies.

Well even at my advanced age I can still learn something new each day. What I don't understand is how an aircraft can be identified to any degree from its weather radar...???

@ Heathrow Director:

The reason lies behind the fact that radar is electromagnetic energy being transmitted, or in other words, it is a radio signal being transmitted and the reflections (Primary Radar) or the responses (Secondary Radar) are received. Put simply, anyone with the correct equipment is also able to 'listen' to the radar transmissions of others, much like someone with a scanner is able to listen to ATC chatter by tuning their receiver to the correct frequency.

By building databases of various radar transmitters, military users are able to discern the type of radar being employed. I've heard that in some cases military users are even able to distinguish between different aircraft/ships using the same radar equipment, due to small differences between sets.

In any case, Wikipedia (out of many sources) goes into far more detail than I have here.

General Radar Article
ESM Article (Interception of signals for military purposes)

NZScion.. Many thanks. I know all about your first para having been an Air Traffic Controller and radio freak all my life! But why should they develop such sophisticated equipment to identify particular weather radars when the majority of aircraft have SSR? Guess I'm missing something somewhere!

A more basic question: why would you fly around with your weather radar off:ugh:

Heathrow Director,

The main reason for developing such systems is almost exclusively military - identifying enemy radar transmissions and using these transmissions against the enemy.

For example, if a flight of unknown aircraft is flying in a war zone with radar operating, friendly ground or air based platforms are able to pick up these signals (often at distances several times greater than the useful range of the radar), and based on the 'signature' of the signals received, the contact can be classified as friendly/civilian/enemy as the case may be, and often the type of aircraft can also be determined.

Then, via triangulation (when several stations at different locations have intercepted the signals) or through a process called 'target motion analysis' (when only one station is receiving the signals), the position, track and speed of the target can be determined and fighters can be deployed to intercept it, all without the use of friendly radar.

This is obviously just a brief overview, the entire system is very complex, with data links and EMCON (emmisions control) restricting friendly use of radar.

OK many thanks.. For someone like me who is used to using SSR and Mode S and ADS-B it all seems terribly archaic in the context of this particular thread. However, I appreciate that from a militray point of view things might be different.