weird weather radar indication on an A320 (picture attached)
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weird weather radar indication on an A320 (picture attached)
Hi,
we had an unusual indication on the ND (weather radar). The captain said this is how it looks when a fighter jet is directing its radar beam towards us. Is that true? Do fighter jets even have a weather radar? If it wasn't a fighter jet, what causes this indication?
Thanks
we had an unusual indication on the ND (weather radar). The captain said this is how it looks when a fighter jet is directing its radar beam towards us. Is that true? Do fighter jets even have a weather radar? If it wasn't a fighter jet, what causes this indication?
Thanks
FCTM-AS-WXR-analysis of weather radar.
The image is almost identical to yours, look up the answer to get familiar with the books (or iPad).
The image is almost identical to yours, look up the answer to get familiar with the books (or iPad).
Think Airbus refer to that anomaly on Wx Radar as 'spoking' or 'alien radar'...and define it as interference from an external high power radio frequency that operates at a frequency next to that of the weather radar itself.
FCTM has a reference; FCTM SI-070-ANALYSIS OF WEATHER RADAR DATA
FCTM has a reference; FCTM SI-070-ANALYSIS OF WEATHER RADAR DATA
Something at an unknown distance along the azimuth of the "spoke" on the screen is pushing out RF energy and your weather radar is displaying it, now it might just be another weather radar though as I understand the designers have methods of reducing the chances of that happening, otherwise you'd see them all the time.......OTOH your captain could be correct, it could indeed be something higher powered such as a fighter's radar (they do have them, but not a weather radar, it is used for interception and other purposes) a ground based radar, perhaps military, or perhaps it is the result of a jamming exercise, again for the military.
For some of us who had a another line of work before our civvie flying days those spokes bring back memories (and cold sweats) of time of groping around in the clag and darkness in an attempt to trying to find whatever it was that was producing the phenomenon.
For some of us who had a another line of work before our civvie flying days those spokes bring back memories (and cold sweats) of time of groping around in the clag and darkness in an attempt to trying to find whatever it was that was producing the phenomenon.
Last edited by wiggy; 31st May 2017 at 14:16.
" said it was radar jamming?"
As I mentioned earlier that's one of several possible options; some forms of jamming, especially basic "area" noise jamming does produce "spokes" on radar displays and the military do ( or certainly used to do) jamming exercises at times for training purposes but probably/hopefully not on a frequency and/or not with enough energy to significantly interfere with the commercial weather radars in the adjacent airspace..
As I mentioned earlier that's one of several possible options; some forms of jamming, especially basic "area" noise jamming does produce "spokes" on radar displays and the military do ( or certainly used to do) jamming exercises at times for training purposes but probably/hopefully not on a frequency and/or not with enough energy to significantly interfere with the commercial weather radars in the adjacent airspace..
Last edited by wiggy; 31st May 2017 at 19:34.
I don't think so. The 'spoke' is a transmission from a fixed point, e.g. another radar dish. To be seen on our airborne weather radars, the source of the 'spoke' transmission would have to be on the same frequency, i.e. about 10GHz. I don't know what frequencies military primary (i.e, non weather) radars use.
The power would not have to be very high though: The weather returns we see on our own radar are reflections from rain drops from our transmissions of about 100-200 watts of transmitted power, so a tiny tiny signal level coming back.
The power would not have to be very high though: The weather returns we see on our own radar are reflections from rain drops from our transmissions of about 100-200 watts of transmitted power, so a tiny tiny signal level coming back.
Seen it once or twice on commercial weather radars, on older radars on jamming exercises it was due to RF Energy getting into the sidelobes.
Last edited by wiggy; 7th Jun 2017 at 20:47. Reason: cleaning up (belatedly)
It's radio frequency interference (RFI) - you most likely got painted by a military system using you for target practice. It's unlikely to be another WXR as the pulses are uniquely encoded so as to avoid that exact problem.
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And the other day our Rhine friends had this in their sector right in the middle of several storm cells. We were getting rubbish returns from nearby cells. My theory is they can saturate or use up a wx radar's capability to report real threats. Needs to be resolved.
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What a BS. It is a problem with your radar. Try moving the tilt up and down fast you will get the same but multiple spoke patterns.
If it happens next time move the tilt up and down slowly and hope it removes the spoke.
If it happens next time move the tilt up and down slowly and hope it removes the spoke.