Radar height

[SKYWOLF]

Could someone please help me with this:

If a helicopter takes off, lets say from its private helipad and flys around under 500 feet, would it be visible to radar?

What is the minimum height that radar can detect in West Yorkshire for instance?

[HEATHROW DIRECTOR]

I'd expect to see it at around 15-20 miles under good conditions. The closer you are to the radar head, the more chance you have of being seen. I don't know the geography around N Yorks but ATC radars are basically "line of sight", although other factors come into the equation - for example the location of buildings adjacent to the radar head in the direction of the target and, in basic terms, whether the radar in question is tuned for low cover.

[KPax]

At Shawbury we can see rotarys down to quite a low level, and if you are SSR equipped then even better. Primary returns down to 100' within 10 miles.

[Finishing the ATPL]

I'm not an air traffic controller, but on a recent visit to an ATCC in the Med region, I followed a target on an approach to an airport about 150Nm away, the radar actually tracked the target (MD80) after touchdown, filtering it out once it decelerated to 60kts. I asked the controllers if their radar system received information from a closer radar head, but they assured me they didn't and said it happens quite often. Maybe the High pressure has something to do with it?

[Lon More]

In the light of continuing threats is this the sort of info we should be giving out?

[chiglet]

As an ATSA on Pennine Radar, I [with the help of the Great Dun Fell radar] have seen a/c taxying at Tees-Side :D
we aim to please, it keeps the cleaners happy

[BDiONU]

As has previously been stated it all depends on the radar, buildins, topography of the land etc.
For example the Tiree radar, situated fairly high on the island of Tiree, looks out over the Atlantic and quite often picked up ships at some distance. The Aberdeen radar is tilted slightly to view down onto the North Sea giving better coverage for the helicopters, but over the mountains inland its poor.
So to 'see' your mythical chopper depends on many factors.

[SKYWOLF]

I would like to thank all those people who replied to this post.
It has proved very helpful.
Just one more question if I may.

Do you ATCs come across aircraft with no transponders from time to time?
If you saw an aircraft take of from somewhere in the countryside for instance and it had no transponder signal, what would be the course of action?

Lon More wrote this:
In the light of continuing threats is this the sort of info we should be giving out?

I can assure you Lon More I am not a terrorist, I am quite the contrary.

[eyeinthesky]

Your second question suggests more suspicion than interest.

Transponders are not mandatory outside controlled airspace, so on any one day there are hundreds of primary only targets floating about. In fact, many ATC units (Area control particularly) can filter out primary squawks to reduce clutter on the radar.

The days of Big Brother or not yet fully upon us, and we do allow the aviation community a little freedom of movement without being monitored!;)

[eastern wiseguy]

Whats a primary squawk then? Action taken ...none unless it wanders into controlled airspace....then we pay attention.

[eyeinthesky]

Wisguy: Doh!!
One-Nil to you! I wrote 'squawk' twice and corrected the first but missed the second.:o

[Dances with Boffins]

One other possible outcome of stooging around at 500' agl is that you would be liable to run into, or more correctly, be run into by, some of our blue suit wearing kindred, at about 480kts. West Yorks is a nice place for routing low-level into the Lake District, and during week-days you could watch Jaguars, Tornados, Harriers, Hawks and even the occasional Tucano or Hercules come past you, shaking their fists in derision. mad:
Issuing a NOTAM of intentions to perform actions of this nature would inform the RAF of your location, so that they could either avoid the area, or at least be forwarned of your presence. Unless of course you are up to nefarious activities, in which case there will ba a radar, somewhere, which may be watching your every move. Transponder or no.:D :

[Lon More]

SKYWOLF wrote,"I can assure you Lon More I am not a terrorist, I am quite the contrary."

Quite possibly, however Danny writes, "As these are anonymous forums the origins of the contributions may be opposite to what may be apparent. In fact the press may use it, or the unscrupulous, to elicit certain reactions.,"

Sorry, I stand by my earlier post.

[contact_tower]

Check my signature.......... ;)