I have never seen the designated "signal square" on any US airfield.. even
US ICAO approved airfields..

http://www.faa.gov/ATPubs/AIM/AIM_Basic_2-14-08.pdf

do a word search on "segmented circle"

B


"Kai Rode" wrote in message
...
square... outside the tower?
that must be a euro thing..

It is an ICAO thing, I believe. These:

http://tinyurl.com/6knnaw

are the German regulations on marking aerodromes with VFR traffic, and
they
claim to be in accordance with ICAO annex 14, volume I. The landing-T is
shown on page 3.

and what if there is no tower?

There is a signal field between the operations building and the runway,
even
if there is no tower.