On 1 Apr 2006 00:40:31 -0800, "Giancarlo Gian Moda, I7SWX"
wrote:

Hi Paul,

This installation was somewhere on the Andes were there was a
astronomic site.

Apparently this was much before the Atacama site in Chile became
popular.

We did not need to use extra fans or other "helping" devices. Certainly
this set-up
was not on an open air site, it was in an building. So "air" presence
was OK for humans.

At sea level, the air density is about 1.2 kg/m³ and at altitudes of
4000 m (La Paz?), the air density is only 0,8 kg/m³. In a forced
cooled system, the critical parameter is the _mass_ flowing though the
system and the amount of degrees the air is heated.

In order to run the same mass of air through the system, you would
have to use 1.2:0.8 or 1.5 times the air volume in the mountains.

BTW, in 1966 while working in UK for a small specialized company, I was
involved in a project were we were producing the Eidofor Colour TV
Projectors (Philips Group). Philips had sold 3 of these units to be
used in Mexico City for the Olympic Games. To be sure we would not have
problems with the 3 colour tubes for explosion (I forgot M.C. height
a.s.l.) we tested the system in the BAC UK air chamber (vy expensive
tubes...hi).

Wasn't Eidophores used during the Apollo flights to show the orbits in
Huston ?

Paul OH3LWR