Topband: lower ionosphere?

[Michael Keane K1MK]

On 1/10/2009 7:38 PM, k3bu at optimum.net wrote:

> So, you are trying to imply that atmosphere/ionosphere is only lowered around equator?
> What magic keeps it unaffected at higher latitudes?

No. Unless, as in Arthur C. Clarke's Third Law of Prediction, you happen 
to consider any sufficiently advanced technology indistinguishable from 
magic.

Karl's caveat is just be cognizant of the data before accepting to 
conclusions which may not necessarily be well supported by the data.

The measurements in question (a) refer to the height of the TOPSIDE of 
the F2 region (that's a part of the ionosphere where an MF/HF radio wave 
only reaches if the wave is headed off into space) and not being 
propagated; and (b) were only made along the equator.

You do know the one about the drunk looking for his keys under the 
street lamp, right?

> NASA found out that during high sunspot cycle atmo/ionosphere expands and that is 
 > what slowed down SPACELAB and caused its premature descent.

The effects of solar activity on atmospheric density and satellite drag 
have been were observed starting with Sputnik and Explorer 1 and were 
understood well before Skylab.

Well enough understood that the re-entry of Skylab can be considered to 
have been "premature" only in the sense that solar Cycle 21 came in 
faster and more intensely than had been predicted.

What was unexpected was the level of solar activity in the late 1970s 
NOT the atmosphere's response to that activity.

73,
Mike K1MK