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Posted by: paulanderson Oct 27 2005, 05:26 PM

A routine communications test in 2003 yields some other interesting, unexpected results:

http://marsprogram.jpl.nasa.gov/odyssey/spotlight/20051024.html



Thankfully, the communications team didn't ignore the "noise" from the original test (now thought to be genuine subsurface echoes) and the bi-static radar experiment is now looking for subsurface ice through October, until just past Halloween.

Posted by: mike Oct 27 2005, 07:10 PM

I wonder how much 'Evian Mars' will cost here on Earth.

Posted by: RNeuhaus Oct 27 2005, 07:32 PM

I tought that the subsurface radar are done best by ones of very low frequency (60-120 Hz) that UHF is not the same. I am still doubtfull about the interpretation of echoes comes from subsurface instead of Mars surface.

At this point, I am not well skilled on the radar matters. But, the transmission of radio UHF waves from one point to another is affected by many variables such as atmospheric moisture, the stream of particles from the sun called solar wind, and time of day.

All radio waves are somewhat absorbed by atmospheric moisture. This reduces, or attenuates, the strength of radio signals over long distances. However, this effect increases according to the frequency: UHF (300 Mhz - 3.0 Ghz) signals are generally more degraded by moisture than lower bands such as VHF.

As well, the layer of the Earth's atmosphere called the ionosphere is filled with charged particles that can reflect radio waves. This can be helpful in transmitting a radio signal, since the wave bounces from the sky to the ground over and over, convering long distances. However, UHF benefits less from this effect than lower (VHF, etc.) frequencies.

As the atmosphere warms and cools throughout the day, UHF transmissions may be enhanced by tropospheric ducting.

Rodolfo

Posted by: paulanderson Oct 27 2005, 07:45 PM

Rather pricey I would imagine.

I like the idea of bottled Martian water though...

I'm wondering also, when I posted this, I typed the 'c' in can (in the title) in caps and it looked ok in the preview, but came out lowercase in the post - ? I wish there was a way of editing the titles of posts as well as the body text. I couldn't see a way of deleting the post either and then re-posting it. Any helpful tricks for this?

Posted by: odave Oct 27 2005, 08:04 PM

I remember Doug saying in some other post (I searched for it but couldn't get the right keyword combo) that he has the board set to not let two shifted characters exist side by side in a title. For example, type "MRO" for a title, and you get "Mro" back. I think the quotation mark in the title of this thread probably counts as a shifted character, so the board lowercased your "C".

Doug said he did this to prevent titles from being ALL IN CAPS...

Posted by: RGClark Oct 29 2005, 05:12 PM

Beware the subsurface microbes though!



- Bob