agreed 100%. Perhaps I should have said "While I agree that QRP EME is going to be Extremely difficult...." instead of just difficult. Brain teaser: Good question. I don't know, but would guess that the darker side would produce the better S/N Ratio, since it would be reflecting less solar noise back to Earth.
You win 73 internet's! All objects radiate rf in direct proportion to their temperature. The light side, being hotter, radiates more noise. Rege
Absolutely. Although all 'thermal' radiators predominantly radiate at and near the Wien peak, these 'greybodies' (not perfect blackbodies) still radiate at all wavelengths, albeit rather feebly. The full moon both reflects solar radiation , AND has an LTE (local thermodynamic equilibrium)surface temperature of roughly 350K, both of which contribute measureable noise floors at RF, even though the peak for thermal radiation is at IR for the lunar surface. You radiate X-rays (as a grey body) but they are mighty feeble. VHF rf also. Pee weak, as they say. Your Wien peak is at IR. The new moon is roughly 100K and the RF radiation is even more feeble, but the IR peak is in far IR. Oddly, if the moon were in LTE at a far colder temperature than this, then the new moon would get NOISIER because the Wien peak would happen at VHF. Approaching absolute zero for that. This never happens because the universe is permeated by a roughly 3 degree background. Everything holds at 3 degrees, or above. With some exceptions. Obviously another factor is perigee and apogee--others can comment on that. Ham radio is an INVITATION to explore the physics of interesting things--like how to do moonbounce AND when it is feasible. Here's an interesting factoid: W9GFZ (Grote Reber) was really the first bona fide 'radio astronomer' (Jansky did not seek to be such).. He built a dish in his backyard (!). He set its size to get a 1/2 degree beamwidth at the frequency he wanted to conduct the first moonbounce. That angle is what the moon subtends. Reber started his radio astronomy exploits because he failed at moonbounce. He said: 'what else can I do with this?'Trace fact! That was 1938. Hams have impact. Then, and now.
so that brings up the question of frequency. I like 70cm over 2m because of reduced atmospheric effects. If what you say above is correct, and I assume it is, then the Moon would be quieter at ~430mhz. Would it not?
Also, for smaller antennas, that cover more than just the moon you have to consider what's behind the moon, Sagittarius is noiser than cold sky, and the sun is noiser still. Also, it's possible to tune a given size antenna for a "sharper pattern", giving up a bit of absolute gain (a better g/t) and have a somewhat weaker signal in absolute strength, but a better s+n/n ! It's really amazing all the things that you get to learn about when you set out to bounce signals off the moon Rege
I don't know about that, but I do know, for a given amount of aluminum a 430 mhz antenna array will return a stronger echo than a 144 mhz array! And the higher in frequency you go, the stronger it gets (untill the frequency where your entire beam hits the moon) Here is a link to some Japanese hams who got time on a 32meter dish, they could "only" run 500 watts on 5760 (they weren't allowed to touch the stations 3kw amplifier ) http://www.eme2008.org/papers/Siste...nt With A 32m KDDI Cassegrain Antenna_rev.pdf I know where there is a similar station for sale, I used to work there: http://www.orarc.org/?p=1097 Rege
