[Moon-net] Sidelobe noise question

[Bob Baker]

Dear Moon-net,

Recently I have been trying to build a modest 432 eme system, and previous
responses from moon-net have been very helpful. Thank you.

One of the inputs to the eme planner software is sidelobe noise in degrees
Kelvin. I have been using the wsjt software, but the question is independent
of software and mode.

I presume the sidelobe noise is primarily dependant on the size of the
sidelobes and how much noise they are pointing at. I guess both celestial
and terrestrial noise are significant. I realize that no one on moonnet can
answer accurately how much sidelobe noise I would get on a given night, but
I would be happy with any reasonable rough estimate.

Since I am only 100W on 432 for the near future, it is reasonable to assume
that most of my qso partners will be higher power than me. So it is actually
more important to know the sidelobe noise temperature of the big gun I will
be working. This is clearly an impossible question since I do not know who
that will be! Obviously I am not expecting an accurate answer to an
impossible question.

What would be a reasonable guess for the sidelobe noise of a well designed
big gun 432 eme antenna, say 8 long yagis, on a typical night, pointing well
above the horizon? How about 2M?

What sidelobe noise temperature should I expect with my future 2 x 12 wl
homebrew 432 array (the sidelobes are modeled at -12db) when elevated? How
about 2M, with 2 x 4 wl?

Again, I don't expect an accurate answer, but it would be nice to know
whether the "correct" value is 10, 100 or 1000 deg. K.

Thanks again moon-net,

73,
Bob
KD3UY