The Earth-Moon distance is at the absolute minimum and
The Moon is in the coldest sky region (less background noise) along the moon path.
The effect of distance is independent of frequency, but sky temperature
decreases with frequency, up to ~1 GHz and then levels out. The EME
signal-to-noise ratio, in dB, is DGRDaded, from the minimum, by a factor (DGRD,
see below), which varies over hourly, daily, weekly, monthly and yearly time
periods. As a guide for the basic weekend EME conditions the present calendar lists the
expected conditions based on the DGRDadation (DGRD) value. Factors such as local
noise, antenna beam width, side lobes, polarization, etc. can also affect the
s/n ratio of moon bounce signals.
Summary of EME conditions as controlled by DGRD at 144
MHz and New Moon. Conditions may be worse, due to ionospheric disturbance, local
noise and polarity, but not better than indicated.
In general, 144 MHz DGRD:
<1.0 dB is considered Excellent
1.0 to 1.5 is Very Good
1.5 to 2.5 is Good
2.5 to 4.0 is Moderate
4.0 to 5.5 is Poor
and over 5.5 is Very Poor
Within a day of New Moon (NM), high sun noise can make conditions
regardless of the DGRD.
When two different conditions are indicated for the same weekend, it means
that they change from the value indicated on the left at Saturday's moonrise to
the value indicated on the right at Sunday's moonset. For instance:
Moderate -> Poor
means that on Dec, 7th Moonrise conditions are
Moderate and get worse until Dec, 8th
Moonset when they are Poor.