Det har under en tid diskuterats om mjligheten att placera en transponder p mnen, jag publicerar ett inlgg frn en av dom ivrigaste fresprkarna.
73 Hkan SM7WSJ
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Moon station or L1 satellite is not like EME !!
Hello,
The view of most amateurs on the path losses for a moon station or L1 orbit are not really true. For such large distances you don t need bigger stations than for EME ! An EME contact is completely different with a direct contact between the ground station and the satellite.
To give you some examples:
Path losses
EME: Direct (Earth -> moon-station) Difference
– ———————————————————-
70cm 261dB 197dB 64dB !!
3cm 289dB 225dB 64dB !!
Communication with a station on the moon can be done with common HAM equipment, like shown below:
On 70cm when both stations use 20W power and 13dB antennas:
– ———————————————————
Uplink 20W = +43dBm
Uplink ant. gain = +13db (medium yagi)
——————-
Uplink ERP = +56dBm
path losses = -197dB
———————
ERP on the moon = -141dB
Ant gain moon = +13dB (medium yagi)
———————
Moon reciever input = -128dBm
On 10GHz when both station use 10W power and 80cm dish ant. (36dB):
———————————————————–
Uplink 1W = +40dBm
Uplink 80cm dish = +36dB
———————–
Uplink ERP = +76dBm
path losses = -225dB
———————–
ERP on the moon = -149dBm
80cm dish moon = +36dB
———————–
Moon reciever input = -113dBm
These stations are not like EME station 🙂
When looking at L1 satellites with lets say 4x more distance the situation gets some more path losses but still possible for amateurs.
Path losses:
to Moon to L1 sat difference
70cm 197dB 199dB 12dB
10GHz 225dB 237dB 12dB
When both station increase their antenna gain by 6dB the same path conditions will stay. On 70cm the satellite can also use 6dB more power (80W), and the ground station can use an 16dB yagi instead of the 10dB yagi.
This is still within the common ham possibility.
On 10GHz the ground station can use a 1,5m dish instead of the 80cm, and the satellites power and antenna could be increased to overcome its 6dB. 🙂
This is all well within the normal amateur equipment, and still far below the needed EME equipment 🙂 What most
people think More away from the moon is more difficult than EME… is not always true 🙂
So, when do we start to build the first Moon station ? 🙂
73 de PE1RAH, William
Klla: PE1RAH