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Author Topic: Moon Base Alpha  (Read 2218 times)
KE4VVF
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Posts: 61




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« on: March 23, 2012, 12:32:36 PM »

If we had a base on the moon and it had an Amateur Radio Station, how hard would it be to communicate back and forth to the operators on earth?

Which band would be the most effective?  I'd like to use 2 meters or 440.

How many watts would you need?   We wouldn't have the reflection issues / losses of EME.  It would be line of sight communication.

How about a repeater?

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K0JEG
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Posts: 679




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« Reply #1 on: March 23, 2012, 01:03:40 PM »

http://www.ab9il.net/aviation/apollo-s-band.html
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KG4NEL
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Posts: 443




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« Reply #2 on: March 23, 2012, 01:06:23 PM »

Just as long as they count for DXCC.
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2E0OZI
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Posts: 270




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« Reply #3 on: March 23, 2012, 04:17:46 PM »

Spacce 1999 and UFO were two of my favourite shows as a kid. Oh and The Thunderbirds.
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Men can only be happy when they do not assume that the object of life is happiness.
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K8AXW
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« Reply #4 on: March 23, 2012, 05:24:06 PM »

Google Amateur Radio EME......  you'll find that it really wouldn't be a big hairy deal!
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WX7G
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« Reply #5 on: March 23, 2012, 05:46:17 PM »

I calculate dipole-to-dipole on 144 MHz you'd need 10 kW for an S-9 signal. For a usable 1 uV signal 4 watts would do. One could do it with two handhelds sporting 1/2 wavelength whips. But given faraday rotation through the ionosphere you might want to use antennas having circular polarization such as turnstyle.

For 432 MHz you need 10X the power given the same dipole-to-dipole senario. This is due to the smaller capture area, or higher AF (Antenna Factor) of the 432 MHz dipole.

« Last Edit: March 23, 2012, 05:50:09 PM by WX7G » Logged
LB5KE
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Posts: 141




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« Reply #6 on: March 23, 2012, 07:26:37 PM »

The path loss for 440MHz and to the moon (one way 380000km) is -196db. I used my Yaesu FM mobile as an example and the receiver sensitivity + cable loss at -113 dbm. The TX at antenna to more than 25watts (55watt @ transmitter) that's 44dbm.
That's 39 dbm missing. I need 39 db more  so a long 19 dbi yagi on both sides are probably going to work.

At 2 meter since the path loss is 10 db lower, you could use smaller (10dbd) yagis.

The path loss @ 28 MHz to the moon is  -173 dbm.  I used the spec for a 857d in SSB mode and put the receiver and cable loss sensitivity to -116dbm. Th output at the antenna to around 80watts (49dbm). So i am now missing  8 db. So a 2 element yagi in both ends would work. But cosmic noise could be a problem.





 
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KB2FCV
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« Reply #7 on: March 29, 2012, 01:35:35 PM »


Fascinating article, thanks for sharing the link!
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