UHF signals by the MOON ..... on 437 Mhz , info to received it ?

[1enry1]

Probe on the moon and cw signals!

Japan on the moon, the Slim mission touched the soil !!!
The Japanese radio amateur station JQ1ymg is entrusted

QRG 437.410 MHz, 1 Watt with CW emission !!!


You can use a normal radio amateur transceiver e

What antenna is used in circular polarization (and what size?) or a parable disk and what type and sizes?


Thanks for the info, 73

[MarkT]

70cm band helical. Something like this? https://www.wimo.com/en/helix-70. You need to check whether RH or LH helix.

[RoGeorge]

You can use a normal radio amateur transceiver e

What antenna is used in circular polarization (and what size?) or a parable disk and what type and sizes?

Are you sure it can be received with a DIY antenna and a ham transceiver?

Asking because these guys were mentioning a 25 meters dish radiotelescope to receive the 437.410 MHz/1W station from the Moon:  https://destevez.net/2024/01/trying-to-decode-lev-1/
Then, this comment in the above linked article:

comment by Fabio at February 2, 2024 at 18:00 UTC   

Hi,
I’ve checked the link budget https://robotics.isas.jaxa.jp/lev/LEV_HAM_Club and its seems not to be reliable.
They present -144dBm while it should be -133dBm with displayed data, I was just wondering if I made any mistake in my calculation.
I just wanted to determine the minimum antenna gain required to receive LEV-1 on 70cm.
It seems that only large antenna were able to receive its signal, does anybody have more info?
73s, Fabio IZ5XRC

[vk3yedotcom]

Whereas low earth orbiting satellites are easy to receive on simple equipment due to only being several hundred to about 1000km up, the moon is nearly 400 000km away.

This means there's a big path loss to overcome.

Which needs a high gain antenna, quiet location and good receiver.

More info:

https://www.fcc.gov/help/public-safety-tech-topic-17-propagation-characterization

https://www.pasternack.com/t-calculator-fspl.aspx?fbclid=IwAR1qbJEB1AToS0mBC_VS4m3PLhPzkjQN4t8xZohTNTqkfMvTO8A3y5kGY60

https://destevez.net/2024/01/trying-to-decode-lev-1/?fbclid=IwAR1_vfdLac-fM-d2vjuv3Du6xu901cedsE36MHmkcNVKlxS4lI6V9f82Nn8

[MarkT]

But not as demending as moon bounce... (EME)

[glenenglish]

it's at least 40dB easier than moonbounce .

1W into 3dBi will be -163dBm.
so with a RBW of 500Hz,  and a 20dBi antenna, ( 25 elements maybe or a 2m dish) should be quite audible.
SHould be visible on a waterfall with 10dB less than that.

There will be substantial doppler.....  but, you can track it easy enough and drive the radio frequency directly to account for the doppler, its all calculable.

[radiolistener]

Probe on the moon and cw signals!

Japan on the moon, the Slim mission touched the soil !!!
The Japanese radio amateur station JQ1ymg is entrusted

QRG 437.410 MHz, 1 Watt with CW emission !!!


You can use a normal radio amateur transceiver e

The disatance between Moon and Earth surface is about 384400 km, so back and forth distance is about 768800 km.
At 437.410 MHz the free path loss is about 203 dB!

If you're using good Yagi–Uda antenna with 20 dBi gain on receiver and on transmitter, the signal loss will be more than 203-20*2=163 dB.

Using 1W transmitter you have 30 dBm power. So the receiver will get less than +30-163=-133 dBm power. This is about 0.05 uV.

It will be very hard to detect the signal which is less than 0.05 uV.

So, it's better to use 100 W transmitter, which is 50 dBm power. It will give you 20 dB gain in comparison with 1 W, so your receiver will get +50-163=-113 dBm. Which is about 0.5 uV. This is much better and you can detect it with a good receiver.

If you want to receive transmitter placed on the Moon, the distance will be twice shorter 384400 km and free path loss will be 197 dB. The difference is just 6 dB.

As you can see, you're needs to use pretty large antennas with high directivity in order to achieve high enough antenna gain. Otherwise you will be unable to recevie something from the Moon. Just because free path loss is about 200 dB.

[1enry1]

wow ...... GREAT !  thanks to all !   73