DSLWP-B Queqiao (Lunar orbiter)

S

s-band

Specialist Contributor
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My Satellite Setup
1.5m IRTE PF, Octagon OSLO external Ref., TBS6983,
Various L, S, C, X & Ka bits. 1.2m S/X/Ku/Ka Prodelin on Az-El
My Location
SE UK
#1
Launched with the Chang'e-4 relay satellite, DSLWP-B is one of 2 microsatellites carrying ham radio and astronomy packages.
http://www.planetary.org/blogs/guest-blo...-satellite.html
https://amsat-uk.org/2018/05/19/dslwp-sa...es-lunar-orbit/
BG2BHC (@bg2bhc) on Twitter

The plot is of the S-band beacon on DSLWP-B on around 2275.227MHz (+/- doppler). Received using a helical feed on a 1.2m offset dish with a 0.6dB NF LNA and an ADALM-PLUTO SDR.

DSLWP-B Queqiao (Lunar orbiter)_1053440
 
st1

st1

SMC-dish aficionado
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Mostly SMC dishes pointing at 28.2E
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Nordsjælland, Denmark
#2
Hi S-band. Very nice.
You mean you just aim dish at moon, then listen? Or do need to track moon, possibly even compensating for lunar orbit?
 
S

s-band

Specialist Contributor
Messages
751
Likes
1,114
My Satellite Setup
1.5m IRTE PF, Octagon OSLO external Ref., TBS6983,
Various L, S, C, X & Ka bits. 1.2m S/X/Ku/Ka Prodelin on Az-El
My Location
SE UK
#3
Hi S-band. Very nice.
You mean you just aim dish at moon, then listen? Or do need to track moon, possibly even compensating for lunar orbit?
Basically, yes. The 3 dB beam width, at 2.3GHz is around 7.5 degrees so it's not critical. Manual tracking works OK as it only needs to be tweaked every few minutes. The 1.2 on az-el with the RC2000 is OK but count slip can be a pain above 7GHz. I don't think that the lunar orbit would not be noticeable until you have a huge dish.
 
Channel Hopper

Channel Hopper

Suffering fools, so you don't have to.
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A little less analogue, and a lot more crap.
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#4
The moon as observed from the earth is around 0.5 degrees of arc. The 'halo' orbit of the relay satellite has a diameter of the moon plus around 200kms which really won't change a thing at the frequency used.
 
S

s-band

Specialist Contributor
Messages
751
Likes
1,114
My Satellite Setup
1.5m IRTE PF, Octagon OSLO external Ref., TBS6983,
Various L, S, C, X & Ka bits. 1.2m S/X/Ku/Ka Prodelin on Az-El
My Location
SE UK
#5
Here's the beacon for Queqiao, the Lunar relay for the Chang'e 4 mission. It's a bit stronger than DSLWP-B.
Plot 250Hz/div. Slope is doppler change, wobble is the poor reference in the Pluto SDR.

@Mods, please add "Queqiao" to thread title.

DSLWP-B Queqiao (Lunar orbiter)_1053506
 
Chris1979

Chris1979

Live Long and Prosper
Staff member
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My Satellite Setup
Sky Dish
My Location
South Somerset.
#6
Here's the beacon for Queqiao, the Lunar relay for the Chang'e 4 mission. It's a bit stronger than DSLWP-B.
Plot 250Hz/div. Slope is doppler change, wobble is the poor reference in the Pluto SDR.

@Mods, please add "Queqiao" to thread title.

View attachment 118244
Is that ok?
 
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