Beiträge von s-band

I finally managed to decode it using WSJT-X https://physics.princeton.edu/pulsar/k1jt/
It transmits QRA64D on even minutes and FSK CW on odd minutes. The PC time must be set to within a second or so.
The attached output was from a time when the PA must have been off hence the low signal.

This plot shows the doppler change and has a GPS locked reference signal on 2234.521700MHz to show the SDR reference wobble

Beacon on 2242.484MHz LHCP (UHF-Satcom has it on 2242.500)
1.2m, 0.6dB NF LNA, 1Ms/s, 262k FFT (Narrow sweep)
19Ms/s, 262k FFT (Wide sweep showing 1MHz sidebands)

Strong carrier/beacon on 2237.490MHz LHCP
1.2m, 0.6dB NF LNA, 1Ms/s, 262k FFT

See

/edit by qwer: LINKS disappeared (01.08.2020)

for links. This is the beacon from Queqiao, the lunar relay satellite for the Chang'e 4 mission. Stronger than DSLWP-B. 2234.522MHz (+/- doppler) LHCP. 1.2m dish, 0.6dB LNA, 0.5Hz bandwidth, 250Hz/division on plot. The frequency drift is doppler but wobble is due to the poor reference in the Pluto SDR.

At around 24.3W but drifting https://www.n2yo.com/?s=26719&live=1
Identified using data from uhf-satcom.com. TT&C beacon on 2265.0MHz LHCP (or linear). 0.6dB NF LNA, 1.2m dish.

Launched with Queqiao. Chang'e-4's relay satellite, DSLWP-B is one of 2 microsatellites carrying ham radio and astronomy packages.
http://www.planetary.org/blogs…ge-4-relay-satellite.html
https://amsat-uk.org/2018/05/1…p-satellites-lunar-orbit/
https://twitter.com/bg2bhc

The plots are 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.

In circular polarisation now: I don't know which is right and left with these 2 plots. The OMT and polariser are probably not for this band as the X-polar rejection is only about 15dB and I only gained 1.5dB compared to linear. However, there is some structure to the 17930MHz constellation now.

The other beacon is active and visible if you look in the right place
SES-12 was about 3 times the distance compared to the previous capture hence the ~10dB drop in signal. The doppler shift was about -70kHz at the time of the plots. The settings were the same as for the previous post.

The orbit map also shows SES-14 approaching its final location.

The TT&C beacon on 11703.5MHz appears to be circular polarisation but I could not see the other one on 11499.5.
<edit> That may be because it is on 11449.5. Thanks to Marcus_21 on satellites.co.uk for the tip.

The plot was captured when it was on its fast downward trajectory (118Az, 18El), viewed from UK. It was at about 14000km range and there was about 130kHz doppler shift.

http://www.n2yo.com/?s=43488

I get a few dB less than Satesco and also noticed an increased level today. I guess that it must be the same transponder as the feed on 12673H as the levels are very similar.

I measured the signal power density (in dBm/Hz), which ignores total channel bandwidth. 12605/12645 are about 2dB higher than the feed on 12673. My vote is for the European beam to large earth station(s).

Zitat

Original von marval450
Mode 8PSK 3/5 today.

Yesterday's plot from near London on 1.5m before the change above

Zitat

Original von satesco
12737 V-I think it's a beacon and not a test carrier.I hope not to mistaken,but I have not seen posted here.

I can not see anything on that frequency now. All I can see is the CW beacon on 12501R.

Zitat

Original von marval450
21534 locked with 115cm, no content comes out,ofcourse.

Im curious how many dbs are needed for clear picture, 11-12?

It is Ok on a TBS6983 down to about 6dB SNR (normal signal 10.5dB on 1.2m). It can be hard to get these TPs to lock due to the narrow bandwidth and close spacing. Sometimes it works better without blind scan. It can also help to set the frequency slightly offset and away from the nearby channel.

I had a listen to Radio Immaculée Conception (21564H) and I noticed that the data given by "Codec Information" on VLC includes many other things. What is happening here?

StreamReaderEx-BDA 1.2.4.52
Fixed TBS 5580 support in terrestrial/cable mode.
Fixed DVB-C lock for Silabs based devices.

https://sourceforge.net/projects/crazyscan/files/

Hi satesco, I can see similar things but only from 52E. There is a group of narrow data signals (10700-10720V), below my threshold, on 52E V (and a TV MUX on 10721H). I can not see anything around that frequency to the east of 52E. I found Astra 2D on 10701V at around 49.5E incl +2.26 which is drifting west. I am a long way west of you. That together with trees may be reducing what I can see.

Try these ideas?:

UnplugLNB and put a piece of wire in the IF port to check for signals around 955MHz.
Check your skew. If the skew is off or set to opposite polarisation, the beam pattern of the dish changes and may have worse side lobes.

Hi satesco, I can not see the signals at 10704+/- but I can see the GSAT-8, beacon on 11698.4927V (GPS locked RX). It is very weak at 10-15dB SNR in 0.15Hz band width. I do not have a clear view and the variation may be due to trees moving. At that level there is no way I would get any usable signals from GSAT.

I could not detect the GSAT-16 beacon on 11698.0H. Yamal 402's beacon was around 20dB SNR in 1.2Hz on 11459.5 Circular. I could not see any other signals that i thought were from that position.

I could still detect some narrow band data around 10700-10720 but that was from ~52E, I think. I am only using a 1.2m dish so the beam width is quite wide.

I tried again with the circular polariser. It was very confusing as the satellites share frequencies but on opposite polarisations. All beacons appear to be CW only.

Listed are my guesses at the satellites and their beacons. The Az-El values do not have good absolute accuracy but have reasonable relative accuracy, at least to the extent that I have the satellites in the correct position order.

hvdh, do you find it believable?

Zitat

Original von qwer
Yes, best signal in circular - than you s-band!.

I checked and they are RHCP

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Original von hvdh
Great! The Inmarsat-5 frequency plan lists 19600 as 32 MHz gateway transponders, both LHCP and RHCP.
http://frequencyplansatellites…g/Inmarsat/Inmarsat_5.pdf

Interesting. I am still confused as I can't work out what the data format is since I can't see any actual data. The comb is static.

There's another Ka satellite 2 degrees west and 1 degree north of this one. It has a CW beacon at 20202.5 (needs checking) and the wide band data as attached. Expres-AM6?