Posts by s-band

  • Tianwen 2 (TW2)

    Thanks to DF2MZ for the alert that TW2 is getting close to Kamo`oalewa at 38.5Mkm from Earth. It's a couple of degrees away from Kamo`oalewa at the moment. I hadn't noticed the sidebands, at +/- 3.833MHz from the carrier, when it was last seen. However, I may not have looked over a wide enough span.

      

    1.2m dish, ~1.1dB system NF, USRP B210 clone SDR

  • 46.0°W TDRS 6 (Incl.)

    TDRS 6 46.0°W Inclined by +/-14°

    It was almost at the top of its range when captured. The modulation sidebands of the TT&C beacon on 2211MHz are just visible.

    Helical feed, 1.2m dish, 1.2dB NF LNA, USRP B210 clone SDR.

  • Euclid (L2)

    Here's a plot from 7/8/23 which shows about 0.05dB SNR in 3MHz

    and another from 31/8/25 where 421.5MHz = 26240MHz. I think that Euclid uses a suppressed carrier hence looking at the modulation.

  • LRO (Lunar Orbit)

    LRO

    It's taken a while to catch LRO on Ka as I don't have the 26GHz head on the dish very often. LRO isn't always on Ka but checking DSN Now, it was on for about an hour last night..

    The RX is not great. It has a linear feed on a 1.2m dish with a home made LNA, built in an old band C Ka LNB, followed by a modified 23GHz Wavelab down converter. The overall NF is around 4dB. Based on Sun noise on a decent 22GHz LNB, it's sensitivity is about 4dB down on what's possible. Adding that to the 3dB polarisation loss, there's a lot to be gained if it were optimised. The SDR is a USRP B210 clone.

    The Moon noise shows as 0.6dB but tracking could be better as it the noise peaks at around 0.8dB.

       

  • DRO-A & B (Distant Retrograde Orbit Earth-Moon)

    Both are now quite close together and to the east of the moon. Here are their date, time, RA, Dec coordinates measured a few minutes ago. They only remain valid for a few hours for my 1.2m dish.

    2026-02-27 19:42:40 07:10:07 28:19:59 DRO-A
    2026-02-27 19:37:25 07:08:25 28:11:56 DRO-B

    <edit> The coordinates above were probably wrong, I think I recorded figures from the wrong display.

  • 14.5°W Elektro-L 2 (incl.)

    qwer It's still there but much weaker than it was in my plots in this post. It switched from CW to modulated at 10:00UTC just as I found it so I didn't get a chance to measure it. I can no longer see even a hint of the modulated signal. I can't normalise the spectrum to see very weak wideband signal due to the sidelobes capturing other satellites. It was about -3.9deg latitude at the time.

  • DRO-A & B (Distant Retrograde Orbit Earth-Moon)

    This was an accidental capture whilst looking for KPLO (Lunar orbit). DRO-B happened to be within the dish beam width whilst tracking the Moon. There are articles about the DRO program here and here.

    It was on 8474.387MHz initially and about 1 degree up in elevation and 0.5 deg W az from the Moon. I left it tracking, targeted on the Moon and it was about 2 deg W of the Moon after 3 hours. I assume that it was DRO-B. It's hard to get an accurate fix using the 1.2m dish though. The Doppler change was around 0.37Hz/sec. It was quite strong at about 20dB SNR in 10Hz.

       

  • Juno

    Still going but it's hard to tell how long for.

    The 2 plots used different settings, One with 0.4Hz RBW, no averaging and the other with 0.7Hz RBW and 4x averaging. The Doppler was -0.69Hz/sec.

      

    1.2m dish, 0.8dB NF LNA, 6.8GHz LO, B210 clone SDR

  • IMAP (L1)

    I installed SDRAngel on the same PC but I struggled to get anything useful done with SDRAngel but probably due lack of familiarity. Sometimes I thought I could get it running easier if I loaded the FPGA using uhd_usrp_probe first. It did produce a spectrum which looked OK at 61.4Ms but I lost patience with the interface. I don't think having used Zadig broke SDRAngel, I think is just painful to use for me. I ran it on Linux and it seemed better on that but still not useful.

    I have no problems running Satdump on the same PC. I'm using the latest NI/Ettus firmware.

  • IMAP (L1)

    Testing a re-built down-converter with the USRP B210 clone SDR, here's IMAP at 1.39Mkm. 1.2m dish, 0.8dB NF LNA, 6.8GHz LO.

    VMA & impulse0879 I'm using the ExtIO from here on a basic PC with an 8th gen i7 and 32G RAM. The driver will not allow anything higher than 32MHz sampling. It runs without overflows or 'short reads' as long as there's nothing else running on the PC.

    HDSDR was set up to show 32MHz span in the lower window with 48ks/s for the audio window which was zoomed in to show the frequency wobble on IMAP.

  • 25.8°E Es'hail 2 DATV 10.5 GHz

    I think that your 5925 has the STV091x chip set which will tune below 950MHz. If you change these settings in the streamreader.ini file for CrazyScan, you could try it:

    ;IFStart=250
    ;IFStop=2350

    If you just want to power the LNB, then use anything that will give you 13/18V & no tone/22kHz. Use a splitter that has one DC path for the supply and one path that does not pass DC for the SDR.

    This post includes a link to using the software on the Amsat-DL forum which does work but is not the most friendly in use. The rest of VMA's thread includes other useful information on setting a system up with an SDR.

    It looks like you are almost there with SDR Angel but you have the sample rate set quite low which would be OK for some of the narrow signals but the beacon needs a much wider setting. You will also need to set the sample rate correctly. Have a look at VMA's settings. The BATC web RX will give you setting to use for transmissions at the time you look. I don't use SDR Angel but maybe someone else can help with more detail.

  • Testing my new LibreSDR B220 (Ettus USRP B210 clone)

    Thank you, that;s very interesting. I've been using a B210 clone for a while but haven't tried any DVB with it. I chose this one as it is 100% compatible with Ettus firmware. It was about 300GBP delivered.

    https://opensourcesdrlab.com/products/b210-ad9361

    My observations:

    It's very nicely made and in a milled clam-shell style case. However, that's a disaster due to the size of the case and it's waveguide properties. Noise from the USB (at the opposite end of the board to the RF section) propagates to the RF input. In addition, the case is anodised so the 2 halves do not make contact with each other, the PCB or the connectors. The noise levels from about 1-3GHz peak at around -80dB relative to full scale.

    I ground the edges of the case, soldered the USB socket shell to the the PCB ground, filled the lid of the case with abosorber and made spring connections to make sure that the SMAs were connected to the case. This improved things by about 20-30dB. Sometime I will put a shield over the AD9361 and the input circuitry.

    Since I use it mainly for DSN, I needed it to be locked to an external reference. It would not lock. It appears that either a defective VCTCXO was fitted or it was a TCXO (i.e. no voltage control). Changing this to a proper VCTCXO, it locked to an external reference.

    I first tried it on Linux with GnuRadio command line utilities but they are a pain to use. SDR Angel is not ideal for DSN work but a quick test on Linux had it running. I have been using it on Win 10 with HDSDR and Satdump since. Here's an example of using it for FM demodulation.

    On an 8th gen i7, the maximum rate it will run on HDSDR is 32Ms/s and on an 8the gen i5 laptop it will run at 16Ms/s without dropping samples. The HDSDR driver is limited to 32MHz/s. Satdump will run up to about 50Ms/s on the i7 but not with processing enabled. When I get time, I'll try it with DVB and write a better review.