{"id":94,"date":"2022-11-10T22:18:34","date_gmt":"2022-11-10T21:18:34","guid":{"rendered":"https:\/\/fg8oj.com\/news\/?p=94"},"modified":"2023-11-18T17:05:39","modified_gmt":"2023-11-18T16:05:39","slug":"greencube-digipeater","status":"publish","type":"post","link":"https:\/\/fg8oj.com\/news\/greencube-digipeater","title":{"rendered":"Working GreenCube digipeater"},"content":{"rendered":"

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GreenCube satellite is a microgreens cultivation CubeSat satellite who have a MEO (Medium Earth orbit) that carrying a 1200 Bauds packet radio digipeater on UHF amateur radio band. MEO is a game changer because of his fantastic 5 800km apogee, it let work someone up to 13 000km versus 8 000 for Oscar 7 or RS-44 LEO satellites.<\/p>\n

GreenCube have benn build by S5Lab<\/a> a italian Space Systems and Space Surveillance Laboratory from Roma university. The digipeater has been developed in collaboration with AMSAT Italia.<\/p>\n

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My distance record QSO is 11761 km with A65BR but I am sure that the distance record is already more than 12 500km soon.<\/p>\n

Due to this distance to satellite, this also need a very good setup with a high gain Yagi (10 elements) and good LNA to decode packets. With my setup I can decode packets with less than 5\u00b0 of elevation but not more below even if I can hear the packets, loss don’t let me decode them.<\/p>\n

Follow S5Lab on twitter for updates: https:\/\/twitter.com\/S5Lab<\/a><\/p>\n

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This is a simple description of how I did. You will to adapt to yours but maybe it can help you.<\/p>\n

My hardware setup :<\/strong>
\n– Icom IC-9700 with 2 CAT interface<\/strong>
\n– 18 elements V\/H polarization DK7ZB Yagi (10 dBi at least recommended)
\n– Yaesu G5500 rotator with EA4TX ARS-USB direct controler (not using the poor Yaesu controler)
\n– Low loss mast mounted LNA and Polarization mast switch with M5stack console https:\/\/github.com\/fg8oj\/RemotePolarisationSwitch<\/p>\n

My software setup under Window 10 :<\/strong>
\n– PstRotator v17.31 https:\/\/www.qsl.net\/yo3dmu\/index_Page346.htm<\/a>
\nwith
\n– Omnirig http:\/\/dxatlas.com\/Download.asp<\/a><\/p>\n

A deprecated choice (bugs on Doppler correction) wille be to user SatPC32ISS v12.10 www.dk1tb.de\/SatPC32ISS_2.zip<\/a><\/p>\n

And for decode\/transmit GreenCube packets:
\n– SoundModem by UZ7HO ver 0.07b http:\/\/uz7.ho.ua\/greentnc.zip<\/a>
\n– Carsten OZ9AAR Terminal https:\/\/moonbounce.dk\/hamradio\/greencube-terminal-program.html<\/a><\/p>\n

And for Telemtry:
\n– DK3WN GREENCUBE Telemetry Decoder v1.1 https:\/\/www.satblog.info\/software\/<\/a>
\n– DK3WN GetKISS+ v.1.4.2 (Transfer to SATNOGs) https:\/\/www.satblog.info\/software\/<\/a><\/p>\n

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Icom IC-9700 USB have 2 ports that will let use the first serial port for PstRotator Doppler CAT control but you will also need the second IC-9700 serial port to let SoundModem control TX via PTT RTS command. You will need to update your IC-9700 settings to let change PTT control to the B port. To do that, you’ll need to go in Menu\/SET, then Connectors,\u00a0 USB SEND\/Keying and then select “USB (B) RTS” in USB SEND Menu.<\/p>\n

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My Icom IC-9700 have AGC turned OFF for DATA modes that is very important for decode quality. Noise Blanker and Noise Reductor should be also turned OFF for digital communications. You should adapt Baud rate and of course Port.<\/p>\n

You also need to check your IC-9700 setting while you are using USB-D (USA-DATA) mode. The USB audio card input need to be use in Set\/Connectors\/Mod Input\/Data Mod, set-> USB. You you use USB, IC-9700 use the DATA OFF MOD parameter who is normally set to MIC.
\nIt is really important to differentiate this 2 mods otherwise you will transmit your microphone audio during your transmission and nobody want to hear all the wickedness<\/span><\/span><\/span> you say when you didn’t succeed to be digipeated \ud83d\ude42
\nAlso check that none of other software are using your USB card because nobody want to hear on the air the youtube video your are watching (or youp***). That’s a common mistake on FT8 frequencies :-\/<\/p>\n

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PSTROTATOR<\/h3>\n

Omnirig is a CAT interface for PstRotator and needed to be setup with your usual first port. Your setup will change from my configuration :<\/p>\n

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PstRotator antenna and Doppler correction :<\/h3>\n

Assuming you already have download, registered (yes, that’s ham radio life, it is not free but this software is really amazing even if a Linux version doesn’t exist) and also configured to run your antenna manually and had setup your home grid location. Then :<\/p>\n

To access to Satellite tracking, you need to launch Tracker\/Satellites and change mode de Tracking on main window then a new window will appear for Satellites Tracking. From this window, I will also be able to launch a third window with the Satellites Map.<\/p>\n

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Then you will need to update TLE in the Menu. You need to remove celestrak and add amsat.org nasabare TLE file and click on update button :<\/p>\n

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Then in Satellites menu, you will need to add GREENCUBE:<\/p>\n

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Then in Favorites, you can click on Greencube, then click on the UP+DN button and enable “Use OmniRig” and your transceiver should start to use the same frequency than PstRotator screen. You may also need to change then mode to DIGR to have USB-D mode enabled.<\/p>\n

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If you succeed to have the same frequencies on your transceiver and PstRotator on both RX and TX (yes, you can click the TX button to test TX without audio).<\/p>\n

Note: If you are not using PstRotator for rotor tracking (with Portable setup), you need to use the Demo Rotator in EL + AZ\/EL Setup and select Mode Tracking to enable Doppler before your pass to\u00a0 have Doppler correction on your transceiver!<\/strong><\/p>\n

SatPC32ISS<\/h3>\n

SatPC32ISS need to be updated to version v12.10 or more to have ability to run GreenCube specificity.You need to add this line to Doppler.SQF :<\/p>\n

GREENCUBE,435308.5,435308.5,USB-D,USB-D,NOR,0,0<\/pre>\n
If you already use SatPC32, you don’t need to change anything. Just adapt frequency in CAT window. I am using 435308.5 with GPSDO but you need to adapt it to your TCXO precision. USB-D is now supported by this version so you will not have to change to this mode manually and the Doppler correction don’t stop working in the middle of a pass like before.<\/p>\n
Decoding GreenCube packets :<\/h3>\n
Now, you can start SoundModem and launch Settings, , you will then just need to select the second COM port of your Icom in “Select PTT port” in Settings. If you don’t know witch USB ports are used, you can take a look on your Windows Microsoft Management Console :<\/p>\n
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Due to Sound Card sample rate, Oliver DL6KBG advised me to set the TX\/RX SampleRate to 12000 Hz (Maximum available value). You can also check Color waterfall than give you a better readable waterfall.<\/p>\n
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In Modem settings, you just need to check your TXDelay 400ms for old transceiver but 80ms of TXdelay and 1 ms tail is perfect for Icom IC-9700\u00a0 but everything should be as default :<\/p>\n
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You need to check if you can send packet so please check you transmitting power is reduce to 0 and try to listen with a local receiver.<\/p>\n
From this point, you need to wait a Greencube pass and try to receive packets. You will need to adjust Doppler to your receiver. Because I am using GPSDO source, I founded a -1 300 Hz difference but you will need to adjust it with arrow on the PstRotator window :<\/p>\n
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Before transmitting you have to wait if the transponder is active and you are able to receive all incoming packets. If not, don’t try to transmit!<\/strong> You will also have to wait until the Digipeater Status is no more undefined in the bottom page of GreenCube Digipeater software :\"\"<\/p>\n
If the Digipeater is OFF, DO NO TRANSMIT. Command station is maybe sending data to the satellite, don’t disturb the operations but participate collecting the telemetry by sending them to SatNogs DB.<\/p>\n
You will get a minimum of one packet each 45 seconds. It is the telemetry packet that you can send to SatNogs with both DK3WN software.<\/p>\n
It is really easy to hear packets not so easy to decode it! GreenCube will be 6000 to 10000 km far away from you.<\/p>\n
Polarization match, good decodes :<\/p>\n
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Polarization mismatch, no decodes : \"\"<\/p>\n
Also check the arrow horizontal line is perfectly centered to the packet. PstRotator calculate doppler correction with a very high accuracy so you should not have to change it during a pass or maybe because of IC-9700 TCXO precision trouble. Because I am using my 9700 also for EME, I have a LeoBodnar GPSDO and injection board installed and that’s a good help for GreenCube Doppler correction as well.<\/p>\n
If you have difficulties to decode packets bellow 20\u00b0, that’s normal. It is very challenging. But if you have difficulties upper than 20\u00b0, you need to check if:<\/p>\n
– you have sufficient amount of gain from your antenna (7 elements is a minimum)
\n– you don’t have coaxial loss or LNA working
\n– your rotator don’t have positioning problem.
\n– your polarization (Circular is -3dB loss, wrong polarization is -20dB). I am adapting polarization under 20\u00b0 for best reception to optimize decodes. If you loose packet for few minutes et get them few minutes : check the polarization harness or if switching is good. If you only have one polarization (horizontal or vertical), you will loose the digipeater frequently : During a pass, satellites antennas looks vertical to horizontal due to relative orientation (the satellite don’t change is orientation but you are changing).<\/p>\n
<\/h3>\n
Use the Digipeater :<\/strong><\/h3>\n