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Showing posts from April, 2018

PSK-31 on NO-84

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This satellite supports PSK-31 communication although it's rarely used.  The downlink is on 435 MHz and the uplink is on 10 meters. Currently there's no 10 meter antenna on the 847 at W2MMD but we can copy the downlink using FL-Digi.  It looks like this:

Using PstRotator to Track Satellites

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It's pretty easy to track existing satellites using PstRotator. The program is opened when the computer starts up, although it takes a minute or so to load. There are two windows - the satellite window and the rotator window. You don't need to do much with the rotator window other than click the "Tracking" button to tell the program to track the selected satellite.


To select a satellite, go to the Satellite window and click "Next pass" from the top menu.
This will display a list of the next passes for each satellite. To track a satellite, click the name of the satellite on the Next Pass list.
That will select the satellite for rotator and Doppler tracking. The rotator will track automatically if "Tracking" is selected. Doppler tracking is more complicated - clicking the Home button will set the SDC and 847 to the frequencies in the Downlink-Uplink window, which are usually the middle of the passband. Clicking the UP+DN button will lock the VFOs of…

Decoding CAS Telemetry

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The telemetry on CAS4A and CAS4B is easy to decode. Track the telemetry signal with PstRotator and SDR Console. Sometimes it's easier to copy using the WFM setting and manually setting the bandwidth rather than using the NFM setting. Open the Soundmodem 16 program, which will decode the packets into KISS format, and then open the AGW-Kiss program which will decode the KISS and write the ASCII into a file.

Decoding the recorded telemetry file using the CAS4AB Telemetry Decoder (see the Start menu) will give a  readout of the decoded telemetry values: 

Listening to SDR Audio thru Speaker

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The SDR radio defaults to the "Line 1" audio output.  This allows the audio to be directed to another process within the computer such as the SoundModem or the Fox or Funcube telemetry decoders. You can select the output setting of the SRD radio thru this pulldown:
But this doesn't direct any audio to the speakers, so to listen to the audio you need to use the Audio Repeater app on the taskbar. 
In the app select VAC Line 1 as the Wave In and Speakers as the Wave Out, then press Start. You should hear audio from the speakers. You can also map audio from the 847 thru the RigBlaster by using the RigBlaster Audio RX as the source. You can map several different input devices to the speakers at the same time. Note that the SDR radio won't send audio unless the selected frequency is in the displayed bandpass. If you don't hear any audio from the SDR, center the selected freq in the bandpass and the surio should start. 

NOAA Satellite WeFax Reception

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NOAA satellites transmit live weather FAX pictures that can be copied with the SDR radios at the W2MMD site. They transmit in the 137 MHz range that seems to be receivable by the 2 meter beam.
NOAA 15-137.6200 mhzNOAA 18-137.9125 mhzNOAA 19-137.1000 mhz They're programmed into the PST Rotator app and use the WxToImg software to render the images using SDR Console to receive them. WEFAX signals are somewhat broader than amateur FM signals, so set the SDR Console to WFM and manually adjust the bandwidth to surround the signal in the waterfall.



In WxToImg, first be sure that the Mixer control is set to use Line 1 as the audio source (which should be the output for SDR Console). Then under Recording select Auto Record. The WxToImg software contains its own set of Keplerian Elements and will start recording when it believes the satellite hits AOS, which may not exactly correspond to when you first see it on the SDR waterfall. But once the keps and times are synched WxToImg will start do…

Working APRS

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APRS operations at W2MMD use the FT-847 rig for both transmit and receive, since the uplinks and downlinks are both on 2 meters. CAT tuning will work on the 847 but the 2 meter antenna needs to be set to the 847. If the radio isn't set by CAT to 145.825, tune it to that freq. To use the 847 to transmit set the Satellite window of PST Rotator to use R2-T2 - the normal setting is R1-T2 (receive on SDR, transmit on 847).



Next, open UISS on  the computer, which will also open the SoundModem software.  Be sure that the input and output devices are set to the respective Rigblaster settings as shown below.
By default you won't hear audio from the 847 since it's piped into the RigBlaster. To handle that, open the Audio Repeater app on the computer, set the source to Rigblaster RX and the output to Speakers. Don't disconnect the cable from the rig - you'll need it to decode the APRS packets. When the satellite or ISS passes you should hear packets, and when they're stro…

The W2MMD Satellite Station

This is a blog to follow the setup and operation of the satellite station at the Gloucester County Amateur Radio Club station in Mullica Hill. I'll be recording various new features that are set up, some results of operation and instructions on how to use various software packages and work various satellites. I didn't start this blog at the beginning of the process so some entries will be out of order, but hopefully they'll be useful for any readers.

73 de Jon WB2MNF