APRS packet using Kenwood TS2000 and UISS software
Hello all, I am Ground Station Team member of COEP's student satellite mission 'Swayam'(www.coep.org.in/csat).Our Ground Station is functional with uplink and downlink capabilities and is equipped with Kenwood TS2000(having a built-in TNC) transceiver and Yeasu G5500 rotor system.
With the vhf and uhf antenna available with us we have successfully received analog beacons from many satellites. To prove our digital capabilities we are focusing on having APRS contact with ISS. We use UISS software by ON6MU along with AGW Packet Engine to connect PC with TS2000. Using the software we successfully transmit packet on air as transmitted packets are clearly heard on hand held Yeasu VX-3R transceiver which is unable to decode any packet.
Even though we try to digipeat and data is transmitted, we are not able to receive data on the software screen. whenever we have a pass of ISS some signals are detected and a receiving led glows even in squelch on. But the received signals doesn't sound like packet.
Please help us in improvising our ground station for digital communication.
Regards, Rupesh VU2COE
Hello Rupesh,
Even though we try to digipeat and data is transmitted, we are not able to receive data on the software screen. whenever we have a pass of ISS some signals are detected and a receiving led glows even in squelch on.
The new ARISS web pages at http://www.ariss.org are one place to find more information. Select the 'Contact the ISS' link in the top row. This brings you to a page which describes all of the ARISS amateur radio modes. There is a section on this page titled "Packet Operations".
AGWPE only passes the packets that have the correct checksum. Otherwise you will not see the packet displayed via UISS even though it sounds like a good signal.
I am not at all familiar with the operation of the TS-2000 internal modem. If it operates in a mode similar to other TNC-2 configurations you might be able to see non-checksum-computed packets using the TNC's PASSALL command. In this configuration you would not be using AGWPE. Packets received with PASSALL = ON contain the good characters and erroneous characters - but it is often good enough for humans to understand the content.
Both types of packet operation, hardware TNC and soundcard modem, are discussed in a link in the ARISS.org's packet operations section.
The only amateur radio presently in operation on the ISS is the Ericsson HT. The 5 watt downlink and shadowing from the spacecraft structure (depending on the orientation of the ISS) leads to varying signal strengths at the ground station.
A real-time packet log of the 145.825 ARISS signals that have been satgated displays at http://www.ariss.net which is a different page from the ariss.org page I mentioned. If there are no satgate stations near you in India then this may not show much except to gauge prior packet activity on orbits approaching your QTH.
Hope this helps some ... -- 73 de JoAnne K9JKM [email protected] Editor, AMSAT Journal
Hi again Rupesh,
we are not able to receive data on the software screen. whenever we have a pass of ISS some signals are detected and a receiving led glows even in squelch on.
I forgot to mention this in my previous e-mail. If you have your packet station working in both directions, transmit and receive, with terrestrial signals then you will have better luck with signals from space.
I use the APRS beacon frequency 144.390 MHz for testing my packet configuration on receive. I live near a large city (Chicago) so this frequency always has plenty of strong signals. That way I do not have to wait 90 minutes or longer for the next ISS pass. The APRS beacons and local digipeaters have strong signals so that ensures that I am receiving packets with a good checksum (to overcome the software TNC's somewhat rigorous demand for checksums) at which point I can read the messages on UISS, UZ7HO, UI-View, or hardware TNC, etc. I then QSY back 145.825 for ISS packet operating.
Also, try receiving the digital telemetry beacon from FUNcube-1, AO-73. The BPSK downlink is on 145.935 MHz. You will need to set the TS-2000 to receive USB instead of FM (and tune for Doppler). The FUNcube Dashboard software for receiving and decoding the BPSK signal can be downloaded from funcube.org.uk. I get good signals with just a 3-element 2 meter beam with fixed elevation and turned with a TV antenna rotor.
-- 73 de JoAnne K9JKM [email protected] Editor, AMSAT Journal
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JoAnne Maenpaa -
Rupesh Lad