PSK31 and APRS CubeSat Status Update

PSAT PSK31 FM Downlink received by Martin G8JNJ at 1429 UT May 22, 2015 using the online SUWS WebSDR

PSAT PSK31 FM downlink received by Martin G8JNJ at 1429 UT May 22, 2015 using the online SUWS WebSDR

Martin Ehrenfried G8JNJ reports receiving the PSAT PSK31 FM downlink on the online SUWS WebSDR located at Farnham near London.

Bob Bruninga WB4APR has posted two updates on May 21 and May 22 to the AMSAT Bulletin Board about the three USNA CubeSats PSAT, BRICSAT and USS Langley along with a guide on how to use the PSK31 transponder. These can be seen below.

Status Summary – Day 2 – May 21

We now have heard 4 of 5 transmitters from our 3 spacecraft all still in a close cluster:
* PSAT packet is OK but WOD not working (no digipeating for users yet)
* PSAT PSK31 downlink is ok [remember, it is FM!]
* BRICSAT telemetry has been heard but is cycling OFF due to low power
* BRICSAT PSK31 downlink (also FM) has also been heard barely (when ON)
* USS Langley not heard

28 MHz PSK31 Receiver Board Flight Prototype - Brno University of Technology

28 MHz PSK31 Receiver Board Flight Prototype – Brno University of Technology

PSAT CPU shows the 4 day-fail-safe backup reset circuit is not counting down, so we have lost this (1 of 3) fail safe backup RESET capabilities. Bad line of code already found.  But cannot change it.

PSAT is not properly reporting WOD data and S#… STATUS packets are being bundled until 255 byte packet length is reached and then it all comes down at once.  Noone has captured any of these long packets.  Please try with PASSALL ON so that you can receive partial packets.

Awaiting permission from Brno University of Technology to authorize HF user uplinks on PSAT PSK31. UPDATE May 22 Here is the announcement from Brno University: “We can uplink open to all users. Please, do it.”Mirek OK2AQ.

BRICSAT PSK31 transponder is on identical frequencies as PSAT’s.  You can tell them apart because one has PSK Telemetry on 315 Hz and the other is on 365 Hz.  Both on the UHF FM downlink 435.350 MHz

We’d LOVE to hear from USS Langley, and we’d love to capture one of those long WOD packets from PSAT.  Our ground station is only getting a few packets compared to some submissions from others.  Keep it up.

SUMMARY:

145.825 1.5U  CubeSat – PSAT 1200 baud AX.25
435.350 same CubeSat – PSAT PSK31 FM – Brno University transponder

437.975 1.5U  CubeSat – BRICsat 9600 baud
435.350 same CubeSat – BRICsat PSK31 FM – Brno University transponder

437.475 3.0U  CubeSat – USS Langley 9600 bd

ULTRASat3 
1 99993U          15140.67013889  .00040043  00000-0  10235-2 0 00009
2 99993 055.0004 339.9238 0251027 182.3314 074.3075 15.12517086000014

Bob, WB4APR

Status Summary – Day 3 – May 22

* PSAT packet telemetry is OK, Digipeater will be off (secondary mission)
* PSAT PSK31 transponder is ON with 28.120 MHz uplink! (primary mission)
* WOD data fixed.  Spin data now available.  Right now it is at 3 RPM with
+Z pointing at Sun
* Launch TLE elements (below) are 6 minutes ahead of satellite
* PCSAT.APRS.ORG web page is now also capturing PSAT telelmetry downlinks
* BRICSAT telemetry has been heard but is cycling OFF due to low power
* BRICSAT PSK31 downlink (also FM) has also been heard barely (when ON)
* USS Langley not heard

Only fault so far is the loss of the 4 day-fail-safe backup reset circuit
(1 of 3) fail safe backup RESET capabilities.  The lack of WOD data was
because we had a LOW-POWER bits set that was holding it off.

BRICSAT PSK31 transponder is on identical frequencies as PSAT’s.  You can
tell them apart because one has PSK Telemetry on 315 Hz and the other is
on 365 Hz.  Both on the UHF FM downlink 435.350 MHz

Bob, WB4APR

Receiving the PSAT PSK31 FM downlink

BRICsat 435.350 MHz FM PSK31 signal received by Tetsurou Satou JA0CAW at 2057 UT on May 22, 2015

BRICsat 435.350 MHz FM PSK31 signal received by Tetsurou Satou JA0CAW at 2057 UT on May 22, 2015

Receiving the PSAT (and BRICsat) 435.350 MHz FM downlink is as simple as placing  your PSK31 laptop microphone next to the speaker on your FM satellite UHF receiver and just watching the waterfall.

What you see is exactly what everyone else sees (it’s FM).  There is no Doppler added to the tones due to your station’s position relative to the satellite.  But you DO have to retune your FM radio at least 3 times during the pass (+5 kHz, 0, -5 kHz) to stay in the FM passband. [Note: UK users should remember to selected the wide FM (5 kHz deviation) filter setting on their rigs]

User uplinks, however, will shift in the waterfall according to each user’s position relative to the satellite.  The shift can be as low as 1 Hz per second to as high as 6 Hz per second.  This is because the uplink is on 10 meters where the Doppler rate is only 1/15th of what it would be on UHF.

The TELEMETRY channel at 315 Hz (PSAT) or 375 Hz (BRICsat) is FIXED with no Doppler since it is generated onboard into the FM downlink

WHAT TO DO:

1) We will need PSK31 authors to open the PSK31 frequency tracking to accommodate more than 1 Hz per second Doppler tracking.  Current implementations can do 1 Hz/s but completely fail at 3 Hz/s.  2 Hz/s might work a little…

2) Until then, ANY uplink user that is in line with a direct overhead pass will have minimum Doppler at the start and end of his pass (1 Hz/sec) when the satellite is going right at him and directly away from him.  (Though it will be MAX (6 Hz/sec) when it passes over her/his station).

3) Just turn on MULTI CHANNEL window and let the PSK31 decode everyone.The ones with the least Doppler at any instant may be decoded for a while!

USERS can transmit later when BRNO University says it has completed its tests.  Brno provided the transponders for use in the PSAT and BRICsat satellites.

So start preparing your station to TX PSK31 on 10 meters SSB and to receive the audio from an FM UHF rig on 435.350 +/- 5 kHz steps of Doppler.

DOWNLINK Limitations:  The UHF downlink signal is only 300 mW and so a UHF beam is needed on the downlink.

UPLINK RESTRICTIONS:  *NOTHING MORE THAN* a Vertical 1/4 wave or Dipole is authorized on the 10m uplink  and no more than 25 Watts (for now).

Remember a 1/4 wave vertical is the ideal antenna because it maximizes the signal at lower angles and tapers the signal as the satellite gets closer. This keeps  user uplinks about the same during a pass.  Strong stations just drive down the AGC and ruin it for everyone.

Use minimum power!!  Remember, this is crossband FULL DUPLEX so  you can see yourself in the downlink just like everyone else can see you.  Act accordingly.  And of course DO NOT TRANSMIT if you cannot see the waterfall  … Duh!

Enjoy!
Bob, WB4APR

ParkinsonSAT (PSAT) http://www.aprs.org/psat.html

Fldigi PSK31 software http://www.w1hkj.com/Fldigi.html

Listen to satellite signals in the 145 and 435-438 MHz bands from anywhere in the world using the online SUWS WebSDR located near London. Further details at https://amsat-uk.org/2014/08/15/suws-websdr-moves-to-new-site/

AMSAT-UK
Web https://amsat-uk.org/
Twitter https://twitter.com/AmsatUK
Facebook https://facebook.com/AmsatUK
Flickr https://flickr.com/groups/AmsatUK
YouTube https://youtube.com/AmsatUK
Yahoo Group http://groups.yahoo.com/group/FUNcube

APRS balloon heads for UK

CNSP-22 Predicted Track for February 26 to March 1, 2015

CNSP-22 Predicted Track for February 26 to March 1, 2015

An amateur radio balloon CNSP-22, call sign K6RPT-11, is crossing the Atlantic at an altitude of 11,150 metres and should reach the British Isles on Friday, February 27.

The solar powered around-the-world high altitude balloon was released by the California Near Space Project team from San Jose on Monday, February 23 and is expected to reach the UK on Friday. The APRS beacon should have a radio range of up to 400 km.

The amateur radio APRS frequency is not standardized world-wide. The USA uses 144.390 MHz FM while the British Isles and Europe use 144.800 MHz. It is understood the balloon will change frequency to 144.800 MHz when it reaches this side of the Atlantic.

See the K6RPT-11 APRS track at
http://aprs.fi/#!mt=roadmap&z=11&call=a%2FK6RPT-11&timerange=86400&tail=86400

California Near Space Project
Web http://www.cnsp-inc.com/
Facebook https://www.facebook.com/pages/California-Near-Space-Project/255864787858630
Twitter http://twitter.com/k6rpt

APRS http://www.aprs.org/

APRS frequencies used around the world http://info.aprs.net/index.php?title=Frequencies

APRS-UK Yahoo Group https://groups.yahoo.com/group/APRSUK

Tweeting via the ISS

International Space Station - Image Credit NASA

International Space Station – Image Credit NASA

Harold Giddings KR0SIV describes how he Tweeted using amateur radio and the International Space Station.

He says: I sent a message to the International Space Station, it transmits it back down to groundstations in its view and those stations send the message to the APRS-IS network. My server then takes the message parses out useful data and posts it to Twitter as a tweet.

The ISS has two amateur radio stations. One is in the Russian Service Module and uses a Kenwood D710 and can do Slow Scan Television (SSTV) as well as FM voice. The other is in the Columbus Module and uses Ericsson handhelds for 145 and 435 MHz FM, the 2395 MHz HAM-TV system is also in this segment of the space station. In addition to voice contacts the 145 MHz Ericsson handheld is used to provide the APRS packet radio digipeater used by Harold.

Watch Twitter on the International Space Station

Ham Radio Tweets
http://hamradiotweets.com/
https://twitter.com/HamRadioTweets

How to hear the ISS https://amsat-uk.org/beginners/how-to-hear-the-iss/

How to work the ISS on APRS Packet Radio
https://amsat-uk.org/beginners/how-to-work-the-iss-on-aprs-packet-radio/

Help needed to track 144.390 MHz APRS Balloons

James Cutler KF6RFX and Benjamin Longmier KF5KMP - University of Michigan

James Cutler KF6RFX and Benjamin Longmier KF5KMP University of Michigan

Benjamin Longmier KF5KMP and his team are looking for stations in the Azores and Portugal to help track their balloons.

On the UK High Altitude Society (UKHAS) group he writes:

My team (Project Aether) launched a balloon recently that did a lap around the Midwest in the US, headed East past Nova Scotia and is still floating strong. We don’t have any contacts in the Azores or Portugal, and are requesting help in contacting some of these folks that might be able to decode our APRS packets.

Tactical callsign: Aeth21-9
APRS track: http://aprs.fi/#!mt=terrain&z=9&call=a%2FAETH21-9&timerange=259200&tail=259200
144.390 MHz FM

We also have two more experimental balloons that will be heading into the Atlantic within ~24hrs.
Tactical callsign: Aeth22-1
APRS track: http://aprs.fi/#!mt=terrain&z=7&call=a%2FAETH22-1%2Ca%2FAETH22-3&timerange=259200&tail=259200
144.390 MHz FM

Tactical callsign: Aeth22-3
APRS track: http://aprs.fi/#!mt=terrain&z=7&call=a%2FAETH22-1%2Ca%2FAETH22-3&timerange=259200&tail=259200
144.390 MHz FM

Thanks for any help!
-Ben
email: longmier at umich.edu

Links to balloon beginners guides and tracking information
https://amsat-uk.org/beginners/balloons/

Diwali Return for APRS Balloon Payload

Dhruva Space Balloon Payload

Dhruva Space Balloon Payload

The payload of the Indian amateur radio APRS balloon launched on October 13, 2013 has been successfully retrieved.

The balloon payload was returned to Dhruva Space on November 3 during Diwali (Festival of Lights).

The balloon had been launched from the Indian Institute of Astrophysics, Bangalore and drifted into the Arabian sea, off the coast of Udupi. Ham radio operators in Karnataka and Goa in India, and the Middle East and Africa were able to track the APRS signal, containing real time location, altitude and other operating conditions of the flight, for over 600 km into the Arabian sea.

The payload was found about 42.6 km off the coast of Gangoli, Karnataka on October 15 at 11 AM by the sailors of the fishing boat “Suvarna Lakshmi”.

It was only possible to trace the payload because one of the sailors used the sim card that was in one of the pieces of equipment in the payload.

Indian Record for Tracking Ham Radio Balloon
https://amsat-uk.org/2013/10/20/indian-record-for-tracking-ham-radio-balloon/

High Altitude Balloon to Study Comet ISON
https://amsat-uk.org/2013/09/28/high-altitude-balloon-to-study-comet-ison/

Ham radio operators set to help in tracking comet

Hindustan Times October 17, 2013

Hindustan Times October 17, 2013

After helping the Odisha government in disaster relief during cyclone Phailin, amateur radio operators will now help astrophysicists track a comet.

The Hindustan Times reports that astrophysics experts are joining hands with ham (amateur) radio operators to track and read data comet ISON, scheduled to pass nearest to the earth on November 28, 2013.

Scientists of Bengaluru-based Indian Institute of Astrophysics will send a balloon 40 km into the atmosphere to get data on the comet.

As the instruments drop with a parachute it will be a team of ham radio operators, who will track the APRS packet radio signal and retrieve the balloon.

Read the story at
http://www.hindustantimes.com/India-news/kolkata/Post-Phailin-relief-HAM-radio-operators-set-to-help-in-tracking-comet/Article1-1136224.aspx

TNC-Pi APRS packet radio review https://amsat-uk.org/info/tnc-pi-raspberry-pi-packet-radio-board/