The RSGB have responded to the Ofcom Call for Input on Spectrum above 6 GHz for future mobile communications (5G) consultation.
The range of frequencies Ofcom are considering included the Primary amateur and amateur-satellite allocation at 47-47.2 GHz.
Read the RSGB response at
http://rsgb.org/main/files/2015/03/RSGB_Spectrum-above-6GHz_response.pdf
Ofcom consultation on spectrum above 6 GHz
http://www.southgatearc.org/news/2015/january/ofcom_consultation_on_spectrum_above_6_ghz.htm
Yaesu handheld and $50SAT 1.5U PocketQube
Saturday, February 21, 2015 marked the 15 month anniversary of the launch of $50SAT/MO-76, and you guessed it – it is still operating.
Thursday, February 12, 2015 marked a different milestone – its orbit has decayed to the point where its mean motion crossed the 15 orbits per day threshold. The TLEs from Saturday, February 21, 2015 indicate it is now at 15.00521293 orbits per day.
Some of you noticed that something odd started happening on Monday, February 23, and Tuesday, February 24. We also noticed the same thing – during daytime passes in the northern hemisphere, $50SAT was transmitting once per minute, always sending telemetry in RTTY format, but never sending GFSK telemetry packets. Moreover, the total reset count kept going up by one each time.
Here are all the RTTY telemetry messages (that I am aware of) gathered on Monday and Tuesday:
(daytime pass)
2015-02-23,08:57,KO33,EU1XX,$50SAT,128,,2392,,,56,3,,21,141,77,,2910,1492,3521,*74
2015-02-23,08:58,KO33,EU1XX,$50SAT,128,,2393,,,58,3,,21,139,77,,2910,1492,3440,*72
2015-02-23,08:59,KO33,EU1XX,$50SAT,128,,2394,,,59,3,,21,138,77,,2910,1492,3501,*71
2015-02-23,09:01,KO33,EU1XX,$50SAT,128,,2396,,,62,3,,21,135,77,,2930,1492,3460,*72
(daytime pass)
2015-02-23,17:01,EN82,KD8QBA,$50SAT,128,,2503,,,60,3,,21,137,77,,2910,1492,3440,*78
2015-02-23,17:05,EN82,KD8QBA,$50SAT,128,,2506,,,64,3,,21,133,77,,2890,1492,3400,*70
(daytime pass)
2015-02-23,17:04,EM13,WB2A0Z,$50SAT,128,,2505,,,63,3,,21,134,77,,2779,1492,3380,*74
2015-02-23,17:05,EM13,WB2A0Z,$50SAT,128,,2507,,,65,3,,21,133,77,,2890,1492,3400,*70
2015-02-23,17:06,EM13,WB2A0Z,$50SAT,128,,2507,,,66,3,,21,132,78,,2849,1492,3400,*79
2015-02-23,17:07,EM13,WB2A0Z,$50SAT,128,,2508,,,67,3,,21,130,77,,2970,1492,3380,*7E
2015-02-23,17:08,EM13,WB2A0Z,$50SAT,128,,2509,,,68,3,,21,129,78,,2869,1492,3339,*7C
2015-02-23,17:09,EM13,WB2A0Z,$50SAT,,,2510,,,70,2,,21,,77,37,3677,1492,3359,*70
(nighttime pass)
2015-02-23,18:15,LO24,R4UAB/KD8QBA,$50SAT,128,,2510,,,48,3,,21,146,78,,82,1492,3400,*7D
(nighttime pass)
2015-02-24,03:45,EN82,KD8QBA,$50SAT,128,,2654,,,57,3,,21,138,78,,102,1492,3440,*44
(daytime pass)
2015-02-24,16:57,EN82,KD8QBA,$50SAT,128,,2810,,,57,3,,21,140,77,,2910,1492,3481,*7E
2015-02-24,16:58,EN82,KD8QBA,$50SAT,128,,2811,,,58,3,,21,139,77,,2768,1492,3460,*70
2015-02-24,16:59,EN82,KD8QBA,$50SAT,128,,2812,,,60,3,,21,138,77,,2869,1492,3400,*71
2015-02-24,17:00,EN82,KD8QBA,$50SAT,128,,2813,,,61,3,,21,136,78,,2768,1492,3420,*7C
2015-02-24,17:01,EN82,KD8QBA,$50SAT,128,,2814,,,63,3,,21,135,77,,2849,1492,3380,*74
2015-02-24,17:02,EN82,KD8QBA,$50SAT,128,,2815,,,64,3,,21,134,77,,2829,1492,3380,*75
2015-02-24,17:03,EN82,KD8QBA,$50SAT,128,,2816,,,65,3,,21,132,77,,2809,1492,3359,*77
2015-02-24,17:04,EN82,KD8QBA,$50SAT,128,,2817,,,66,3,,21,131,77,,2910,1492,3400,*74
2015-02-24,17:05,EN82,KD8QBA,$50SAT,128,,2818,,,68,3,,21,130,78,,2829,1492,3339,*7D
2015-02-24,17:06,EN82,KD8QBA,50SAT,128,,2819,,,69,3,,21,129,78,,2849,1492,3339,*73
(daytime pass)
2015-02-24,17:03,EM13,WB2A0Z,$50SAT,128,,2815,,,64,3,,21,134,77,,2829,1492,3380,*75
2015-02-24,17:04,EM13,WB2A0Z,$50SAT,128,,2816,,,65,3,,21,132,77,,2809,1492,3359,*77
2015-02-24,17:05,EM13,WB2A0Z,$50SAT,128,,2817,,,66,3,,21,131,77,,2910,1492,3400,*74
2015-02-24,17:06,EM13,WB2A0Z,$50SAT,128,,2818,,,68,3,,21,130,78,,2829,1492,3339,*7D
2015-02-24,17:07,EM13,WB2A0Z,$50SAT,128,,2819,,,69,3,,21,129,78,,2849,1492,3339,*73
2015-02-24,17:08,EM13,WB2A0Z,$50SAT,,,2820,,,70,2,,21,1,77,35,3698,1492,3359,*4C
(nighttime pass)
2015-02-24,18:16,LO24,R4UAB/KD8QBA,$50SAT,128,,2820,,,48,3,,21,147,78,,82,1492,3400,*72
$50SAT Boards
What seems to be happening on the decending (daytime) passes is the CPU is reset just after sending a full RTTY telemetry message, as here are no GFSK packets sent, but within a half minute the FM Morse beacon is heard with Stuart’s callsign (GW7HPW, the first one in the rotation). My guess is the battery voltage is decaying during the operational cycle, and goes below the 2.9V reset threshold just after sending the RTTY or just as it is about to send the GFSK packets. Once the satellite is able to enable solar power (PCB temperature >= 0 degrees C), it starts behaving normally; it is now able to send GFSK packets. During ascending (nighttime) passes, it behaves normally, at least here in EN82 land.
There was a brief time where this behavior stopped (2015-02-25, 17:05 UTC through 2015-02-26, 3:47 UTC). It did, however, start back up sometime before 2015-02-26, 05:21 UTC, and has continued since.
Why is this happening now? We are still investigating, but it is apparent when looking at the chart of battery voltage over the lifetime of $50SAT/MO-76 that the battery has suffered a sizeable drop in capacity. If the battery voltage under load is dropping below 2.9V, how is it able to recover back above 3.3 V (the minimum required to enable transmission) and nearly complete another operational cycle? Moreover, why does it always seem to be able to finish sending an entire RTTY packet before resetting? In the hopes of better understanding what is happening, I am in the process of re-assembling my “BoxSat” test setup in an effort to reproduce on the ground what is happening in space. In the meantime, the once-per-minute transmission is actually convenient from telemetry monitoring standpoint, as one no longer has to wait 3 minutes for $50SAT/MO-76 to start transmitting. So, for any of you who have not heard $50SAT/MO-76, now is the time. Who knows how long it will continue to operate in this manner? Who knows how long it will continue to operated at all? Every time an anomaly has occurred and thought, “this is it – well, it was great while it lasted”, $50SAT/MO-76 has proven me wrong. I hope that is the case here as well.
The Dropbox has been updated with all the telemetry observations through today (Wednesday, March 4 2015), and can be accessed via the following URL:
I have also uploaded an MP3 file from the daytime pass over EN82 land on Friday, February 27, 2015 starting at 16:59 UTC (11:59 AM local time); it can be accessed via the following URL:
https://www.dropbox.com/s/2vfbtu51qn63aoa/50USDSat-LSB-FM-2015-02-27T1659Z.mp3
During the recording, I switch back and forth between FM and LSB modes so I can hear the FM Morse beacon as well as the RTTY telemetry.
Please keep the telemetry observations coming, especially now!
73 Michael Kirkhart KD8QBA
$50SAT/MO-76 team
$50SAT was a collaborative education project between Professor Bob Twiggs, KE6QMD, Morehead State University and three other radio amateurs, Howie DeFelice, AB2S, Michael Kirkhart, KD8QBA, and Stuart Robinson, GW7HPW. The transmitter power is just 100 mW on 437.505 MHz (+/-9 kHz Doppler shift) FM CW/RTTY. $50SAT uses the low cost Hope RFM22B single chip radio and PICAXE 40X2 processor.
There is a discussion group for $50SAT http://groups.yahoo.com/groups/50dollarsat/
50DollarSat http://www.50dollarsat.info/
The RSGB has responded to the Ofcom call for inputs to the strategic review of the 420-470 MHz spectrum.
The review includes the key Amateur 430-440 MHz and Amateur-Satellite 435-438 MHz allocations.
The consultation had been due to close on February 19 but was extended to February 26 to give more time for responses.
Read the RSGB response http://rsgb.org/main/files/2015/02/RSGB_UHF-Review_response.pdf
Ofcom: 420-470 MHz Consultation
http://www.southgatearc.org/news/2014/december/ofcom_420_470_mhz_consultation.htm
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
Paulo PV8DX of AMSAT-BR turned the recent Slow Scan TV transmissions from the International Space Station (ISS) into an education outreach opportunity for amateur radio.
On Monday, February 23, 2015 at the Gonçalves Dias school he explained amateur radio to the students and demonstrated receiving an ISS SSTV picture on 145.800 MHz FM.
The ISS pass he received did not produce a strong signal and only part of the picture was captured but as can be seen from the video the students were enthusiastic and excited to be receiving a signal from space.
Paulo expressed the hope that the ISS will send images on school days more often.
Watch ISS – SSTV , By PV8DX
AMSAT-BR https://sites.google.com/site/amsatbr/
Information on receiving ISS SSTV https://amsat-uk.org/2015/02/11/more-iss-slow-scan-tv/
ISS SSTV and Packet Radio signals on the SUWS WebSDR
Martin Ehrenfried G8JNJ reports excellent SSTV and Packet Radio signals from the International Space Station (ISS) using the online SUWS WebSDR.
144 MHz prototype helix antenna
The omni-direction helix antennas at the WebSDR were designed with high elevation satellites in mind. Conventional antennas concentrate the radiation pattern towards the horizon resulting in weaker signals when a satellite is above 15 degrees elevation. Comparisons with other WebSDRs show the SUWS antennas provide a 6 to 10dB better signal to noise ratio on similar passes.
Martin says: “I had been experimenting with single turn ‘twisted halo’ design, and decided to try stacking them to see if I could achieve more gain. Modelling suggested that a stretched 3 turn helix with a helix circumference of approx 1/2 wave length and an overall length of 1/2 wave at 70cm, and fed with a gamma match at the centre would offer reasonable gain, an omni-directional pattern and mixed polarisation.”
You can use the free online SUWS Web Software Defined Radio from your PC or Laptop to receive the ISS and the many amateur radio satellites transmitting in the 144-146 MHz or 435-438 MHz bands. It also provides reception of High Altitude Balloons in the 434 MHz band and coverage of the microwave 10368-10370 MHz band.
The SUWS WebSDR is located at Farnham not far from London, 51.3 N 1.15 W, listen to it at http://websdr.suws.org.uk/
Full details of the antennas are available at http://g8jnj.webs.com/currentprojects.htm
Brazilian radio amateur uses SUWS WebSDR to receive ISS SSTV
https://amsat-uk.org/2014/09/06/iss-sstv-on-suws-websdr/
ISS SSTV image 9/12 received by Martin Ehrenfried G8JNJ using the SUWS WebSDR on Dec 18, 2014
AMSAT-UK 
You must be logged in to post a comment.