QRP Labs U4B-2

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U3S

Live tracking
Day 60 update: 26-Apr-2020 (Final, RIP)
Day 59 update: 25-Apr-2020
Day 58 update: 24-Apr-2020
Day 57 update: 23-Apr-2020
Day 56 update: 22-Apr-2020
Day 55 update: 21-Apr-2020
Day 54 update: 20-Apr-2020
Day 53 update: 19-Apr-2020
Day 52 update: 18-Apr-2020
Day 51 update: 17-Apr-2020
Day 50 update: 16-Apr-2020
Lap three updates
Lap two updates
Lap one updates
Launch photos
Transmitter

This is the 2nd test flight of the new U4B tracker. For details see below.

U4B-2 was launched by Dave VE3KCL on 01-Mar-2020 early in the morning (1210Z). The transmitter callsign is VE3KCL and telemetry channel 04 (in the old system way of looking at things). Transmissions are on 20m only. Standard WSPR transmission at :08, :18, :28 etc past the hour, followed by the telemetry packet at :10, :20, :30 etc.

Live tracking

Day 60: 26-Apr-2020 (Final, RIP)

There was no Day 60... overnight on 25-Apr-2020 to 26-Apr-2020 U4B-2 came down. Run out of gas, presumably. There are clues in the altitude plot, see below, this is an extract of the altitude data, for the last 7 days of flight. Some altitude change is normal. But you can see a distinct trend in altitude loss right there on the last day.

RIP, U4B-2, that was an AWESOMELY great flight. AWESOMENESS overload. 1 month, 24 days. 124,000 km. And 3.5 laps around the planet Earth. 

DOWNLOAD of the Excel complete data set for this flight, CLICK HERE.

Day 59: 25-Apr-2020

Day 58: 24-Apr-2020

Day 57: 23-Apr-2020

Day 56: 22-Apr-2020

Day 55: 21-Apr-2020

Day 54: 20-Apr-2020

Day 53: 19-Apr-2020

Day 52: 18-Apr-2020

Day 51: 17-Apr-2020

Day 50: 16-Apr-2020

Day 49: 15-Apr-2020

U4B-2 completed circumnavigation number 3!

Day 48: 14-Apr-2020 (again)

Day 47: 14-Apr-2020

Day 46: 13-Apr-2020

Day 45: 12-Apr-2020

Day 44: 11-Apr-2020

Day 43: 10-Apr-2020

Day 42: 09-Apr-2020

Day 41: 08-Apr-2020

Day 40: 07-Apr-2020

Day 39: 06-Apr-2020

Day 38: 05-Apr-2020

Day 36: 03-Apr-2020

Day 35: 02-Apr-2020

Day 33: 31-Mar-2020

Day 32: 30-Mar-2020

Day 31: 29-Mar-2020

Second circumnavigation completed!

Day 30: 28-Mar-2020

Day 29: 27-Mar-2020 (again)

Day 28: 27-Mar-2020

Day 27: 26-Mar-2020

Day 26: 25-Mar-2020

Day 25: 24-Mar-2020

Day 24: 23-Mar-2020

Day 23: 22-Mar-2020

Day 22: 21-Mar-2020

Day 21: 20-Mar-2020

Day 20: 19-Mar-2020

Day 19: 18-Mar-2020

Day 18: 17-Mar-2020

Day 17: 16-Mar-2020

Day 16: 15-Mar-2020

Circumnavigation completed, a complete lap of planet Earth! 

Day 15: 14-Mar-2020

Day 14: 13-Mar-2020

Day 13: 12-Mar-2020

Yes... 12th March AGAIN... because U4B-2 passes the international date line. 

Day 12: 12-Mar-2020

Day 11: 11-Mar-2020

Day 10: 10-Mar-2020

Day 9: 09-Mar-2020

Day 8: 08-Mar-2020

Day 7: 07-Mar-2020

Day 6: 06-Mar-2020

Day 5: 05-Mar-2020

The map (below left) shows reception reports of U4B-2 during the last 3 hours of operation today. 

Day 4: 04-Mar-2020

Day 3: 03-Mar-2020

Great excitement here at QRP Labs HQ today, when I got my 20m WSPR receiver dusted off and back in action after almost a year on the shelf. I was happy to record 14 reports as U4B-2 rushed across France and over the Mediterranean, and a smaller number of telemetry reports too. This is a list of the standard WSPR transmission reports:

                                                       Power       Reported         Distance
       Date        Call    Frequency  SNR  Drift Grid  dBm    W    by         loc   km    mi
 2020-03-03 16:28  VE3KCL  14.097196  -29  0 	 JN40  +10  0.010  TA4/G0UPL  KM46  1793  1114 
 2020-03-03 15:48  VE3KCL  14.097195  -25  -1 	 JN41  +10  0.010  TA4/G0UPL  KM46  1811  1125 
 2020-03-03 15:18  VE3KCL  14.097198  -29  -1 	 JN41  +10  0.010  TA4/G0UPL  KM46  1811  1125 
 2020-03-03 14:48  VE3KCL  14.097198  -28  0 	 JN41  +10  0.010  TA4/G0UPL  KM46  1811  1125 
 2020-03-03 14:28  VE3KCL  14.097198  -25  -1 	 JN31  +10  0.010  TA4/G0UPL  KM46  1975  1227 
 2020-03-03 14:18  VE3KCL  14.097197  -25  0 	 JN32  +10  0.010  TA4/G0UPL  KM46  1996  1240 
 2020-03-03 14:08  VE3KCL  14.097196  -26  0 	 JN32  +10  0.010  TA4/G0UPL  KM46  1996  1240 
 2020-03-03 13:38  VE3KCL  14.097195  -23  0 	 JN32  +10  0.010  TA4/G0UPL  KM46  1996  1240 
 2020-03-03 13:18  VE3KCL  14.097195  -25  0 	 JN32  +10  0.010  TA4/G0UPL  KM46  1996  1240 
 2020-03-03 12:48  VE3KCL  14.097203  -24  0 	 JN22  +10  0.010  TA4/G0UPL  KM46  2157  1340 
 2020-03-03 12:38  VE3KCL  14.097202  -27  0 	 JN22  +10  0.010  TA4/G0UPL  KM46  2157  1340 
 2020-03-03 12:28  VE3KCL  14.097202  -29  0 	 JN22  +10  0.010  TA4/G0UPL  KM46  2157  1340 
 2020-03-03 11:58  VE3KCL  14.097202  -27  0 	 JN23  +10  0.010  TA4/G0UPL  KM46  2179  1354 
 2020-03-03 11:38  VE3KCL  14.097203  -25  0 	 JN23  +10  0.010  TA4/G0UPL  KM46  2179  1354

The receiver is built using two QRP Labs kits:

These two modules are mounted in an aluminium enclosure and powered at 12V using my homebrew linear-regulated radio PSU. Antenna is my OCFD. Along with those modules there's also:

  • 7805 voltage regulator to produce +5V DC for the modules
  • Some L-C filters (random junkbox chokes and electrolytic capacitors) to filter the DC some more
  • On/Off switch and Power LED
  • 12dB and 6dB attenuators which can be switched in or out, providing 0, 6dB, 12dB or 18dB of RF attenuation
  • Multi-turn trimmer potentiometer to set the audio level
  • 3.5mm stereo jack for audio output
  • 3.5mm mono jack where I can connect 1pps from my QLG1 GPS Receiver kit http://qrp-labs.com/qlg1 to calibrate the oscillator reference. 

Some photos below:

U4B-2 continued transmitting until long after dark, the final transmission showed a temperature of -39C and battery voltage of 2.39V, but it was still getting reports! Note that the temperature may not be reliable since the supply voltage is below the specified voltage for the LM temperature sensor; and below 2.7V the GPS module isn't able to provide a position fix either. 

Day 2: 02-Mar-2020

Day 1: 01-Mar-2020

Launch photos

Transmitter

This is the 2nd test flight of the new U4B tracker. U4B-2 was assembled by Dave VE3KCL. This YouTube video explains the features of the U4B tracker. 

The U4B-2 flight features a change in the firmware, which allows the Si5351A Synthesizer to drive the two sides of the dipole in anti-phase, rather than just one side against ground in previous flights. The result is a 3dB increase in output power. High or low power can be controlled also via the BASIC program; for the time being, the I variable is used to control whether high power (I = 1) or low power (I = 0) is used. In this flight, high power is used if the battery voltage is above 3.8V. When the battery voltage falls below 3.8V the system is switched to low power by setting I = 0. 

The BASIC program listing:

5 LET C = 41
10 PRINT BT
11 IF BT < 3200
12 SLEEP 10 1
13 GOTO 10
14 ENDIF
15 LET FR = 27000001
20 OUT 9 0
25 GPS 300 "$PSIMNAV,W,3*3A"
26 OUT 9 CL
28 SLEEP 10 7
30 PRINT BT
32 IF BT > 3800
33 LET I = 1
34 GOTO 40
38 ENDIF
39 LET I = 0
40 CW 0 14097235 12 0 "_VE3KCL"
45 CW 2 14097235 4 10 "TT"
55 TELE
60 GOTO 15

 Photos