Dynasonde diary

2007

• 23 Jan 2007
  MTR back in Tromso. Moved PRE interference out of our receiving window. At 09:01:20 UT PC clock says 08:59:41, i.e. 1 min 39 s slow. Fixed.
• 15 Feb 2007
  Moved PRE interference down.
• 22 Feb 2007
  About 1514 UT found no RF out, etc. Ailtech synth gave no output. Put in the spare which is not very good (variable output with frequency).a
• 23 Feb 2007
  Noticed PC clock wrong: at 08:46:20 UT PC clock says 08:29:48 UT ! Fixed at 08:47 UT. Measured preamp currents: N 175.8 (179), E 176.5 (183), S 171.9 (178), W 265.3 (231), e 177.4 (182), s 129 .1 (188) mA. The values in brackets were measured by M Rose et al. on 22 Aug 2005. Note that thw W value is very high and the s value very low compared to the older values.
• 02 Mar 2007
  Ralf found the faulty chip in the Ailtech synth: A N82S90N (BCD output decade up counter) had failed. He replaced it with a 74196N chip. See Fig. 4-23 Board A4A5 in the manual. The repaired synth was put back in the dynasonde at 13:45 UT. The poor spare synth is now also being examined.
• 05 Mar 2007
  GPS reference oscillator faulty: antenna, no satellites being received. PRE interference drifts upward in range. Change over to Rb standard but still increasing in range. Rb standard can't be adjusted for faster.
• 7 March 2007
  : adjusted thunbwheel a little slower, to see if we can detect the change. It turns out the Rb is just running on the crystal, lamp broken no doubt.
• 9 March 2007
  Preamp currents: 179(N), 179(E), 175(S), 280(W), 176(e), 138(s). Ski tour of inspection. W ant has broken wire to the inner (centre or eastmost) half-dipole. Fixed about 14:56 UT. Dipoles about 1.4 m above snow. s antenna has droopingsouthern half dipole at outer support. Raised it by about 1m. LPA has 2 wires broken, hanging down. One from the SE top wire, corner, hanging in the trees. The other near the centre, also southern curtain.
• 13 March 2007
  I realised that we have been running the sounder from the internal Ailtech oscillator since its repair on 2 March. This explains the drifting PRE interference. Connected to external reference (based on the Rb standard which is probably only a crystal oscillator) at 15:42 UT. PC clock was 30s fast. Set at 15:43 UT.
• 16 April 2007
  Power break from about 09:50 to 10:27 UT After the sounder was started again, the dummy load was connected to the antenna until 17 April 2007. Therefore those soundings (TR682052.b_g to TR682239.b_h should be ignored).
• 19 April 2007
  About 10:55 UT Cable to transmitting antenna disconnected from LPA and moved to one side so that the MORRO radar antenna area can be levelled. Dynasonde switch off for some days.
• 26 April 2007
  Cable to HPTX was put through the 60m long drainage pipe under the MORRO radar area. 11:35 soundings were started again.
• 10 May 2007
  PC clock 1 min 16 s ahead. Fixed at 11:45 UT
• 15 May 2007
  Preamp currents: N 179 mA, E 180 mA, S 176 mA, W 359 mA !!, e 180 mA, s 125 mA.
• 5 June 2007
  , or earlier, HV off.
• 14 June 2007
  MTR back. HV fuse had blown. replaced it and all works again. But RF waveform looks ugly. Also out of the Tx mixer module. Xtal filter is bad. Removed XTAL filter and replaced it with a 100Ohm resistor. Pulse shape better but sharper than normaloff course.
• 18 June 2007
  Put Xtal filter from Recvr cha#2 detector module in the mixer module. But RF pulse very weak.
• 19 June 2007
  Found short circuit where xtal was soldered in. Fixed it.
• 22 June 2007
  No output from HPTx, but HV relay still on. HV fuse blown !! Must have happened about 05 UT today. Replaced fuse and all works.
• 26 June 2007
  Power break 13:08:22 to 13:23:24 UT. Switched off sounder, and examined preamps, esp W one. It was quite warm. Removed it.
• 27 June 2007
  Put back in an older ANZAC AM-107 preamp into W antenna. Preamp currents now: N, 178 mA, E 181 mA, S 175 mA, W 180 mA, e 176 mA, s 137 mA. Also fixed two broken wires on the south curtain of the LPA.
• 30 June 2007
  found HV and Fils both off ! Fault LEDs show pressure. HV fuse blown. Replaced and all works. Introduced 'HV off' orange text in the .gif plots in the real-time display.
• 2 July 2007
  Found HV fuse blown, since about Sat evening, 30 June. New fuse and all works.
• 24 Sept 2007
  Started doing soundings from 2.5 MHz, since I noticed that four out of the five last occurrences of HV fuse blowing without HV relay going were for frequencies less than 2.3 or so MHz. Three of these were around 1.7 MHz. Maybe the fuse won't blow any more ?
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