Dynasonde diary

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1999

19 January 1999
Something in the HPTx has failed. HV can still be switched on (after fuse replaced ?) but no output pulses. Run on A300 driver only.
3 February 1999
Digisonde next door removed for upgrade. This means the "200Hz" prf sync to PRE is removed and PRE runs on its own internal oscillator, so that PRE interference drifts through our PRF, causing about 0.5 MHz holes in our ionograms at 2,75 MHz.
About 8 February 1999
PRE system changed their transmitter from about 20kW, linear polarisation, to 40 kW circular polarisation. Not good for us. They really blast through our attenuators. We must do something.
12 February 1999
We are providing 200 Hz for PRE, so they are in synch with us again.
27 February 1999
The first ski tour of inspection this year. No broken wires or antennas. Snow is only about 60 cm or so high.
7 March 1999
1725 UT, Updated the code for the real-time web display's with M. Pitteway's revised crafted code (e5 calculated later)
8 March 1999
1320 UT, Fixed HPTx. Keying transistor and 2 others had failed. One may have been due to our fixing attempts on Friday. Running B-mode every 6-mins for CP-2 run.
Also introduced linear-scale ionogramme on the Web display.
14 March 1999
I had noticed for several days now that the polarisation, shown in colour on the realtime web display had changed from its normal blue for O-mode to a darker color. Also the skymaps showed echoes centred on about 40 km West. This was back tracked to 22:30 UT on 10 March. Simultaneously the amplitude on the West antenna had dropped by half. (I am logging the mean amplitude from each antenna on: http://129.242.31.16/amplitud.txt since December 1998) Today I investigated the antennas again, thinking I would find broken wires but didnt. I brought in the pre-amp and replaced it with a new one, on the hope that that was the problem. It certainly was. The lack of signal could actually be seen on the scope, but you had to look for it.
Is this a case of the extra strong (ca. 40 kW since a few weeks ago) PRE/MF radar transmissions causing the pre-amp to fail ? I cant remember when a pre-amp failed last. And the West antenna is under and parallel to a PRE/MH dipole. We need to move our array ! Summary: Soundings from 22:20 UT on 10 March until 15:30 UT on 14 March have a faulty West antenna signal. (In this time we ran 6-min soundings up to 12 March as part of CP-2)
23 (+/- a day or so) April 1999
The Digisonde is back in town. However it is not locked to the reference frequency so drifts with respect to the MF (PRE) radar and us in the mean time. The upgraders also forgot or removed the 200Hz output previously used to synchronise with the MF radar (PRE). The university people will build some cicuitry so as to do this synchronisation better.
30 April 1999
Started e-mailing the RAL people our soundings on a regular (every 6 hours) basis again.
2 May 1999
Implemented and started running on a test basis real-time "Imaging Doppler Interferometry (IDI)" sounding analysis of mesospheric P-mode data. The soundings themselves are not saved but only the analysed data. See meso.ps for real-time output updated every hour. Thanks to Owen jones of BAS for this software.
29 May 1999
Dynamite analysis hung after 22:54 UT resulting in no more IDI soundings processed, and loss of B-mode soundings (why ? I thought I fixed this when the networked machine "disappears"). Fixed 31 May, 1240 UT.
18 June 1999
A power break last night (ca 22 UT) caused the power supply in the Ailtech synthesizer to fail. Dynasonde down until further notice. Hopefully up again next week.
21 June 1999
As a temporary solution the PM-3601 AM modulation section was put into the old Ailtech Mainframe. This seems to work. However ionogrammes look strange and synth status=135 instead of 0. Continuing running like this. The fault with the original synthesizer looks to be in the power supply area.
2 July 1999
Dynasonde Ailtech working OK again. Perhaps it had to do with the order of switch on of rec rack before PC ? Also keying transistor Q6 was blown. Q6 and Q8 replaced, but Q8 was probably OK. Running IDI6min for PMSE and Tidal campaign at EISCAT.
13 July 1999
Ran D-region API experiment at 5.423 MHz during heater-induced modulation of PMSE. Both successfull.
16 July 1999
Thunder and lightning. Power break after 21:55UT sounding.
21-22 July 1999
Did calibrations using 1200 Ohm resistors on preamps instead of antennas, as well as receiver-only calibrations.
02 Aug 1999
Between soundings TR170851.B_G and TR170852.B_G, i.e. between 23:30:29 and 23:40:00 UT, the HV/Fil cut out. (HpTx status changed from 255 to 244.) No obvious power break though according to the power monitoring log.
11 Aug 1999
Thorstein found HV and Filament had switched off. HV fuse blown. HV does not switch on with new fuse (which doesnt blow).
22 Sept 1999
Return to Tromso. PRE/Digisonde interference moved out of our recvr window. Some time in Sept PRE uses a new 200 Hz reference derived from EISCAT's frequency but movable with an advance or retard circuit. After this we can really synchronise properly with PRE and Digisonde.
24 Sept 1999
Start trouble shooting the HV problem from early Aug. Stopped IDI mode, since useless with just A300 amplifier.
16 Oct 1999
Running on the HpTx again. It turned out to be one, possibly 2 faulty tubes. (one showed low impedance between grid and cathode). IDI mode running again.
Sometime in November
PRE changed their synch pulse to the Digisonde's 200 Hz. Sometime later I see that we back to the situation where they are out by 5 ms at random intervals.
7 Dec 1999
PRE/Digisonde synch changed again, back to stable freq from EISCAT via divider to produce 200Hz which can then be moved. As a result we need to adjust our timing sometime...
24 Dec 1999
After a power break (between 6 and 7 UT) sounder down.
3 Jan 2000
Sounder back on IDI12min. However PRE interference not quite right I think, through most of Jan.
25 Jan 2000
10 UT: HPTx off since ?.
22 Feb 2000
The Preamp or antenna on the W(est) antenna has failed again. You cant trust the skymaps and other parameters now.

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