Dynasonde diary

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2000

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 ?.
4 Feb 2000
Got HV ON again. HPTx working from 13:11 UT.
22 Feb 2000
The Preamp or antenna on the W(est) antenna has failed again. About 17 UT. You cant trust the skymaps and other parameters now.
24 Feb 2000
Made new CFG file (IDI-T3.CFG) where W antenna is replaced by E antenna. From 11:43 UT. I hope Owens software takes this into account. Perhaps this change will improve the IDI results which look pretty poor at present.
25 Feb 2000
Since about 0540 UT the West preamp seems OK again. It is milder today whereas it has been very cold. Could this be temp related ?
26 Feb 2000
At 1804 UT sounding West preamp failed again !
4 March 2000
First ski tour of inspection. Things look pretty bad with the ca. 1.5-2 m of snow we have. Tx antenna has several broken wires, the feed and first 2 m of height is all under snow/ice.
Also the receiving antennas are in poor shape. W ant about 1m above snow but the rest are at or below snow level. The s ant has the outer half dipole hanging on the feed wire to the preamp. Brought in the W preamp for repairs. Made a temp15.cfg file to replace btik15.cfg (at least during the midday hours) where W is replaced by E. This was an attempt to at least get more echoes instead of no signals even though the analysis will be all screwed up.
11 March 2000
Note that the modification to the original ANZAC preamp described in the manual (1N4153 diode added across base and emitter of each transistor) was not made to the new preamp put in W about a year ago. Made the modification to this same "new" preamp and put it back after tests showed it to work OK, just like the original preamp a year ago. Out at W antenna I see that the real cause of the missing W signal was a coaxial connector with inner pin too short so that only marginal contact was made. The weight of snow on the co-ax must have just pulled enough on the inner pin to break contact. This explains everything, including the normal voltage and current drawn by the preamp in spite of no practically no signal. This is because the dc voltage is fed to both balanced co-ax inner conductors via a transformer so the other co-ax supplied the dc current but the RF signal path was broken. 1835 UT W preamp back in action with new fuse to supply since I shorted it during replacement.
Also at 17:00 UT I reconnected the disconnected 1/2 dipole on the inner part of the E antenna which had fallen down (broken guy wires, since when ?). The guy was temporarily repaired. The other half dipole is still broken but electrically still connected. Also the S antenna has inner 1/2 dipole drooping due to broken support guy, but electrically still connected.
The IDI-T3.CFG file was changed to use W again instead of E.
16 March 2000
16:20 UT The 70cm droop at the non-preamp end of the outer half of the e antenna was fixed by rescrewing guy support into wood about 2-3 cm below original hole. This screw needs replacing: it is rusty. 16:35 UT the perhaps 30-40 cm droop at the preamp end of the E antenna outer half-dipole was fixed by new guy wire. 16:45 UT about, the preamp end of the inner E half-dipole was raised by 5-8 cm.
25 March 2000
Skied to Tx antenna. Dug out the feed transformer etc. and part of the south part of the log periodic antenna. Digging out the north part I found that it is broken about a meter from the central feed. So we are only transmitting on the southern half dipole ! Since when ? I would guess since some time in January when there was much snow. The problem is that a heavy layer of wet snow and ice about 1.5 m under the present surface has pulled the central part of the LPA down almost to the ground I would guess. This strain caused the north part to sever, and several wires on both halves to break at various places. This probably explains, at least in part, the poor echo detection seen especially noticeable near critical frequencies. A temporary wire across the snow could reconnect the fed to the north half. Maybe tomorrow.
26 March 2000
A wire is used to reconnect the 2 broken bits on the Tx antenna.
7 April 2000
Inspection showed both N dipole halves under snow and disconnected. The skymaps showed strange NS directions, and amplitude was practically zero. Broken wires due to weight of snow. At 15 UT both were reconnected again. The inner half of S antenna also broken.Temporary fix by 17:20 UT. Outer half also drooping but electrically still connected. E and e ants also under snow. W also under snow: dug out.
10 April 2000
Ski tour again. Inner half-dipole on S was disconnected (broken wire). Repaired at 16:18 UT. The s ant outer half dipole which was low by about 50cm was re-attached to its proper height. Several other antennas re-fixed, but were electrically still connected.
18 April 2000
Dynasonde clock 26s slow. corrected at 1741 UT
19 April 2000
I return to Germany.
8 May 2000
Power break
26 May 2000
Stein Eliassen died after a long struggle with cancer.
2 June 2000
PC clock 1 min and 54 secs slow. Corrected at 1356 UT.
3 June 2000
On arrival at 1122 UT found HV dump, with fil and HV off. PkI and AvI LEDS on, as well as Press and Temp. HV fuse blown. Replaced fuse and sounder went OK.
5 June 2000
Sudden HV dump, during B-mode sounding when f=2-3MHz. AvI LED on but not PkI, Temp and Press also on, but no HV fuse blown. Started sounder again. Strange.
9 June 2000
From 00 to 06 UT power break, Dynasonde on again about 08 UT.

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