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HPTx found off. Replaced keying transistor. 1254 UT running with HPTx.
HPTx off again, continue with low power amplifier.
Sounder had stopped at 16:18:25 UT on 15 Jan due to 10MHz ref cable problem. Replaced coax between Ailtech and power splitter unit. 08:13 UT running again.
R11 & R12 in HPTX & keying transistor replaced.
1243 UT: sounder running again with HPTx (robust 6-ant 4-pulse)
10:37 UT stopped sounder due to extreme weather forecast.
MTR back from Lindau after 2 months away. Changed CLUSTER.SCH to run the 8-pulse soundings instead of the 4-pulse soundings.
1019 UT: HV fuse and filament suddenly went. Continue on low power (300W) amplifier.
the DOS date was wrong for the following soundings, but the time was
correct:
tr064631.b_g.-tr064638.b_g add 1 day
tr064639.b_g.-tr064640.b_g add 2 days
tr064641.b_g.-tr064642.b_g add 4 days
tr064643.b_g.-tr064874.b_g add 5 days
During a skiing tour of inspection of the Dynasonde receiving antennas
on 17 Feb 1997 I found two of the wires connecting dipole tubes to the
pre-amplifier broken. (in both cases it was a crimped cable foot which
had broken, suggesting that it may be better not to use crimped foot but
bolt the more flexible wire directly under a bolt with washer). They appear
to have been like this for some time and I/we need to do some detective
work to determine when this happened for each antenna. I suspect it happened
this winter during the rather extreme weather we have been having. Plots
of amplitude vs time from the various antennas may help detect when it
happened. Bill’s analysis programs may help here. The broken wires were
to the southern half dipole element of the S antenna and to the northern
half of the s (new_south) antenna. The wires were repaired at 1405 UT (S
antenna) and 1419 (+/- 2mins) (s ant) on 17 Feb 1997 After the repairs
I noticed much better traces below about 2 MHz which is perhaps not surprising.
Ionospheric conditions may also be a contributing factor, however.
Implications:
Apart from the reduced signal amplitudes on the s and S antennas, the phases
will also be affected. I think that this can be expressed as a shift in
these antennas effective position by half the dipole element length (i.e.
half of 11m) in the direction of the remaining element. Such a correction
would need hard coding in an analysis program.
Found PC clock to be wrong again. MCRO reports this is a bug in CRMCLK
which appeared on 1 Jan 1997. The affected files are: tr064978.b_g to tr065084.b_g
where 1 day needs to be added to their date (19 instead of 18 Feb 1997).
D-region API experiments with very good results.
Measuring the new 50 Ohm calibration cable with a cable cable tester (TDR) we found it to be open after about 290m ! It appears to be broken possibly explaining the strange results (and lack of them) I have been getting with it.
Decided to start this diary to inform Dynasonde users of important facts which I otherwise write in the log book and may stay buried there. Stuff before this date will be filled in as time permits.
Made some test soundings with 8192 us inter-pulse period. Only 100 Hz Tx rate is changed, all else same on CRAM board. Hardware works but first result disapointing in that few echoes were found and many (>800) lost echoes. As a result the AGC did not function correctly even after trying AGC=1 and AGC=4. Need to investigate this (software ?).
That buggy CRMCLK causes the date to change when setting the time! Consequently soundings TR000926.P_G to TR000942.P_G and TR065871.B_G to TR065990.B_G need 1 day subtracted. Further, TR066002.B_T to TR066002.B_T need 1 day added.
Managed to get the 8192us soundings working. Needed to reduce the number
of heights to process in the shorter time available. Shows that AGC=4 unusable
with PRE interference, but the original AGC=1 works. Recorded several 4-pulse
and 8-pulse soundings (Still on low power amplifier). These are obtainable
as http://www.eiscat.uit.no/heating/Dynasonde/data/b4p-122.zip and b8p-122.zip.
Soundings TR066002.B_T to TR066041.B_T (with a few B_G in there) have an
inconsistency between header information and actual parameters in that
the stored 10000us Inter Pulse Period is really 8192us.
Removed HPTx for repair. Continue running on A300. Will replace HV capacitors in bias supply which look very old and dried out.
Record snow depth in Tromso of 1.98 m !
Ran a set of soundings overnight to compare AGC=4 cf AGC=1: Results in a short AGC report
Put in new capacitors, keying transistor and HV fuse. In testing with hand transmitter controller the Variac fuse (not HV fuse) blew at the end of a sounding with 6kV and 12-13A peak current. Fault in HV power supply. Opened it to find arcing around the vacuum relay (RL7 and R3 which is 1K, 225W).
Try to find new vaccum relay. Testing 24 and 5V power supplies but appear OK. Running B-mode and K-mode in succession, every 6 mins for CP-2 veloc comparison. A300 connected directly to antenna. Note that FAIS thinks the HV is on when it isnt because, apart from the A300, the transmitter hardware is all off.
More API experiments at 4.544 MHz with excellent D/E region signals.
(These experiments involve the Heater, see API.
Ordered Vacuum relay(s).
HPTx back together again, but continueing running on only A300.
Another skiing tour of inspection of the Dynasonde antennas. The snow
accummulation since the last time is such as to cover the antennas in part
or even whole. Significant damage due to forces from snow and ice since
last tour a few weeks ago.
(new) s antenna support cable broken on northern end of the northern half-dipole.
End hanging down on snow about 70cm from horizontal.
S antenna: inner end of each half-dipole under snow by 10-20 cm. cleared
snow so dipole is a surface level.
E antenna: eastern-most half dipole fully under snow up to about 50 cm.
Partly uncovered it to find the inner support cable broken so dipole drooping
about 10 cm.
N antenna: centre part of northern half-dipole covered by snow. Uncovering
it reveals fractured tube so that it droops about 70cm in the middle. Electrically
still "whole".
After re-assembling HV power supply last week with new higher voltage rating (10kV) vacuum relay etc., switched on HPTx and left running B-mode every 12 mins over Easter.
Another ski tour: Tied up the drooping north end of s and inner end of E antennas, and supported fractured N antenna with wood. E antenna still under snow and suspected fractured also.
After a weeks successful operation of HPTx we thought it was fixed, but no, the same (or very similar)symptons to those on 7 Jan 97 re-appeared: HV and Filament switching off with 3 fault LEDS lit, TEMP, PRESSURE and PEAK I. HV fuse blows but keying transistor survives. Happened twice today.
Some API experiments. Poor results
Some API experiments. Some positive but poor results. UHF running CP-3.
Ski tour of the antennas. Snow much higher. E ant dug out of snow which
was about a meter above it. Antenna not damaged though. S ant which was
3/4 under snow was dug out. s and N ants partly under snow.
Killed mouse on dynserv PC through static charge.
Dyn PC clock 12 secs slow. Corrected.
UHF radar changed to CP-1: sounder running alternate B and K-modes, every 3 minutes. (Low power though).
API experiments with poor results
API experiments with poor results
New snow record in Tromso: 2.04m
New snow record in Tromso: 2.18m
Start UK heating campaign. 2 or 3-min B-mode soundings for parts of this and the following days. 4-pulse B-modes often used because the old files were so configured.
New snow record in Tromso: 2.27m
New snow record in Tromso: 2.34m
New snow record in Tromso: 2.40m
Last day of UK heating campaign. Leave the sounder running 8-pulse Bmodes
every 12 minutes. Unfortunately still with the low power amplifiier because
we have not had time to fix it and we have a Heating engineer on sick leave.
I leave for MPAe, Germany.
Thorstein discovered the sounder PC clock was 2 days out ! (again). The old CRMCLCK routine had krept back in via the DOBOOT configurations which I thought I had updated. This fault probably since 30 April but needs checking.
Ski tour of antenna inspection. Still about 1m of snow under antennas. No further damage. North antenna half-dipole still droops about 1 m but not severed.
Replaced D14 (varistor) which so far has not been replaced, and new keying transistor (Q8) even though previous one may still be OK. HPTx works ! Ran IDI mode from 9-14 June (UK experiments) with good mesospheric echoes at times.
HV fuse blew overnight. Leave HPTx off.
Thorstein and helper repaired the receiving antennas.
GE heating campaign. Sounder run more often and faster, but poorer data due to heater operation and lack of HPTx.
API experiment with good mesospheric signals. No signals with tilted beam as expected.
Decided to leave sounder off as I leave for Lindau. No EISCAT experiments for a month or so, we are still on the low power amplifier, less data to archive on my return, and if anyone is interested in the ionosphere they can look at the digisonde (http://digisonde.phys.uit.no/cgi-bin/latest.exe?).
University of Tromso people re-arranged the PRE transmitter connections to transmit only on the north-west quadrant whereas formerly it was the whole array (but with some faulty antenna connections).
Sounder started again. Thorstein found fault in Tx antenna, I quote: "I walked a short trip under the Dynasonde TX antenna which has not been too closely inspected this year it seems... I could see a total of three faults, two of them on the outmost 'element' (longest, low f), hanging down to ground at the ends. The last fault is about three metres from the feed point, wire being broken and hanging to ground. ... The fault closest to the feed can be easily fixed by soldering, but the outmost ones requires down-hoisting of the antenna. This will take about one days work." (It turned out the NW wire was broken at the end near mast, while the SW wire was broken near mid-point).
UK/GE heating campaign.
Significant snowfalls.
After rain and partial snow thaw, repaired parts of Tx antenna. The
longest (outermost) wire to north-west mast, which hung down to ground
due to break near mast was spliced about 30cm from end (at a previous repair,
1995?). A smaller wire near centre was soldered, and the feed from balun
to the antenna was improved by soldering copper wire and bypassing a corroded
screwed connection. A vertical wooden post near centre secured. The other
long broken wire from outermost wire to south-west mast still not fixed.
Put in a new HV fuse. It works, touch wood !. So previous blown fuse from
July did not blow the keying transistor. Running on HPTx until further.
Evening rocket launch window 19-01 UT for Tim Cain sporadic-E rocket.
Started tests with varying AGCH and AGCL in the *.cfg files to see the effect on getting weaker echoes in the presence of strong ones. (Preliminary finding: increasing AGCH from 75% to 85% and decreasing AGCL from 29% to 40% seems to increase the number of echoes under quiet conditoons). No permanent change implemented pending further tests.
Afternoon: Fixed remaining broken long wire in SW quadrant which was hanging down from the wooden mast end and perhaps shorting to ground. Hopefully the lower freq transmissions are better. Cannot see the effect on forward and reflected power since the front panel of the HPTx, which contains those meters, is still off.
Try tests with AGCH=85 (new) and AGCL=29 (as before).
Rocket launched from Andennes reaching apogee at 20.02 UT into sporadic
E layer.
Switched Dynasonde off for Christmas break.