[ present & archived diaries ]
- 15 February
Calibrations using 1200 Ohm resistors on the pre-amp inputs.
- 23 March
Removed the Kenwood low pass filter between A300 amplifier and the HPTx.
This had been put in (when ?) in an attempt at removing harmonic interference
we sometimes generated. The real cause was most likely poor antenna matching/connections.
- 8 March
Test with the Leicester Datong active antenna connected to our system.
See report by Bill Wright on the conclusions.
- 10 March
about 1257 UT noticed the 40.625 MHz local oscillator (Schomandl ND60M)
has an unstable output showing on the meter. The output amplitude jitters
sometimes and goes far too high. Is this a phase detector(s) was found
damaged last summer ?
- 13 March
Unstable output of ND60M fixed: fault was in the -14V power supply. It
was intermittently shorted by a faulty tantalum capacitor in the output
- 25 April
Replaced attenuator relay unit in IF module (#16) of Rx 1 (upper one) with
a repaired one. (Note that they were replaced in Nov 1995 also !)
- 26 April
From now on B-modes should all be using JWW's "new" 4-pulse,
robust 6-ant scheme.
- 10 July
- 22-26 July
PMSE experiments using Heater Tx
- 29 July
Looks like attenuators sticking again in Rx1.
- 1 August
Installed the latest version of FAIS (V3.30) which uses BMODE34, SCHEDL32
and separate latest.dat and locals.dat files.
- 4 August
Replaced the 16 dB relay in IF module (#16) of Rx1. (MTR)
Sometime late October a new 50 Ohm calibration cable was put down.
- 16 October
Tests with alternate 4-pulse and 8-pulse soundings, variable ECOID.
- 19 October
Strange things with dynasonde PC: Probably some static caused BIOS not
to recognise the hard disk, and ethernet card (Etherlink-2) was blown.
Put in 3COM etherlink-3 card from Stein's old PC. Manualy re-entered HD
- 11 November
10:48 UT, stopped 8-pulse soundings, revert to 4-pulse robust 6-ant as
default but 8-pulse for special requests.
- 15 November
Sounder stopped at 19:21 UT on 14 Nov due to loss of 10MHz reference. Found
broken co-ax between Ailtech and clock-modifier unit; replaced and running
08:00 UT. (SE)
- 19 November
Noted Rx1 attenuator sticking again. Turns out to be the 16dB relay in
the IF module (#16). (The very one which I replaced in August !). This
time we put in one of our brand new attenuator units and we'll see how
long this lasts.
- 16 December
08:30 UT sounder stopped to repair HPTx. Keying transistor replaced. 10:36
- 17 December
07:16 UT, sounder stopped because of missing 10MHz reference. Changed coax
between power splitter (after Ailtech) and "Sync modifier box"
which goes to CRAM board.
- 19 December
13:01 Running B12MIN.SCH which is now 8-pulse.
- 31 December
HPTx found off:- blown HV fuse, keying transistor etc. Run on A300.
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