[A-DX] Shortwave Transmission Faults

Fr Sep 27 13:04:03 CEST 2019


13/04/2019     Woofferton 15180kHz AM     Massive distortion (halfwave 
rectified audio).
Cause: Faulty sound card in audio source.
Once notified, they fixed it in about 4 minutes!
Good work, Woofferton Engineers!     recording available

17/04/2019     WINB 9265kHz AM     Severe phase noise/frequency wobble 
(from a faulty synthesizer?).
Despite being notified on April 17, the problem has not been fixed.
"Our engineer is out of the country at the moment", they said.
No reply to my follow-up emails. The problem continues!
This fault degrades reception, and severely degrades reception using AM 
Sync or SSB detectors.

02/06/2019     WWV on 10MHz AM     Distortion on low tones and voice 
Sounds like overmodulation, with simultaneous carrier phase modulation.
Probably due to overmodulation or PA/Modulator linearity problems.
Sounds very bad on SSB or AM Sync, and better on a normal AM detector.
NIST have been informed by email. No reply as of June 10.

08/09/2019     Nauen (Media Broadcast)
KBC 5960kHz     KBC broadcast due to start at 0000UTC started 7 minutes 
late at 0007UTC.
Once again, a very fast response to a transmission problem... (I am told 
"a transmitter arc")
But this is happening too often!
No longer can I say "Never a problem at Nauen"...

23/09/2019     WRMI 9955kHz     Significant 29Hz, 58Hz (and higher 
harmonics) phase modulation on the carrier, causing hum and buzzing.
Unclear whether the midrange buzzing is also phase modulation.
WRMI were contacted on 23/09/2019, but are denying there is a problem.
More data is being gathered.


Der WRMI-Brumm ist auch auf anderen WRMI-Frequenzen präsent, siehe hier 
das Sonogram von 5850 kHz,
während einer "TIAMS":