Whining on frequency?
Thread Starter
Joined: Oct 2005
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From: Despite the handle - am now about 10d east of 'BCN'
Whining on frequency?
Hi,
Something I've long wondered is why some aircraft's radio transmissions carry with them a distinctive whine?
Its far less common that it once was - but it was very noticeable when a certain Nordic operator's MD82 came on frequency the other day - kind of took me back to the 1980s !
What is it? is it a fault that has developed? or is it a property of poor voltage regulation and bad design on some radios?
Cheers
Something I've long wondered is why some aircraft's radio transmissions carry with them a distinctive whine?
Its far less common that it once was - but it was very noticeable when a certain Nordic operator's MD82 came on frequency the other day - kind of took me back to the 1980s !
What is it? is it a fault that has developed? or is it a property of poor voltage regulation and bad design on some radios?
Cheers
Joined: Jan 2003
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From: The Heart
Probably the 'certain nordic airline' 's pilots prefer using the hand mike, which picks up more background noise, to wearing a headset.
I seem to remember a certain nordic airline being criticized for not hearing ATC transmissions (in connection with a TCAS RA report, if memory serves) for the same reason. It was recommended that they use headsets.
I seem to remember a certain nordic airline being criticized for not hearing ATC transmissions (in connection with a TCAS RA report, if memory serves) for the same reason. It was recommended that they use headsets.
Joined: Mar 2002
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From: The Dark Side
This used to be a common problem with Ansett and I believe that Qantas still experience it.
The ex-pat Engineers tried to troubleshoot it but could never reproduce it although our Aussie colleagues had it every time.
It remained one of lifes great mysteries.
The ex-pat Engineers tried to troubleshoot it but could never reproduce it although our Aussie colleagues had it every time.
It remained one of lifes great mysteries.
Joined: Mar 1999
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From: KDEN
The whine you hear is probably right at 400hz, one can hear it in many birds, it is the same frequency as the aircraft's AC systems. The bulk of the electrical power used on the aircraft is of this frequency, so it can be expected to bleed through from time to time. You can hear the identical noise standing next to a jetway power supply - also 400hz. One also notices that its never heard from small, piston aircraft with an exclusively DC electrical system. Lots of other squeals and scratchiness, but never the 400hz hum.
