RON ' I do have twisted pair power supply lines to the strobe power
supply thanks.
PETE ' Thanks for that tip . . . . . LED Strobe will be considered if
all else fails.
JAN ' Comments / answers embedded below . . . .
Thank you all
Kingsley
From: Jan de Jong
Sent: Wednesday, December 23, 2015 7:36 PM
Subject: Re: Europa-List: Strobe noise in radio
I don't know what you mean when you say "chew chew"?
It is hard to describe a noise in words . . . =91Chew Chew=94 is the
best I can come up with I=92m afraid.
Does it appear when receiving radio or always?
Always ' whenever the radio is turned on. Volume of the noise can be
controlled with the Vol control.
The "chew chew" could be the power supply charging its capacitor after
each discharge?
Think you are right on the mark here Jan . . . . the noise immediately
follows the flash and it does sound like the power supply charging its
capacitor.
How did you prove that it is radiation coupling to the antenna?
1 Disconnected the power wires to the strobe unit to isolate the unit
---From the rest of the aircraft wiring and then supplied power from a
second battery direct to the strobe unit. Made absolutely no difference
to the noise.
2 Disconnecting the aerial from the back of the radio completely
eliminates the noise as does connecting an aerial from a hand held
radio.
5V USB switchers are made to behave in the presence of AM radio mainly
by a filter on the input (2 capacitors and an inductor).
Sorry but you have lost me here.
Thanks again
K
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