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Re: LEILA suggestion

Greg K06TH wrote:

How about we have LEILA do it's warning tones, apply the notch, and then
either turn off the tones, or scale them back to an occasional beep (just to
let us know that the corresponding uplink is aimed at a black hole)?  That
will help preserve all of the transponder's power for our communications.

Wayne W9AE replies:

I really like your suggestion, even tough the main purpose of LEILA isn't
necessarily to reduce power consumption.  Long, powerful siren tones can't
possibly be good for the power budget.  I can't think of any reason why the
siren tone duration needs to be longer than 5 seconds to get the attention
of anyone who is actually listening to the downlink.  Sustained high-power
interferers are probably not listening to the downlink, so the siren tone
serves no purpose then.  After the initial short warning siren an occasional
beep would be sufficient to inform users that a notch is applied to that
frequency, with very low power consumption.

By the way, what is the LEILA notch bandwidth?  I have noticed that my
downlink can be significantly attenuated even when I don't hear the LEILA
siren.  My SSB IF crystal filter has a -60 dB bandwidth of 3.35 kHz, so I
don't hear the LEILA siren when it's 3 kHz away from my frequency.  But I
definitely "hear" the notch 3 kHz away.

Wayne Estes W9AE
Mundelein, IL, USA

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