[CQ-Contest] Re: Choice of CW Narrow filters
k2kir at telenet.net
Sat Apr 17 14:29:46 EDT 1999
Yep, that's it!!! (I thought of it about six hours after posting my original message, when I was nowhere near an e-mail connection. Thanks for the assist.
At 10:26 AM 1999-04-17 +0100, G4TSH wrote:
>I think this is what is called Stochastic Resonance.
>At 21:18 16/04/99 , Bud Hippisley wrote:
>>Well, there's a name for this effect, which has been documented
>>previously in other fields. In my advanced years I can't remember it,
>>though. The essence, as I recall, is that the "right" amount of
>>background noise can enhance your perception of the desired signal.
>>I, too, find it easier to pick weak CW signals out of the noise with
>>the 2 kHz SSB filters (stopped down to about 1.2 kHz with the VBT
>>control) than with the 500 Hz CW filters at full BW, but I've also
>>used the effect (and in fact first noticed it) when trying to analyze
>>a strange noise from the car while driving. Turning on the radio and
>>having some background music actually enhanced my ability to hear the
>>alien noise from the engine compartment. Talk to the psycho-acoustics
>>specialists -- they'll know the name of it!
>>At 11:07 AM 99/04/16 -0600, you wrote:
>>>n6tr at teleport.com wrote:
>>>> I recently discovered the power of this DSP when doing moonbounce
>>>> work on six meters. I have always thought that you had to use really
>>>> narrow filters on your receiver to hear weak EME signals. However,
>>>> what I found was that it was EASIER to copy weak EME signals using
>>>> the SSB bandwidth positions!
>>>I've observed the same thing on HF. In the absence of strong QRM, a weak
>>>signal is just as easy, or easier, to copy with a wide bandwidth. Since
>>>filter bandwidth clearly must reduce the S/N ratio, the effective bandwidth
>>>organic DSP must be much smaller. Quite amazing.
>>>sdelling at facstaff.wisc.edu
>>>Madison, Wisconsin USA
>>>CQ-Contest on WWW: http://www.contesting.com/_cq-contest/
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>Justin Snow G4TSH
>justin at g4tsh.demon.co.uk
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