Jerry,
That is a very interesting article. 10 years ago you could have bought
most of the components at Radio Shack. I just had a quick look at the
j. W. Miller line....Winding toroids seem to be the way to go now. Now
to find that switch you used. Only commenting. What you have said
makes sense to me (a network security person) My Dad was the mostly self
taught audio guy (Thanks to WWII).
John / WA1JG
Dr. Gerald N. Johnson wrote:
> One solution I use for really noise free audio is posted at:
> http://www.geraldj.networkiowa.com/papers/speakerfilter.pdf This filter
> has selectable cut off frequencies and being passive and built for
> speaker impedance there is no high frequency noise introduced after it
> by 100 KHz bandwidth audio output ICs.
>
> 73, Jerry, K0CQ
>
> On 8/12/2010 2:46 PM, Stuart Rohre wrote:
>> Joe,
>>
>> You may want to read Rob Sherwood's web site on receiver and rig
>> testing, about excess audio response. He reports operators get tired
>> listening to any audio above the voice or SSB, needed frequencies.
>> In fact, you may want to put a band limiting filter in front of any hi
>> fi headphones to avoid operator fatigue if you do much DX operating.
>>
>> That has also been our finding at the Acoustics research lab where I
>> work for the Navy sonar folks. Sonar operators need to only have the
>> sonar frequency audible components and not a full span of ocean noise.
>>
>> 73,
>> Stuart Rohre
>> K5KVH
>>
>>
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--
John Graves
WA1JG
jh.graves@verizon.net
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