I use an external speaker passive low pass filter to tone down high
frequency howling in my receiver audios when needed. I have a couple
circuits, but one that I published is on line at:
http://www.geraldj.networkiowa.com/papers/speakerfilter.pdf Unlike an
external DSP filter this one has no digital artifacts or noise. It does
require turning up the audio gain to make up for its power loss.
73, Jerry, K0CQ
On 1/27/2011 10:51 PM, Don Jones wrote:
> John 'CQ and John 'RE,
> Good points guys. I do have the TT 250Hz CW Filter in the 2nd IF. Which
> pretty much matches what John has described. I do notice that things are
> reasonable using the INRAD Roofing Filter& 1st IF 400Hz filter with the TT
> 500Hz 2nd IF combination.
> I do use the passband tuning of the OMNI VI, but I use it mainly to tone
> down the high frequency howling in the receiver audio. To be honest, it is
> I think I will begin looking for a 2nd IF INRAD Narrow CW Filter and give it
> a try.
> I know this might offend some of the TT guys here, but I have been unable to
> match the performance of my Drake/Sherwood R-4C. It has a full complement of
> the Sherwood mod's and is beating my OMNI VI (opt 3) in every way.
> In the mean time I am going to focus on getting VP8ORK into my logbook. It
> will be very interesting to see how my VI handles the dog-pile on the VP8.
> Don Jones KO7i
> Arlington, WA
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