Their description (to me at least) indicates an elliptic filter with a stopband
peak of -40 dB at 1 MHZ and ranging to infinity (in theory) elsewhere in the
stopband. In other words, 40 dB is the maximum for the discrimination factor.
"Indicates" is a word I feel is necessary as their filter really is poorly
described. They should have said what filter type and order are used and used
standard nomenclature for filter parameters. And there's no mention of passband
ripple.
Chuck
> Date: Mon, 22 Sep 2014 11:21:29 -0700
> From: jim@audiosystemsgroup.com
> To: topband@contesting.com
> Subject: Re: Topband: BCB interference ?
>
> On Mon,9/22/2014 6:50 AM, Ed Stallman wrote:
> > Has anyone used this High Pass Filter ?
> > http://www.dunestar.com/store/160-Meter-Highpass-Filter-pid-8.html
>
> The spec for this filter is ambiguous. Is the -40dB at all frequencies
> below 1.6 MHz, or at 1 MHz? BIG difference. OTOH, the Dunestar filters
> are decent for the price.
> 73, Jim K9YC
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