[RTTY] K3 filter for rtty?

[Jerry Pixton]

Thanks gang.

That is the info i was needing. Have to get my Xmas list ready early if 
I want any toys.

Jerry, W6IHG

On 8/21/2014 1:56 PM, Joe Subich, W4TV wrote:
>
> > Is the 250 Hz 8 pole too sharp?
>
> The 250 Hz 8-pole filter is really 370Hz at -6dB (250 Hz at -1 dB)
> - see the curves at http://www.elecraft.com/K3/K3_filter_plots.htm
>
> The 250 Hz 8-pole filter coupled with DSP set to 400 or 500 Hz is
> fine for RTTY.  However, I would not spend the money for both a
> 400 Hz 8 Pole filter or 500 Hz 5 pole filter *and* the 250 Hz 8 pole
> filter as the difference between the 400 Hz (435 Hz @ -6dB) and 250
> Hz filters is not enough to justify having both.
>
> I am not a fan of the 500 Hz - 5 pole filter.  Having had four of
> them (main/sub in a pair of K3s), I find them to have excess ripple
> in the passband and poor shape factor (> 3:1 6/60 dB).
>
> I find the 400 Hz filter a minimum useable bandwidth for general
> CW operation and would recommend either 500 Hz 8 Pole (from INRAD
> - actual bandwidth not specified, estimated 525 Hz @ -6dB) and
> 250 Hz 8 pole *or* 400 Hz 8 pole and 200 Hz 5 pole for critical CW.
>
> 73,
>
>    ... Joe, W4TV
>
>
> On 2014-08-21 8:53 AM, Jerry Pixton wrote:
>> Fellow rttyers,
>>
>> If I get a new K3, what filter do I want for rtty? Bandwidth and 5 or 8
>> pole? Is the 250 Hz 8 pole too sharp?
>>
>> My primary operating mode is rtty followed by cw for Dxpeds
>>
>> Jerry, W6IHG
>>
> .
>

-- 
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Dr. Jerry R. Pixton, PIXOS Designs
http://www.shentel.net/pixosdesigns/RadioTuner
jpixton at shentel.net
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