[Elecraft] Roofing Filters - An Empirical Test

[Rick Tavan N6XI]

You can mitigate that problem somewhat by listening to the DX on the wide
sub and the pileup with the narrow main rx. If the split is (roughly)
larger than the filter bandwidth difference, then loud, continuous callers
in the pile don't bother the DX signal, only your ability to locate the
weak caller in the strong pile. That being said, I put a narrow filter in
both receivers.

The unconventional technique of listening to the DX on the sub and the
pileup on the main has another benefit - you don't have to use SPLIT mode
which degrades keying at high speed and disables QRQ mode. It took me a
while to get used to it after decades of doing it the other way, but I
think the benefits outweigh the change in my cage.

73,

/Rick N6XI


On Mon, May 12, 2014 at 2:49 PM, Vic Rosenthal K2VCO <k2vco.vic at gmail.com>wrote:

> My K3 was originally set up this way, 400 Hz in the main and 2.8 kHz in
> the sub.
>
> When working DX pileups with the main on the DX and the sub on the pileup,
> I definitely noticed the 'pumping' effect on the sub only. It was sometimes
> annoying when the DX was working a weak caller and the usual loud idiots
> were continuing to call.
>
>
> On 5/12/2014 12:54 PM, Dauer, Edward wrote:
>
>> I would be interested in knowing if anyone has done an empirical test and
>> observed the difference directly.  Specifically, since the sub receiver is
>> identical to the main receiver in every way, if someone has a K3 with, for
>> example, a 400 Hz filter in the main but only a wider set in the sub, and
>> then set the DSP bandwidth on both receivers to 200 Hz or so, what
>> differences they actually noticed.  I have no doubt the theory and the
>> engineering are sound - just curious what the difference sounds like in
>> the field . . .
>>
>> Ted, KN1CBR
>>
>
> --
> 73,
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco/
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to rtavan at gmail.com
>



-- 
Rick Tavan N6XI
Truckee, CA