[Elecraft] K3 sub rx matched filters

[Steve Ellington]

About this "wush, wush" sound....Does this wushing occur as you tune across 
stations when in diversity mode or does it just set there and constantly 
wush wush? Can't you adjust the compensation for these filters in the menu? 
I don't understand why this happens. I had an IC-7800 and played with 
diversity recption. Of course there were no physical filter options but 
there was no wushing sounds either.

Steve Ellington
N4LQ at carolina.rr.com
----- Original Message ----- 
From: "Don Wilhelm" <w3fpr at embarqmail.com>
To: "jeff kb2m" <kb2m at comcast.net>
Cc: <Elecraft at mailman.qth.net>
Sent: Friday, March 27, 2009 10:23 AM
Subject: Re: [Elecraft] K3 sub rx matched filters


> Jeff,
>
> The filter offsets should be set the same for diversity reception, and
> for that to happen most easily, the filters can be matched.  You may
> notice a "wush, wush" sound if the offsets are different.
> But being practical, the *difference* between the actual offsets of the
> filters will be within tens of Hz, and for a wide filter (1.8 kHz or 2.7
> kHz), setting the K3 offset values to the average of the two filters
> will work fine.  OTOH, with narrow filters such as those used for CW,
> the two offsets must be closely matched because the difference in the
> offsets is a larger percentage of the filter width, and requires matched
> filters.  It is the difference between the offsets that matters, not the
> actual offset value.
>
> Supposedly, the 8 pole filters do not have to be matched (they do not
> have offset numbers associated with them), but in practice, they may
> have a small offset and some ''tweaking" of the offset values may be
> required to eliminate the "wush, wush" sound when using diversity.
>
> 73,
> Don W3FPR
>
> jeff kb2m wrote:
>>  I'm thinking of upgrading my K3 by adding a KRX3 sub receiver. One of 
>> the
>> things I want to try in the near future is diversity reception. Now, I 
>> think
>> I need a matched pair of filters to operate in diversity mode? Or does 
>> this
>> just pertain to the 5 pole  filters?  Or, if I already have an 8 pole 1.8
>> filter would I just have to buy another one ? I tried to search the 
>> archives
>> and there appears to be no keyword search? Thanks in advance for any help
>> with this....
>>
>> 73 Jeff kb2m
>>
>>
> ______________________________________________________________
> 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


--------------------------------------------------------------------------------



No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.0.238 / Virus Database: 270.11.30/2026 - Release Date: 03/27/09 
07:13:00