[Elecraft] KRX3 questions

[Joe Subich, W4TV]

> The magicians at Elecraft are now at work on an improved DUAL 
> PB which will allow more flexibility in the context WIDTH 
> setting, which would accomplish somewhat similar results (but 
> the context BW is attenuated by -24 dB versus the focus BW).

I've tried the updated context filter in beta 2.34.  The problem 
for me is that the context area is attenuated more than I would 
like and the peak (50 Hz?) is a bit narrow.   I would like to 
try the transmit antenna on the subreceiver with a relatively 
wide filter (600 - 1000 Hz) to get an idea of the overall 
activity and a low noise (Beverage, K9AY, phased array, etc.) 
receive antenna on the main antenna with a narrow (e.g. 200Hz) 
filter to focus on the desired signal. 

73, 

   ... Joe, W4TV 
 


> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Bill W4ZV
> Sent: Saturday, August 30, 2008 12:21 PM
> To: elecraft at mailman.qth.net
> Subject: RE: [Elecraft] KRX3 questions
> 
> 
> 
> 
> 
> Joe Subich, W4TV-3 wrote:
> > 
> > 
> > Bill,
> > 
> >> I have 2.7k/1.8k/500/200 in my Main but
> >> only 2.7k/500 in the Sub.  When I want to use diversity, I 
> >> just remember to use a WIDTH which will auto-select either 
> >> the 2.7k or 500.  This way I can still use the 1.8k/200 for 
> >> severe QRM situations in non-diversity and the 2.7k/500 for 
> >> diversity and/or other situations.
> > 
> > With some thought would it not be possible to get 500 and 200 Hz
> > filters with matched offsets so one could use bandwidth diversity 
> > in addition to antenna diversity?  I will not be able to try that 
> > with my first K3 when that KRX3 arrives since the existing 500 
> > and 250 Hz filters have different offsets but I will look at the 
> > 200 Hz filter in the second rig to see if it is close enough to 
> > the -790 Hz (measured in radio #1, specified for radio 2) to be 
> > useful. 
> > 
> 
> Sure you could probably do that if the offsets between the 
> 500 and 200 are
> not too far off.  You'll probably want to set the 500 equal to the 200
> rather than vice versa if they aren't identical (i.e. a shift 
> in a 500 Hz BW
> is not as critical as the same shift in a 200).  I'm not at 
> home now but I
> recall my 500s are both -0.84 and my 200 is -0.91.  If I 
> wanted to try what
> you described I would set both 500s to -0.91 since a shift of 
> 70 Hz is still
> not unreasonable in ~500 Hz total BW.
> 
> The magicians at Elecraft are now at work on an improved DUAL 
> PB which will
> allow more flexibility in the context WIDTH setting, which 
> would accomplish
> somewhat similar results (but the context BW is attenuated by 
> -24 dB versus
> the focus BW).
> 
> 73,  Bill
>