[Elecraft] P3 vs SDR-IQ

[Stewart]

I would be interested in comments from Elecraft as to why the KX3/P3 differ from 
the products you list in the way averaging is handled.

73
Stewart G3RXQ

On Fri, 31 Jul 2015 10:13:25 +0200, John Kramer wrote:
> I think I know what Joe is getting at....and I agree with him, if I understand 
him correctly. When he refers to "noise floor"
> he means that he loses averaging when he tunes, resulting in the crazy 
spectrum display (what Joe refers to as noise).
>
> I haven't seen or used a P3, but I bought my first Elecraft products 3 weeks 
ago - a KX3 and PX3. If the P3 behaves in the
> same manner as the PX3 then I can see what Joe is complaining about. Right out 
the box my PX3 had this frustrating
> feature of losing averaging the moment you spun the VFO on the KX3. I pointed 
this out to a local KX3/PX3 owner, and
> he told me to download the latest firmware which allows you to select "fixed 
mode" or "fixed track". I downloaded the
> firmware. YES, it kinda fixes the problem....you can now tune the radio and 
KEEP the averaging....but the problem is
> that now your receive filter goes down the display as you tune. This is better 
than the previous method, however
> you now have your receive filter heavily offset from the centre of the 
display. You might tune down the band, with your
> RX filter at the bottom of the scale, and you are now unable to see much 
below, but you can see a huge chunk of
> the band above you.
>
> I bought the KX3 and PX3 for portable ops. My main rigs for the past 5 years 
are Flex rigs. I have the 5000/3000/1500
> and will be getting a 6500 soon as my shack rigs. With these rigs and PSDR, 
your RX filter REMAINS CENTRED and when
> you tune around the band, you DON'T LOSE your averaging. This is how I like it 
to be, and if Elecraft can achieve this
> in a firmware update, I would be very happy.
>
> 73
> John, ZS5J
>
>
> On 31 Jul 2015, at 2:56 AM, Eric Swartz - WA6HHQ, Elecraft <eric at elecraft.com> 
wrote:
>
> Hi Joe - Do you have signal averaging turned on to reduce the noise floor? If 
you do, it has to stop averaging when the freq is being changed while tuning, 
temporarily raising the noise floor slightly. It then re-starts multi-pass 
averaging once you stop tuning. This is normal for signal averaging. I run with 
averaging set =2 or 3 passes. When I tune I barely notice a small increase in 
the noise floor.
>
> If you have a lot of local pulse noise, you might want to turn on the P3s NB 
function to help.
>
> If Averaging is turned off, I can't think of a normal scenario where the noise 
floor would go up when tuning the band. It certainly does not here.
>
> Anyone else have any ideas?
>
> 73,
>
> Eric
> /elecraft.com/
>
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