[Elecraft] K3 Hi Cut & Low Cut granularity bug?

[Ken Roberson]

Rich,

Maybe I'm missing something , but I use Bandwidth control
and shift.
73 Ken K5DNL
---------------------------------------------------------


--- On Tue, 6/7/11, Rich - K1HTV <k1htv at comcast.net> wrote:

> From: Rich - K1HTV <k1htv at comcast.net>
> Subject: Re: [Elecraft] K3 Hi Cut & Low Cut granularity bug?
> To: "'Joe Subich, W4TV'" <lists at subich.com>
> Cc: elecraft at mailman.qth.net
> Date: Tuesday, June 7, 2011, 8:51 PM
> Joe,
>   I'm aware of the SHIFT granularity being settable
> from 50 Hz to 10 Hz. What I
> was questioning is why, when this change is made, that the
> K3's  HI CUT and LOW
> CUT controls are disabled. After you set  CONFIG:PB
> CTL to 10 Hz, when you press
> either HI-CUT or LOW-CUT. nothing happens and you can no
> longer roll off either
> side of the passband as you could when PB CTL is configured
> to 50 Hz.  Is this
> an undocumented feature? If so, I think it is a bad one.
> 
> 73,
> Rich - K1HTV
> 
> = = = 
> 
> -----Original Message-----
> From: Joe Subich, W4TV [mailto:lists at subich.com]
> 
> Sent: Tuesday, June 07, 2011 19:42 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] K3 Hi Cut & Low Cut granularity
> bug?
> 
> 
> > Also, when the SHIFT granularity (CONFIG:PB CTL) is
> changed from 50Hz 
> > to 10Hz, > the Hi Cut and Low Cut controls do not
> work at all! Is this 
> > a BUG ora FEATURE? I'm presently using K3 firmware
> update MCU
> > 4.36 .
> 
> Feature ... as documented every since the 10 Hz steps for
> shift/width was first
> provided in beta testing.
> 
> 73,
> 
>     ... Joe, W4TV
> 
> 
> On 6/7/2011 5:26 PM, Rich - K1HTV wrote:
> > K3 Hi Cut&  Low Cut granularity bug?
> >
> > Lately I've been running a number of digital modes
> (JT65A, PSK31&  
> > RTTY) on the HF bands. The K3's APF and dual PB
> filters really help to 
> > copy weak RTTY signals, especially when there is QRM.
> When using the 
> > JT65A mode, signals even weaker than -20 dB can be
> copied. These very 
> > weak signals are often effected by much stronger
> signals within the 
> > receiver's pass band. Often, these very strong signals
> will act on the 
> > K3's AGC and push the weaker signals farther into the
> noise, making them
> uncopyable.
> >
> > I have found that adjusting the K3's 'Hi' and 'Lo' cut
> filters to be 
> > the quickest and easiest way to reduce the QRM from
> adjacent loud 
> > signals. At times an offending strong station is very
> close to the 
> > weak signal's frequency. The 'Hi-Cut' and 'Lo-Cut'
> filters must be 
> > adjusted so they attenuate the nearby loud interfering
> signal but not the weak
> signal you are attempting to copy.
> > Unfortunately, these controls can only be adjusted in
> 100 Hz increments.
> >
> > Although the SHIFT can be set up for 10Hz or 50 Hz
> increments, at 
> > present the granularity of the K3's WIDTH, HI CUT, and
> LOW CUT 
> > controls can only be set to 100 Hz in the
> CW&  Digital modes.
> >
> > Also, when the SHIFT granularity (CONFIG:PB CTL) is
> changed from 50Hz 
> > to 10Hz, the Hi Cut and Low Cut controls do not work
> at all!  Is this a BUG or
> a FEATURE?
> > I'm presently using K3 firmware update MCU 4.36 
> .
> >
> > It would be very helpful if the 'Hi-Cut' and 'Lo-Cut'
> filtering could 
> > be adjusted in smaller increments than the present
> 100Hz.  Being able 
> > to fine tune the Hi and Low cut filters would really
> help to quickly 
> > and easily reduce QRM that might develop either above
> or below the digital
> signal being copied.
> >
> > I hope that this request can be implemented in a
> future revision of K3
> software.
> >
> > 73,
> > Rich - K1HTV
> >
> >
> >
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