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

[Rich - K1HTV]

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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