Guy K2AV and Dave AB7E!
Your comments are incredibly helpful. I and many others would be very grateful
if you would post all your Config setting related to coping with RX mush.
73, Dick WC1M
73, Dick WC1M
> On Mar 3, 2017, at 1:59 PM, David Gilbert wrote:
>
>
> I
This has been an interesting discussion. We've certainly passed the posting
overload limit on it though, so lets wind it down in the next hour to let others
recuperate from email overload ;-)
73,
Eric
List mooderator..
/elecraft.com/
On 3/3/2017 10:59 AM, David Gilbert wrote:
I agree with
I agree with your comments. Thanks for the clarifications!
And I did indeed forget to mention the attack/decay speed influences. I
even posted comments here about that myself back shortly after I bought
my K3 ... that the time rate of change in gain is itself a
non-linearity. I think my
There is some conflation of two quite different concepts going on here.
The first thing you need to know about an AGC response graph is the speed
that the incoming signal was varied to produce the curve. In many cases,
the input signal was steady state from a signal generator, set to a list of
I've had my K3 since 2008 or so, and over the years I've seen people
describe different forms of "mush". One set of comments indeed involved
complaints about the hard limit at the upper end that has nothing to do
with AGC. It is, as you say, simply a hard limit ... pretty much a
clipper to
I tend to use the CWT display a lot, and then the S-meter doesn't show 20 dB
over S9. Actively using RF gain, ATT, PRE, as one should, makes the S-meter
even less interesting. Eyes tend to spend a lot of time on the P3 display
when available. Spectrum peaks don't show how close we are to the
One problem here is that a lot of the discussion has been in analog terms.
We have to remember that in the K3, the digital AGC controlled by the AGC
parms is just that, a digital algorithm. What it does has nothing to do
with diodes. It can do anything weird and completely non analog resembling,
Oh no! I fear this is going to get bogged down in definitions. From Wikipedia:
"Limiting can refer to non-linear clipping, in which a signal is passed through
normally but 'sheared off' when it would normally exceed a certain threshold.
It can also refer to a type of variable-gain audio level
The AGC will not cause "hard limiting" - in other words, it should
maintain linearity.
Even though the strongest signal in the passband will control how much
AGC is applied, weaker signals in the passband should sound
proportionally weaker.
Now that you mention hard limiting, there is a
Hi,
Where in Smith's article does it say that AGC with the slope set for 15 acts
as a hard limiter? There is a huge difference between AGC action (which is
simply a reduction in gain with linearity retained) and hard limiting. I
have read the article and agree that his measurements are very
It isn't so much that 'the strongest signal in the passband determines the gain
of the receiver', it's that once that strong signal sends the
receiver into AGC, additional signals in the passband do not increase the audio
output power when the Slope is set at or near its extreme. This is a form
On Wed,3/1/2017 10:29 PM, David Gilbert wrote:
I recently purchased the new synths for my K3 and supposedly they help
significantly on that score, but I haven't had the opportunity to
install them yet.
Don't put it off -- it's an easy 30 minute job.
73, Jim K9YC
That isn't actually true. Threshold and slope combine to form a point
of non-linearity that can cause all sorts of in-band mixing products
when multiple signals exist at roughly the same levels. I and others
have experienced that first hand in the past. I can running stations in
a
I am not certain what it has to do with "mush", but it does seem to help.
What is certain is that if the AGC Threshold is set too low, the AGC
will be activated on band noise. Whether that 'band noise' is the
result of ambient noise level, or the ambient 'noise' of a multitude of
signals in
My thoughts on this are that those who are concerned about the slope
and threshold settings are barking up the wrong tree. The mush would
result if you have your hold time or hang time or decay set too short.
With a brief hold time the weaker signal pops up to the level of the
stronger on as
I too have come to that same surmise, Wes, and I hope whoever explains
it [someone always does] does so on the reflector so I can benefit too.
One of my K3's two AGC systems is highly configurable. I finally found
a threshold and fairly flat slope that, for my compromised hearing works
very
I must confess to some bewilderment about the seemingly endless discussion about
the adjustment, or mis-adjustment, of AGC slope, threshold or "RF" gain.
Claims are made that one's favorite settings cause signals within the passband
to retain their relative amplitudes thus allowing the
17 matches
Mail list logo