[Elecraft] Pileup Mush (was:audio board)

Wed Mar 23 11:24:04 EDT 2016

It's not a question of whether "your ears can handle the increased range of
audio levels."

I've been in the trenches battling against pileup mush since the K3's
release.  This is only one guy's opinion, but there's another important
prerequisite that's been missing from this discussion.  And that's to use
highly isolating headphones.  That is the ONLY effective way of presenting
the required wide audio dynamic range to your ears.  Unless that's in the
picture, you're significantly handicapped from vanquishing pileup mush.

The use of highly isolating headphones is what allows you to use lower
levels of RF Gain and still clearly hear the weakest signals.  And only
then will the strongest signal levels be below the ear's attenuation reflex
level

K3NA wrote the book on this 8 or so years ago.

73, Barry N1EU

On Wed, Mar 23, 2016 at 11:08 AM, Ian White <gm3sek at ifwtech.co.uk> wrote:

> Don wrote:
>
> >Gene (and all),
> >
> >Yes, the AGC settings do help a lot.  The K3/K3S has enough gain that
> >often the AGC is activated on the atmospheric noise in the band.
>
> It isn't so much that the K3/K3S has "gain", but that the factory
> default AGC THReshold is so very, very low. Measurements by KE7X [1]
> have shown that the default setting of THR=5 corresponds to an AGC onset
> at less than S3, whereas competing rigs have a threshold of S7 or even
> higher. This very low AGC threshold is what allows the AGC to be
> activated by band noise.
>
> Elecraft's factory defaults of THR=5 and SLP=12 compress all signals
> above the AGC threshold into a very narrow range of audio output levels
> [see the measurements by KE7X]. This makes for comfortable
> broadcast-style listening - but there is price to be paid. The default
> settings greatly reduce the differences in the *true* strengths of
> incoming signals - important differences that DXers and contesters
> *need* to hear, in order to pick individual signals out of a pileup.
>
> Following complaints from DXers, DXpeditioners and contesters about this
> so-called "pileup mush", and following further series of measurements by
> KE7X, Elecraft eventually did increase the available range of AGC
> THReshold settings (the v4.51 firmware upgrade).
>
> Following the release of FW v4.51, consensus within the [K3-contesting]
> Yahoo group about the most important settings for DXing and contesting
> has been as follows.
>
> * AGC THR: increase to at least 8 (from default = 5) and preferably to
> 12 or even 14 if your ears can handle the increased range of audio
> levels [2].
>
> * AGC SLP: decrease to 8 or even less (from default = 12). Lower SLP
> settings allow stronger signals to sound somewhat louder, and thus more
> realistic, but the range of variation will be partly determined by the
> THR setting already made; so always experiment with THR first, and with
> SLP afterwards.
>
> * AGC DCY = SOFT (not default=NOR). The User Manual claims that "The
> SOFT setting can reduce IMD caused by traditional AGC, and is especially
> useful in 'pileup' conditions, in some cases making it unnecessary to
> turn AGC off."
>
> The settings recommended above have essentially solved the problem of
> "pileup mush" for those who have tried them... but regrettably, Elecraft
> has done almost nothing to make DXers and contesters  aware that such
> changes are possible.
>
> More than 3 years after the firmware release notes boasted that v4.51
> "greatly improves signal clarity in pile-ups and other high-noise or
> dense-signal situations, especially with threshold set to 12 or higher",
> that information is *still* missing from the User Manual. There is also
> no information on how to create different 'profiles' of AGC settings for
> different types of users.
>
> Meanwhile, Elecraft's factory AGC defaults remain exactly as they were,
> still optimized apparently for comfortable 'listening', while many DXers
> and contesters remain unaware that their K3/K3S could actually be *so*
> much better.
>
>
>
> [1] http://www.ke7x.com/home/miscellaneous-k3-information
>
> [2] It is important to give any increased AGC THReshold setting an
> extended trial. To anyone accustomed to an artificially restricted range
> of audio signal levels, a higher setting will initially sound quite
> 'aggressive' -even though the new setting is much closer to real life.
>
>
> 73 from Ian GM3SEK
>
>
> >-----Original Message-----
> >
> >On 3/22/2016 6:32 PM, Gene Gabry wrote:
> >> This has been an interesting thread to which I have experimented a
> bit
> >more
> >> and found the AGC setting recommendations from a couple of posters to
> >be
> >> very valuable, and Eric's suggestions on BW settings to be a nice
> >compliment
> >> to play with. Although, my ears still like a little HF, I like the
> sound of
> >> a BW from 100hz to 2.7khz for SSB and usually the 500hz filter set to
> >300hz
> >> with DSP. I now have AGC THR set to max and AGC SLP set to 0. I also
> set
> >RX
> >> EQ to flat and use hi/lo cut when needed. Really cuts down on the
> high
> >> frequency hash I get from this qth. I leave the AGC settings the same
> for
> >> SSB and CW and play with BW and cut between the two modes, depending
> >on
> >> conditions.
> >>
> >
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