http://elecraft.85.s1.nabble.com/K3-in-a-cw-pileup-needs-work-tp4523884p4546194.html
Can you elaborate your reasons for this suggestion. I had come to
be beneficial. I have felt the default of 005 was too low.
> Perhaps one should get the ambient well down in the ADC operating
> range but killing gain (adding loss) before the first mixer and
> the roofing filter is not the way to do it. If you want to
> better align the dynamic range of the receiver (or specifically
> the ADC) to conditions, the attenuation should come in the
> IF - preferably divided between the first IF and 2nd IF.
>
> However, there would still be no apparent reason that the K3
> should not be capable of sustaining an AGC threshold at least
> 10 db higher than currently set with AGC THR = 008 whether
> that be reached with preamp on, preamp off or attenuator on.
>
> 73,
>
> ... Joe, W4TV
>
>
>
>
>> -----Original Message-----
>> From:
[hidden email]
>> [mailto:
[hidden email]] On Behalf Of Guy
>> Olinger K2AV
>> Sent: Monday, February 08, 2010 1:49 PM
>> To:
[hidden email]
>> Cc:
[hidden email]
>> Subject: Re: [Elecraft] K3 DSP AGC Question
>>
>>
>> It may be a dance, but hopefully careful intelligent musing
>> over the matter is convincing people that they should get the
>> ambient well down in the analog-to-digital converter (ADC)
>> operating range. If they do, a -99 threshold is a -109
>> threshold, and further backing off RF gain can make it a -119
>> or -129 threshold as far as the ADC is concerned, and
>> headroom is being used for what headroom should be used for.
>>
>> One thing for sure, there has not been a good-enough
>> presentation of what is going on, and people really don't
>> seem to get it. For something that is plain indisputable
>> physics, people are still running PRE and max RFgain on 80
>> with fast AGC, and are honestly dismayed and confused about
>> the inevitable outcome, incorrectly blaming the rig for being
>> natively noisy, no-work NR and NB, filter "ringing", unable
>> to pull signals out of noise, and more.
>>
>> Maybe the variable gain by band in the MP (with a menu
>> override) was really a better strategy for a default. This
>> same issue dogged Orion owners, and by the chatter a lot of
>> them never understood either.
>>
>> There IS something entirely separate with the headphone audio
>> and HI-Z headsets, high volume levels, maybe a sharp
>> saturation point, and mush, just haven't nailed it yet.
>>
>> 73, Guy.
>>
>> On Mon, Feb 8, 2010 at 12:01 PM, Joe Subich, W4TV
>> <
[hidden email]> wrote:
>>
>>>
>>>> Likely? I don't know.
>>>>
>>> Likely is a better choice since raising the AGC threshold
>>>
>> seems to be
>>
>>> the primary goal of much of the "PRE/ATT/RF Gain dance" we've seen
>>> recently.
>>>
>>> The hardware AGC (HAGC) would seem to provide an ultimate limit on
>>> level to the ADC - unless the ADC can't handle the
>>>
>> transient peaks -
>>
>>> so a higher threshold for the DSP derived AGC would be
>>>
>> helpful in many
>>
>>> ways.
>>>
>>> 73,
>>>
>>> ... Joe, W4TV
>>>
>>>
>>>
>>>
>>>
>>>> -----Original Message-----
>>>> From:
[hidden email]
>>>> [mailto:
[hidden email]] On Behalf Of Lyle Johnson
>>>> Sent: Monday, February 08, 2010 11:24 AM
>>>> To:
[hidden email]
>>>> Subject: Re: [Elecraft] K3 DSP AGC Question
>>>>
>>>>
>>>> Hello Joe!
>>>>
>>>>> Assuming that the threshold values have not changed in a
>>>>>
>> major way
>>
>>>>> since Jack's measurements, would it be possible to
>>>>>
>> extend the range
>>
>>>>> of threshold values - say to AGC THR=016 at about -80dBm
>>>>>
>> (assuming
>>
>>>>> 2 dB per step)?
>>>>>
>>>>>
>>>> Possible? Yes.
>>>>
>>>> Likely? I don't know. There are a lot of side effects
>>>>
>> that happen
>>
>>>> when the threshold is raised...
>>>>
>>>> 73,
>>>>
>>>> Lyle KK7P
>>>>
>>>>
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