[Elecraft] K3 receiver noise questionable test results

[Steve Ellington]

One can easily use a fatigueometer to quantify these complaints.
Fatigueometers are calibrated in F units.
Typically, we would connect the F meter across the receiver's AF output 
along with a "Popoutometer".
The P meter accurately measures the degree in which signals "pop out" of the 
noise. A high number of P's is desirable.
Once these numbers are obtained we apply the formula, G=P/F
Where G = Goodness,  P = Popouts units in poppiemites and F= Fatigue units 
in fatigueamites
After years of frustration, trying to evaluate radios by ear, I finally 
broke down and purchased both meters.
Don't bother asking me where you can purchase these. You can't afford them.
If you would like for me to evaluate your radio, ship it to me. I will 
evaluate carefully and send you a full report.
The radio will be considered payment for my services.
73
Steve
N4LQ
N4LQ at carolina.rr.com
----- Original Message ----- 
From: "Don Wilhelm" <w3fpr at embarqmail.com>
To: "Al Lorona" <alorona at sbcglobal.net>
Cc: <elecraft at mailman.qth.net>
Sent: Friday, December 18, 2009 9:22 PM
Subject: Re: [Elecraft] K3 receiver noise questionable test results


> Al,
>
> Your points are well taken,  But a few of the K3 owners that have
> pro-audio instrumentation have reported that the K3 audio response is
> more like 'white noise' (a flat response), as opposed to other receivers
> which have a 'pink noise' audio spectrum.  That says that the K3 more
> faithfully reproduces any noise on the band, but that noise  faithfully
> reproduced can be more irritating than receivers that have a 'pink
> noise' audio spectrum response.
>
> I believe that we are hearing a variety of responses, and unfortunately,
> it is difficult to interpret and de-cipher the real source of each
> person's perception, so we are offering several suggestions, but it is
> like 'spitting into the wind' because we are not clear what the target
> really is.
>
> 73,
> Don W3FPR
>
> Al Lorona wrote:
>> I have been frustrated by the lack of measurements that we can hold on to 
>> as we discuss the noisy K3 receiver that many folks are reporting.
>>
>> Help me out here: are we talking about the *amount* of noise, or the 
>> *character* of the noise? I don't even think we've established the answer 
>> to this.
>>
>> If it's the amount of noise that folks are hearing, wouldn't you just 
>> turn the gain down to match your Other receiver? No two receivers have 
>> the same amount of gain, and I think this point has been lost on some of 
>> us.
>>
>> If it's the character of the noise, and if you find it objectionable, and 
>> if no settings of gain, filtering or noise reduction change it, I'd say 
>> it's time to go back to the Other receiver, and I'm not being facetious 
>> about this.
>>
>> But in lieu of measured data, let's ask the folks with noisy K3 receivers 
>> a few empirical questions:
>>
>> 1. Set up your K3 and your favorite Other receiver to receive the same 
>> band noise. Set them up like you usually do: AF gain, RF gain, etc. Note 
>> the noise level of the Other receiver... don't look at S-meters, 
>> voltmeters, etc., just memorize the noise.
>>
>> Now switch to the K3 and go into the CONFIG menu.
>>
>> a. Is there any setting of AGC THR that gives you the same noise as 
>> Other?
>>
>> If so, use it.
>>
>> If not, proceed to step b.
>>
>> b. Is there any setting of AGC SLP that gives you the same noise as 
>> Other?
>>
>> If so, use it.
>>
>> If not, I don't know what to tell you.
>>
>> Actually, there might be a possible Step c., and that would be to adjust 
>> the RF gain on the K3 to match Other.
>>
>>
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