[Elecraft] K3 noise B and R

[David Cutter]

I don't know what level QRN crashes add to the general noise level:  it 
would be interesting to know what difference the roofing filters add to the 
dsp filter in these condx.

David
G3UNA



> The local noise level on 80 shows up as anywhere up to S7or 8.
> With ATT ON, it still shows on the meter, but is nothing like as 
> aggressive.
> On SSB I use the stock filter and leave other things alone most of the 
> time.
> Two things:
> First:   ATT drops the noise and apparently (it must be a bit of an 
> illusion)
> leaves the signal. It seems that ATT ON limits the peak effect of noise
> crashes. Not very scientific, I'm afraid. You just play and see whats best 
> at
> the time !
> Second:  AGC OFF results in a significant drop in strength of everything. 
> This
> is not what I am used to, so I have AGC ON all the time, usually set to 
> FAST,
> but there can be a problem with if there is a strong signal on frequency. 
> The
> transition from TX to RX and vice versa can be marked by loud pops and/or
> clicks. I believe this is to do with the way the DSP and AGC systems 
> respond
> and I understand, very much off record, that a mod for the AGC behaviour 
> is
> in the works.
> In fact I suspect it is already in current production K3s,  like another 
> mod
> to fix a keying characteristic glitch in an early batch where an 
> overly-large
> capacitor was installed in error. I did that mod myself.
> If I ever get the info (and parts) I will do the AGC mod and see how it 
> goes,
> but the general advice I got was to "leave well alone unless you are sure 
> you
> need the mod !"
> Marvellous radio; the best receiver I have had, even better than my
> much-modified TenTec Omni-5. But better antennas would help.
> and I'm adding a 200Hz roofing filter when I get one.
> 73 John G3JAG
>
> On Saturday 23 February 2008 11:25:25 you wrote:
>> What noise levels were you receiving? It would be interesting to know 
>> what
>> they were before and after you selected filters, but you were probably so
>> amazed with your contacts withVP6DX that sort of stuff went out of the
>> window : o )
>> Do you operate with or without AGC, full rf gain?  Sorry for the 3rd
>> degree, just getting a handle on real band condx with weak signal 
>> reception
>>  : o / I will be severely limited on antennas as well.
>>
>> David
>> G3UNA