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K3 noise B and R

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JACrux

K3 noise B and R

The N0SS demo is very impressive. The noise sounds like what I have here in
the city suburbs most (all) of the time. But here hitting "NB" has no
tangible effect. I have not found it useful ! (OK; I probably need to read
the manual and play with the settings.)
On the other hand, "NR" does work well provided the wanted signal is strong
enough. (Once again, read the manual, I know ...)

On 80m I have now adopted a different approach to the awful local noise
levels. I found that hitting "ATT" was very effective in reducing unwanted
noise, especially when listening to weaker signals, including VP6DX over 8000
miles away and nothing like as loud in here as on the N0SS recordings.
Today I tried listening to VP6DX on 80 with ATT set to OFF and the noise was
painful. Hitting PRE made it far worse. NR did not really help, but with ATT
ON, I worked them on 80m CW with just 10w ....
The antenna here is a 20m wire bisquare, bottom corner about 7 feet off the
ground and firing vertically upwards on 80.
As the VP6 op said when I told him .... "OUCH"
But the mojo sure works, because I also made it on 80 with 100w of SSB !
Again this was with ATT ON. PRE seems best left for the HF bands, 20m and
up. But ATT is a powerful option when all else fails.
John G3JAG K3 #107 K2 # 609
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David Cutter

Re: K3 noise B and R

John

I wondered what filter bandwidth settings you had. A narrow bw of course
reduces the noise getting to our ears. How did you handle cw and ssb in
that respect?

David
G3UNA

> The N0SS demo is very impressive. The noise sounds like what I have here
> in
> the city suburbs most (all) of the time. But here hitting "NB" has no
> tangible effect. I have not found it useful ! (OK; I probably need to
> read
> the manual and play with the settings.)
> On the other hand, "NR" does work well provided the wanted signal is
> strong
> enough. (Once again, read the manual, I know ...)
>
> On 80m I have now adopted a different approach to the awful local noise
> levels. I found that hitting "ATT" was very effective in reducing unwanted
> noise, especially when listening to weaker signals, including VP6DX over
> 8000
> miles away and nothing like as loud in here as on the N0SS recordings.
> Today I tried listening to VP6DX on 80 with ATT set to OFF and the noise
> was
> painful. Hitting PRE made it far worse. NR did not really help, but with
> ATT
> ON, I worked them on 80m CW with just 10w ....
> The antenna here is a 20m wire bisquare, bottom corner about 7 feet off
> the
> ground and firing vertically upwards on 80.
> As the VP6 op said when I told him .... "OUCH"
> But the mojo sure works, because I also made it on 80 with 100w of SSB !
> Again this was with ATT ON. PRE seems best left for the HF bands, 20m and
> up. But ATT is a powerful option when all else fails.
> John G3JAG K3 #107 K2 # 609
>

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Stewart Baker

Re: K3 noise B and R

In reply to this post by JACrux

My suggestion would be to use a separate RX antenna. Your existing
wire will be very effective at picking up all your local
electrical noise.

73
Stewart G3RXQ
On Sat, 23 Feb 2008 10:20:34 +0000, jacrux wrote:
> The N0SS demo is very impressive. The noise sounds like what I
have here in
> the city suburbs most (all) of the time. But here hitting "NB"
has no
> tangible effect. I have not found it useful ! (OK; I probably
need to read
> the manual and play with the settings.)
> On the other hand, "NR" does work well provided the wanted
signal is strong
> enough. (Once again, read the manual, I know ...)
>
> On 80m I have now adopted a different approach to the awful
local noise
> levels. I found that hitting "ATT" was very effective in
reducing unwanted
> noise, especially when listening to weaker signals, including
VP6DX over 8000
> miles away and nothing like as loud in here as on the N0SS
recordings.
> Today I tried listening to VP6DX on 80 with ATT set to OFF and
the noise was
> painful. Hitting PRE made it far worse. NR did not really help,
but with ATT
> ON, I worked them on 80m CW with just 10w ....
> The antenna here is a 20m wire bisquare, bottom corner about 7
feet off the
> ground and firing vertically upwards on 80.
> As the VP6 op said when I told him .... "OUCH"
> But the mojo sure works, because I also made it on 80 with 100w
of SSB !
> Again this was with ATT ON. PRE seems best left for the HF
bands, 20m and

> up. But ATT is a powerful option when all else fails.
> John G3JAG K3 #107 K2 # 609
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
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David Cutter

Re: K3 noise B and R

In reply to this post by JACrux

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