[Elecraft] Pumping with K3

[Guy Olinger, K2AV]

Gary,

First off engage the ATT and turn off PRE for receiving on your transmit 
antenna on 160.  (You may not notice you have these on if you are running 
SMTR MD in the Config Menu.) If the offending station is really loud he may 
be kicking the hardware AGC.

Make sure you actually are using your 250 8-pole filter.  Have seen some 
tripups on that issue here.  One person moved filters and didn't change the 
Config Menu to match it. Another added a filter but didn't turn it on in 
Config Menu. Make sure you are running a zero offset on 8-pole types.

Make sure in Config Menu you have AGC PLS nor.

Then set up the Noise Blanker:

NB Level    IF OFF  <and>   dsp t1-7  <or>  dsp t2-7 <or> dsp t3-7    Try 
t3-7 first.

Use NB when you are next to clicky or sharp sounding stations.

This NB setting will make all the CW signals sound soft, t3-7 most so.  But 
in some conditions this has dropped key click S-meter pumping by 4 or 5 
ticks on the S-meter.  (Thank you Lyle...)

I'm using FW 2.78, and don't know when Lyle's cute NB functions showed up. 
I have zero problems with 2.78, upgrade if you're backlevel.

73, Guy
K2/K3 #1239


----- Original Message ----- 
From: "wayne burdick" <n6kr at elecraft.com>
To: <Gary at doctorgary.net>
Cc: <Elecraft at mailman.qth.net>
Sent: Saturday, January 24, 2009 5:42 PM
Subject: Re: [Elecraft] Pumping with K3


> Gary,
>
> If your AGC is getting pumped by nearby stations even with the 250-Hz
> filter engaged, it's almost surely due to excessive transmit bandwidth
> on the part of those stations. Their keying sidebands may extend far
> beyond their carrier frequency. This is a common problem with rigs that
> have poorly-shaped keying and/or poor phase noise characteristics. If
> these stations are well over S9 and very close to your frequency, you
> may not have any really effective defense other than to ask them to
> reduce power, improve key shaping, or get a new rig.
>
> The K3 is extremely clean in both regards, so chances are you're not
> bothering *them*  :)
>
> You might try speeding up AGC-F (see associated menu entry) or even
> turning AGC off, backing down the RF GAIN, and possibly NR and DSP NB.
>
> 73,
> Wayne
> N6KR
>
> On Jan 24, 2009, at 2:20 PM, Gary Smith wrote:
>
>> I'm working the 160 contest and am wondering if there's some hint to
>> help me overcome pumping from nearby stations. I am using the 8 pole
>> 2.8K, 1K & 250Hz filters on CW. I'm mostly tuned down to 50Hz as
>> that's what I need to do to find the DX that's being covered by the
>> local stations calling CQ.
>
> ---
>
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