[Elecraft] K2 antenna 2 no antenna observation

[Don Wilhelm]

  Even with the very poor antenna I use at my test bench (just a piece 
of wire hung outside and tied to the deck railing), I would go crazy 
listening to the noise on 160, 80, 40, and often 30 meters on my K2 if I 
had the preamp on.

The preamp (and attenuator) settings are remembered by band (both the K2 
and the K3).  If your noise level is bothersome on any band, turn the 
preamp off and if that is not enough, turn the attenuator on.  You will 
hear more signals that you are able to copy.  There is nothing more 
tiring than listening to a lot of band noise - do your ears/brain a 
favor and use those techniques available to us.

AGC will reduce the "noise stuff" on the band if it is above the AGC 
threshold - but it reduces the signals too, so that is not the best way 
to attack it because that AGC action also reduces the dynamic range of 
the receiver.  Turning the preamp off when not required and turning the 
attenuator on is the right way to control that band noise level -- you 
will hear more weak signals that way, and have better Q5 copy.

There are several instructions on the web giving instructions on how to 
set a receiver (any brand) for maximum copy-ability.  All say to reduce 
the RF gain (the preamp off.attenuator on do that) so that the band 
noise is just barely audible.  That applies to all receivers (not just 
the K2 and K3) for all situations where you want to have the best 
receiver performance.  A lot of band noise in the ears is NOT a good 
thing - as the initial post in this thread had indicated - when the band 
noise is reduced, weak signals become easier copy.

73,
Don W3FPR

On 6/5/2011 7:25 PM, Guy Olinger K2AV wrote:
> Without thinking at all about it, many people run with the preamp on all the
> time.  Since one has AGC, this has the effect of compressing the signal to
> noise ratio.  It IS really important to get used to setting ATT/PRE to move
> the noise down to where it is only moderate.  Just as true on a K2 as on a
> K3.  The other thing is to use slow AGC, particularly in non-contest
> conditions.  I almost never use fast AGC any more, including contests.
>
> 73, Guy.
>
> On Sun, Jun 5, 2011 at 5:55 PM, Don Wilhelm<w3fpr at embarqmail.com>  wrote:
>
>>   There is some leakage between ANT1 and ANT2 -- so you just switched in
>> an attenuator of some unknown value.  I will wager you had the preamp on
>> too.  Next time, you might want to try turning off the preamp to lower
>> the noise, and possibly turning on the attenuator.  That way, you do not
>> have to switch to "no antenna", and you can answer the station without
>> changing antennas.
>>
>> 73,
>> Don W3FPR
>>
>> On 6/5/2011 4:52 PM, W2bpi1 at aol.com wrote:
>>> I was working a weak station with QSB that was at about my S4 noise
>> level.
>>> Happened to hit ant. 2 button. Now the noise is gone but I can hear the
>>> station  weak but now solid copy. Interesting indeed! 72  Geo/W2BPI
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