[Elecraft] K3 and Preamp

[Fred Jensen]

On 9/6/2014 2:28 PM, W2RU - Bud Hippisley wrote:
> On Sep 6, 2014, at 2:34 17PM, Dauer, Edward <edauer at law.du.edu>
> wrote:
>
>> I received a couple of off-list comments that might be of interest
>> to those who are following this thread.  One was that narrowing the
>> BW also improves the S/N.
>
> Maybe.  Maybe not.  Or, maybe up to a point.

Agreed, and it depends on the character of the noise for me.  The 51J4's 
we used in coastal marine service so long ago had the crystal filters of 
the day, and it took some acquired skill to operate it effectively. 
They weren't terribly good at weak signals, but then, weak signals and 
QRM weren't usually a problem ... except on 500 KCs.

A dozen years later, I had a 2B with the 2BQ along with an S3-line in 
Houston TX.  The 2B/2BQ offered very precise tailoring of the passband 
and I could copy signals on it that I couldn't hear [or could barely 
discern] of the 75S3.  It would be fun to compare my K3 with the 2B.

I've never had much luck with the K3 APF, I know others do and its 
probably pilot error for me, but I wonder what it would take to make it 
adjustable both in BW and frequency?  DSP Q-Multiplier? :-)

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org