[Elecraft] K1 band pass filter alignment

[Alexey Kats]

Greg,

You can use XG2 kit from Elecraft as a signal source for K1 on 80m,
40m and 20m bands (it'll also give you a chance to adjust S-meter as
well). 80m might be a little problematic if you selected 80kHz tuning
range because it is close to the upper end of the band, but you should
still be able to use it unless your VFO is misaligned.

Or you could use N-gen kit too, but  be careful with it - it's easy to
adjust all filters on receive so it will look like you reached the
peak, while in reality your IF will not align properly with center
frequency of crystal filters. This is because it produces relatively
strong noise signal. If that happens (the giveaway is that you can
hear noise generator, but nothing from the antenna) - move all
adjustments for the problematic band to their neutral positions and
start over.

But the easiest method is to use another QRP rig or a signal generator
as a signal source.

On Wed, May 26, 2010 at 5:19 PM, Don Wilhelm <w3fpr at embarqmail.com> wrote:
> Greg,
>
> You will "peak the inductors" two times - first in receive to get then
> into the approximate correct position, and then in transmit for the
> final setting.
> NOTE WELL - you will peak the inductors if you have the 2 band board,
> but if you have the 4 band board, you will be peaking the capacitive
> trimmers instead - and for the 4 band board, follow the band order - 30
> meters must be peaked before 40 meters and 15/17 meters must be peaked
> before 20 meters.
>
> OK, what does "peaking" mean - for receive, you will simply adjust for
> maximum signal (or band noise if you cannot hear any signals)  You can
> use another QRP transmitter running into a dummy load as a signal
> source, or if you have a signal generator, that is ideal - listen to the
> signal and adjust the inductors (or capacitors for the 4 band board) to
> achieve the strongest received signal
>
> On transmit, things are a bit easier - you have already pre-set the
> tuning during receive, so this is just a matter of refining the tuning -
> in other words, you should not have to move the adjustment very far.
> Set the power (menu OUT parameter) to about 1.5 watts, and then adjust
> for the maximum power output.  Problem - if the power output rises to
> more than 5 watts, the peak will "hide". and you will reach the power
> output capability of the transistors rather than finding the peak, so
> exit TUNE and re-enter (or in the case of the K1, often repetitively
> tapping the WPM- button will reduce the power) keep the power level low
> so you can discern the peak.  You will find a point where the power
> output increases, and then decreases as you adjust the inductor (or
> capacitor).  The point in between where the power is maximum is the peak
> that you are searching for.
>
> 73,
> Don W3FPR
>
> ki4bbl at cox.net wrote:
>> I love this rig already!  My wife was sure I was having an affair last
>> night when I came in from my man cave just smiling ear to ear because
>> my led backlight lit up, and I was able to play with the controls.  I
>> was most notably giddy when I aligned the VFO by manipulating the L1
>> toroidal....I love electricity, but I digress.  I am on page 40 doing
>> the band-pass filter alignment.  What does it mean to peak the
>> inductors?  I am not sure what I am looking for there.  Thanks so much.
>>
>> Greg Doughty

-- 
Alexey Kats (neko)