Scanning

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Scanning

Kevin Rock

I was going to set my K2 up to scan again when I noticed the scan resume
feature notes on page 97.  It states: "The frequency will jump up 0.5 kHz
to avoid having scan re-lock on the same frequency."  How do I get mine to
do this?  I've never had it jump 0.5 kHz.  Is there something I am missing
in the scan setup procedure?  It scans just fine and then when I hit PF2
it starts at the very same frequency.  I normally restart the scan by
turning the tuning knob if the thousands place decimal point is blinking.  
Otherwise I start the scan again and manually tune upward to avoid
relocking.  How do I get it to work like in the manual?  That would be
convenient.
    Kevin.  KD5ONS
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Re: Scanning

wayne burdick
Administrator
Kevin,

You've discovered a bug in the firmware that I fixed in the most recent
version (2.04P). This version has been shipping for several months.
Full details can be found on our web page.

73,
Wayne
N6KR

On Jun 10, 2004, at 9:15 PM, Kevin Rock wrote:

>
> I was going to set my K2 up to scan again when I noticed the scan
> resume feature notes on page 97.  It states: "The frequency will jump
> up 0.5 kHz to avoid having scan re-lock on the same frequency."  How
> do I get mine to do this?  I've never had it jump 0.5 kHz....

---

http://www.elecraft.com

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KX1 Zero Beat

Leigh L. Klotz Jr WA5ZNU
Administrator

I find zero-beating the KX1 hard.

1. The KX1 mutes the RX, so I can't hear the sidetone and the signal at the same time.
2. I find the sidetone's rich harmonic content distracting.  

Proposal:
I think it would be desirable to clean up the sidetone audio, and to provide a mechanism
to inject the sidetone into the RX audio for zero beat, perhaps with a menu item so that
Menu-Hold could do it in one touch.

Workaround:
For now, I've taken to using the USB/LSB method, or actually tuning to zero and going up
(or down depending on band) 600Hz.

Details:

1. Sidetone and RX Muting
The STL/STP sidetone test mode and PLY=non keyer test modes block out the RX so you can't listen for actual beats against the incoming signal; instead, you have to compare them.  Perhaps I've assembled my kit incorrectly,
but I found that even at STL 0 the sidetone  is easily louder than most of the signals I hear so it seems like it would be possible to inject it without a problem.  

Wayne said the sidetone is driven from the PIC. and looking at the schematic I see it is from PIC outputs  RC0 and RC1 combined through R12 and R13.  
It looks like MUTE-bar comes from RA4, so it should be possible to do this with a firmware change.  I suppose I could test it by removing R29...



2. Sidetone harmonic content
A second problem for me is the rich harmonic content.  When set at 600Hz, I see a strong component at 1800 and 3KHz and a weaker one at 1200. As an experiment I tried listening through an audio filter (an Autek QF-1A)
and found it much easier to tune by pitch matching.  For the more musically-challenged of us, it might be desirable to round off the sidetone a little more.

At first  thought that C2 and R15 were a low-pass filter, but 37KHz seems a bit high so I'm confused.

If the two PIC outputs RC0 and RC1 are used only to provide the 4 levels, it might be possible to use them (at least in zero-beat mode) to generate a slightly better sine wave with values 0-3.  Unfortunately,
that would mean increasing the value of R12 and R13 which might cause an undesirable reduction in sidetone volume during TX.


Leigh WA5ZNU


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Re: KX1 Zero Beat

Leigh L. Klotz Jr WA5ZNU
Administrator
Yes, thanks.  I have used that to get in the right octave and then tried
to pitch match.

Thank you for the info about not narrowing past 500Hz.  I have used
gMFSK on Linux to examine the spectrum, and used that for training my
ear, and seen the bandpass but did not know to look for the Jones
effect.

I remember having trouble with my HW-16 when I was a novice and I think
we lowered the output of the neon lamp relaxation oscillator to reduce
its tendency towards ear-splitting.

On Fri, 11 Jun 2004 5:49am, Michael Babineau wrote:
> "Leigh L. Klotz Jr" <[hidden email]>  wrote :
> I find zero-beating the KX1 hard.

> Try setting the filter to 500hz and peaking the received signal ...
> works for me. It takes a bit of practice but become intuitive in a
> short while.

> The reason I use the 500 hz setting and not a narrower setting is ...If
> you hook the KX1 up to a PC running something like Spectogram you'll
> probably see that the center of the passband shifts a bit lower than
> normal with the filter at the 300 hz position, such that 600Hz is no
> longer in the center of the filter passband.

> I'm not sure what the reason it but I have observed the same thing on
> my Ten Tec Scout with the variable "Jones" filter so I an inclined to
> believe that this is an artifact of the design / implementation of this
> sort of filter ...
> perhaps Wayne can comment on this.
73,
WA5ZNU Leigh
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Re: Re: KX1 Zero Beat

Leigh L. Klotz Jr WA5ZNU
Administrator
Over the 4th of July vacation, I built a zero-beat detector for my KX1.
At first I was using a data book design, but I found this one by KR5L on
N0SS's site and just built his on perfboard.    

  http://home.earthlink.net/~n0ss/kr5l_cw_tuning_ind.pdf

I was visiting my sister (ex WN5UOE) in San Luis Obispo, CA and looked
for a parts store where I might find the 567; oddly enough, Mid State
Electronics (http://tinyurl.com/33m7s) was within walking distance of
where we were staying!  It's a great store, and if you are ever in
central California, it's worth a visit.  They had lots of great parts,
grab bags, mixer and FM chips, APP connectors, tools, PC etching
supplies, tens of thousands of through-hole parts, hobby kits, you name
it.

Anyway, I wired up a couple of stereo headphone jacks in parallel, and
tapped one channel to the PLL circuit's input.  I used a PSK program
waterfall to measure the PLL's reference oscillator and set it to 600 Hz
(actually I measured its 5th harmonic ;-).  If I were to go whole hog,
I'd probably put in switched jacks to control the power, and maybe an
optional pad for mixing both output channels from the KX1 to boost the
signal for weak stations.

With a comfortable listening volume for a CW signal, the LED is on for
+/10Hz, but it's easily centered, or you can turn the audio gain down
and get it to illuminate for only one 10Hz segment.  With really low
signals it doesn't lock.  I built an LM386 mono amp to go with it, which
I thought about using for low signals and also to drive an external
speaker, but I couldn't fit all three (PLL circuit, 386 and speaker) in
the plastic case so I figured I'd house the amplified speaker
separately.

The zero beat detector seems to draw about 20mA from a 9V battery
through a 6.2V Zener, which is roughly half the draw of the entire KX1.
Jerry KR5L said he was experimenting with a low-power PLL...

I probably won't be taking this everywhere I take my KX1, but I might
throw it in a suitcase.

Leigh WA5ZNU


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Re: Re: KX1 Zero Beat

David Pratt-3
In a recent message, Leigh L. Klotz Jr <[hidden email]> said....
>Over the 4th of July vacation, I built a zero-beat detector for my KX1.
>At first I was using a data book design, but I found this one by KR5L on
>N0SS's site and just built his on perfboard.

That device is excellent, Leigh.  I have one built into my K2 and would
not do without it.  Likewise, it is sensitive to +/- 10Hz.

There is a CMOS version of the zero-beat indicator around by LA3ZA using
the LMC567 although I have not tried it. It is said to draw 0.9mA at 5V
compared with 20mA at 8V for the LM567 version.

Have a look at http://www.qsl.net/la3za/QRP_Zero.html

73 de David G4DMP