FW: Re: IC-7800 vs K2

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FW: Re: IC-7800 vs K2

Dan Barker
I haven't heard one, but looking at the report, it appears they need to do
some work on the CW keying shape. Looks rather clicky to me!

<snip>
It's on the web. http://www.arrl.org/members-only/prodrev/pdf/pr0408.pdf
</snip>

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KX1 Freq & Filter Offset?

Don Nesbitt
Using the narrowest filter setting to battle qrm in FD confirms that I have
the best copy on signals when they give me a recovered audio tone of about
470 hz - and - when I tune them in for that peak, I am (of course) off their
frequency since the KX1 seems to have a "fixed" offset of about 600 +/- hz.
At QRO it's no big deal but running about 1/2 watt output (weak batteries!)
I am having great fun but sure would like to be able to zero-beat them and
still receive them on my peak.  So - is there any way to "slide" the filter
response up and down in the KX1 as can be done with the K2?  I've confirmed
the narrow filter peak at about 470 hz using a broadband noise source and
Spectrogram and can't see any way to "move" the filter response to where I
need it to be.  The way I read the bfo and dds circuits it may end up to be
a capacitor substitution as opposed to a software fix.  Surely I'm missing
something simple.    Any ideas?  73 es have fun --don n4hh

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Re: KX1 Freq & Filter Offset?

Leigh L. Klotz Jr WA5ZNU
Administrator
Try using the RIT function to change the RX freq so you get 470 Hz. I
read on this list that the filter response shifts below 500Hz - have you
checked the peak at the 500Hz width?  It would be nice to know when it
shifts down.
Leigh WA6ZNU

On Sun, 27 Jun 2004 12:17pm, Donald Nesbitt wrote:

> Using the narrowest filter setting to battle qrm in FD confirms that I
> have
> the best copy on signals when they give me a recovered audio tone of
> about
> 470 hz - and - when I tune them in for that peak, I am (of course) off
> their
> frequency since the KX1 seems to have a "fixed" offset of about 600 +/-
> hz.
> At QRO it's no big deal but running about 1/2 watt output (weak
> batteries!)
> I am having great fun but sure would like to be able to zero-beat them
> and
> still receive them on my peak.  So - is there any way to "slide" the
> filter
> response up and down in the KX1 as can be done with the K2?  I've
> confirmed
> the narrow filter peak at about 470 hz using a broadband noise source
> and
> Spectrogram and can't see any way to "move" the filter response to
> where I
> need it to be.  The way I read the bfo and dds circuits it may end up
> to be
> a capacitor substitution as opposed to a software fix.  Surely I'm
> missing
> something simple.    Any ideas?  73 es have fun --don n4hh
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft    Help:  
> http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
73,
WA5ZNU Leigh
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Re: KX1 Freq & Filter Offset?

Eric Ward-3
In reply to this post by Don Nesbitt
KX1 gurus: is it true that the offset is fixed at 600Hz?  I was under the
(mistaken?) impression that the offset changed when the sidetone pitch is
changed--i.e. if you set sidetone pitch to 500Hz, then you still zero beat
to your sidetone frequency to determine the received station's carrier freq
(as is described on p.66 of the manual).  Is that wrong?  Does zero beating
to match the sidetone pitch only work at 600Hz?
Thanks!
73,
Eric
N0HHS
____________________________________________________
Using the narrowest filter setting to battle qrm in FD confirms that I have
the best copy on signals when they give me a recovered audio tone of about
470 hz - and - when I tune them in for that peak, I am (of course) off their
frequency since the KX1 seems to have a "fixed" offset of about 600 +/- hz.
__________________________________

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RE: KX1 Freq & Filter Offset?

Ron D'Eau Claire-2
Yes. The xmit offset is fixed at 600 Hz on the KX1.

Ron AC7AC

-----Original Message-----
...is it true that the offset is fixed at 600Hz?  I was under the
(mistaken?) impression that the offset changed when the sidetone pitch is
changed--i.e. if you set sidetone pitch to 500Hz, then you still zero beat
to your sidetone frequency to determine the received station's carrier freq
(as is described on p.66 of the manual).  Is that wrong?  Does zero beating
to match the sidetone pitch only work at 600Hz? Thanks! 73, Eric N0HHS


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Re: KX1 Freq & Filter Offset?

Michael Babineau
In reply to this post by Don Nesbitt
Eric Ward" <[hidden email]> wrote

 >Using the narrowest filter setting to battle qrm in FD confirms that I
have
 >the best copy on signals when they give me a recovered audio tone of
about
 >470 hz - and - when I tune them in for that peak, I am (of course) off
their
 >frequency since the KX1 seems to have a "fixed" offset of about 600
+/- hz.

Eric :

I can't comment as to whether the offset is fixed as I am using a side
tone pitch
  of 600HZ. However,  I have verified that the center
of the audio filter shifts to somewhere around 500hz when cranked down
to its lowest setting (I piped the KX1 audio into my computer running
Spectogram).  I see the same sort of behavior on my Ten-Tec Scout,
which has a similar type of filter (Jones) so I am not sure if this is a
artifact of the design / implementation of this sort of filter.

The trick I use to tune signals is to peak the signal with the filter
at about the 500hz setting ... this gives me a filter center of around
600hz. If I need to crank the filter down to 300hz I then engage the RIT
if it is a particularly weak signal. I also notice some signal
attenuation
as the filter is tightened but I believe that this is normal.


Michael VE3WMB

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