[KX1] Xtal Filter Performance?

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[KX1] Xtal Filter Performance?

Joe Planisky
I just finished building my KX1, including the KXAT1 and KXB3080  
modules.  (The KXB3080 is probably the most challenging kit item I've  
ever built and installed! There are only 19 parts, how hard could it  
be? ;-)

Anyway, everything with the rig seems to be working, but I've noticed  
the filtering of the unwanted sideband is a bit less than I expected.  
With my XG2 signal generator connected to the antenna input, I can  
hear a 1uV signal on both sides of zero beat.  The desired side is  
clearly louder than the undesired side, and with normal band noise I  
probably wouldn't notice the undesired side.  However, a 50uV signal  
(S9) is very clearly copyable on the unwanted side.

I realize that the 3 pole variable bandwidth filter in the KX1 isn't  
going to provide the same performance as the filters in my K3, but  
still, I wonder if what I'm hearing is normal.

Can anyone with experience with the KX1 comment on whether or not this  
is normal?

Tnx & 73
--
Joe KB8AP

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Re: [KX1] Xtal Filter Performance?

wayne burdick
Administrator
Hi Joe,

This is normal. A 3-crystal filter at ~5 MHz will definitely allow  
some opposite-sideband leakthrough, especially when lightly loaded. If  
you dial the bandwidth way down, the leakthrough will be lessened.

73,
Wayne
N6KR


Joe Planisky wrote:

> ...I've noticed
> the filtering of the unwanted sideband is a bit less than I  
> expected....
>
> I realize that the 3 pole variable bandwidth filter in the KX1 isn't
> going to provide the same performance as the filters in my K3, but
> still, I wonder if what I'm hearing is normal.



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Re: [KX1] Xtal Filter Performance?

Joe Planisky
Thanks Wayne.  I suspected it was normal since everything else seems  
to be working FB.

I still get a thrill from working coast-to-coast on 6 AA batteries!  
(First QSO was 2300 miles :-)

73
--
Joe KB8AP

On Aug 22, 2010, at 5:57 PM, Wayne Burdick wrote:

> Hi Joe,
>
> This is normal. A 3-crystal filter at ~5 MHz will definitely allow  
> some opposite-sideband leakthrough, especially when lightly loaded.  
> If you dial the bandwidth way down, the leakthrough will be lessened.
>
> 73,
> Wayne
> N6KR
>
>
> Joe Planisky wrote:
>
>> ...I've noticed
>> the filtering of the unwanted sideband is a bit less than I  
>> expected....

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Re: [KX1] Xtal Filter Performance?

wayne burdick
Administrator
Me too. I've made QSOs on the KX1 up to 3000 miles on 20 m, just  
walking around outside with a 4' whip, trailing a ground wire.

73,
Wayne
N6KR

On Aug 22, 2010, at 6:39 PM, Joe Planisky wrote:

> Thanks Wayne.  I suspected it was normal since everything else seems  
> to be working FB.
>
> I still get a thrill from working coast-to-coast on 6 AA batteries!  
> (First QSO was 2300 miles :-)
>
> 73
> --
> Joe KB8AP

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Re: [KX1] Xtal Filter Performance?

The Smiths

I took a KX1 to the Philippines with me and I was able to work over 12 different countries including Russia, the North Pole, the Bahamas, as well as pretty much everything in Asia (seriously).  I used a 28 AWG wire 28 feet long thrown up into a Coconut tree with 2 pieces of 28 awg wire thrown on the ground.. One 16' and the other 35' long.  I worked on 20 and 30 meters all day and night long.
That rig impressed me to no end.  I wouldn't go on vacation again without it!  Thanks Wayne
 

> From: [hidden email]
> To: [hidden email]
> Date: Sun, 22 Aug 2010 18:45:16 -0700
> CC: [hidden email]
> Subject: Re: [Elecraft] [KX1] Xtal Filter Performance?
>
> Me too. I've made QSOs on the KX1 up to 3000 miles on 20 m, just
> walking around outside with a 4' whip, trailing a ground wire.
>
> 73,
> Wayne
> N6KR
>
> On Aug 22, 2010, at 6:39 PM, Joe Planisky wrote:
>
> > Thanks Wayne. I suspected it was normal since everything else seems
> > to be working FB.
> >
> > I still get a thrill from working coast-to-coast on 6 AA batteries!
> > (First QSO was 2300 miles :-)
> >
> > 73
> > --
> > Joe KB8AP
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
     
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