RE: K2: VFO clicks/pops in the presence of strong sign als

[Linden, Mike (BRC-Hes)]

Sverre,

  Thank you for the information. While I do not necessarily like the
behavior, it is comforting to know that it is simply an attribute of the
design and not a problem with my particularly K2.

  Thanks, Michael N9BDF
 

-----Original Message-----
From: Sverre Holm [mailto:[hidden email]]
Sent: Monday, July 12, 2004 7:54 AM
To: Linden, Mike (BRC-Hes); [hidden email]
Subject: RE: [Elecraft] K2: VFO clicks/pops in the presence of strong
signals



>  I hear clicks/pops (about
> S-5/6) when the VFO transitions the following boundaries:
>
> 7015.79/80 (click/pop getting very weak here) 7020.79/80 7025.79/80
> 7030.79/80 7035.79/80

Such clicks about every 5 kHz is normal and is part of the construction of
the PLL/VFO-system of the K2. Let me see if I can explain it. The reference
oscillator of the PLL is based on a 12 and something MHz crystal, with a
variable division ratio following it. However, these steps would be way too
course, and therefore the crystal is pulled by varicaps over about 5 kHz
between every change of division ratio. The pops you hear is when you are
the end of the pulling range, and the divisor changes and the varicap
voltage goes to the other end of the pulling range.

--
73,
Sverre

------------------
Sverre Holm, LA3ZA
www.qsl.net/la3za

 
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[Linden, Mike (BRC-Hes)]

Sverre,

  Now that I think about it, it appears that the magnitude (strength) of the
clicks/pops is proportional to the strength of any nearby signal. Does that
make sense based upon you knowledge of the PLL/VFO system?

  Thanks, Michael N9BDF


-----Original Message-----
From: Linden, Mike (BRC-Hes)
Sent: Monday, July 12, 2004 8:34 AM
To: '[hidden email]'; [hidden email]
Subject: RE: [Elecraft] K2: VFO clicks/pops in the presence of strong
signals

Sverre,

  Thank you for the information. While I do not necessarily like the
behavior, it is comforting to know that it is simply an attribute of the
design and not a problem with my particularly K2.

  Thanks, Michael N9BDF
 

-----Original Message-----
From: Sverre Holm [mailto:[hidden email]]
Sent: Monday, July 12, 2004 7:54 AM
To: Linden, Mike (BRC-Hes); [hidden email]
Subject: RE: [Elecraft] K2: VFO clicks/pops in the presence of strong
signals



>  I hear clicks/pops (about
> S-5/6) when the VFO transitions the following boundaries:
>
> 7015.79/80 (click/pop getting very weak here) 7020.79/80 7025.79/80
> 7030.79/80 7035.79/80

Such clicks about every 5 kHz is normal and is part of the construction of
the PLL/VFO-system of the K2. Let me see if I can explain it. The reference
oscillator of the PLL is based on a 12 and something MHz crystal, with a
variable division ratio following it. However, these steps would be way too
course, and therefore the crystal is pulled by varicaps over about 5 kHz
between every change of division ratio. The pops you hear is when you are
the end of the pulling range, and the divisor changes and the varicap
voltage goes to the other end of the pulling range.

--
73,
Sverre

------------------
Sverre Holm, LA3ZA
www.qsl.net/la3za

 
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Post to: [hidden email]
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Elecraft web page: http://www.elecraft.com