[Test-Equipment] HP-606A Calibration question

[Richard Knoppow]

----- Original Message ----- 
From: "Barry" <n4buq at knology.net>
To: "Discussion of Electronic Test Equipment" 
<test-equipment at mailman.qth.net>
Sent: Tuesday, May 26, 2009 6:02 PM
Subject: Re: [Test-Equipment] HP-606A Calibration question


>I was just looking into this again and I notice that there 
>are two
> independent slugs for the 530kc to 1800kc range (and other 
> ranges too).  I
> had not noticed this before.  The manual makes no mention 
> of separate
> adjustments.  What's the proper way to set both slugs?  Is 
> it possible this
> is what is causing the linearity problem (one or both 
> slugs is not in a
> correct position)?
>
> Barry - N4BUQ
>
     The coils are balanced beause both oscillator and 
amplifier are push-pull. In theory the inductance of each 
coil should be equal but its good enough if they are 
approximately the same. Note that there is only a single 
slug on the high band coils. I don't know what procedure was 
used on the production line for setting the slugs but I 
suspect that when they are about the same second harmonic is 
minimised. The frequency error is not coming from the slugs. 
Have a look at the clearance from the end of the slug to the 
end of the coil form. If both sides are about the same don't 
worry about it. You will find a couple of other undocumented 
adjustments in there.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com