[AMPS] Band Switch Heath SB-1000

[Rich Measures]

>Get the switch from Ameritron...it is a PnP replacement.
>
>Then quit underloading the amp; that is the major cause of zapped
>switches. Load it up to maximum obtainable output with 100W of drive.
>Then back the drive ONLY down until you have ~ 800W. Do not reduce power
>with the amp controls. 
>There is something amiss in the basic design...same as the AL-80... that
>causes zapped switches when underloaded. 
>
>73...Carl   KM1H

This was apparently not the case in the zapped bandswitches whose 
photographs are available on my Web site. 
http://www.vcnet.com/measures
 Unless showered with spilt coffee, the AL-80 and the SB-1000 
bandswitches can withstand over 5500v.   The piv in typical use is under 
2900v.  Statements about tank voltage soaring off into the heavens during 
mistuning makes zero technical sense to me.  In a mistuning test, the 
measured piv increased a bit under 30% maximum.  However, the settings to 
produce this condition were far, far removed from the settings that 
produced max. RF to the antenna, which is how most folks tune an 
amplifier.  
--.Carl:  Have you measured the VHF suppressor resistance in an amplifier 
that came in for repair with a crispy-crittered bandswitch?  
Rich---

R. L. Measures, 805-386-3734, AG6K   


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