>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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