Posted by
alsopb on
Jul 14, 2011; 12:02pm
URL: http://elecraft.85.s1.nabble.com/KPA500-and-KAT500-Ports-tp6574422p6582917.html
Unfortunately, this scenerio is exactly what I expect many with
KAT-500's to actually try and tune. Unless there is some logic built in
to the tuner to inhibit operation for these crazy conditions, the future
is going to be full of "toasted toroids."
The scenerio goes as follows. The tuner tunes up a 8:1 SWR OK at tune
power levels. The amp is turned on and "FLASH". The amp might be
protected but the tuner won't be.
This isn't fiction. The roadsides are littered with autotuners that
have been fried. Of course the tuner is at fault, not the user....
A tuner is not a cure all. You've got to get your antenna(s) to
reasonable impedance levels first. Hopefully, Elecraft will supply some
kind of "operating range" info. Prudent users will then stay within
those limits.
BTW how do you remote antenna tuner users protect against lightning
destroying the tuner?
73 de Brian/K3KO
On 7/14/2011 04:50, Joe Subich, W4TV wrote:
>
>
> A 10:1 VSWR load rating is craziness - particularly for a 600W rated
> tuner. 10:1 VSWR means 5KV/50A peak ratings ... something that would
> handle 3:1 SWR at the W/VE "legal limit." 3:1 or 5:1 is far more
> reasonable for a "high power" tuner ... and can handle the open wire
> fed doublet or inverted L as long as the user avoids pathological
> lengths of feedline (1/4 wave of open wire line) or antenna length
> (full wave doublet or half wave inverted L).
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