[Elecraft] KPA500 active devices!!

[Tom W8JI]

<
The VRF2933 is rated "3:1 Load VSWR Capability at Specifi ed 
Operating
Conditions" according to its datasheet; perhaps that's why 
there no
built-in ATU.>

.....but that doesn't mean SSB IMD would be acceptable, or 
it would be safe in every circuit at that mismatch, so keep 
that in mind. :-)

No matter what the data sheets say about device life, the PA 
often needs to be kept within 1.5:1 or better SWR to meet 
IMD specs. 3:1 is a huge loadline move, depending on the 
direction of the impedance move it could really put the PA 
into severe flattopping. Use a tuner or fix the antenna, be 
safe.

73 Tom

On Sat, Apr 17, 2010 at 6:44 PM, Doug Faunt N6TQS 
+1-510-655-8604
<faunt at panix.com> wrote:
> There are two VRF2933's in push-pull, so they're not 750 
> watts each,
> but per pair.  There are only three amps in existance, and 
> no devices have
> been destroyed (yet).  Again, 500 watts is a very 
> conservative rating.
> It's been key-down for 10 minutes withy no problems.
>
> 73, doug
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