[Amps] Overdrive protection

Roger (K8RI) k8ri at rogerhalstead.com
Sat Jul 28 12:36:23 PDT 2012


On 7/28/2012 7:45 AM, Jim Thomson wrote:
> Date: Fri, 27 Jul 2012 10:28:49 -0400

>
> ##  in any case, I would suggest tweaking  the LOAD control  such that the¨PO  drops 2%.    Tune ur amp
> up to say 1550 watts pep out,, THEN increase the loading ( decrease the C of the load cap), so the
> PO  drops down to  1500 w pep out.  ( 3.7% drop)  Or tune up to 1600 pep out..then tweak load cap
> for 1500w pep out.   Then its linear..and will absorb  most spikes.

That's pretty much how I run it.  Actually I tune for about 2KW into the 
dummy load then increase the loading to bring it back to 1500.  The amp 
will run 2500 pep, but running it like this gets me lots of unasked for 
quality signal reports.


>
> ## see my other post on how to get rid of the spikes.
>
> ##  Im surprised alpha has not made  a list  of lousy xcvrs .

As not all rigs of these makes have the problem all they'd have to do is 
show one that doesn't and it'd be lawsuit time.  Tempting as it is I 
don't think they'd dare do it.  They should at least warn "some rigs 
have a leading edge spike and some have poor IMD at maximum power.

73

Roger (K8RI)


   “warranty void if ICOM 775 used”   etc.
> That would smarten up the  xcvr makers real fast.   “ warning, do not use the following xcvrs, due to their
> poor  IMD.  These IMD products will be amplified by your Alpha linear amplifier to a much greater level”
>
> later........ Jim  VE7RF
>
> Jim  VE7RF
>
>
>
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