[Elecraft] K3 voltage under load

[Ed K1EP]

At 6/2/2009 05:09 PM, Hector Padron wrote:
>Certainly there is mot enough evidence to blame the PS yet,he will 
>have to read the drop at the PS output poles to see  if is the same 
>or worse,otherwise its losses at his DC cable or something lose in 
>the DC line at the K3,even a cold solder can create that,but if the 
>radio makes 100W all the time,why to worry?

There are a number of reasons to worry.  If there is a defective 
connection, it could (and will) heat up and melt (or self destruct), 
causing other problems.  I have seen the plastic on power poles melt 
due to incorrect installation and high  resistance.   Typically, the 
voltage to the PA is not regulated, in the sense that it uses the 
voltage supplied to the radio which it assumes is regulated.  It does 
that because there is no room to supply a 20A regulator in the 
radio.  (if you want that, you will be buying a bigger and more 
expensive radio)  But if the voltage becomes modulated with the audio 
or other parameters, you will introduce RF distortion and other 
unwanted byproducts.  Not a good thing either.

>
>AD4C
>
>
>"The difference between genius and stupidity is that genius has its 
>limits". -- Albert Einstein
>
>--- On Tue, 6/2/09, Ed K1EP <k1ep.list at gmail.com> wrote:
>From: Ed K1EP <k1ep.list at gmail.com>
>Subject: Re: [Elecraft] K3 voltage under load
>To: "Bill W5WVO" <w5wvo at cybermesa.net>, "Harris Leck" 
><vk6av at yahoo.com>, elecraft at mailman.qth..net
>Date: Tuesday, June 2, 2009, 12:39 PM
>At 6/2/2009 08:26 AM, Bill W5WVO wrote:
> >I own an Astron analog power supply, and there is NO fluctuation of voltage
> >under full load, without load, or anything in between. That's what a
> >regulated
> >power supply is supposed to do. I would say you have a defective 
> power supply.
>No, not necessarily.  He stated that the 12.3V was measured inside of
>the radio.  That reflects any IR loss to that point and not
>necessarily poor regulation on the supply.  More data is necessary to
>come to that conclusion.
>
> >Harris Leck wrote:
> > > I am running my K3 off an Astron RS-35M. No load voltage at the rig
> > > is 14.0V (per the K3 display). Running approximately 100W this
> > > reading drops to 12.3V. Is this the norm? BTW current reads just
> > > under 18 amps. The amp meter reading on the Astron is way off.73
> > > Harris K9RJ
> > >
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