Posted by
Chester Alderman on
Oct 29, 2010; 10:57pm
URL: http://elecraft.85.s1.nabble.com/K3-LPA-power-level-accuracy-tp5688027p5688282.html
James,
You are beginning to venture on a losing battle!! What used to be the 'old
reliable' Bird watt meters had an accuracy of +/- 5%. Typical ham watt
meters, especially the ones that use diodes to produce forward and reflected
power, typically never mention an accuracy specification. You will also
notice that for a given constant load, the same watt meter will change the
SWR reading as you change your power. As you know, SWR is not a function of
RF output power! 4.5 watts is 10% of 5 watts and if you change watt meters
you are going to get a completely different answer. Very few watt meters are
calibrated to any standard and if they are, they most likely are not
recalibrated once a year.
The only solution to the answer you are seeking is $$$$$$$$$$! 'Close
enough' will have to do with watt meters.
Tom - W4BQF
-----Original Message-----
From:
[hidden email]
[mailto:
[hidden email]] On Behalf Of James Sarte
Sent: Friday, October 29, 2010 5:18 PM
To: The Smiths
Cc: Elecraft Reflector
Subject: Re: [Elecraft] K3: LPA power level accuracy?
No, wasn't aware of that. It's been a while since I've delved into the K3's
menus. Do you know what that option is called, or where to find it in the
manual?
Also, just to make sure I'm understanding you correctly - do you mean to
suggest that if the K3's watt meter reads 5W, but actual output power is
4.5W, you can adjust output power to match the K3's meter? As it is, the
K3's meter and LPA power settings do not match the readings displayed on my
outboard analog and digital forward power meters. When the LPA is in use,
displayed power is always a .5 to 1 watt lower on the external meters.
73 de James K2QI
On Fri, Oct 29, 2010 at 5:04 PM, The Smiths <
[hidden email]> wrote:
> There's also an adjustment that you can make manually to move the power
up
> or down from what the meter is reflecting on the K3, have you tried that
> too?
>
> > Date: Fri, 29 Oct 2010 17:00:21 -0400
> > From:
[hidden email]
> > To:
[hidden email]
> > Subject: [Elecraft] K3: LPA power level accuracy?
>
> >
> > Hello fellow Elecrafters,
> >
> > Quick question - I've noticed that when using the LPA, output power is
> > always slightly off compared to the reading given off by two fairly
> accurate
> > meters. For example, a constant carrier output of 5 watts always reads
> > about a half-watt less on the external meters. The output power from the
> > KPA3 however has always been on the dot - 80 watts drive reads 80 on the
> > meter, 100 watts output reads 100W on the meter, etc. etc.
> >
> > I'm not really concerned, but was wondering if this was typical? I've
> > calibrated several times in the past using the K3 utility, but the
> results
> > are usually the same.
> >
> > --
> > 73 de James K2QI
> > President UNARC/4U1UN
> > ______________________________________________________________
> > Elecraft mailing list
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> >
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--
73 de James K2QI
President UNARC/4U1UN
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