Hi Jerry,
> Bifocals on /or/ off Tom? You didn't read the fine print their only
> 8% accurate. You can calibrate it with a sledge hammer for all care.
> It's only gona do P.E.P. to 8%. #4314B #4391A And from my experience has
> a hard time reaching for 5% in non P.E.P. measuring. Seeings how their
> calorimeters are only 3% accurate. With that said, Do we see 1500 or 1620
> P.E.P. or is it only 1380 P.E.P. I will further state that my amp
> manufacture says and I quote:
Bird's calorimeters are less than 1% error.
The manual for my Bird says Accuracy:
Power Readings 5% of full
SWR 10% of reading
Return loss +-.3 dB of reading
A Bird 43 has the same spec. Maybe your meter is some cheap
model?
> "Every well informed operator should be familiar with measurement
> procedures and with mathematical calculations of power level.
>
> Whenever possible, an oscilloscope should be used to monitor
> peak power levels, since ordinary meters are unable to do so."
Wonderful reference. Who wrote that pearl of wisdom?
> Within 8% with a Bird 4314B. All measurements. So you could have up to 16%
> total error in a >1:3.0:1v.s.w.r., with two different peak reading values.
Your total error of 16% would apply, if you have the 8% right (my
meters are 5%), only when reflected power and forward power were
equal and you used one slug for both readings. If you correctly use
two different slugs because reflected power is a lot lower than
forward power, the error (assuming you have a meter with 8%
tolerance) varies with SWR, but would typically be less than 10%
and with a 1:1 SWR would be within 8% of actual power at full
scale.
> And thats before we even consider all the variables you missed that error
> you.
I don't understand that sentence.
> It's got be real love Tom or no Love at all! The F.C.C. isn't interested
> in your approximations. And personally neither am I. 1500 watts P.E.P. no
> 1515w P.E.P. (1%) at the antenna feed point. The most we could run with
> your methods under worse case is 1260w P.E.P. to be safe. And under the
> best conditions we could run at 1620w P.E.P. pushing limits and safely
> only 1380w P.E.P.
. Better look at how the measure and specify things. They allow
tolerances, they aren't launching a space shuttle. For example, AM
BC stations are allowed a certain percentage over the licensed
power because of the limits of power measuring.
By the way, can you point out an AM broadcast station or
transmitter that uses a scope to measure power?
> Either way doesn't work and here's why:
> Rubber Ducks work and are models. Ok. But some how the wild ones in my
> back yard won't mate with it. In fact they ignore it. Just like I'm going
> to do with your methods of madness, thus far.
Models are an acceptable way of understanding circuit behavior.
For example, while we say "reflected power" and "forward power"
net energy really only flows one way on the transmission line at
any time.
If you don't understand or "like" models for complex actions or
circuits, that's fine. In that case you just went against virtually
every engineering text in the world.
73, Tom W8JI
w8ji@contesting.com
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