Well, If there is a voltage, there is a current (albeit, at times very
small)--the opposite is also true, ohms law is standing proof...



Why can't I measure the standing wave ratio as a ratio of power, as opposed
to voltage or even current reflected... the three are tied together, isn't
it impossible to separate any one from the other two (and, I mean in
reality, NOT in theory)--even though at times one can appear as
insignificant to an observer?



I see the design I sketched as an SWR device, perhaps not VSWR, or
ISWR--but, PSWR...



What would favor choosing the voltage device over the current or power SWR
devices?



Or, am I imagining something?



Warmest regards,

John


"Cecil Moore" wrote in message
...
| John Smith wrote:
| It seems to work, all I have is another SWR with analog meter I
constructed
| myself to compare it with, soon as I locate someone with a commercial
| meter--I will compare both of mine to it... Only real apparent problem
is
| the REF led changes brightness slowly (and here it is hard to "judge"
SWR by
| brilliance), until right at, or near, match, when it will plunge to
darkness
| rather quickly...
|
| You are not reading SWR. All you are reading is net current.
| Both LEDs have the same rectified net current through them.
|
| Well, show me what is wrong and suggest an alternative circuit or mods
to
| set it proper (or explain in text, I will see how good I am at word
problems
| here)--I am all EARS Cecil... smile
|
| Here's the last one I looked at:
|
| http://www.mfjenterprises.com/man/pdf/MFJ-974H.pdf
|
| You'll recognize the SWR circuitry at the input connector. Note
| the capacitive dividers. That's what your circuit is missing.
| Nowhere does your circuit sample the RF voltage.
|
| This type of SWR meter samples the RF voltage (using a capacitive
| divider) as one parameter. It samples the RF current (using the
| toroid) as the other parameter. The two parameters are added before
| rectification to obtain the forward power. The two parameters are
| subtracted before rectification to obtain the reflected power. The
| phasor addition and subtraction must be done before rectification.
| --
| 73, Cecil http://www.qsl.net/w5dxp
|
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