[Elecraft] OT: Bird Wattmeter "meter failures" (scope probes)

[Al Gulseth]

David,

As no one else appears to have replied, I'll take a stab at it. Basically, 
a "combiner" is a transformerish arrangement which isolates the ports from 
each other to keep them from interfering while maintaining the correct 
impedance. They can be pretty simple and inexpensive, with basic versions 
requiring just a couple of small ferrite cores (of the correct mix for the 
frequency range involved) with tapped or bifiliar windings and a terminating 
resistor or so. The following articles explain things far better than I can:

AN10-006 Understanding Power Splitters - Mini Circuits
www.minicircuits.com/app/AN10-006.pdf
‎
Magic T combiners splitters and how they work - W8JI.com
www.w8ji.com/combiner_and_splitters.htm

Hope this helps.

73, Al

On Sun November 22 2015 8:16:28 am David Christ wrote:
> Interesting article, but being a little dense at times, what is inside the
> box labeled combiner?
>
> David K0LUM
>
> > On Nov 22, 2015, at 6:10 AM, CR <ka5s at earthlink.net> wrote:
> >
> > If you don't need to probe HV or more than about 1 KOhm, the probes, (or
> > indeed, the whole setup) used in Doug Smiths came up with for balanced HF
> > probing looks like a good alternative to"what came with" probes. from
> > 1994: Balanced Scope Probe Extends High Frequency Measurements,
> > http://emcesd.com/pdf/cd94scr.pdf
>
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