[Radio1950]

And the answers to my deceptively simple questions to Jeremy, with sometimes complicated side concepts?

As he says, the sum of two unrelated pure sine CW signals is the sum of each algebraic voltage vector, which allows for phase.

So eg 0.0 dBm and 0.1 dBm summed is +0.1 dBm, or 1.1 mW.


The level at which one interferes with the other in a AD8307 meter environment is a difference of 1.0 dB.

A bolometer (thermal sensor) will give identical results, it has to.

But the end effects of two unrelated pure sine CW signals when analysing a Device Under Test, depends entirely on the non-linearities of that particular DUT.





Sorry if I am preaching.



New question.

If I combine two 0.0 dBm CW signals, S1 is 5 MHz, S2 is 6 MHz in a 6 dB hybrid combiner (eg ARRL HBK 2007), and monitor the output of the combiner with my AD8307 Milliwattmeter, I see -6.0 dBm.

If I remove one of the input cables to the combiner, the AD8307 meter still shows -6 dBm.

I reconnect the cable and remove the other cable it shows -6 dBm.

If I remove both cables, the meter falls to nothing.

I did this last night.

What is going on?
Why don't I see -3 dBm, the power sum?.

Kewpie Doll available for cautious responder with correct answer, personal pickup.

With thanks to moderators for tolerance with slightly off topic stuff.
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