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Re: [LW] ... --- ...

To: [email protected], [email protected]
Subject: Re: [LW] ... --- ...
From: "Scott Tilley" <[email protected]>
Date: Tue, 1 Mar 2005 00:50:17 -0800
Cc: "Steve McDonald" <[email protected]>
References: <[email protected]>
Reply-to: [email protected]
Sender: [email protected]
Seems I was alittle quick to call for help!
I found the problem.  When the two 4013 dividers are powered up individually they sinc differently (of course they would!).   Solution: reset one TXs LV PSU until it is in phase or share one PSU!
With the TXs running with a conservative 36V supply we get 750W output to the dummy load.
I love the smell of burning dummy load in the morning...
73 Scott
----- Original Message -----
Sent: Monday, February 28, 2005 10:51 PM
Subject: [LW] ... --- ...

The smoke test of this Wilkinson Combiner was successfull in that no smoke came out and nothing died.  However, we get enough heat to cook an egg on the 100ohm balance resistor.  
We have a scope match on the output to the dummy load and it shows about 225W from one transmitter, add another and we get 450W, success NOPE!  The transmitters are outputting ~450W each! Therefore, half the power is being absorbed in the 100ohm balance resistor.  Examining the phase relationship of the input to the combiner waveforms indicates they are in phase within ~10degrees and almost equal in amplitude.  So what gives!  Anyone have some idea what may be going wrong?  Of course we have checked and doubled checked the circuit for errors and nothing...  All seems as it should according to formulas and drawings we have viewed and designed it from.
Does anyone have an idea how we could troubleshoot our way through this?
Any advice would be appreciated.
73 Scott and Steve(It's all his fault ;-)
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