Hey Alan
We got the bugs out... Once I found the problem with the lack of sinc in
the 4013 divider stages things have been working as expected. I thought
about the inductor coupling; however, based on my observations the combiner
is not doing anything negative to the signal train. We still have >80% eff.
I would like to try this with toroids next and compact it down. I'm also
dreaming up a bigger badder amp using this concept. It seems real stable
and doesn't require running the system 'balls to the wall' to get some
serious power from 4 FET and a reasonable PSU voltage.
73 Scott
----- Original Message -----
From: "Alan Melia" <[email protected]>
To: <[email protected]>
Sent: Tuesday, March 01, 2005 2:49 AM
Subject: LF: Re: ... --- ...
Hi Steve I have just had a thought your construction looks fine....BUT
maybe
the two coils are too close together and there is some coupling. I wonder
if
it is possible to temporarily turn one at right angles to kill any
coupling
and see if that helps??
The biggies in my Web page were made with big toroids I believe probably
iron dust rather than ferrite, as the inductance reqquired is not that
high
Cheers de Alan G3NYK
----- Original Message -----
From: "Scott Tilley" <[email protected]>
To: <[email protected]>; <[email protected]>
Sent: 01 March 2005 06:51
Subject: LF: ... --- ...
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 ;-)
Check the status of radio beacon 'TIL' in CN89lg at:
www.scottboxx.com/radio
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