Message-ID: <002801c51e4d$170bede0$6507a8c0@Main>
From: "Alan Melia" <Alan.Melia@btinternet.com>
To: rsgb_lf_group@blacksheep.org
References: <003e01c51e2b$0f93d220$0201a8c0@private.network> <000b01c51e3b$b1aaed40$0201a8c0@private.network>
Date: Tue, 1 Mar 2005 10:54:45 -0000
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Subject: LF: Re: Re: [LW] ... --- ...
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Hi Scott....Ah yes you do need to be "in phase"......glad it works well
....keep a fire extinguisher handy !!

It looks my ideas about conditions may be about right..... I have a
decodable signal from Laurence's WD2XDW last night. I have not seen that for
a long time.

Alan G3NYK

----- Original Message -----
From: "Scott Tilley" <sthed475@telus.net>
To: <lowfer@lwca.org>; <rsgb_lf_group@blacksheep.org>
Cc: "Steve McDonald" <jsm@gulfislands.com>
Sent: 01 March 2005 08:50
Subject: LF: Re: [LW] ... --- ...


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 -----
  From: Scott Tilley
  To: lowfer@lwca.org ; rsgb_lf_group@blacksheep.org
  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 ;-)


  Check the status of radio beacon 'TIL'  in CN89lg at:
  www.scottboxx.com/radio