[TenTec] Keying lockup problem continued

[Joe]

de Joe, aa4nn,
I had similar lockup using CW with OmniVI+ and Titan.  I don't use TX EN TX OUT lines.  Output from CW keyer goes to Titan Key-In.  Titan Key-Out goes to Omni's Key-In.  Also input (in parallel) to Titan Key-In is a keying line from a PC's LPT1 port which is keyed by contesting software.  I believe the lockup problem to be RF related but not necessarily due to poorly shielded keying lines.  Something in the PC.  Lockup would occur only on 20 meters and only when the yagi was pointing 300-360 degrees.  <Ctl-Alt-Del> kills the PC and kills the lockup.  Later I found if I just reduce RF drive to the Titan the lockup would release, no need to kill the PC.  hmmmm  My fix was to not point the yagi thataway.

The LPT1 keying interface was built directly onto a DB-25 connector with no shielding.  Adding by-pass caps to the circuit did not help.  It never occurred to me to try a different key line from the cheap audio cable I was using.  I can't do further tests now because there's a different PC here, and I can't even get a printer to work off LPT1, much less a keying circuit.
73, Joe, aa4nn
  ----- Original Message ----- 
  From: Ken Brown 
  To: tentec at contesting.com 
  Sent: Wednesday, September 24, 2003 4:28 AM
  Subject: [TenTec] Keying lockup problem continued


  Hi all,

  I posted a message a few days ago about a problem with my Omni VI and
  Titan getting locked in TX. The problem seems to be related to RF pickup
  by the QSK control cables between the Omni and the Titan. I thought I
  had solved the problem, only to have it happen again tonight. I am
  expecting that better quality cables will solve the problem. Another
  detail I discovered tonight is quite interesting: I turned on another
  receiver to monitor my signal, heard my signal where it should be when I
  key the Omni. When not keyed, and locked up by the RF into the QSK
  cables problem (I presume) I did not hear my signal, even though the
  Bird 43 wattmeter is indicating the same power output as when keyed. I
  do not have a spectrum analyzer, or other way to quickly see where (in
  frequency) the RF is, and I am certainly not going to let this continue
  while I tune the other receiver around to find it. Better just to fix
  it. Interesting though.

  Ken N6KB



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