What is an appropriate TXDelay to use for a THP 1.5KFX amp

  • 1
  • Question
  • Updated 5 years ago
  • Answered
I have a THP 1.5KFX amp that I have been using with the 6300 on SSB and it works fine without any TXDelay. However, when I try CW it trips the Pr (reflected power) safety, even with fairly low drive power and a resonant antenna. I suspect that I need to put in a small TXDelay. Any suggestions short of incrementally increasing it until it doesn't trip?
Photo of Doug Seyler

Doug Seyler

  • 11 Posts
  • 0 Reply Likes

Posted 5 years ago

  • 1
Photo of Ken N9VV

Ken N9VV

  • 22 Posts
  • 5 Reply Likes
Hi Doug,
the ARRL "TOR" test was for ancient PACTOR and AMTOR digital programs that required a T/R time of 20ms of less. In the "old days" there were many rigs that met this requirement. However recent rigs vary quite a bit in their T/R times.  If I remember correctly, a dit at 40WPM = 20ms.  
To avoid "hot switching" I would recommend 40ms or greater and see how it works out for your favorite speed and switching circuits.
GL de Ken N9VV

Photo of Ken N9VV

Ken N9VV

  • 22 Posts
  • 5 Reply Likes
Doug, you might find this chart interesting. Go to the right hand columns and you will see the ARRL T/R test results for various modern Transceivers;
<URL: http://www.remeeus.eu/hamradio/pa1hr/productreview.htm >
GL de Ken N9VV
Photo of Charlie

Charlie

  • 34 Posts
  • 13 Reply Likes
Official Response
I had the same problem with my 6300 and THP.  I am using 5 ms TX delay and it works fine.  No more Pr errors.
Photo of Doug Seyler

Doug Seyler

  • 11 Posts
  • 0 Reply Likes
Thanks, guys, for all of the help!

Doug WB5TKI

This conversation is no longer open for comments or replies.