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

Doug Seyler

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?

Ken N9VV

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

Ken N9VV

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

Charlie

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.

Doug Seyler

Thanks, guys, for all of the help!

Doug WB5TKI