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Calculating dial frequency

Moleculo

Ham Radio Nerd
Apr 14, 2002
9,322
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Lately it seems that I've been answering questions about how to determine the dial frequency when using frequency shift modes w/ a TNC (rtty, amtor, pactor, etc.) Here is a good website that has a calculator to do it for you and a brief explanation

http://kn4gc.us/dialcalculator.html

Here's the math, if you want to do it yourself:

For LSB, take the starting frequency + TNC Center frequency.

For USB, take starting frequency - TNC center frequency.

Some TNCs have fixed center frequencies that you can't change. Some (most) don't have a "center frequency" value, but have a "mark" and "space" frequency value, in Hz. In this case you must calculate the center frequency. This is accomplished as: (space + mark)/2.

Hope this helps someone.
 

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  • @ heartbreaker3473:
    Hello gentlemen and Ladies. I have the dreaded RCI-2990 receive issue where my radio gets distorted when people get close to my location. I found the C90 Capacitor, but I can not for the life of me find the C89 capacitor. Can or does anyone have a picture of the exact location of C89 ? Thank you in advance, Wes
  • @ AudioShockwav:
    Wes, it's better if you start a thread on the main forum, more people are going to see your question.
  • @ heartbreaker3473:
    Okay, sorry, will put in a forum
  • @ heartbreaker3473:
    I put it in the general disscution help area and started a new thread. Thank you for letting me know.