dBCalc: Signal Power & dB Comparison

KD WY5R & David KJ4IZW

JT65A on HF, or Terrestrial JT65, is a weak signal mode with it's roots in EME/Moonbounce operations. It is a data mode designed to copy signals as much as 15dB below the noise level. On HF, operators take this ability for granted by using power levels which are not necessary. It is recommended that you examine your logbook on a regular basis, and check your average signal report. If you find that you consistently receive signal reports better than -10 dB, you can safely lower your power to 1/4th or 1/8th of what you currently use. The purpose of dBCalc is to provide an operator with alternative power levels required to acheive other readable signal reports with programs such as WSJT or JT65-HF.

To calculate alternative power levels, enter your current power output in the TX Power box. Next, select the signal level you received from your latest QSO. You will be presented with a list of power levels required for other signal reports to the same station.

TX Power: Watts
Signal Report: dB

Report Power
-01dB 316.23 W
-02dB 251.19 W
-03dB 199.53 W
-04dB 158.49 W
-05dB 125.89 W
-06dB 100.00 W
-07dB 79.43 W
-08dB 63.10 W
-09dB 50.12 W
-10dB 39.81 W
-11dB 31.62 W
-12dB 25.12 W
-13dB 19.95 W
-14dB 15.85 W
-15dB 12.59 W
-16dB 10.00 W
-17dB 7.94 W
-18dB 6.31 W
-19dB 5.01 W
-20dB 3.98 W
-21dB 3.16 W
-22dB 2.51 W
-23dB 2.00 W
-24dB 1.58 W
-25dB 1.26 W
-26dB 1.00 W

Website by David - KJ4IZW - dwestbrook@gmail.com