Worleys online conversion tools assist in converting watt to db, db to watt ( decibels to watts), dbm to watts and various line loss incurred at given frequency.
Note: Power conversions are based on 50 Ohm resistance unless otherwise stated.
When working with wireless systems, calculations should consider total working kit gain. Often, conversion of watt to db is necessary kit design. Kit gain of a wireless system includes the transmission device, associated transmission lines, transmitting antenna, free space loss, receiving antenna, receiving transmission lines and the receiver itself. This allows for practical real world calculations along with expected results.

Watts to dBm:

dBw = 10Log10(Power Watts)

dBm = (10Log10(Power Watts)) + 30

Insert Power in Watts: Watts.
= dBw.
= dBm.

dBw to Watts:

Watts = 10(dBw/10)
MilliWatts = 10((dBw + 30)/10)

Insert Power in dBw: dBw.

= Watts.
= MilliWatts.

Conversion of watts to amps is dependend on volatge of the circuit. Amps = watts divided by volts. A 100 watt light bulb on a 120 volt circuit is pulling .83 Amps. Amps = Watts / Volts. For percentage calculators dealing with total circuit loading, look further down the page.

dBm to Watts:

Watts = 10((dBm - 30)/10)
MilliWatts = 10(dBm/10)

Insert Power in dBm: dBm.

= Watts.
= MilliWatts.

Voltage Gain / Loss to dB:

dB(gain / loss) = 20Log10(Gain or Loss)

Insert Voltage Gain or Loss: Volts

= dB.

dBm to Volts / uVolts:

Volts = Log10-1[(dBm -13)/20]
uVolts = Log10-1[(dBm + 107)/20]

Insert Power in dBm: dBm

= Volts.

= uVolts.

dBw to Volts / uVolts:

Volts = Log10-1[(dBw - 17)/20]
uVolts = Log10-1[(dbw + 137)/20]

Insert Power in dBw: dBw

= Volts.

= uVolts.

Anytime your working with volts watts or ohms, coversions like these come into play. When designing your RF system make sure you're staying withing the legal limit for the spectrum. Converting the manufacturer power ratings may not be accurate. When working with parabolic antenna, make sure you're including the launch cable in your calculations, especially if you are operating in higher frequencies of the spectrum. Conversions are more critical at these frequencies.

Parabolic Antenna Tilt (Degrees):

Tilt(a -> b) = 57.2957795[((hb - ha)/5280DistMi) - (DistMi/7920 K-Factor)]
Tilt(b -> a) = 57.2957795[((ha- hb )/5280DistMi) - (DistMi/7920 K-Factor)]

Insert Height of Antenna A: Above Mean Sea Level (AMSL)
Insert Height of Antenna B: Above Mean Sea Level (AMSL)

Insert Distance in Miles: Miles

Insert K-Factor: (effective earth radius)

Tilt(a -> b) = Degrees.

Tilt(b -> a) = Degrees.

Parabolic 3-dB Beam width (Degrees):
Parabolic Antenna Gain (dB) - 55% efficiency:

Beam Width = 70 / Diameter in Feet * Frequency in GHz
Antenna Gain = 20Log10(Distance in Feet) + 20Log10(Frequency in GHz) + 7.5

Insert Antenna Diameter in Feet: Feet
Insert Antenna Frequency in GHz: GHz

Antenna Beam Width (3dB) = Degrees.

Antenna Gain (dB) = dB

Free Space Loss Percentage Calculator(isotropic):
Free Space Loss (di-pole):

Free Space Loss percentage calculator uses assumed isotropic space/distance loss calculations in best practice. When working with power across distane, percentage calculators can be used to assist in designing kit with weather margin capabilities while still delivering sufficient transport bandwidth.

FSL(isotropic) = 20Log10(Frequency in MHz) + 20Log10 (Distance in Miles) + 36.6
FSL(di-pole) = 20Log10(Frequency in MHz) + 20Log10 (Distance in Miles) + 32.3

Insert Frequency in MHz: MHz
Insert Distance in Miles: Miles

FSL(isotropic) = dB.
FSL(di-pole) = dB.

Fresnel Zone Clearance:

1st Fresnel = 72.1 * SqrRoot(dist1Mi * dist2Mi / FreqGHz * DistanceMi)
nth Fresnel = 1st Fresnel * SqrRoot(n)

Insert dist1Mi : Miles
Insert dist2Mi: Miles

Insert Frequency in GHz: GHz

Insert n (Less then 1 = 0.n * 1st): nth Fresnel zone.

nth Fresnel Zone = Feet.

Inverse Position (Azimuth and Distance):

The equation is too long to add, sorry.

Latitude A: Deg. Min. Sec. 
Longitude A: Deg. Min. Sec.   
Latitude B: Deg. Min. Sec.  
Longitude B: Deg. Min. Sec.  

Azimuth From A to B: Deg.
Azimuth From B to A: Deg.

Distance From A to B: Miles.
Distance From A to B: Kilometers.

Power (Watts) to Voltage :

Voltage = SqrRT(Watts * Resistance)

Insert Power:  Watts.
Insert Resistance:  Ohms.

Voltage =  

Voltage to Power (Watts):

Powerw = Volts2 / ResistanceOhms

Insert Voltage:  
Insert Resistance:  Ohms.

Power =  Watts.

Special thanks to Victor at
Worley Consulting for his help putting this together.