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Ham Radio - RF Units Conversion
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7 Q2 o) y* H# X# X- gDecibel Conversions
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9 c+ R! g* X8 c4 I5 U. i0 D6 RdB = 10 log [P2/P1]. W" _# K4 L, w$ @
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Decibels relative to Power
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1 [% L* j1 \# b+ k; G+ \) V$ vDecibel Conversions1 S+ {/ ?$ P) @- s
- k: I( ~0 i1 J$ `/ ?4 w2 |3 udB = 20 log [V1/V2]+ e) \- N- f" O- Q+ ^( Q6 e1 z6 _
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Decibels relative to Voltage across same resistance+ o6 g5 h* l1 X4 H7 V5 ]
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# D2 O( G& n1 g7 _Decibel Conversions
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dB = 20 log [I1/I2]
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- j4 U$ s& b; iDecibels relative to Current through same resistance
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Decibel Conversions! q- g7 U9 n% U
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dBmV = 20 log [Signal (mV)/1mV]; {& @- Z0 S- I$ a2 ~
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Decibels relative to one microvolt across same resistance0 U+ J8 [" z8 V4 Z
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Decibel Conversions
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dBm = 10 log [Signal (mW)/1mW]/ g' H# H4 n3 Y; c& b- w; ^ j4 {) l
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Decibels relative to one milliwatt
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: O( E+ t* {6 ?Decibel Conversions; s0 z' Y) s, I" a
- \5 p; x( {4 f4 c% vdBmA = 20 log [Signal (mA)/1mA]
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M2 @% _* w2 ]Decibels relative to one microamp through same resistance
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Power Conversions
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g: s k3 d" A$ U0 SdBm = dBw + 30; h7 g/ C( V( f; X" o
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Conversion from dBw to dBm.$ D9 l* V$ b# z
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Voltage Conversions1 ]5 \4 w; f. T7 p7 S! P
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dBuv = dBv + 120% R. o* d$ u% g1 ^
: f8 V! O$ t4 ~5 L1 J; J* k+ OConversion from dBv to dBuv.( }3 E6 B C4 g$ r+ b( F$ j5 s5 t
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# Z! q3 y9 D$ K7 } RVoltage to Power
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dBm = dBmV - 107* P/ t$ C% H2 j: k3 J7 X0 r
( M- f. {: k% P5 n9 F9 DWhere the constant 107 is as follows:6 D/ V- B, m+ ], z
* RF systems are matched to 50W, R0 t& p) w; S6 g& f2 B
P = V2 / R2 t" v: L1 I5 M; u. G1 a
10Log10[P] = 20Log10[V] - 10Log10[50W]
! R0 Z8 W8 q6 gV = (PR)0.5 = 0.223 V = 223000 mV
& O1 N6 ~( }! g" l% ^For a resistance of 50W and a power of 1 mW:1 t$ e/ t0 v+ m8 V0 U1 u7 L
20Log10[223000mV] = 107 dB 0 V$ Q9 y5 M! [8 n% {) a8 f& _
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9 ~8 o* d3 ^" _' |( }1 uPower Density5 s7 U2 ^7 X9 M Y* ?. m1 }3 k
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dBw/M2 = 10Log10[V/M - A/M]
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4 B- D; K X* F: l3 G" y. PDecibel-Watts per square meter.$ G: i9 R, Y9 K* X2 _3 P3 [, C
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Power Density
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dBm/M2 = dBw/M2 + 30
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Where the constant 30 is the decibel equivalent of the factor 1000 used to convert between W and mW:: y0 l- f1 B" C' n3 ?$ h/ p
10Log10[1000] = 30
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Conversion Units
' v, Q' l0 b) g" o( b! ddB = decibels (Log10)) R+ |; ~0 b' a7 Y& [4 k, [
u = micro = 10E-61 [/ r& N8 Z5 v1 e
m = milli = 10E-3( \4 e) g9 n: v6 I
dBw = decibels relative to one watt9 k5 X) ^$ R/ z3 @" d6 j- o e$ p4 k
dBm = decibels relative to one milliwatt
& F. F" ~8 P" u/ B7 ?2 S5 B# b& kdBV = decibels relative to one volt
! V" @$ E/ D3 w' M$ `$ S. |dBuV = decibels relative to one microvolt
+ H4 W5 @( o+ C0 J; n9 \dBuA = decibels relative to one microamp
* x. E* W/ g* E1 l% d CV = Volts! {8 }9 c) T3 n0 L- n( n0 y
A = Amps0 Q0 y! h: `- X2 n, h" w; A1 d& r0 n8 S
I = Current* o' Z; {5 f q9 p- u
R = Ohms (50)! \. n+ h8 W5 ~7 x( ?
W = Watts
0 [5 U' Z" |; q6 ^2 q- ` ~. ZP = Power
~9 ]: |. i3 u$ ]3 Y3 CM = Meter |
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