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Ham Radio - RF Units Conversion / l: g+ n7 S, A# i
6 N& Z6 S& V( m4 Y" z$ yDecibel Conversions
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4 A0 C8 }* n- @( YdB = 10 log [P2/P1]
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% p" w7 ~) Z& n$ X( P1 q# [; lDecibels relative to Power5 a B% H( X, a2 k" M
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( u5 C: r; @6 h2 `" ~ UDecibel Conversions
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% }$ S1 S. z! ~) [, gdB = 20 log [V1/V2]
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1 k0 Q- F8 _1 ?% }- W0 TDecibels relative to Voltage across same resistance
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( @& M0 [5 o- `& RDecibel Conversions
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dB = 20 log [I1/I2]
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; B8 q. _) M3 |1 t Y9 t& E+ K( c# eDecibels relative to Current through same resistance- S' a; Q3 e8 n( {
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: _; b- P d+ t0 c0 nDecibel Conversions& a$ _$ w' s% l5 f5 N& ?3 B/ k
: @0 m O8 \8 r; x6 pdBmV = 20 log [Signal (mV)/1mV]/ P: E* O' m1 b" u- W: I" d
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Decibels relative to one microvolt across same resistance$ v& n- v3 |" S6 W) e! U3 \
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/ I+ B. A2 y7 q; K- [' }Decibel Conversions
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dBm = 10 log [Signal (mW)/1mW]
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Decibels relative to one milliwatt
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Decibel Conversions4 L% G& j5 L. z8 O4 W& P
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dBmA = 20 log [Signal (mA)/1mA]
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Decibels relative to one microamp through same resistance9 ^' f) {) R3 N6 z7 H( ]# g% a
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Power Conversions
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dBm = dBw + 30
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2 E/ ?+ b4 i$ z3 R% YConversion from dBw to dBm.
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+ r6 g9 |- ?1 N) j" \( tVoltage Conversions+ C% R: J9 S4 W$ C6 q! ~
! d* p$ Q) x$ m8 OdBuv = dBv + 120! |( F8 N: C& l, ~$ v
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Conversion from dBv to dBuv.0 ?- b4 m; ]1 Z' t# y2 n+ R$ h/ @+ S4 A& \
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Voltage to Power& n4 t8 o) ?. J9 a
" v* A. }1 w& Z- x# t4 WdBm = dBmV - 107! ^( A( t! t" X+ T
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Where the constant 107 is as follows:
& E/ \) [+ s( _- e. j6 T7 Z" J" ]* RF systems are matched to 50W
/ \& c! R- E8 N& s2 e* zP = V2 / R1 i+ Q$ n& f: n7 l
10Log10[P] = 20Log10[V] - 10Log10[50W]
" n# j- f2 E) w9 v* H+ eV = (PR)0.5 = 0.223 V = 223000 mV4 U" S- }2 V' c9 K' k- ]$ o1 M# x
For a resistance of 50W and a power of 1 mW:
3 ~: B$ t, z" v* a, a2 t20Log10[223000mV] = 107 dB
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Power Density, ~. e$ }% D, J L6 a7 p. I
3 t/ S1 Z5 j2 Z2 K1 AdBw/M2 = 10Log10[V/M - A/M]
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6 q8 ?3 V' } d) z/ sDecibel-Watts per square meter.
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Power Density, ?8 D8 z3 G+ J
+ a( H3 B* b1 P& w, R8 c) ?dBm/M2 = dBw/M2 + 30. t& P8 t1 p& ~3 h% M
' Q$ h: D* ?) \: i/ A5 @Where the constant 30 is the decibel equivalent of the factor 1000 used to convert between W and mW:
& }& z* h1 w+ Y/ e u10Log10[1000] = 30 p% Y+ l1 t% u' {& t3 I
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Conversion Units
: a) Q0 h1 \$ LdB = decibels (Log10)% c2 O. v: m9 l. k9 D9 [
u = micro = 10E-6% s2 K9 R1 W, K+ F! {/ Y" z
m = milli = 10E-3
3 o9 i! n: Y; ydBw = decibels relative to one watt8 K5 O5 F/ N! I8 }4 P
dBm = decibels relative to one milliwatt
$ C- T9 [% D5 A: U& c9 KdBV = decibels relative to one volt
8 c' m. y5 c' n+ K" wdBuV = decibels relative to one microvolt; E. {5 E* v5 U" ]- k" Q. E& n
dBuA = decibels relative to one microamp4 j# ~8 m6 f6 J8 Q9 M' u4 y
V = Volts3 q0 J6 B: _0 ?9 a% n! S
A = Amps9 e# `8 A/ s( ?* T. z
I = Current
& p2 }7 G( T1 _) `R = Ohms (50)+ n, B7 X1 r- z: v$ h
W = Watts
2 L4 B( J1 Q. N/ G9 z# q* @! M5 JP = Power, U: B9 l7 O5 l- \6 d K
M = Meter |
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