Useful Bits of Information
Available as a tri-fold mini-brochure designed to meet the SESP (Standard Engineers Shirt Pocket.)
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| dB | Power Ratio |
Voltage Current Ratio |
dB | Power Ratio |
Voltage Current Ratio |
|---|---|---|---|---|---|
| 0 | 1.0 | 1.0 | 0 | 1.0 | 1.0 |
| 3 | 2.0 | 1.4 | -3 | 0.50 | 0.71 |
| 6 | 4.0 | 2.0 | -6 | 0.25 | 0.50 |
| 10 | 10.0 | 3.2 | -10 | 0.10 | 0.32 |
| 12 | 16.0 | 4.0 | -12 | 0.05 | 0.25 |
| 14 | 25.0 | 5.0 | -14 | 0.04 | 0.20 |
| 20 | 10E2 | 10 | -20 | 10E-2 | 0.10 |
| 30 | 10E3 | 32 | -30 | 10E-3 | 0.03 |
| 40 | 10E4 | 10E2 | -40 | 10E-4 | 10E-2 |
| 60 | 10E6 | 10E3 | -60 | 10E-6 | 10E-3 |
| 80 | 10E8 | 10E4 | -80 | 10E-8 | 10E-4 |
| 100 | 10E10 | 10E5 | -100 | 10E-10 | 10E-5 |
| 120 | 10E12 | 10E6 | -120 | 10E-12 | 10E-6 |
| 140 | 10E14 | 10E7 | -140 | 10E-14 | 10E-7 |
| Total Lead Length | |||
| 1/4? | 1/2? | 1? | |
| 500 pf | 100 MHz | 72 MHz | 50 MHz |
| 1000 pf | 72 | 51 | 36 |
| 0.01 uf | 23 | 16 | 11 |
| 0.1 uf | 7.2 | 5.1 | 3.6 |
| 0.3 uf | 4.2 | 2.9 | 2.1 |
| 0.5 uf | 3.2 | 2.3 | 1.6 |
fo = 1/2pi*sqrt(LC)
| 1 m | 10 m | 100 m | 1 km | 10 km | |
| 1 W | 5.5 V/m | 0.55 V/m | 55 mV/m | 5.5 mV/m | 0.55 mV/m |
| 10 W | 17.4 V/m | 1.7 V/m | 170 mV/m | 17 mV/m | 1.7 mV/m |
| 100 W | 55 V/m | 5.5 V/m | 550 mV/m | 55 mV/m | 5.5 mV/m |
| 1 kW | 174 V/m | 17 V/m | 1.7 V/m | 170 mV/m | 17 mV/m |
| 10 kW | 550 V/m | 55 V/m | 5.5 V/m | 550 mV/m | 55 mV/m |
| 100 kW | 1.74 kV/m | 174 V/m | 17 V/m | 1.7 V/m | 170 mV/m |
| 1 MW | 5.5 kV/m | 550 V/m | 55 V/m | 5.5 V/m | 550 mV/m |
E = 5.5*SQRT (PA)/d, Electric Field in V/m
P = Power at Antenna in watts
A = Antenna Gain (assumed = 1 in Table)
d = Distance from Antenna in meters (for d > l/2pi)
| tr | feq | Lcross | Lcross/2 | Lterm |
| 0.1 nsec | 3.2 GHz | 1.2 in | 0.6 in | 0.3 in |
| 0.3 nsec | 950 MHz | 4 in | 2 in | 1 in |
| 1 nsec | 318 MHz | 1.0 ft | 6 in | 3 in |
| 3 nsec | 95 MHz | 3.0 ft | 1.5 ft | 9 in |
| 10 nsec | 32 MHz | 10 ft | 5 ft | 2.5 ft |
| 30 nsec | 9.5 MHz | 30 ft | 15 ft | 7.5 ft |
| 100 nsec | 3.2 MHz | 100 ft | 50 ft | 25 ft |
| 300 nsec | 950 KHz | 300 ft | 150 ft | 75 ft |
| 1 usec | 320 KHz | 1000 ft | 500 ft | 250 ft |
tr = rise time
feq = equivalent frequency (1/pi*tr)
Lcross = length of one rise time in free space
Lcross/2 = typical length of rise time on cable or printed circuit board (crosstalk)
Lterm = length to terminate on cable or printed circuit board
| F | lambda | lambda/2*pi | lambda/20 |
|---|---|---|---|
| 10 Hz | 30,000 KM | 4,800 KM | 1,500 KM |
| 60 Hz | 5,000 KM | 800 KM | 250 KM |
| 100 Hz | 3,000 KM | 480 KM | 150 KM |
| 400 Hz | 750 KM | 120 KM | 37 KM |
| 1 KHz | 300 KM | 48 KM | 15 KM |
| 10 KHz | 30 KM | 4.8 KM | 1.5 KM |
| 100 KHz | 3 KM | 480 M | 150 M |
| 1 MHz | 300 M | 48 M | 15 M |
| 10 MHz | 30 M | 4.8 M | 1.5 M |
| 100 MHz | 3 M | 0.48 M | 15 CM |
| 1 GHz | 30 CM | 4.8 CM | 1.5 CM |
| 10 GHz | 3 CM | 4.8 MM | 1.5 MM |
F = Frequency
lambda = Wavelength
l/2*pi = Near Field to Far Field Distance
lambda/20 = Antenna Effects of Wires and Slots
| RadiatedQuasi-
Peak |
FREQ (MHz) | Class A | Class B |
|---|---|---|---|
| 30-230 | 40 dBuv/m | 30 dBuv/m | |
| 230-1000 | 47 dBuv/m | 37 dBuv/m | |
| ConductedAverage | 0.15-50 | 66 dBuv | 56 to 46dBuv |
| 0.50-5 | 60 dBuv | 46 dBuv | |
| 5-30 | 60 dBuv | 50 dBuv |
For equivalent values at 3 meters, add 10 dB
For Equivalent values at 30 meters, subtract 10 dB