05+j51. Gamma matching is the most commonly used matching device used for a planar dipole in the Yagi-Uda antenna. The Pi (pad) RF attenuator calculator allows you to determine the Resistor values (R1 & R2) for a Pi attenuator. If the impedance of the load matches that of the source, impedance matching is not required, and the balun has a 1 : 1 impedance ratio. × 10 −12 F/m is the. The impedance of a coaxial cable is determined by its physical. For example, in a vacuum, the velocity of propagation would be 100% or 1 (depending on how it is represented). ε 0 = 8. Then ta ke the potentiometer and measure itsI have a passive GNSS antenna with a 6" 1. TF-047; SF-047; PT-047; IB 047; XF 045; SpaceFlight; SiO2; High Power; Radiating Cables. . f 2 = Upper operational frequency in GHz. My thoughts: The source sees from DC to approximately 300 kHz 117 Ohm Real Component (as 2x50 Ohm + 10*1. A microstrip is a type of transmission line in which a strip of a conducting material like copper is mounted on a dielectric material and routed to a ground plane. Use RG 58 cable (or any 50 ohm cable) You will ear the. Looking at the datapoints and moving back from the antenna (75. These cables usually consists of an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield and an outer covering. In-Ear Sensors Record Health Metrics From Brain Activity and SweatDistributed Inductance (L') For a coaxial cable, the inductance per unit length L' in henries per meter (H/m) is defined as. Pasternack's RF cable impedance measurement tool Coaxial Cable Impedance Calculator allows for the calculation of the impedance of the coax. Capacitance of Cables, Charging Current, and Charging Reactive Power. 6 Coaxial Line. You can use either a 1:1 balun or a choke balun at the feed point of the antenna or where the balanced part of the system meets the unbalanced part. **Note: Like our microstrip line impedance calculator, all of our RF calculators allow SI prefix input. They also have an impedance of 75 ohms, which is a standard for coax cable used in the broadcast industry. This calculator is designed to calculate the characteristic impedance of a microstrip - a flat conductor suspended over a ground plane with a dielectric between them (see diagram below). Z = 138 * log (D/d) / Sqrt (pr) Z = 138 ∗ log(D/d)/Sqrt(pr) Where Z is the impedance. Feed line chokes are a special case of impedance transformer with an input/output impedance ratio of 1:1. where. 6 dB/100 m yields 1 dB. f if the frequency of the RF signals. **Note: Like our stripline impedance calculator, all of our RF calculators allow SI prefix input. For a coaxial line, the electric fields extend in a radial direction from the center conductor to the outer conductor. As can be seen in the following graphs, the only time a 1:1 choke-balun accomplishes a 1:1 transformation is when it sees 50 ohms at its output. MiniVNA or MFJ-269 or similar). The Characteristic Impedance of Coaxial Transmission Lines* Figure 1 shows a voltage source, V, connected to a load impedance ZL by a coaxial cable. ε 0 = 8. coax cross section. e. Distributed Inductance (L') For a coaxial cable, the inductance per unit length L' in henries per meter (H/m) is defined as. R2 is the resistance of the protective conductors. 6/1. This model computes the electric and magnetic field distribution inside of the coaxial cable. Outer diameter of the co-axial cable (D) Inner. Impedance per unit length (Z) Ω. These calculators help with unit conversions, VSWR calculations, attenuator design, antenna design, radars, and various other basic. As such, the outer (braided) conductor completely. . However, the twisted. 9913 and LMR-400 are popular “low-loss” RG-8 types. For discussion of impedance matching of the voltage source to the transmissionJul 22, 2019. Wireless Converters and Calculators. Martin and Mendenhall (1984) proposed to use an addi-tional braid (i. ) using the high and low frequency approximations. ScopeThe purpose of this procedure is to provide instructions for measuring 75 ohm coaxial cable impedance. 7 - 29. 850c-0. 39 ohms. So… If you need a 1/4 wave piece of coax for, say, 7. When a balanced source is to be isolated from an un-balanced load, the impedance matching transformer is referred to as a balun. RG178B/U part number from Pasternack is a RG178 coax cable that is flexible. The epsilon_r of the cable isolation is 2 so total electric permittivity is 2 * 8. d is the diameter of the inner conductor of the coax cable; units of D and d must be the same,. √ 50*12. The width of the conducting layer is important to calculate the radiation intensity since it directly affects. 2. Geometriy is not that critical. c is the speed of light 299,792,458 m⋅s −1,. 25 inches and a dielectric constant of 2. So when the coax is connected to an antenna that is fairly reactive like $ 23-j300 $ then the coax is no longer matching my radio. 854187817620. ,100 % power transferred from a source to a load via a transmission line/cable). Get precise results by providing the outer diameter, inner diameter, and relative permittivity. The calculator allows you to make an approximate calculation of the characteristic impedance of a microstrip transmission line, provided that the line. This is a required field. 2. Lumped Port Impedance - User Specified The complex impedance Z s, defined when the port gets created, serves as the source impedance of the S-matrix of the lumped port. Over time properties of standard coaxial type cables have been standardized. This formula is used to calculate the VSWR from the given return loss. The TV Broadcasting Industry chose to use the 75 Ohm standard for coaxial cable in SDI video. 2. The impedance is maintained so long as L/C is maintained. This coaxial cable cutoff frequency calculator that helps the user to calculate the cutoff frequency of a coax cable based on outer and inner conductor. How is the turn ratio calculated? The turn ratio of the RF transformer is calculated by using the following formula. How to calculate the dimensions or diameter of coaxial feed as per impedance of the equilateral antenna. Recommended Frequency Band: 8. This page allows you to calculate the impedance required for a 1/4 wave (electrical) section of line. A quarter wave transformer is used to match two transmission lines with different impedances. 035 in), outer conductor diameter 3. In fact, striplines often make components such as band-pass filter's more accurately, with more symmetric roll-off and no lower cutoff frequency. Suitable for higher power (~1800 watts) at HF. Finding the Impedance of a Coaxial Cable. The cable dictates how much current initially flows based (mainly) on its inductance, capacitance and resistance. 9 mm (0. 125 MHz. This cable should connect to an identical impedance. Coaxial cable is typically rated to operate at 50 or 75 ohms so the scale should be at or greater than these ratings. com If it. × 10 −12 F/m is the. 405 inches and has a maximum working voltage of up to 5000 Vrms. A coax is a common transmission line construction and most rf cables are coax. the total current in the input coaxial cable is real for a set of positions along the cable, which permits matching at these points using the techniques considered in the rest of this problem. It is recommended not to operate RF Connectors above their max. Note that the very first dip is where the cable is less than 1/4 wavelength. 9)dB = 1. Insulation service (cable tray, conduit, direct burial, etc. 3. To calculate the impedance of a coaxial cable with a diameter of 0. Co-axial cable. WR90 Specifications. D is the inside diameter of the coax cable shield,. This is the only way to calculate the total impedance of a circuit in parallel that includes both resistance and reactance. All signals that travel on a transmission line are waves, whether they are harmonic analog. The twisted pair helps create a more uniform inductance and capacitance per unit length of wire to ensure a constant impedance, by keeping the return path as close to the signal as possible. One online calculator tool that seems to work well and gives expected results is Coaxial Cable Impedance Calculator. The concept of Shield Transfer Impedance (Zt), introduced by S. This configurator will generate a bill of materials for a Constellation power delivery system. . None of this really matters for hams! You can see the impedance of the coaxial cable is stable down to 100 kHz. I also tried to calculate the capacitance with this below formula but I get a value of 1. You can calculate it with the following equation: Z (z) = V (z)/I (z). 0. Line Type: Belden 8215 (RG-6A) Belden 8237 (RG-8) Belden 9913 (RG-8) Belden 9258 (RG-8X) Belden 8213 (RG-11) Belden 8261 (RG-11A) Belden 8240 (RG-58) Belden. Question 17. Distributed Inductance (L') For a coaxial cable, the inductance per unit length L' in henries per meter (H/m) is defined as. You can use these cables with a 50 Ohm. A commonly-encountered form of parallel wire transmission line is 300 Ω 300 Ω twin-lead. D is the inside diameter of the coax cable shield,. I might add that if you're looking to calculate the electrical impedance of a circuit, they have a separate impedance matching calculator and a PCB impedance calculator for various PCB-mounted conductors. 95 metersA microstrip width calculator can calculate the width of a microstrip. After all, if there is a mismatch of the antenna with this cable, the signal will be reflected before it enters to the cable. This calculator is able to calculate the impedance, delay, inductance, and capacitance of a coaxial cable. 150 MHz start by calculating the freespace wavelength… Wavelength(Freespace-7. 5). Coaxial Cable Calculator. DX Engineering Coaxial Cable Reference Chart LMR-240 50 ohm Cable LMR-240 Ultraflex 50 ohm Cable LMR-400 & 400 DB 50 ohm Cable LMR-400 Ultraflex 50 ohm Cable Indoor/Outdoor Peak Power 5. Free Windows program for calculating the loss and impedance transformation. 4w. Example. × 10 −12 F/m is the. L = Series inductance per unit length. The formula is this: -. In fact, striplines often make components such as band-pass filter's more accurately, with more symmetric roll-off and no lower cutoff frequency. VSWR / Return Loss Calculator. a = r = 0. Where: Z = the 1/4 wave coax line impedance, Zr = terminating resistive impedance (antenna) ( input resistive impedance as read on the RF impedance bridge at the end of the 1/2 wave line). . Thus, for this system, VSWR = 1:1 (i. Show Me Cables' high quality RG6 quad shield coaxial cable consists of an 18 AWG solid bare copper. Example 25. Impedance mismatch of 75 Ohm Cable. Operating above the cut-off frequency that results in interference in signal propagation. Why these values? One explanation is that the value of 50 ohms was selected because a coaxial cable with polyethylene dielectric with relative permittivity ε r = 2. One pole (rod) is continuous with a length of λ/2 and the other is split at the center. The distance between the first two dips (deltaF) is 99 MHz. Another way is to use ladder line. Pasternack's RF Calculators and Conversions section provides engineers valuable and easy-to-use tools ranging from complex mathematical formulas to simple conversions. Characteristic impedance = R + jωL G + jωC− −−−−−−−√ R + j ω L G + j ω C. This works from DC to 1. D is the inside diameter of the coax cable shield,. 49 m. If you'd insert a 1/4 wave section of 27. Conductor DCR Nom. SIC = Dielectric constant of the cable insulation (Table-3) = cthe speed of the voltage/current signal on the cable is the speed of light. The RG-63/A/B/U is a 125-ohm coaxial cable with an overall diameter of 0. on the calculator devide 29. Twisted pairs are used with balanced signals. Characteristic Impedance (Zo) 50 (±2) ohms. 25 provides minimum signal loss at about 50 ohms and at the same time it can carry large power for a given. The area just becomes the effective area, so for the inner shell, 2πaδ 2 π. Visit to learn more about our other electrical engineering tools. RF Calculators. VSWR Conversion Table. The impedance of a coaxial cable is determined by its physical. f if the frequency of the RF signals. 20 to 12. High return loss means low reflected power, so high return loss is good for a system. S. The measure of this reflected power is called as return loss. The relation between the R, Zo, and amount of power division is given by the following formula. Print - Advertisement - This calculator. These connectors have screw type coupling mechanism which minimizes reflections and attenuation by ensuring uniform contact. Instructions – Scenario 1 – Measured capacitance and inductance values. RG-63/A/B/U. Some industry-standard coax cables. Most RF systems are built around 50 Ω impedance. R is resistance per metre, L is inductance per metre, C is parallel capacitance per metre and G is parallel. Distributed Inductance (L') For a coaxial cable, the inductance per unit length L' in henries per meter (H/m) is defined as. f 1 = Lower operational frequency in GHz. Coaxial Impedance Calculator. If the cable is 50 ohms it means that the impedance driving the cable must be 50 ohms and that the termination impedance at the output of the cable must also be 50 ohms. Step by Step Procedure The 125 ohm cable is connected at the end of a regular 50 ohm RG-213 cable. Email. On the shield is written COAXIAL CABLE 5C-2V 75 ohm. The characteristic impedance of coaxial cable can be determined from the formula: ZO is the Characteristic Impedance ZOC is the Open Circuit Impedance. 10. You can perform the calculations, but by changing the outer diameter in Figure 3 by just two millimeters, you will find that the coaxial cable’s impedance changes from 75 ohms to 46 ohms. For this calculation the diameter and length units are in cm. com Coax Cable Impedance Calculator Where, d = The outside diameter of the inner or center conductor. The advantage of using coax for a 1:1 choke-balun is the constant Z0 of 50 ohms. Coax Impedance Calculator. It has an inner copper weld wire (CW) or copper-clad steel (CCS) conductor (carrying the electrical signal), which is enclosed by an insulation layer typically made of air space Polyethylene (ASP). Over time properties of standard coaxial type cables have been standardized. This tool will help you find the inductance for a given length of coax cable. Coaxial Cable Calculator. This calculator calculates the impedance of a coaxial cable. d is the diameter of the inner conductor of the coax cable; units of D and d must be the same,. The history of 50 Ohm impedance goes back to the late 1920s/early 1930s, when the telecom industry was in its infancy. Cutoff Frequency of Lowest Order Mode: 6. More consistent results will usually be obtained by using a dedicated cable joiner or a plug and socket with the same impedance as the cable. EEWeb offers a free online twisted pair impedance (transmission line) calculator. Input the capacitance measured between the cores or conductor and shield in pF/m. Gamma matching online calculator. Use the frequency and layer thickness/Dk value to determine the antenna size. The development of the expressions for L and R is more involved, as there will be current in the interior of the inner conductor. × 10 −12 F/m is the. Where, f c = Cut-off frequency of rectangular waveguide in GHz. This causes an impedance mismatch at each staple location resulting in micro-reflections. This is the online directional coupler calculator that calculates the coupling (dB), coupling loss(dB), insertion loss (dB), and directivity (dB) of a directional coupler by entering the value of input power P1 (dBm/Watt(s)), output power. The cutoff frequency is the frequency up to which the system functions efficiently. Short the cable ends and measure the ZSC (cable short circuited). 035 in), outer conductor diameter 3. I used 100m for l. Scroll down to find formulas for determining attenuation, wavelength, characteristic impedance, time delay, and more. Attenuation (dB/100 ft , @ 400 MHz). The length of the dipole is usually one-half of the wavelength of the RF signals. Gamma matching online calculator. For example, if you wish to input "25000000", just type "25M" instead. Z = R + jX, where j is the imaginary component:. RG6 Coaxial Cable in Black. This will also provide the time delay the cable provides for a signal and also the capacitan…Coax Cable Transmission Line Models. e. × 10 −12 F/m is the. A Coaxial cable is a type of cable that is used to make transfer RF/Microwave signals. 854187817620. Picking it interactively in the 3D view and. e. c is the speed of light 299,792,458 m⋅s −1,. RG-8 and RG-213 (50 ohm); and RG-11 (75 ohm) are about 0. #2. where. I leave it to other sources to provide the complex equations needed to precisely model coaxial cables. 124 in), type of insulation is polyethylene with the relative permittivity of 2. For the students of scientific history, this is the same Oliver Heaviside who formulated Maxwell’s equations in the vector form that we are familiar with today; first used the term “impedance”; and. The following equation is used to calculate the ZS (Earth Loop Impedance). SMA Connectors are 50 Ohm RF Coaxial connectors that operate up to a 18 GHz. Note: The value of μr in this calculator has been taken as 1. 4w to achieve 100w at the aerial. 854187817620. Length of the three-quarter-wave section 3λ g /4: mm. To use the calculator you first need to measure the impedance (resistance + reactance(j)) of your antenna, this can be done with an antenna analyzer (i. In particular, as radio frequency (RF) signals pass through coaxial cable, connectors, attenuators (pads), equalizers, and passive components such as splitters and directional couplers, those RF signals. diameter coax (RG-8 or LMR-400) coil wound on a 5 in. Coaxial Cable: A common type of coaxial cable has a characteristic impedance of 50 ohms. for a typical polyethylene-insulated cable. On the two smaller coils, a small piece of heavy cardboard holds the coax in. The coaxial cable is so fundamental that Oliver Heaviside patented it in 1880, just a few years after Maxwell published his famous equations. 3. See full list on allaboutcircuits. EXAMPLE: INPUTS: Outer diameter = 36 , Inner diameter = 10 , Relative permittivity =2. ABOUT US. × 10 −12 F/m is the. Below the cutoff frequency, power flow will be reduced. Where we basically use the effective area instead. The device output impedance is usually low at high power levels; so, to match this impedance with a standard 50-ohm load, coax-ial-line transformers with specifiedThe cut-off frequency of the coaxial cable represents the maximum upper operating frequency of the cable. A differential cable is usually constructed with a UTP, STP, STQ or twin-axial configuration and achieves 100-Ω differential impedance. The waveguide width determines the lower cutoff frequency and is equal (ideally) to ½ wavelength of the lower cutoff frequency. Cable Capacitance (pF/ft) 20. 1: Coaxial line: (a) with inner an conductor of radius a and an outer conductor with inside radius b; and (b) with cylindrical coordinates used in calculation. The fabrication procedure for slot lines is the same as that for microstrip lines. Coaxial Cable Calculator. A Coaxial cable is a type of cable that is used to make transfer RF/Microwave signals. Γ = Reflection coefficient. 3pF) in the tuner to 111. Semi-rigid coax (new for June 2021!) Triax (new for August 2023!) Coax cable vendors . Most professional engineers and technicians will never have the need to calculate the capacitance, inductance, or impedance of a coaxial cable since they are usually. Coaxial cable characteristic impedance Calculator and formula. As can be seen in the following graphs, the only time a 1:1 choke-balun accomplishes a 1:1 transformation is when it sees 50 ohms at its output. Nist, KQ6QV has free software for calculating arbitrary transmission line impedance, as well as transmission. An air-spaced cable would shift signals at the speed of light c. Input. Coaxial cable combiners with ferrite cores are often used to combine the output powers of power amplifiers intended for wideband applica-tions. Output values are rounded to the second decimal place. Return loss (RL) is the ratio of the reflected power to the incident power, in decibels (dB). where. The Smith Chart graphically maps S11=reflection coefficient= (ZL-Z0)/ (ZL+Z0) to Load Impedance (ZL), normalized to Z0 (source impedance = center of chart). 336 ° (degrees) that is a portion of a 360° angle. 6 . 150 MHz = 41. The coaxial cable, along with the balanced two-wire, is the most common type of transmission line used in RF communications. thus a big transmission line can have the same impedance as a small transmission line if one is scaled in proportion from the other. Using our own calculators which, for impedance, is based on the formula above (which is the same as the calculator in the tool section of this site) our characteristic impedance turns out about 8% - 10% higher than calculated. which can be algebraically solved for Z 0 as: Z 0 = Z a Z b. Pasternack's Coaxial Cable Impedance Calculator allows you to enter the Outer Diameter Dielectric width, Inner onductor Diameter width and either the Dielectric Constant or. 1312. where. Schelkunoff in 1934, is a very convenient parameter for the prediction and control of EMI coupling through cable shields. 854187817620. Transmission line impedance is an important aspect of RF electronics, as it greatly influences the quality of a signal. RG-8 and RG-213 (50 ohm); and RG-11 (75 ohm) are about 0. This can cause an impedance discontinuity where the join is made. D is the inside diameter of the coax cable shield,. 0815 λ (wavelength, lambda or Wave) The physical length L is 0. It is also relatively straightforward to calculate the inductance per. A-INFO carries hundreds of RF cables all in-stock and available for same-day shipping worldwide. A 50Ω coax has an impedance of 50Ω whether it's one metre or one kilometre long. 900c. e. The following formula relates the return loss and VSWR. Micro Coax & Twinax Cable Specifications 20Ω Coax Cable – 26 AWG 50Ω Coax Cable – 34 AWG Ω Coax Cable – 36 AWG50 Ω Coax Cable – 38 AWG 85Ω & 100Ω Twinax Cable – 30 AWG 85 Ω & 100 Twinax Cable – 32 AWG 75Ω Coax Cable – 38 AWG 100Ω Twinax Cable – 30 AWG Board-to-Board Assemblies = Eye Speed ® Coax = Eye Speed Twinax. 124 in), type of insulation is polyethylene with the relative permittivity of 2. The standard impedance choice for systems requiring low attenuation is 75 Ohm. 035 in), outer conductor diameter 3. Good enough, because the calculation for 15 m of typical coax with 6. FL connector I have a 2" microstrip transmission line to the RF input of my GPS receiver. For any cable type, it is equal to the reciprocal (1/x) of the square root of the relative permittivity of the cable’s insulation. Calculation Dielectric Outer Diameter: Inner Conductor Diameter: Result: Pasternack carries hundreds of coaxial RF cables all in-stock and available for same-day shipping worldwide. Question 17. Distributed Inductance (L') For a coaxial cable, the inductance per unit length L' in henries per meter (H/m) is defined as. This calculator helps you calculate the characteristic impedance of a coaxial cable given its dimensions. Identify as much information as you can about your piece of cable prior to discussion: Characteristic impedance. It supports both balanced and unbalanced lines. εr = Dielectric constant of the insulator. Calculate the impedance of a coaxial transmission line. in both cases, the speed and the Characteristic Impedance depend upon logarithms of the ratio of two distances in the cross. Image 1, "matched") : Cable is impedance matched with 50 Ohm. 20. 5 dB. Wi-Fi 7 will enable consumer, enterprise, Industry 4. Np = Number of turns in the primary coil. is required to do the impedance transformation from 50 ohms to 292 ohms at 146 MHz. Where: Zo = Characteristic impedance in ΩDistributed Inductance (L') For a coaxial cable, the inductance per unit length L' in henries per meter (H/m) is defined as. The coax cable has a capacitance as a result of the gap between inner conductor and outer shield of the cable. You can calculate it with the following equation: Z (z) = V (z)/I (z). VSWR (Voltage Standing Wave Ratio) and Return Loss both measure the same parameter i. 5 Surge Impedance (ohms): 35. If I place a trans-match between the rig and the feed, then I'm tuning the feed line. This online reflection coefficient calculator calculates the reflection coefficient (Γ) by entering the value of the characteristic impedance Z o (in ohms. There are more than 75 different RF Coaxial Connectors that can be used in wireless systems. Example 7. The calculator will calculate one possible solution for a Single Stub Match that you can implement in your antenna system. Check the velocity factor for bare copper, which is 0. Among the commonly used connectors for 50 Ω coaxial cable is the venerable PL-259, available from Amphenol RF as the 83-1SP-1050 (Figure 5), as well as the wideband Type N, such as the VNS30-2051. 9 mm (0. fc = Cutoff frequency. 86 mm] x 0. The calculator is designed mostly for hobbyists, university students, and researchers. The return loss of a system is defined as the ratio of incident power to reflected power and is measured in dB. Below the cutoff frequency, power flow will be reduced. September 8, 2022. Following table provides links to useful Wireless converters and calculators. æ k s /), is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric (insulating material); many coaxial cables also have a protective outer sheath or jacket. Just look at the power handling at 60 ohms - below 50%. Insulation service. Throughout this document the shorter term cable impedance may be used. RF calculations and conversions include metric-standard, link. LOGIN. 1. If we calculate the inner and the outer impedance using formula Z=R+j (XL-XC), where. 66 and 0. Micro-coaxial cables. Suitable for VHF (~1. Cascaded Noise Figure Calculator. LOGIN. Where, Np/Ns = Turn ratio. Most RF systems are built around 50 Ω impedance. A coax loss calculator is an essential tool for network planning that helps in calculating attenuation and choosing the right coaxial cable for your network. Once the dialog is open a segment to use for the impedance calculation can be defined by either: Selecting it in the dialog opened by "Segment List". Apr 22, 2009. Due to its geometry, the coaxial cable impedance requires you to know the inner wire's diameter and the outer shielding. 2022. Here it is: For outer diameter D, inner diameter d, and eccentricity c: Z0= [60/sqrt (ER)] x acosh [ (1/2)x (D/d+d/D-4c^2/ (dxD)] We entered the equation into Excel, and sure enough, if c=0 you get the same exact impedance you get from the. **Note: Like our stripline impedance calculator, all of our RF calculators allow SI prefix input. The length of a half-wavelength dipole can be calculated by the given formula: L =. and 1/12 λ of 75Ω coax. These features make the 3. From my measurement I got data as below: From that table, we can see that there is significant impedance of the cable. Plugging this into the equation we calculate the cable length. If you would use different values, the signal would reflect and distort itself. Twisted-Pair Impedance Calculator; Embedded Microstrip Impedance Calculator; Microstrip Impedance Calculator;A twisted-pair cable is simply two wires that are twisted together so as to reduce radiated EMI (electromagnetic interference) and mitigate the effects of received EMI. d is the diameter of the inner conductor of the coax cable; units of D and d must be the same,. Frequency to Wavelength Calculator. Generally, a wave is reflected back. c is the speed of light 299,792,458 m⋅s −1,. I've added the formulae to my answer. c is the speed of light 299,792,458 m⋅s −1,. It include antenna gain calculator, Antenna G/T ratio calculator, coaxial cable Impedance calculator, Noise temperature to Noise Figure Converter, Radar Range Calculator, resonant frequency calculator, wavelength to. D (inches) d (inches) for a typical polyethylene-insulated cable.