1 Return Loss. To do so, calculate the desired return loss and subtract the known load return. 1. But, for a practical system, there will be a small impedance. 02 VSWR (i. 1 Return loss in dB = 26. Electrical waves reflect when they encounter a change in the impedance of the medium they are traveling in. S-parameters are a valuable tool for calculating reflection coefficients and transmission gains for a two-port network's input and output sides. This is an online calculator that calculates VSWR located on Return Loss. If we measure the power of a reflected signal from an antenna near a radio transmitter, the measurement of the reflected signal’s amplitude at this juncture compared to the initially transmitted. Return loss load -2. Just enter the value additionally mouse calculate. ABOUT US. When the VSWR is known, the return loss can be calculated as: Or in Excel, use the following formula: =20*LOG10 ( (I2-1)/ (I2+1))*-1. The voltage standing wave ratio (VSWR) is defined. Return loss is a measure in dB of the ratio of power in the incident wave to that in the reflected wave, and we define it to have a negative value. Cascaded Noise Figure Calculator Calculate the input referred noise figure for cascaded stages. Because the reflection coefficient Γ < 1, then the return loss will have a positive dB value. It's also the case that your first equation isn't correctly written, though in contrast to that your actual C code is written correctly to calculate the result. Mismatch loss. VSWR is the voltage standing wave ratio it used to measure the all-types waves (example: antenna waves) during transmission. From the table we can understand that when the return loss is <10dB, the antenna will be at VSWR >2, indicating the system will reflect >30% power and the performance of the antenna will be <70%. 5. A VSWR value of 2 or under is typically acceptable for antennae in communications systems. In the above. Note: The historical definition of return loss results in a negative sign. 2:1 (or simply 1. Forward Power (dBm)Return loss tells you how much of the input signal is reflected. To use this calculator, enter one of the following data: the voltage standing waves ratio VSWR, the return loss RL, the reflection coefficient ρ, the power ratio ρ 2, the forward and reflected power P fwd and P ref; or the impedances Z c and Z l. Please Support RF Cafe by purchasing my ridiculously low−priced products, all of which I created. Formula. Conclusion : In summary, RL and VSWR formulas and calculators are valuable tools that enhance the efficiency. 1) RL dB = 10 log P i P r. 1-800-761-3041 Contact Account Cart Search Waveform. As an example, if the return loss of the amplifier is 4 dB, use the calculator below. The VSWR calculator helps in finding the reflection coefficient, return loss, and mismatch loss from the VSWR value. This can and online calculator that calculates VSWR based on Return Loss. Return loss can be converted to mismatch loss and the calculator also gives an intuitive sense of the impact by providing the forward and reflected power ; Related Posts. . For. This usually means that there is an impedance mismatch at the load. The two VSWRs produce a combined return loss, as follows: The uncertainty in the total measurement stemming from the source and load VSWRs is Uncertainty (+)=20log 10 (1+ γ 1 ·γ 2 ) dB, and Uncertainty (–)=20log 10 (1–γ 1 ·γ 2 ) dB. For a VSWR of 2, the mismatch loss is calculated to be 0. Return Loss has surfaced in our ham world due to the new handheld antenna system analyzers like the Nano VNA and others. 5 (-14. 16-Feb-2022. , if RL = 20dB, then calculate Rho = (10 ^ (20/-20)) = 10 ^ (-1) = 0. This is an ideal open or short circuit, equivalent to VSWR=infinite. g. Return Loss in decibels (RLdb): Definition: Return loss is the ratio between Forward and Reflected Power in decibels. See the vswr table below to see a numerical mapping between reflected power, s11 and VSWR. Equitable enter the value and click calculate. Author: Marki Engineering Created Date: 11/24/2009 10:57:28 AM. The first-factor ohmic loss is an unavoidable loss as it is a property of conductor used for connecting the components and the resistor used. This VSWR calculator will calculate return loss, mismatch loss, loss in percentage and the reflection coefficient. I have already calculated the cascaded VSWR and RL using the RSS method (very similar result to simply multiplying each components VSWR as Itay mentioned), but the problem is that the result is not even close to the measured value of return loss. Return loss is related to both standing wave ratio (SWR) and reflection coef-ficient (Γ). Step 2. entirety RF has the largest selection of online calculators for the RF and Microwave Industry. 5:1. An antenna’s Return Loss is a figure that indicates the proportion of radio waves arriving at the antenna input that are rejected as a ratio against those that are accepted. Radio Frequency Engineering Calculator. The measure of this reflected power is called as return loss. Do y. Return loss can be measured by using microwave and RF test equipment such as a signal generator, directional coupler along with a spectrum analyser or power meter, or alternatively by using a vector network analyser. In general, a lower VSWR means a system and load is well matched with most of the power being radiated by the antenna and a relatively small amount reflected. 89% of the power is transmitted forward, while 11% is reflected back into the source. Not responsible for errors. S11 then would be the reflected power radio 1 is trying to deliver to antenna 1. By converting between VSWR and RL, this calculator aids in assessing signal quality, minimizing signal loss, and ensuring efficient RF system. They will show SWR and Return Loss (RL). In no event will Qorvo be liable to any user of these tools for any loss or damages, including without limitation, indirect or consequential damages arising out of or associated with the use of these tools. For a VSWR of around 5. com . The path loss that might be measured in a system however will not be this. 51 dB, and a return loss of 9. RF insertion loss is the reduction in signal power as it passes through an RF component or system. The equivalent VSWR is 1. 794 VSWR to Return Loss (dB) Converter; Return Loss (dB) to VSWR Converter; Power Conversion : dBm - volts - watts; Phase Noise to Phase Jitter Converter; Phase Jitter to Phase Noise Converter; ppm to Hz Converter; misc. 72 0. Pressing the [Calculate] button with no inputs will load the example below. Just enter the value and click calculate. everything RF has the largest selection of online calculators for the RF and Microwave Industry. Return Loss. termination would give a VSWR of 1. Understanding the role and implications of impedance in RF transmission lines and antennas is vital to successful system performance. The method generally makes sense in that the return loss, or VSWR, performance of each element in a transmission system additively degrades the system return loss. In this situation (refer to the equations above), Γ = 1 and VSWR = 2/0 = ∞. e. The MCL Microwave Calculator performs 21 calculations commonly needed by RF and microwave system designers in a wide range of applications. VSWR (Voltage Standing Wave Ratio) is the measure of how efficiently RF power is transmitted and is expressed as a ratio of the maximum to minimum. Calculation Select input type: Result: VSWR (pronounced "viswar"), or the Voltage Standing Wave Ratio, is the ratio of the maximum standing wave amplitude at one node to the. The return loss at that point has degraded by approximately 5 dB. Γ = (VSWR – 1)/(VSWR + 1) Return Loss (dB) = -20*Log 10 (|Γ|) Mismatch Loss (dB) = -10*Log 10 (1 – |Γ| 2) That said, there are also passive non-reciprocal devices such as isolators, circulators (and gyrators). Just entry the appreciate and click calculate. com Enter VSWR, Reflection Coefficient, or Return Loss to calculate remaining values. com1) VSWR Calculation. 0. 25 on the worst path and the insertion loss is 0. 3% of the power back towards the transmitter. Therefore, the return loss parameter RL can only be used to express the mismatch of R L to Z 0. Return Loss (dB) 3. When someone says that the antenna is poorly matched, very often it means that the VSWR value exceeds 2 for a frequency of interest. The term ‘forward power is synonymous with powered deliver to the load, or thru power. Γ is then used to calculate the return loss. It also indicates the in of forward to reflected power. return loss Calculator:(by using VSWR) Formula is:: VSWR= return loss = VSWR Calculator: This is the ratio of maximum voltage to minimum voltage in standing wave pattern. Put a decent isolator in your signal chain (typically ~1 dB insertion loss, >10 dB return loss and > 20 dB reverse isolation over relevant bandwidth) and subsequent VSWRs won't matter either. There is an equivalent definition for VSWR, which can also be expressed in terms of the Return Loss (RL). Return Loss (dB) VSWR. In this case the problem was a loose connector. Furthermore, a small VSWR reduces reflections from the antenna. This test determines the return loss value of each connector pair, cable component and cable to identify the problem location. It turns out that -13. com +1 (718) 934 4500 +1 (800) 654 7949. When you look at a graph of a return loss formula, the negative sign is often omitted and is sometimes used interchangeably with the S11 parameter. There is an equivalent definition for VSWR, which can also be expressed in terms of the Return Loss (RL). Title:. 333, a mismatch loss of 0. It measures how much energy is reflected back to the transmitter when a signal is transmitted through an antenna. This is an online calculator is calculates VSWR based on Return Loss. Due to mismatches in impedance within the connector, some of the signal is reflected. Return Loss to VSWR Calculator. 0708,min,max = =This is an online calculator that calculates Return Loss based on VSWR. How to Calculate VSWR . VSWR Mismatch Errors: Both amplitude and phase errors are introduced when mismatched impedances are present at an electrical interface. In an RF system, when power is sent from the source to load, there are three main parameters to be considered: (1) incident power. The VSWR/return loss calculator from Pasternack will find VSWR, return Loss, mismatch loss, and the reflection coefficient given any one of. This means return loss will always be positive. 98 dB. Avg. Just by entering the. s. The MAX2016 is a dual logarithmic detector/controller used to monitor the VSWR/return loss of an. 5:1. An example of this would be a. If we look at the Return Loss chart for this. Once the VSWR is known, return loss can be calculated as follows: Return Loss = 20 ∙ log10 () Generally, a higher return loss value is preferable. 98dB = 96. 6275 GHz with a −10 dB bandwidth of. 8. This calculator converts values between VSWR, Return loss, Reflection Coefficient and Mis-Match Loss. The ideal condition, whereFigure 2: VSWR Measurement Principle The return loss at the input and output ports can be calculated from the respective reflection coefficients as follows: Input return loss (RL IN) is a scalar measure of how close the actual input impedance of the network is to theAn unfeasible VSWR of 50 reflects 92. Subscribe to receive Mini-Circuits News. Just enter the value of source return loss, input return loss, output return loss, load return loss, device gain, and isolation then the calculator will compute the minimum and maximum gain. A calculator designed to compute the VSWR, reflection coefficient, return loss and matching loss in a transmission line2. 예를 들어 Return loss가 10dB 정도라면, VSWR은 2:1 이하가 되어서 입력매칭이 비교적 잘된 경우로 평가하며, Return loss가 14 dB 정도가 되면 VSWR은 1. This is an online calculator that calculated Returned Loss based on VSWR. dl. 8. Return loss and insertion loss are both measurements of how a component or device affects the transmission of signals in a system. 8. You would think this answers the question. The reflection coefficient is calculated from the VSWR and used to compute the mismatch loss in dB as shown below. Assuming the systems have no internal loss. 4 ms—500 forward and 500 reverse samples are collected on each cycle. 12] = 6 dB. Return loss and mismatch loss Calculator Return Loss and Mismatch Loss Calculator Calculates the absolute load impedance, reflection coefficient, VSWR, return. Γ = Reflection coefficient. With the initial values in place, you need only click on Calculate. Particularly, reflected power and mismatch loss help describe the need for the antenna (with its matching network) the provide a suitability return loss the the active electronics. voltage standing wave ratio 020710. VSWR, Return Loss and Reflection Coefficient Calculators; Reflection Coefficient to. This calculator computes the VSWR, reflection coefficient, return loss and matching loss in a transmission line. Mismatch Loss: Reflected Power Through Power (dB) Coefficient, Γ (dB) (%) (%) 1 17. VSWR Return Loss Calculator. However, each field, when changed will allow. To do so, calculate the desired return loss and subtract the known load return loss. It provides a measure of how efficiently RF power is transmitted from a power source, through a transmission line, to a load such as an antenna. VSWR (Voltage Standing Wave Ratio) is the measure of how efficiently RF power is transmitted and is expressed as a ratio of the maximum to minimum. AJ4CO Observatory Online Calculator. A power meter may also be used to calculate cable loss. LM = Matching loss in decibels Example . Some are based on look-up tables, some completely hide their algorithms. The relationship between these two variables is not linear, meaning that each point on the table must be determined separately. The voltage standing wave ratio (VSWR) at a port, represented by the lower case 's', is a similar measure of port match to return loss but is a scalar linear quantity, the ratio of the standing wave maximum voltage to the standing wave minimum voltage. ☯ Return Loss=20log 10 (VSWR+1/VSWR-1) (dB)A calculator designed to compute the VSWR, reflection coefficient, return loss and matching loss in a transmission lineIt is the ratio between transmitted and reflected waves. 3 dB. The VNAs with math modes can also directly calculate and display the resulting VSWR value. Assuming that the source and load are perfect then when the signal from the source arrives at the switch some of that signal is reflected. VSWR and impedance, Part 2: Reflected power. reflection coefficient definition. 2 times the minimum voltage along that line, if the line is at least one half wavelength long. Return Loss is a measure of the amount of energy that is reflected back at a discontinuity in a Radio Frequency Circuit . VSWR to Return Loss Calculator; Cavity Resonance Frequency Calculator; Circular Waveguide Calculator; Rectangular Waveguide Cut-off Frequency Calculator; All Conversion Calculators . VSWR & Return Loss Calculator: Enter forward and reflected power or match to determine equivalent values. 41:1 with a return loss of 15. Find VSWR (Voltage Standing Wave Ratio), Return Loss, Mismatch Loss, and the Reflection Coefficient given any one of the listed input types. ,100 % power transferred from a source to a load via a transmission line/cable). 51 dB, and a return loss of 9. Reflection Calculator: RL = dB: VSWR = Γ = VSWR = RL = dB: Γ = Zo . Input Return Loss Var2. Antenna efficiency is the percentage of radiated power compared to non-relected power. 44. R = 20log 10 (E incident /E reflected)This can an online calculator that estimates VSWR based on Return Loss. See the relationship between VSWR and return loss. Archive Documentation Data Software. RF calculations and RF conversions include metric. Refl Coeff Power TransCalculate VSWR, Return Loss, Reflection Coefficient, Match Efficiency, and Net Transmission Loss from an RF broadcast transmitters forward and reflected power readings. Return Loss is a measure of the amount of energy that is reflected back at a discontinuity in a Radio Frequency Circuit . Conclusion : In summary, RL and VSWR formulas and calculators are valuable tools that enhance the efficiency. Reflection -10dB: 1/10 th of the RF energy is being reflected. 4. 011. Previous Next. Assuming that the source and load are perfect then when the signal from the source arrives at the switch some of that signal is reflected. The VSWR/return loss calculator from Pasternack will find VSWR, return Loss, mismatch loss, and the reflection coefficient given any one of the listed input types. 0 dB return loss). Reflected Power. 500VSWR Calculates VSWR 1. This video provides a basic introduction to voltage standing wave ratio (VSWR) and return loss, and explains how these measurements are used in radio frequen. From a certain perspective 'Return Loss' is a misnomer. Just enter the value and click calculate. Lower insertion loss values are preferable, indicating less signal power loss and better component/system efficiency for RF applications. As an added bonus, the results are modifiable and can calculate the other values. Click here to go go to our main page on VSWR We offer an Excel spreadsheet that will help you visualize how voltage standing waves are created. everything RF has the largest selection in online hand for the RF and Microwave Industry. 01. Consumers; Contact Us;This VSWR calculator will calculate return loss, mismatch loss, loss in percentage and the reflection coefficient. Increasing return loss corresponds to lower SWR. Unused stages should be zeroed. A calculator designed to compute the VSWR, reflection coefficient, return loss and matching loss in a transmission line LOGIN. VSWR is defined as the ratio of the maximum to minimum voltage on a loss-less transmission line (expressed as 3. The return loss of a system is defined as the ratio of incident power to reflected power and is measured in dB. Just keep in mind that SWR and Return Loss are both indicators of the quality of the transmission line to antenna feedpoint Z match. What is the VSWR ratio to return loss? There is an inverse relationship between Voltage Standing Wave Ratio (VSWR) and Return Loss. 2 8. The formula and equations used by this calculator are also provided. In addition, the calculation takes into account the effect of signal attenuation in the transmission line. This is equivalent to VSWR 5. Then, take the logarithm base 10 of the result and multiply it by 20. VSWR. 01:1 to 3. The ratio of the input to the reflected signal is. VSWR. Products. Increasing return loss corresponds to lower SWR. Calculations Pathloss / RSSI; Missmatch Loss; IP3 / SFDR Calculator; IP3, IP2, 1dB Comp. A table of convenient values are presented at the bottom. Since the signal velocity through the network is a known constant, like the sound velocity in our analogy above, the time it takes for the reflections or echoes to return can be converted to distance. Return Loss in dB What It Means VSWR Number; 0 dB: 100% reflection, no power into the antenna, all reflected back: Infinite: 1 dB: 80% reflection, 20% power into the antenna: 17: 2 dB: 63% reflection, 37% power into the antenna: 9:The Reflectometer Calculatorallows engineers to input any one of three known values, (Reflection Coefficient (p), VSWR or Return Loss), to . VSWR = Voltage standing wave ratio. 500 1 Enter Reflected Power 4. be used to add or subtract an arbitrary number of power, to convert power and voltage units from the linear to the logarithmic. It is often expressed in terms of a percentage, or in dB. Power to Voltage. p. ,100 % power transferred from a source to a load via a transmission line/cable). Poor VSWR can cause shadowing in a TV broadcast system as the signal reflected off the antenna reflects again off the power amplifier and is then rebroadcast. Coaxial Photos;. A low VSWR will minimize reflections from the antenna. Reflection. VSWR is defined as the ratio of the maximum voltage to the minimum voltage in standing wave pattern along the length of a transmission line structure. The MAX2016 outputs the difference between the two power detectors. 5115. High return loss means low reflected power, so high return loss is good for a system. Click here to use the VSWR Calculator. This is an online numeric that calculates VSWR based on Return Loss. VSWR to Return loss calculator. Q. Just enter the value and click calculate. VSWR to Return Loss (dB) Converter; Return Loss (dB) to VSWR Converter; Power Conversion : dBm - volts - watts; Phase Noise to Phase Jitter Converter; Phase Jitter to Phase Noise Converter; ppm to Hz Converter; misc. For VSWR=2, reflection coefficient will be=1/3 and 20log (1/3) =-9. This impedance mismatch can be with a device inserted in the line or with the terminating load. A network analyzer can be used to make S parameter measurements. It is the major factor contributing to the total signal efficiency of the connector. Note: impedance is a complex quantity, it has real and imaginary parts or magnitude and phase; instruments are almost always calibrated for Zo being some nominal real value, is Xo=0 (eg when people speak of a 50Ω instrument, that means 50+j0Ω even if they don't. This calculator allows calculation of VSWR from Zload (or Yload or S11) and Zo. Formula is:: reflection coefficient(Γ)= VSWR = VSWR Calculator:(by using RL)From the table we can understand that when the return loss is <10dB, the antenna will be at VSWR >2, indicating the system will reflect >30% power and the performance of the antenna will be <70%. Return Loss is similar to VSWR and is generally preferred in the cable industry to a VSWR. Return loss, also known as reflection loss, is a measure of the fraction of available power that is not delivered by a source to a load. The calculator converts between return-loss, VSWR, reflection coefficient, and mismatch lost. I'll keep it short: Yes, the computation of: $$Gamma=frac{Z-Z_0}{Z+Z_0}$$ can be properly composed in the way you suggest. VSWR - Return Loss - Γ Conversions These are the standard set of equations for converting between VSWR, return loss, and reflection coefficient (Γ). Simply enter the value and click calculate. Matching Pi Attenuator Calculator. Next, plug in the calculated return loss value into the formula VSWR = (1 + 10^ (RL/20))/ (1 - 10^ (RL/20)). 1. Bernard Sklar, Communications Engineer and author. Γ = Reflection coefficient. 43 20. When using VSWR and Reflection Coefficient it is often encessary to use formulas or equations to determien the values. 707. As we know that the reflection coefficient defines the amount of the electromagnetic wave is reflected due to the impedance discontinuity in a transmission path. Note the same numerals are used with just a shift in the decimal point. 14 dB per hundred feet. Return loss decibel is mostly read by the the antenna analyzer test equipment. Voltage standing wave ratio (VSWR)The return loss is a convenient parameter to use when the value of Γ becomes small. And S12 is the power from radio 2 that is delivered through antenna 1 to radio 1. Calculate VSWR, Return Loss, etc. 2 means a peak voltage 1. It’s typically expressed in decibels (dB) and calculated as the input power minus the output power. Return Loss is a amount of power that is lost to the load and does not return in to the system as a reflection. How to Calculate VSWR . 1-800-761-3041 Contact Account Cart Search Waveform. Just enter the value and click calculate. As a result, you have a range of either plus or minus uncertainty. Impedance Matching Pi Attenuator Calculator. But for a practical transmission system with load, there will be a small impedance mismatch that will lead to a small amount of incident power reflected back to the source. Reflected power ratio for system 1 is 0. Return Loss (dB) = 10 x Log ( Pr / Pf ) Match Efficiency (%) = 100% x (1 - Pr / Pf)A calculator designed to compute the VSWR, reflection coefficient, return loss and matching loss in a transmission lineA calculator designed to compute the VSWR,return loss and matching loss in a transmission line. In order to improve the VSWR, this calculator also has an extra input for adding an attenuator to improve or reduce the system VSWR. It is expressed in dB - A high return loss means more power is lost at the load. Any other value indicates that a portion of the energy is reflected. Unless you have a piece of slotted line-test equipment this is a hard definition to use, especially since the concept of voltage. , some amount of incident power will reflect the source in a practical system). Return loss can be converted to mismatch loss and the calculator also gives an intuitive sense of the impact by providing the forward and reflected power ; Related Posts. As we know that the reflection coefficient defines the amount of the electromagnetic wave is reflected due to the impedance discontinuity in a transmission path. function doValidate_3 form { window[ cff_enabling_form ] = functi. 44. This is known as mismatch loss. 000:There are many antenna parameters out there. number) VSWR or % Reflected Power: MHz: a wavelength in inches or feet: Get Help. This online reflection coefficient to return loss calculator calculates the return loss (dB) by entering the reflection efficient Γ (= value. It is specified in dB. In the example below an attenuator is added between the input and amplifier to improve its return loss. 99 $ = 1-Gamma^2$. complimentary copy of the "RF Calculator" at . As part of Qorvo’s commitment to the engineering community, we are providing this collection of RF design tools to assist engineers. total RF has the largest selection of online calculators for the RF and Micro Industry. 1) (2. Return loss and VSWR are two important measures of efficient power transmission and both of them can be interconverted to obtain the value of one another. 868. 54. 5. (5. As it can be seen from the above equation, VSWR is always a real and positive number with a minimum value of 1. The VSWR is a measure of the efficiency of a transmission line and is used to determine how well the line is matched to the impedance of the. 21b) VSWR = 1/(q + p), where q = 0. com Reflections propagate back and forth in a line, but most assessments only consider the effects of the initial reflection because the back and forth energy attenuates until it is untraceable. The load can be an antenna, filter or other equipment connected to a transmission line. Therefore, a VSWR of less than 1. Typically, for field applications, the DTF Return Loss mode is used. Where I2 is the cell containing the VSWR. What is the actual antenna VSWR or return loss?You can calculate return loss when the VSWR is known. The return loss is the proportion of a signal that is reflected as a result of an impedance mismatch. This makes it a more direct measure of reflections than VSWR. Calculates the VSWR, reflection coefficient, return loss & matching loss in a. everything RF has an largest selection of wired calculators for. 0 10. Calculations Pathloss / RSSI; Missmatch Loss; IP3 / SFDR Calculator; IP3, IP2, 1dB Comp. But, for a practical system, there will be a small impedance. Reflection Coef. The path loss that might be measured in a system however will not be this. The graph below shows input return loss for an amplifier. Home Return Loss to VSWR Conversion Chart Due to mismatches in impedance within the connector, some of the signal is reflected. A table of convenient values are presented at the bottom. The return loss vs. 50 from 6 votes. VSWR and Return Loss Calculations. 4 GHz and 5. This ratio can also be measured in dB, and expressed as Return Loss. VSWR and Return Loss RF Calculator. The time taken to measure both forward and reverse coupled signals, and calculate return loss is approximately 1. Path loss calculator Phase Noise to Jitter converter PLL PFD Frequency calculator PLL loop filter calculator Potential divider calculator Propagation time calculator Gamma to Impedance converter Reactance calculator. 5), which will give us 6. The concept of loss factor is discussed on this page. Return loss can be measured by using microwave and RF test. Measure the magnitude of the wave voltages at the coupled and isolated ports. As an added bonus, the. If the power incident on a load is Pi P i and the power reflected by the load is Pr P r, then the return loss in decibels is [1, 2] RLdB = 10 log Pi Pr (7. The table is created by plotting VSWR values against the corresponding return loss values. CF 210 Cable Loss; CF 300 Cable Loss; CF 500 Cable Loss; VSWR Calculator; Waveguide Gasket Selection; Photos. Our RF and microwave calculators and converters will provide the figures you need for your radio frequency engineering needs. 8. Return Loss to VSWR Conversion Chart. 0. The return loss at the input and output ports can be calculated from the reflection coefficient, S11 or S22, as follows: RLIN = 20log10|S11| dB (Eq. ElectronicsForU. Free Online. Straight enter that evaluate and click calculate. Stage: NF (dB) Gain (dB)0. Note: The calculations for Total P1dB and NF use linear values.