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From The Help DeskChris Prioli AD2CS[email protected] |
About From the Help Desk
[email protected]
A new monthly feature of CrossTalk is the From the Help Desk column, to be penned by Chris Prioli AD2CS. The purpose of this column is to provide public answers to questions that have been asked, frequently at the Clubhouse where a one-on-one answer was most likely already given. However, due to the probable widespread interest in the topic, it may seem to be an appropriate topic for this feature.
If you have a question to which you would like a thorough answer to be provided and shared with the wider group, feel free to submit the question to [email protected]. If selected for an answer, the question and answer will be published in an upcoming issue of CrossTalk as well as showing up on www.ad2cs.com.
We are kicking off the feature with a big question that takes a bit of a longer answer to do it justice. Rest assured, most of them will not be anywhere near as long as the kick-off.
[email protected]
A new monthly feature of CrossTalk is the From the Help Desk column, to be penned by Chris Prioli AD2CS. The purpose of this column is to provide public answers to questions that have been asked, frequently at the Clubhouse where a one-on-one answer was most likely already given. However, due to the probable widespread interest in the topic, it may seem to be an appropriate topic for this feature.
If you have a question to which you would like a thorough answer to be provided and shared with the wider group, feel free to submit the question to [email protected]. If selected for an answer, the question and answer will be published in an upcoming issue of CrossTalk as well as showing up on www.ad2cs.com.
We are kicking off the feature with a big question that takes a bit of a longer answer to do it justice. Rest assured, most of them will not be anywhere near as long as the kick-off.
December 2025
Q : I keep hearing about the need to calibrate my NanoVNA before using it. What is this all about, and how does one calibrate a NanoVNA?
A : The NanoVNA is an incredibly powerful tool for the radio amateur, and even more so when the price of the tool is considered. However, any tool is only as good as its sharpest edge, and the sharpest edge of the NanoVNA is found in that condition where it has been properly calibrated for the task at hand.
What’s it all about? Simply put, while the unit has been factory calibrated and is electronically “adjusted” to give the best results possible, those results can be skewed by certain operating conditions. The calibration process is designed to “zero out” the specific circumstances that would otherwise skew the measurement results displayed on the NanoVNA. Any time that we change the NanoVNA connection plane or the stimulus frequency to be used, we must perform a calibration in order to garner proper accuracy under the current test conditions.
To better understand the need for calibration, let’s explore the operational conditions of the NanoVNA. Suppose that you are about to use the NanoVNA to determine a complex impedance of an antenna system, as displayed on a Smith chart. Radio theory tells us that making a change to the length of an antenna feedline will not affect the VSWR of that antenna system, but it will affect the impedance of the system. Remember that the impedance inverts every λ/4 of feedline length, and that the impedance repeats every λ/2 along a feedline. Thus, if we add a segment of feedline equal to anything less than λ/2 in length, we will end up with a different impedance. This is pretty clear, and is black-letter law as related to radio theory. It does not stop there, however.
If we want to measure the complex impedance of an antenna system via the NanoVNA, we must, as a part of that measurement, connect the antenna system to the NanoVNA. If, in doing so, we add a length of coaxial cable between the antenna system feed point and the NanoVNA, we will have the same effect as if we were simply adding feedline length to the antenna system - it will change the overall impedance of the antenna system.
So… in order to “see” just the actual impedance of the antenna system and not to have that impedance padded by the connecting cable, we must have a means of “zeroing” out the effect of the connecting cable. That method is what we call “NanoVNA calibration.”
It is important to understand that the calibration is to be made to the connection plane at which the antenna system under test will be connected. In this manner, the “zero” point is at the far end of the connecting cable, and that cable length will therefore not be taken as a part of the antenna system - it will effectively be invisible to the NanoVNA.
Calibration is done by use of a set of so-called “calibration standards”, a set that consists of three different external resistances in a physical form that will allow the standards to be installed to the connecting cable at the connection plane to be used. The three resistances used most often are infinite resistance (open), zero resistance (short), and the characteristic impedance for the antenna system under test (load). More often than not, for amateur radio, that load value is fifty ohms. In addition to the three calibration standards, a calibration kit will also include a double-ended female adapter that will permit connection of two cables with male connectors to each other, and a pair of short connecting cables. Ideally, the calibration kit will also contain a second “load” standard, though this is not often the case. (More about that later.)
Anyone who works with multiple different cable types in conjunction with the NanoVNA will have a set of calibration standards for each connector type frequently used, and in both genders. My calibration kit includes standards in male BNC, female BNC, female UHF, male N, and female N. The NanoVNA normally ships with a set of male SMA standards. My plan is to expand my set further to include female SMA and male UHF standards, though I seldom have a need for those types.
The intent in having all of these different standards is that they will enable calibration right at the connection plane without the use of adapters during the calibration process. Even the length of cable adapters and gender changers will add effective feedline length to the overall net, and will therefore affect the final complex impedance measurement. That small length will make a difference if the intent is to design a matching network that will bring the antenna system impedance to a true and clean fifty ohms.
Let’s now look at the calibration procedure :
1. Install any needed or desired connecting cables for attaching the antenna system to the NanoVNA
2. Determine what type of calibration will be made
a. If only Port S11 will be used, a single port calibration is acceptable; but
b. If a through (Port S21) connection will be used, then a through calibration must be done
3. Set up the NanoVNA for the test to be made, including setting up the…
a. Traces to be displayed
b. Markers to be used
c. Port and format to be used
d. Any other specific settings necessary; and
e. Stimulus frequencies, either START and STOP or CENTER and SPAN
4. Go to CALIBRATE > RESET to reset the calibration in preparation for the new calibration
5. Go to CALIBRATE > CALIBRATE
6. Install the open standard at the S11 connection plane
7. Tap OPEN and wait for the check mark to appear
8. Remove the open standard
9. Install the short standard at the S11 connection plane
10. Tap SHORT and wait for the check mark to appear
11. Remove the short standard
12. Install the load standard at the S11 connection plane
13. Tap LOAD and wait for the check mark to appear
14. If a single-port test is to be made, proceed to Step 15 below; if a two-port test is to be made, jump ahead to Step 18 below
15. Remove the load standard
16. Tap DONE and then select a suitable storage slot to save the calibration if so desired (recommended)
17. Proceed to test(s) to be made
18. Install a load standard to the second port, at the S21 connection plane. Note that this step requires the use of a second load standard, which may not always be on hand
19. Tap ISOLN and wait for the check mark to appear
20. Remove the load standards from the two ports
21. Connect the two ports to each other at the connection plane, using the shortest connecting adapter possible
22. Tap THRU and wait for the check mark to appear.
23. Disconnect the port jumper.
24. Tap DONE and then select a suitable storage slot to save the calibration if so desired (recommended).
25. Proceed to the test(s) to be made.
The NanoVNA is now calibrated and ready for use. On-screen, along the left edge, will be a legend that indicates which stored calibration is in use, and if it is in use directly as stored, or if there is a change from the stored settings.
The legend starts out with the letter “C”. If the “C” is in upper case text, the calibration is in use exactly as it was saved. However, if the “c” is in lower case text, it indicates that the stimulus frequency has been changed from that which was stored. The numeral after the “C” indicates which specific memory storage slot is in use. If the calibration has not been saved to a slot, the numeral will be replaced with an asterisk (*).
In addition, there are some letters that appear in a column under the calibration indicator, as follows :
Other power levels that can be selected are 2mA, 4mA, 6mA and 8mA. These are selected under the MENU > POWER menu item. If the text in the calibration status indicator is red in color, the “no calibration” calibration status is indicated. A properly calibrated NanoVNA will show its calibration status in white text, but during the calibration process, the text will show in a red color until the calibration is complete.
I hope that this article makes your NanoVNA just a bit more friendly and useful. Proper calibration is absolutely necessary for any degree of accuracy to be achieved. Knowing how and when to perform the calibration makes you more adept at using the NanoVNA.
Q : I keep hearing about the need to calibrate my NanoVNA before using it. What is this all about, and how does one calibrate a NanoVNA?
A : The NanoVNA is an incredibly powerful tool for the radio amateur, and even more so when the price of the tool is considered. However, any tool is only as good as its sharpest edge, and the sharpest edge of the NanoVNA is found in that condition where it has been properly calibrated for the task at hand.
What’s it all about? Simply put, while the unit has been factory calibrated and is electronically “adjusted” to give the best results possible, those results can be skewed by certain operating conditions. The calibration process is designed to “zero out” the specific circumstances that would otherwise skew the measurement results displayed on the NanoVNA. Any time that we change the NanoVNA connection plane or the stimulus frequency to be used, we must perform a calibration in order to garner proper accuracy under the current test conditions.
To better understand the need for calibration, let’s explore the operational conditions of the NanoVNA. Suppose that you are about to use the NanoVNA to determine a complex impedance of an antenna system, as displayed on a Smith chart. Radio theory tells us that making a change to the length of an antenna feedline will not affect the VSWR of that antenna system, but it will affect the impedance of the system. Remember that the impedance inverts every λ/4 of feedline length, and that the impedance repeats every λ/2 along a feedline. Thus, if we add a segment of feedline equal to anything less than λ/2 in length, we will end up with a different impedance. This is pretty clear, and is black-letter law as related to radio theory. It does not stop there, however.
If we want to measure the complex impedance of an antenna system via the NanoVNA, we must, as a part of that measurement, connect the antenna system to the NanoVNA. If, in doing so, we add a length of coaxial cable between the antenna system feed point and the NanoVNA, we will have the same effect as if we were simply adding feedline length to the antenna system - it will change the overall impedance of the antenna system.
So… in order to “see” just the actual impedance of the antenna system and not to have that impedance padded by the connecting cable, we must have a means of “zeroing” out the effect of the connecting cable. That method is what we call “NanoVNA calibration.”
It is important to understand that the calibration is to be made to the connection plane at which the antenna system under test will be connected. In this manner, the “zero” point is at the far end of the connecting cable, and that cable length will therefore not be taken as a part of the antenna system - it will effectively be invisible to the NanoVNA.
Calibration is done by use of a set of so-called “calibration standards”, a set that consists of three different external resistances in a physical form that will allow the standards to be installed to the connecting cable at the connection plane to be used. The three resistances used most often are infinite resistance (open), zero resistance (short), and the characteristic impedance for the antenna system under test (load). More often than not, for amateur radio, that load value is fifty ohms. In addition to the three calibration standards, a calibration kit will also include a double-ended female adapter that will permit connection of two cables with male connectors to each other, and a pair of short connecting cables. Ideally, the calibration kit will also contain a second “load” standard, though this is not often the case. (More about that later.)
Anyone who works with multiple different cable types in conjunction with the NanoVNA will have a set of calibration standards for each connector type frequently used, and in both genders. My calibration kit includes standards in male BNC, female BNC, female UHF, male N, and female N. The NanoVNA normally ships with a set of male SMA standards. My plan is to expand my set further to include female SMA and male UHF standards, though I seldom have a need for those types.
The intent in having all of these different standards is that they will enable calibration right at the connection plane without the use of adapters during the calibration process. Even the length of cable adapters and gender changers will add effective feedline length to the overall net, and will therefore affect the final complex impedance measurement. That small length will make a difference if the intent is to design a matching network that will bring the antenna system impedance to a true and clean fifty ohms.
Let’s now look at the calibration procedure :
1. Install any needed or desired connecting cables for attaching the antenna system to the NanoVNA
2. Determine what type of calibration will be made
a. If only Port S11 will be used, a single port calibration is acceptable; but
b. If a through (Port S21) connection will be used, then a through calibration must be done
3. Set up the NanoVNA for the test to be made, including setting up the…
a. Traces to be displayed
b. Markers to be used
c. Port and format to be used
d. Any other specific settings necessary; and
e. Stimulus frequencies, either START and STOP or CENTER and SPAN
4. Go to CALIBRATE > RESET to reset the calibration in preparation for the new calibration
5. Go to CALIBRATE > CALIBRATE
6. Install the open standard at the S11 connection plane
7. Tap OPEN and wait for the check mark to appear
8. Remove the open standard
9. Install the short standard at the S11 connection plane
10. Tap SHORT and wait for the check mark to appear
11. Remove the short standard
12. Install the load standard at the S11 connection plane
13. Tap LOAD and wait for the check mark to appear
14. If a single-port test is to be made, proceed to Step 15 below; if a two-port test is to be made, jump ahead to Step 18 below
15. Remove the load standard
16. Tap DONE and then select a suitable storage slot to save the calibration if so desired (recommended)
17. Proceed to test(s) to be made
18. Install a load standard to the second port, at the S21 connection plane. Note that this step requires the use of a second load standard, which may not always be on hand
19. Tap ISOLN and wait for the check mark to appear
20. Remove the load standards from the two ports
21. Connect the two ports to each other at the connection plane, using the shortest connecting adapter possible
22. Tap THRU and wait for the check mark to appear.
23. Disconnect the port jumper.
24. Tap DONE and then select a suitable storage slot to save the calibration if so desired (recommended).
25. Proceed to the test(s) to be made.
The NanoVNA is now calibrated and ready for use. On-screen, along the left edge, will be a legend that indicates which stored calibration is in use, and if it is in use directly as stored, or if there is a change from the stored settings.
The legend starts out with the letter “C”. If the “C” is in upper case text, the calibration is in use exactly as it was saved. However, if the “c” is in lower case text, it indicates that the stimulus frequency has been changed from that which was stored. The numeral after the “C” indicates which specific memory storage slot is in use. If the calibration has not been saved to a slot, the numeral will be replaced with an asterisk (*).
In addition, there are some letters that appear in a column under the calibration indicator, as follows :
- D : Directivity - indicates that directivity error correction is applied
- R : Reflection tracking - indicates that error correction is applied
- S : Source match - indicates that error correction is applied
- T : Transmission tracking - indicates that error correction is applied
- X : Crosstalk - a indicates that isolation (crosstalk) error correction is applied; and
- P : Power - indicates power level set at time of calibration (a - automatic)
Other power levels that can be selected are 2mA, 4mA, 6mA and 8mA. These are selected under the MENU > POWER menu item. If the text in the calibration status indicator is red in color, the “no calibration” calibration status is indicated. A properly calibrated NanoVNA will show its calibration status in white text, but during the calibration process, the text will show in a red color until the calibration is complete.
I hope that this article makes your NanoVNA just a bit more friendly and useful. Proper calibration is absolutely necessary for any degree of accuracy to be achieved. Knowing how and when to perform the calibration makes you more adept at using the NanoVNA.
November 2025
Q: Can the impedance of a section of unknown coaxial cable be determined using a NanoVNA? If so, how is it done?
A: The short answer is “YES” - coax line impedance can be determined using a NanoVNA. For the second part of the question, some preparatory information becomes necessary. The information provided herein is specific to the NanoVNA H4 with firmware version 1.2.40, but it should be very similar for other NanoVNA models and firmware versions.
Q: Can the impedance of a section of unknown coaxial cable be determined using a NanoVNA? If so, how is it done?
A: The short answer is “YES” - coax line impedance can be determined using a NanoVNA. For the second part of the question, some preparatory information becomes necessary. The information provided herein is specific to the NanoVNA H4 with firmware version 1.2.40, but it should be very similar for other NanoVNA models and firmware versions.
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This process will take advantage of the fact that the impedance in a feedline inverts every quarter-wavelength (λ/4) along its length, called the λ/4 inversion property. In a feedline, the impedance looking into the end of the feedline divided by the line impedance is equal to the line impedance divided by the load impedance. There is a simple equation that describes this relationship, as follows : |
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which can be rearranged or simplified as : |
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and then simplified again as : |
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These equations show how the line impedance is mathematically derived. The NanoVNA will provide us with the ZIN value for use in the equation. However, we must also do a little bit more very simple math before we are ready to go.
The math that we need to work now deals with the STOP frequency of the RF sweep that we will use to measure the cable. The intent is to determine a sweep STOP frequency that is greater than the λ/4 frequency of the cable under test. This can be determined easily by dividing estimated length of the cable under test into one-quarter of the speed of light. When done as explained below, this calculation will produce the free space λ/4 frequency in megahertz, which will always be somewhat greater than the actual cable λ/4 frequency. If estimating the cable length in feet, divide that length into 246, but if estimating the cable length in meters, divide that length into 75. You should by now understand the significance of these numbers. Once you have an estimated STOP frequency, use the procedure below to determine the cable impedance.
Procedure
Example
The complex impedance value displayed on the NanoVNA at the prime axis crossing point is 52.23-j29.5mΩ. If the real resistance value of 52.23Ω is then multiplied by the load impedance of 50Ω, we get a product of 2611.5. If we then determine the square root of that product, we find a line impedance value of 51.10Ω, which we can then assume indicates a 50-ohm cable.
I hope that this article will help to make your NanoVNA more useful to you as well as helping to improve your NanoVNA operational skills. The NanoVNA is an incredibly useful and powerful tool for the radio amateur to have in his/her tool arsenal. Knowing how to use it makes it just that much more valuable.
These equations show how the line impedance is mathematically derived. The NanoVNA will provide us with the ZIN value for use in the equation. However, we must also do a little bit more very simple math before we are ready to go.
The math that we need to work now deals with the STOP frequency of the RF sweep that we will use to measure the cable. The intent is to determine a sweep STOP frequency that is greater than the λ/4 frequency of the cable under test. This can be determined easily by dividing estimated length of the cable under test into one-quarter of the speed of light. When done as explained below, this calculation will produce the free space λ/4 frequency in megahertz, which will always be somewhat greater than the actual cable λ/4 frequency. If estimating the cable length in feet, divide that length into 246, but if estimating the cable length in meters, divide that length into 75. You should by now understand the significance of these numbers. Once you have an estimated STOP frequency, use the procedure below to determine the cable impedance.
Procedure
- Go to MENU > DISPLAY > TRACE and turn off all traces except TRACE 0.
- Go to MENU > DISPLAY > FORMAT S11 (REFL) > and select SMITH, and then be sure that the SMITH form is set to R + jX.
- Go to MENU > DISPLAY > MARKER and make sure that only MARKER 1 is selected and active.
- Go to MENU > STIMULUS > START and set the START frequency to 50kHz.
- Go to MENU > STIMULUS > STOP and set the STOP frequency to the value determined using the simple equation discussed above.
- Connect any adapters needed to connect the cable to be tested to the NanoVNA.
- Perform a calibration of the NanoVNA at the connection plane established in the previous step.
- Save the calibration to a suitable memory slot in the NanoVNA.
- Attach a 50Ω load (terminator) to the cable to be tested.
- Connect the cable to be tested to the NanoVNA at the connection plane established in Step 6 above.
- Use the jog wheel to move MARKER 1 along the displayed trace just until the first time that it crosses the prime axis.
- Read the real (resistive) portion of the displayed complex impedance at the upper left corner of the display screen.
- Use that resistance value in the impedance equation explained earlier, multiplying the resistance value by the load value of 50Ω, and then determine the square root of that product. This result will be the approximate line impedance of the cable under test.
Example
The complex impedance value displayed on the NanoVNA at the prime axis crossing point is 52.23-j29.5mΩ. If the real resistance value of 52.23Ω is then multiplied by the load impedance of 50Ω, we get a product of 2611.5. If we then determine the square root of that product, we find a line impedance value of 51.10Ω, which we can then assume indicates a 50-ohm cable.
I hope that this article will help to make your NanoVNA more useful to you as well as helping to improve your NanoVNA operational skills. The NanoVNA is an incredibly useful and powerful tool for the radio amateur to have in his/her tool arsenal. Knowing how to use it makes it just that much more valuable.
October 2025
Q : How can the length of a coil of wire be measured using the NanoVNA?
A : Not just any coil or length of cable can be measured in this fashion. The cable under test must have at least two conductors, such as a length of coaxial cable, or window line, or even Cat-5 LAN cable with its four twisted pairs inside the jacket. The measurement test methodology utilizes a scheme known as time domain reflectometry or TDR. In this test, a relatively low-frequency signal is placed onto the cable under test, where it travels down the cable to the opposite end and is then reflected back toward the source. The time that it takes to make the round trip to the opposite end of the cable is then used, together with the cable’s velocity factor (VF), to calculate the length of the cable. The TDR function utilizes the NanoVNA’s TRANSFORM function to support its calculations.
Velocity factor is a rating, expressed as a percentage of the speed of light, at which an RF signal will travel within a cable of a given type. The increased molecular density of the cable causes the RF signal to be slowed down in the cable as compared to the speed of light in free space. However, it is actually the material of the dielectric used in the cable construction that has the greatest effect upon the velocity factor of that cable type. Table 1 provides VF’s for many typical dielectric materials used in cable construction while Table 2 list the VF’s for several common cable types.
Q : How can the length of a coil of wire be measured using the NanoVNA?
A : Not just any coil or length of cable can be measured in this fashion. The cable under test must have at least two conductors, such as a length of coaxial cable, or window line, or even Cat-5 LAN cable with its four twisted pairs inside the jacket. The measurement test methodology utilizes a scheme known as time domain reflectometry or TDR. In this test, a relatively low-frequency signal is placed onto the cable under test, where it travels down the cable to the opposite end and is then reflected back toward the source. The time that it takes to make the round trip to the opposite end of the cable is then used, together with the cable’s velocity factor (VF), to calculate the length of the cable. The TDR function utilizes the NanoVNA’s TRANSFORM function to support its calculations.
Velocity factor is a rating, expressed as a percentage of the speed of light, at which an RF signal will travel within a cable of a given type. The increased molecular density of the cable causes the RF signal to be slowed down in the cable as compared to the speed of light in free space. However, it is actually the material of the dielectric used in the cable construction that has the greatest effect upon the velocity factor of that cable type. Table 1 provides VF’s for many typical dielectric materials used in cable construction while Table 2 list the VF’s for several common cable types.
The specific velocity factor of the cable to be tested must be known in order to properly calculate the length of that cable via NanoVNA TDR measurement. If you cannot identify the specific cable or cable type and do not have a datasheet for the cable, find the most similar cable in Table 2 and use that VF value. If that is not possible, then just use the Table 1 VF value for the dielectric material used in the cable to be tested.
Before we can make the measurement, we have to do some basic mathematics. The math is used to determine a suitable STOP frequency for the RF sweep that will be used for the test; the sweep START frequency is generally set at 50kHz.
The STOP frequency chosen will determine the maximum distance range and resolution for the test being made. The higher the STOP frequency is, the shorter the total distance capability will be, while a lower STOP frequency will provide for a longer total distance measurement capability.
Although it is not the best choice for a calculation constant, the value 6000 is an easy value to remember and is also an easy value for working out arithmetic results. We will use that value to determine our STOP frequency, dividing 6000 by the estimated maximum length to be measured in meters. The equation to be used is as follows :
The STOP frequency chosen will determine the maximum distance range and resolution for the test being made. The higher the STOP frequency is, the shorter the total distance capability will be, while a lower STOP frequency will provide for a longer total distance measurement capability.
Although it is not the best choice for a calculation constant, the value 6000 is an easy value to remember and is also an easy value for working out arithmetic results. We will use that value to determine our STOP frequency, dividing 6000 by the estimated maximum length to be measured in meters. The equation to be used is as follows :
where we use 6000 as the dividend and the maximum length in meters as the divisor. For example, if we are anticipating a maximum length that is just under 300 feet, we might choose 100 meters as the divisor, giving us a STOP frequency of 60MHz.
Once the NanoVNA is properly calibrated and configured, we will be able to read the calculated length directly from the NanoVNA display. Before we can begin, however, we must also prepare the cable to be tested for the measurement process. If the cable has a connector installed to at least one end of the cable, we can use that connector to attach the cable to the NanoVNA by way of suitable adapter(s). On the other hand, if the cable is unterminated, it must be prepared by exposing and stripping both conductors of the cable to be tested, so that alligator clips can be attached to those conductors. Then, we would use a suitable adapter that will connect to the NanoVNA and has alligator clips at the opposite end. For example, I have a twelve-inch length of RG174 cable that has a male SMA connector at one end and alligator clips at the other end. Similarly, I have another one, this time of RG-58 cable, that has a male BNC connector at one end and has alligator clips at its opposite end. These adapter cables are suitable for this type of test measurement. Note that is it advisable to use the mated wires of a single twisted pair when making TDR measurements on cables like Cat-5 LAN cable, e.g., the blue and blue/white or the orange and orange/white wire pairs. When measurements are being made on double-shielded coaxial cables, use the center conductor and the inner-most shield layer for the TDR measurement.
Follow the procedure below to make the TDR measurement with your NanoVNA. Note that these steps are specific to the NanoVNA H4 with firmware version 1.2.40 installed. The procedure for other NanoVNA models and firmware versions should be very similar.
Procedure
Conclusion
I hope that this article will help to make your NanoVNA more useful to you as well as helping to improve your NanoVNA operational skills. The NanoVNA is an incredibly useful and powerful tool for the radio amateur to have in his/her tool arsenal. Knowing more about how to use the NanoVNA makes it just that much more valuable. This particular use of the NanoVNA will help you to identify the lengths of all of those many assorted cable sections that we all have sitting around our shacks.
Once the NanoVNA is properly calibrated and configured, we will be able to read the calculated length directly from the NanoVNA display. Before we can begin, however, we must also prepare the cable to be tested for the measurement process. If the cable has a connector installed to at least one end of the cable, we can use that connector to attach the cable to the NanoVNA by way of suitable adapter(s). On the other hand, if the cable is unterminated, it must be prepared by exposing and stripping both conductors of the cable to be tested, so that alligator clips can be attached to those conductors. Then, we would use a suitable adapter that will connect to the NanoVNA and has alligator clips at the opposite end. For example, I have a twelve-inch length of RG174 cable that has a male SMA connector at one end and alligator clips at the other end. Similarly, I have another one, this time of RG-58 cable, that has a male BNC connector at one end and has alligator clips at its opposite end. These adapter cables are suitable for this type of test measurement. Note that is it advisable to use the mated wires of a single twisted pair when making TDR measurements on cables like Cat-5 LAN cable, e.g., the blue and blue/white or the orange and orange/white wire pairs. When measurements are being made on double-shielded coaxial cables, use the center conductor and the inner-most shield layer for the TDR measurement.
Follow the procedure below to make the TDR measurement with your NanoVNA. Note that these steps are specific to the NanoVNA H4 with firmware version 1.2.40 installed. The procedure for other NanoVNA models and firmware versions should be very similar.
Procedure
- Go to MENU > DISPLAY > TRACE and turn off all traces except TRACE 0.
- Go to MENU > DISPLAY > FORMAT S11 (REFL) > and select REAL or LINEAR.
- Go to MENU > DISPLAY > MARKER and make sure that only MARKER 1 is selected and active.
- Go to MENU > STIMULUS > START and set the START frequency to 50kHz.
- Go to MENU > STIMULUS > STOP and set the STOP frequency to the value determined using the simple equation discussed above.
- Go to MENU > DISPLAY > TRANSFORM > VELOCITY F and enter the appropriate velocity factor value for the cable under study.
- Go to MENU > DISPLAY > TRANSFORM and select LOW PASS IMPULSE.
- Go to MENU > DISPLAY > TRANSFORM and set the TRANSFORM function to ON.
- Install (to port S11) any adapters needed to connect the cable to be tested to the NanoVNA.
- Perform a proper calibration of the NanoVNA at that connection plane.
- Save the calibration to a suitable slot in the NanoVNA.
- Connect the cable to be tested to the NanoVNA to port S11.
- Go to MENU > DISPLAY > MARKER and tap SEARCH until it shows SEARCH MAXIMUM.
- Read the displayed propagation time and the calculated length in meters from the MARKER 1 (M1:) field at the upper-right corner of the NanoVNA display screen.
Conclusion
I hope that this article will help to make your NanoVNA more useful to you as well as helping to improve your NanoVNA operational skills. The NanoVNA is an incredibly useful and powerful tool for the radio amateur to have in his/her tool arsenal. Knowing more about how to use the NanoVNA makes it just that much more valuable. This particular use of the NanoVNA will help you to identify the lengths of all of those many assorted cable sections that we all have sitting around our shacks.
September 2025
Q: I am getting ready for a road trip to Florida, and I want to put a radio in the car for the trip, and then possibly make it a permanent installation afterwards. What would you suggest in terms of equipment, installation, and the best way to program the radio?
A: I might suggest several different approaches here, depending upon just which bands you may want to have available in the car, whether or not you are bothered by drilling holes in the interior panels, and what is available as to antenna mounting and positioning. Let’s take a look at some options, starting with the radio.
Several very compact radios are available. A good choice for a two-band set might be the TYT TH-8600 2m/70cm transceiver. This is the set that I have in my own POV for VHF/UHF use. The TH-8600 is a 25-watt miniature set capable of two-way comms on the 144-148 MHz and 420-450 MHz band segments. The radio is a mere 4.2” wide, 1.8” high, and 5.4” deep, weighing only about 3-1/2 pounds. While the faceplate is not removable, the radio is compact enough to fit in minimalistic spaces and is light enough that the strong interlocking strip fasteners can hold it to the dash if necessary. This radio has 200 memory channels and a dual VFO display. The microphone has a full numeric keypad, making control via the mic a snap. Programming is via a custom cable that plugs into a rear-panel data port and utilizes a USB connection to the PC. The antenna connection for a dual-band 2m/70cm antenna is via a single SO-239 socket on the radio rear panel. While antenna choices here are almost endless, I personally like and recommend the UAYESOK two-band dual-mast compact magnetic-base antenna, installed near the center of the vehicle roof if possible.
If instead a three-band radio is desired, a good choice might be the BTECH UV-25X4 tri-band transceiver. While I also own one of these units, I have not yet installed it. It too is a 25-watt unit (a 50-watt version, the UV-50X4, is also available, but is somewhat larger), operating on frequencies from 136 to 174 MHz, from 220 to 225 MHz, and from 400 to 520 MHz. Note that some of these ranges extend beyond the legal limits of the amateur bands in the USA. This unit is tiny! It measures only 3.85” wide by 1.83” high by 4.65” deep, and weighs an amazing 0.9 pounds. Its size and weight also lend themselves well to a Velcro®-type of temporary mount. While accessing all three available bands in this radio would require the use of a tri-band antenna, it can, of course, be utilized as a dual-band unit with a standard 2m/70cm antenna, connected via the SO-239 connector on the radio rear panel. A suitable antenna here might be the Nagoya TB-320A tri-band antenna, but other choices are available including the quad-band KT-7900 antenna that I purchased. Programming is via a standard Baofeng-type programming cable, which is then tied into the radio mic port via the specialized “Y” cable that ships with the radio.
Both of the above radios come in at just about $135 plus tax and shipping; the antennas mentioned are about $30 to $40 each. So, let’s talk about the installation of these two units.
Because all else depends upon the location of the radio itself, that location must be selected at the outset. A typical location for a dash-mounted radio might be below and to the left of the steering wheel. Another popular choice is to mount the radio to the side of the center console, which often places the radio at ninety degrees to the viewer. In many cases, most of the radio control is accomplished by way of the buttons on the mic, so all that is really necessary as far as the radio itself goes is to be able to see and read the front panel frequency display. Once the user has become familiar with the radio, actually needing to refer to the front panel is greatly reduced. However, if the radio has a “remote” type of removable face plate (front panel), the options become much broader. For example, the radio body can be installed underneath the driver’s seat with the wire-connected face plate mounted to or on top of the dashboard or even on the steering column shroud.
Wherever (and however) you ultimately decide to install the radio body, it must be secured against free movement. This is important both to protect the radio and to protect the vehicle occupants in the event of a sudden stop or impact. As a driver, I certainly would not want a four-pound projectile accelerating towards my head during an emergency stop.
Protection of the radio revolves around keeping extraneous vibration and bouncing of the radio to a bare minimum. Most if not all modern radios are assembled using lead-free assembly methods, but there is a clear-cut reason why lead-free solder is not permitted in any mission critical equipment such as aircraft avionics, medical or healthcare appliances, and in most military applications. Lead solder joints simply will not remain intact over time, and motion or vibration can accelerate their failure, thus hastening the demise of the equipment. Do your part to help avoid such early failures by properly securing all radios in fixed locations. Your bank account will thank you later.
It is recommended that the radio chosen for vehicle installation be as small as possible while still providing the requisite features. For example, a typical dual-band 2m/70cm unit should provide at least the following features :
Once you have selected a radio and determined how and where to mount it, it is time to move on to the antenna. You must choose an antenna mounting location that will give good performance while permitting the antenna to be securely mounted. I have had the Amazon-purchased UAYESOK dual-band antenna on my POV for almost four years now, with absolutely no problems. The magnetic base is strong, but is well padded to avoid damage to the vehicle. I have never knocked it off the roof despite its having hit low-hanging tree limbs on several occasions. Its installed position at the center of the roof provides the best possible ground plane, which in turn offers the most desirable radiation pattern.
Routing of the antenna cable is an area where some thought must be given. It is important to choose a cable path that will not cause chafing or cutting of the cable, while still maintaining the water-exclusion capability of the door seals through which the cable will probably need to pass. It is often possible to work the cable into the gap under the door seal, dressing it in such a manner that any drip lines formed will release their water load on the outside of the seal. Many modern vehicles have dual-lipped door seals. In such cases, place the cable so that it lies between the lips, routing it so that it follows the door frame down to a point where the cable can be brought inside the vehicle without compromising the seal’s integrity. Inside the vehicle, run the cable along and, if possible, under the carpet at the door sill, ultimately bringing it to the location of the radio.
Be sure to leave sufficient extra coaxial cable length near the radio to permit removal of the radio from its mount while still connected to the antenna. For example, it may at some point become necessary or desirable to set the radio on the seat while programming and testing it. Some radios have data ports that are very difficult to access without being able to actually see the rear panel of the radio. Some require the removal of a screw-retained cover in order to access the data port. The extra cable length can be stowed under the dashboard or under the seat, depending upon the installation location of the radio.
If it becomes necessary to drill any holes in order to accommodate the antenna coaxial cable feedline, be sure to drill the hole(s) large enough for the cable connector to pass through. Then, afterwards, be prepared to seal the hole around the cable using a rubber grommet with a membrane in its center. A grommet such as the Keystone #778 is an ideal choice for this purpose. It has an OD of 1.125” and fits a 1” hole in panels up to 0.062” thick. The center membrane has an expandable 0.25” hole at its center, and fits cables up to 0.3125” in diameter. The seal is necessary to a) prevent chafing of the cable, b) to exclude dust, dirt, and water, and c) to support the cable where it passes through the panel.
Once the antenna cable has been routed and the antenna installed, it is time to move on to the power provision. Despite the fact that some radios are shipped with so-called cigar lighter plugs for the power connection, it is NEVER advisable to use such a connection for the radio power. On most if not all vehicles, the cigar lighter power capability is far beneath that required by the radio. Usually, the wiring to the cigar lighter socket is no more than about a 20AWG wire, certainly not adequate for the eight to ten amperes (or more) required by the radio during TX operation. The general rule of thumb for 20AWG stranded wire is 3.5A continuous duty. Remember that although the radio will receive OK with low current supplied, it will not transmit properly under those conditions, with different results depending upon the radio and the current available. The radio may simply shut down, or it may attempt to transmit to the best of its ability. Such transmissions can be full of spurious signals and distorted audio.
The recommended method of connecting power to the radio is to run the heavy-gauge twin-lead wire from the radio directly to the battery. At the battery, connection is made to each of the battery posts if the vehicle does not have an alternate auxiliary power connection scheme. Many newer vehicles require that any such direct-power connections be made to a dedicated connection point designed and provided specifically for that purpose. Either way, it is necessary to fuse the wire leads as close to the source connection point as is possible. If the harness supplied by the radio manufacturer has a fuse in each lead (the positive and the negative), it is very important to maintain that methodology when making your power connections. On the other hand, if the radio manufacturer fused only the positive lead, it is acceptable to do the same when making your connections. In case it is necessary for some readers, I will mention that the standard color-coding of the power cable is red for positive and black for negative.
The reason that the two fuses are important if the manufacturer shipped the radio with two fuses is because some radios use both the positive and negative leads as incoming power lines, meaning that the black lead does not connect directly to the chassis of the radio, but is instead tied into some of the circuitry as a power supply feed. The purpose of mounting the fuses as close to the power source connection is so that the entire length of the power line(s) will be protected against short circuits, potentially from chafing in the vehicle.
Once again, wherever the power lines feed through from the engine compartment (or other battery location) into the cabin of the vehicle, the power lines must be protected from chafing and the opening must be sealed as with the antenna cable. Be sure to route the power lines in such a manner that there is no probability of burning on hot under-hood parts, no probability of pinching or chafing of the wires, and no interference with any moving parts under the hood. Also as with the antenna cable, allow for some extra wire length at the radio mounting location so that the radio can be removed from its mount while still connected to power.
If running the power lines to the battery is beyond your skill level, don’t feel bad! I was a heavy-duty truck mechanic for many years, but I had a local garage run my power feed to the battery when I first installed my radio in the POV. That shop has a lift and can easily get to the area of the firewall where the wires needed to pass into the cabin. Many independent garages and most car audio shops will run these wires for you for a small fee, and it only takes a few minutes to do the job with the correct equipment available.
Once the power is available at the radio, it is time to make that connection. For this purpose, I fully endorse the use of Anderson Powerpole® connectors. You will need four connector bodies (two red and two black), and then you will need a total of four crimp-on terminals. The crimp-on terminals used for this purpose are available in three different sizes, rated for current and related to wire gauge. The 15A, 30A, and 45A crimp-on connectors all fit into the same connector bodies. Select two pairs of crimp-on connectors appropriate for the wire sizes involved here – the two attached to the radio and the two coming from the battery. Installing the crimp-on terminals to the wires and then into the connector body is a simple task with the proper equipment, but you may want to see the process demonstrated at least once so that you know how to do the job. The W2MMD Clubhouse has the connectors, terminals, and crimp tool all available at the test and repair bench. Don’t forget to contribute to the replenishment kitty if you use Club supplies.
Anderson Powerpole® connectors are “gender-less” connectors, meaning that any body of a given size will mate with another body of that same size. This makes connecting to the radio quite simple. With an Anderson Powerpole® connector pair installed to the power wire coming from the battery and another set installed to the power leads on the radio itself, these two connector sets will simply plug into each other, observing the colors when making the connection.
With all of the connections to the radio made, all that is left is to program and test the radio. In many cases, the programming is easily handled with the CHIRP computer software package. Programming is a topic for another article, so I will not go into it in depth here. However, I will mention a few pertinent pointers about using CHIRP to program a radio :
If planning a road trip, you may want to use Repeater Book or some similar reference to identify all of the repeaters along your proposed route of travel. In that way, you can then program each of the repeaters identified, in route sequence, into an empty segment of the radio’s memory range, making it easy to move from one repeater to another as you travel down the highway. On the return trip, the sequence will still work, except that it will be used in reverse order.
I hope that this information will be useful to anyone planning such an installation. While it is not intended to be a comprehensive, cover all the bases type of explanation, it should nevertheless help to get you started with the job.
Q: I am getting ready for a road trip to Florida, and I want to put a radio in the car for the trip, and then possibly make it a permanent installation afterwards. What would you suggest in terms of equipment, installation, and the best way to program the radio?
A: I might suggest several different approaches here, depending upon just which bands you may want to have available in the car, whether or not you are bothered by drilling holes in the interior panels, and what is available as to antenna mounting and positioning. Let’s take a look at some options, starting with the radio.
Several very compact radios are available. A good choice for a two-band set might be the TYT TH-8600 2m/70cm transceiver. This is the set that I have in my own POV for VHF/UHF use. The TH-8600 is a 25-watt miniature set capable of two-way comms on the 144-148 MHz and 420-450 MHz band segments. The radio is a mere 4.2” wide, 1.8” high, and 5.4” deep, weighing only about 3-1/2 pounds. While the faceplate is not removable, the radio is compact enough to fit in minimalistic spaces and is light enough that the strong interlocking strip fasteners can hold it to the dash if necessary. This radio has 200 memory channels and a dual VFO display. The microphone has a full numeric keypad, making control via the mic a snap. Programming is via a custom cable that plugs into a rear-panel data port and utilizes a USB connection to the PC. The antenna connection for a dual-band 2m/70cm antenna is via a single SO-239 socket on the radio rear panel. While antenna choices here are almost endless, I personally like and recommend the UAYESOK two-band dual-mast compact magnetic-base antenna, installed near the center of the vehicle roof if possible.
If instead a three-band radio is desired, a good choice might be the BTECH UV-25X4 tri-band transceiver. While I also own one of these units, I have not yet installed it. It too is a 25-watt unit (a 50-watt version, the UV-50X4, is also available, but is somewhat larger), operating on frequencies from 136 to 174 MHz, from 220 to 225 MHz, and from 400 to 520 MHz. Note that some of these ranges extend beyond the legal limits of the amateur bands in the USA. This unit is tiny! It measures only 3.85” wide by 1.83” high by 4.65” deep, and weighs an amazing 0.9 pounds. Its size and weight also lend themselves well to a Velcro®-type of temporary mount. While accessing all three available bands in this radio would require the use of a tri-band antenna, it can, of course, be utilized as a dual-band unit with a standard 2m/70cm antenna, connected via the SO-239 connector on the radio rear panel. A suitable antenna here might be the Nagoya TB-320A tri-band antenna, but other choices are available including the quad-band KT-7900 antenna that I purchased. Programming is via a standard Baofeng-type programming cable, which is then tied into the radio mic port via the specialized “Y” cable that ships with the radio.
Both of the above radios come in at just about $135 plus tax and shipping; the antennas mentioned are about $30 to $40 each. So, let’s talk about the installation of these two units.
Because all else depends upon the location of the radio itself, that location must be selected at the outset. A typical location for a dash-mounted radio might be below and to the left of the steering wheel. Another popular choice is to mount the radio to the side of the center console, which often places the radio at ninety degrees to the viewer. In many cases, most of the radio control is accomplished by way of the buttons on the mic, so all that is really necessary as far as the radio itself goes is to be able to see and read the front panel frequency display. Once the user has become familiar with the radio, actually needing to refer to the front panel is greatly reduced. However, if the radio has a “remote” type of removable face plate (front panel), the options become much broader. For example, the radio body can be installed underneath the driver’s seat with the wire-connected face plate mounted to or on top of the dashboard or even on the steering column shroud.
Wherever (and however) you ultimately decide to install the radio body, it must be secured against free movement. This is important both to protect the radio and to protect the vehicle occupants in the event of a sudden stop or impact. As a driver, I certainly would not want a four-pound projectile accelerating towards my head during an emergency stop.
Protection of the radio revolves around keeping extraneous vibration and bouncing of the radio to a bare minimum. Most if not all modern radios are assembled using lead-free assembly methods, but there is a clear-cut reason why lead-free solder is not permitted in any mission critical equipment such as aircraft avionics, medical or healthcare appliances, and in most military applications. Lead solder joints simply will not remain intact over time, and motion or vibration can accelerate their failure, thus hastening the demise of the equipment. Do your part to help avoid such early failures by properly securing all radios in fixed locations. Your bank account will thank you later.
It is recommended that the radio chosen for vehicle installation be as small as possible while still providing the requisite features. For example, a typical dual-band 2m/70cm unit should provide at least the following features :
- Easily readable display with large numerals in a clean typeface
- Adjustable squelch control
- Full CTCSS access (50 discrete frequencies available)
- Simple programming method (non-complex or complicated), preferably via CHIRP
- A number of memory slots for storage of favorite frequencies, the more the better
- Compact size
- Integrated cooling fan
- Simplified switching between VFO and MEM modes
- At least 25 watts RF output on 2m and 20 watts RF output on 70cm bands
- Mic with capability to control the radio via buttons on the mic
Once you have selected a radio and determined how and where to mount it, it is time to move on to the antenna. You must choose an antenna mounting location that will give good performance while permitting the antenna to be securely mounted. I have had the Amazon-purchased UAYESOK dual-band antenna on my POV for almost four years now, with absolutely no problems. The magnetic base is strong, but is well padded to avoid damage to the vehicle. I have never knocked it off the roof despite its having hit low-hanging tree limbs on several occasions. Its installed position at the center of the roof provides the best possible ground plane, which in turn offers the most desirable radiation pattern.
Routing of the antenna cable is an area where some thought must be given. It is important to choose a cable path that will not cause chafing or cutting of the cable, while still maintaining the water-exclusion capability of the door seals through which the cable will probably need to pass. It is often possible to work the cable into the gap under the door seal, dressing it in such a manner that any drip lines formed will release their water load on the outside of the seal. Many modern vehicles have dual-lipped door seals. In such cases, place the cable so that it lies between the lips, routing it so that it follows the door frame down to a point where the cable can be brought inside the vehicle without compromising the seal’s integrity. Inside the vehicle, run the cable along and, if possible, under the carpet at the door sill, ultimately bringing it to the location of the radio.
Be sure to leave sufficient extra coaxial cable length near the radio to permit removal of the radio from its mount while still connected to the antenna. For example, it may at some point become necessary or desirable to set the radio on the seat while programming and testing it. Some radios have data ports that are very difficult to access without being able to actually see the rear panel of the radio. Some require the removal of a screw-retained cover in order to access the data port. The extra cable length can be stowed under the dashboard or under the seat, depending upon the installation location of the radio.
If it becomes necessary to drill any holes in order to accommodate the antenna coaxial cable feedline, be sure to drill the hole(s) large enough for the cable connector to pass through. Then, afterwards, be prepared to seal the hole around the cable using a rubber grommet with a membrane in its center. A grommet such as the Keystone #778 is an ideal choice for this purpose. It has an OD of 1.125” and fits a 1” hole in panels up to 0.062” thick. The center membrane has an expandable 0.25” hole at its center, and fits cables up to 0.3125” in diameter. The seal is necessary to a) prevent chafing of the cable, b) to exclude dust, dirt, and water, and c) to support the cable where it passes through the panel.
Once the antenna cable has been routed and the antenna installed, it is time to move on to the power provision. Despite the fact that some radios are shipped with so-called cigar lighter plugs for the power connection, it is NEVER advisable to use such a connection for the radio power. On most if not all vehicles, the cigar lighter power capability is far beneath that required by the radio. Usually, the wiring to the cigar lighter socket is no more than about a 20AWG wire, certainly not adequate for the eight to ten amperes (or more) required by the radio during TX operation. The general rule of thumb for 20AWG stranded wire is 3.5A continuous duty. Remember that although the radio will receive OK with low current supplied, it will not transmit properly under those conditions, with different results depending upon the radio and the current available. The radio may simply shut down, or it may attempt to transmit to the best of its ability. Such transmissions can be full of spurious signals and distorted audio.
The recommended method of connecting power to the radio is to run the heavy-gauge twin-lead wire from the radio directly to the battery. At the battery, connection is made to each of the battery posts if the vehicle does not have an alternate auxiliary power connection scheme. Many newer vehicles require that any such direct-power connections be made to a dedicated connection point designed and provided specifically for that purpose. Either way, it is necessary to fuse the wire leads as close to the source connection point as is possible. If the harness supplied by the radio manufacturer has a fuse in each lead (the positive and the negative), it is very important to maintain that methodology when making your power connections. On the other hand, if the radio manufacturer fused only the positive lead, it is acceptable to do the same when making your connections. In case it is necessary for some readers, I will mention that the standard color-coding of the power cable is red for positive and black for negative.
The reason that the two fuses are important if the manufacturer shipped the radio with two fuses is because some radios use both the positive and negative leads as incoming power lines, meaning that the black lead does not connect directly to the chassis of the radio, but is instead tied into some of the circuitry as a power supply feed. The purpose of mounting the fuses as close to the power source connection is so that the entire length of the power line(s) will be protected against short circuits, potentially from chafing in the vehicle.
Once again, wherever the power lines feed through from the engine compartment (or other battery location) into the cabin of the vehicle, the power lines must be protected from chafing and the opening must be sealed as with the antenna cable. Be sure to route the power lines in such a manner that there is no probability of burning on hot under-hood parts, no probability of pinching or chafing of the wires, and no interference with any moving parts under the hood. Also as with the antenna cable, allow for some extra wire length at the radio mounting location so that the radio can be removed from its mount while still connected to power.
If running the power lines to the battery is beyond your skill level, don’t feel bad! I was a heavy-duty truck mechanic for many years, but I had a local garage run my power feed to the battery when I first installed my radio in the POV. That shop has a lift and can easily get to the area of the firewall where the wires needed to pass into the cabin. Many independent garages and most car audio shops will run these wires for you for a small fee, and it only takes a few minutes to do the job with the correct equipment available.
Once the power is available at the radio, it is time to make that connection. For this purpose, I fully endorse the use of Anderson Powerpole® connectors. You will need four connector bodies (two red and two black), and then you will need a total of four crimp-on terminals. The crimp-on terminals used for this purpose are available in three different sizes, rated for current and related to wire gauge. The 15A, 30A, and 45A crimp-on connectors all fit into the same connector bodies. Select two pairs of crimp-on connectors appropriate for the wire sizes involved here – the two attached to the radio and the two coming from the battery. Installing the crimp-on terminals to the wires and then into the connector body is a simple task with the proper equipment, but you may want to see the process demonstrated at least once so that you know how to do the job. The W2MMD Clubhouse has the connectors, terminals, and crimp tool all available at the test and repair bench. Don’t forget to contribute to the replenishment kitty if you use Club supplies.
Anderson Powerpole® connectors are “gender-less” connectors, meaning that any body of a given size will mate with another body of that same size. This makes connecting to the radio quite simple. With an Anderson Powerpole® connector pair installed to the power wire coming from the battery and another set installed to the power leads on the radio itself, these two connector sets will simply plug into each other, observing the colors when making the connection.
With all of the connections to the radio made, all that is left is to program and test the radio. In many cases, the programming is easily handled with the CHIRP computer software package. Programming is a topic for another article, so I will not go into it in depth here. However, I will mention a few pertinent pointers about using CHIRP to program a radio :
- Be sure to update CHIRP to the most recent release so as to have the best possible list of radio definitions
- It may be necessary to use a radio definition other than the actual make and model of radio at hand, as the radio that you are programming may be a clone of a different and previously defined make and model
- Be sure to save all data files developed with CHIRP against future needs
If planning a road trip, you may want to use Repeater Book or some similar reference to identify all of the repeaters along your proposed route of travel. In that way, you can then program each of the repeaters identified, in route sequence, into an empty segment of the radio’s memory range, making it easy to move from one repeater to another as you travel down the highway. On the return trip, the sequence will still work, except that it will be used in reverse order.
I hope that this information will be useful to anyone planning such an installation. While it is not intended to be a comprehensive, cover all the bases type of explanation, it should nevertheless help to get you started with the job.