What is SWR and the SWR CAL for?

Thanks for avoiding by, we"re confident this short article can prove helpful! countless CB radios have a integrated meter for trial and error your antenna system. It"s very useful role to have as it deserve to make your device work well. This testing procedure revolves approximately something called "S.W.R." or Standing tide Ratio. Countless Cobra CB"s, choose the Cobra 29 LTD Classic and also the Cobra 29 LX, have both a switch, or a button, and also an SWR CAL knob. Some radios execute not have actually the SWR calibration knob and also instead will automatically calibrate your meter (not the antenna!). Study which radio has these functions first. We"ll describe in simple to recognize language what all of these features are for, and also how to correctly use them.

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Testing your antenna system

Checking, and also tuning your antennas SWR is essential for 2 reasons. First, this is the easiest way for you come tell if your antenna device (coax + mount + antenna + etc) was correctly installed. Second, if her SWR analysis is also high (higher number = reflected, wasted power) then you can damages your radio. Considering how vital both of these points are, you"ll always want to inspect the SWR reading of your antenna system. Either by making use of the integrated meter that many radios have, or by buying an outside SWR meter choose our SWRKIT. What you are doing is making certain that once you transmit, her signal is passing v your antenna mechanism like that should. If your SWR reading is also high then your transmit power isn"t leaving v your antenna properly, and component of your radio"s output power is feeding back to the radio. Remember, the closer your ratio is to 1:1 (standing wave ratio), the an ext optimised her CB device will be. Short SWR readings will administer a sturdy and better performing CB radio.

How perform I examine my SWR?

Checking SWR through radios that have actually an SWR CAL knob CAL Switch: upper and lower reversal the SRF/SWR/CAL move to CAL This changes what her radio"s meter is going come tell you. Best now, we want it to tell us where the SWR meter is calibrated.SWR CAL Knob: turn your radio to channel 20. Crucial your microphone and turn the SWR CAL knob till the needle on your radio"s meter goes come the CAL note on the height right the the meter. Unkey the mic as soon as adjusted.SWR Switch: currently you"ve calibrated your meter. The next step is to get the reading. Flip her SRF/SWR/CAL move to SWR.Get your reading: an essential your microphone. Look in ~ the bar or line significant SWR. On countless radios, this is the optimal line. You need to see the complying with numbers on the SWR heat of her meter: 1, a space for 1.5, 2, and also 3. If your SWR reading is listed below the 2 mark, your analysis is in ~ tolerance. If your SWR analysis is listed below the 1.5 notch, her antenna system is working really well. If the reading is almost or precisely a 1, then your mechanism is functioning as great as that can.

Checking SWR with radios that have integrated automatic SWR calibration (this is her radio if you have an SWR meter, but do not have an SWR CAL knob, a an extremely helpful feature). Unsure which friend have, do your own reseach to find out!SWR Switch: her radio should have actually a switch or a move that states "SWR". Revolve this on now. Start with channel 20.Get your reading: key your microphone. Look in ~ the bar or line marked SWR. On numerous radios, this is the peak line. You have to see the adhering to numbers ~ above the SWR heat of your meter: 1, a an are for 1.5, 2, and also 3. If her SWR reading is below the 2 mark, your analysis is in ~ tolerance. If your SWR reading is below the 1.5 notch, your antenna device is working really well. If the reading is nearly or exactly a 1, climate your device is working as great as the can.

How walk tuning mine SWR affect my radio?

It"s important to note, contrary to popular opinion, your SWR go not affect your squelch. Instead, tuning her antenna device to your auto directly affects the optimal performance of your CB system. When we talk around swr meter tuning, really what we average is making her antenna work on the channels (frequencies) you"re operation on. If your antenna is not tuned correctly, her radio"s optimal performance will certainly suffer and you run the danger of damaging your radio. Suitable SWR tuning is an important to the health and performance of your radio system!

What is standing Wave proportion (SWR) anyhow?

SWR is a reflection of the impedence equivalent in her antenna system. The SWR Meter really procedures impedence, which in basic terms, is the measurement how effectively your signal have the right to pass with your antenna system. If you have an impedence mismatch, some amount of your radiated signal will certainly not be able to pass through your antenna system. Instead, part of it will obtain reflected ago to your transceiver. When this ocurrs, an amount of her potential output isn"t radiated far from your antenna and instead travels earlier along her system producing standing waves.

Now what do I do with this SWR number?

The answer relies on what your meter analysis was, and also what you are doing through your CB radio. If your analysis was less than a 2, and also you mainly use her CB for casual use, then you space done. Congrats! there is nothing else you have to do. However, if her SWR reading was above a 2, or if you desire to talk on a different channel (or channels) or if you want to optimize your mechanism for the finest peak performance, store reading.

How carry out I track my antenna currently that I have my SWR reading?

The procedure can be summed up choose this. 1. Inspect your SWR reading. 2. Adjust something on her antenna. 3. Re-check her SWR to verify your adjustments. Here"s a action by step process for setup or tuning the SWR on your CB antenna:Check your SWR meter : write down the SWR reading on channels 1, 20, and also 40 based on the indict above.Adjust your antenna: If her SWR analysis is greater on channel 40 보다 it is ~ above channel 1, lower something on her antenna. If channel 1 is greater than 40, raise something on her antenna. If channels 1 and also 40 room (about) the same, and your lowest analysis is top top channel 20, climate you room done.Verify her SWR: In most cases you"re looking for the very same SWR reading on networks 1 and 40, v your shortest on 20. As lengthy as your SWR is less than a 2 on every 40 channels, you"re good.What about twin antennas?: The process is the same, just readjust both antennas at the exact same amount.

Impedence in many CB systems

Your CB radio, antenna, and also cable room all rated in ~ 50 ohms. This analysis is reflected in your SWR meter. If you"re making use of a co-phase, or twin antenna system, the coax cable is rated in ~ 75 ohms every side. Once two 75 OHM cables meet, the impedence i do not care 50, thus permitting your 2 antennas to actually act as a 50 ohm device - which is what your antenna and also radio space designed for.

Additional research study Source

Helpful web page such as Wikipedia, Firestik and the ARRL.org room all an excellent tools to use when trying to learn an ext about SWR. Discover an write-up you need, and also they can suggest you in the right direction. In radio engineering and also telecommunications, was standing wave ratio is a measure up of impedance matching of loads to the characteristics impedance the a infection line or waveguide. Impedance mismatches an outcome in standing waves along the transmission line, and SWR is defined as the proportion of the partial was standing wave"s amplitude at an antinode come the amplitude at a node follow me the line. The SWR is usually thought of in regards to the maximum and minimum AC voltages along the infection line, thus referred to as the voltage standing wave ratio or VSWR. For example, the VSWR value 1.2:1 denotes one AC voltage because of standing waves follow me the infection line getting to a optimal value 1.2 times the of the minimum AC voltage follow me that line. The SWR can as well be defined as the proportion of the best amplitude to minimum amplitude of the transmission line"s currents, electrical field strength, or the magnetic field strength. Neglecting infection line loss, this ratios space identical. The strength standing wave ratio is characterized as the square that the VSWR, however this terminology has no physics relation come actual powers involved in transmission. Wikipedia

Tuning her CB Radio

A common misconception with SWR tuning is that you room tuning her radio, or tuning your antenna to your radio. This isn"t what"s happening in ~ all, rather, you are tuning her antenna come the vehicle on i beg your pardon it"s mounted. When you"ve collection your SWR, transforming radios will certainly NOT impact your readings. You carry out not track your antenna to your CB! extr research top top radio and also antenna tuning can be discovered on wikipedia.

Real People, genuine store

If friend need useful assistance through tuning your SWR readings indigenous an antenna friend purchased from us, you re welcome call, email, or avoid by or retail location for help.

SWR Troubleshooting

I believed I tuned mine CB to my antenna?This is a common misconception. To be very helpful here: You are not tuning your CB to her antenna. Nor room you tuning her antenna to her CB. Instead, you space using your radio meter to examine your SWR reading, and also then tuning your antenna(s) to your vehicle. This is critical distinction! your antenna is tuned to the ground plane your automobile provides, and once you"ve collection the SWR (aka tuned your antenna), then it is ready for any type of radio you want to use. Allow me make that abundantly clear. As soon as you have a short SWR reading, you have the right to use any kind of CB friend want. Her antenna is NOT tuned to your radio!
My SWR reading is greater than a 2Follow the steps provided above and check your reading on networks 1, 20, and also 40. If you find an SWR analysis at or over a 2 on every channels, the may show something is installed incorrectly, or broken. You might need to replace your coax cable, mounts, and antenna(s) to resolve.
What execute I do to my antennas to change them?First, check your antenna"s package for the specific instructions because that tuning. The Firestik FS series CB Antenna, and other comparable fiberglass antennas, have actually a screw in ~ the top of the antenna. Change this increase or down based on your SWR readings. Part fiberglass antennas do not have actually a "tuneable tip", v these "cut come tune" antennas favor the Firestik KW collection CB antenna you have to remove the antenna"s cap, then reduced off the outer insulation till you can obtain to the copper wire. Reduced this wire down to track (if your reading on 40 is greater than 1) * it"s not unusual to have to remove A lot of copper cable to gain these antennas tuned. For stole whip antennas, prefer the Wilson 2000 Trucker Antenna, you may need to use bolt cutters to trim the "whip" part of the antenna. Eliminate the whip from the holder (held in with collection screws) and also either move up or down according come the readings. If her readings tell you come go down more, girlfriend will require to cut the whip with bolt cutters. (this is pretty common).
My radio"s SWR light or "ANT" irradiate is comes on?This way your SWR analysis is too high and you can damage your radio by talking. Either attempt to track your SWR making use of the procedures above, or start replacing her antenna system parts until it"s resolved. If you"re near Iowa, come visit us and a beneficial technician can test your antenna system and also find the end what"s in reality going on.
Where are my SWIRLS at!?

After act this heat of work-related for end 20 years, I have the right to tell girlfriend I"ve heard every surname / butchered expression for the ax "SWR". Most likely you"ve heard world call that SRW - getting the W and also R backwards. I"ve likewise heard SWIRLS, traditional wave, and S-doubleyahs, to name a few. While civilization are make the efforts to it is in helpful, if girlfriend encounter this strange sayings and also don"t recognize what that means, you"re no alone. Similar to any component of the English language, when world use it, it changes. Simply know the correct acronym is either SWR or VSWR, and also squelch the end the nonsense! do your very own research and you"ll see similar results.

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Final keep in mind on radio tuning

One last point to remember is to be clear once talking around tuning, and what you"re after. Tuning a CB radio usually way a technician peforming a change inside the radio to optimize performance. Tuning an antenna is completely different, and also as discussed above, and also is no tuning her radio at all. Her antenna system and radio run as two components of a totality system, and tuning is done independantly of each other.