You shouldn't have to but its still good to check.A 102" whip is an antenna thats almost always perfectly matched because it is almost like a 5/8 wave antenna.
SOURCE: SWR calibration waaay off the chart
You are using an inline swr meter to set your swr right, not looking at the meter on the radio? Here is the process to set swr on an antenna:
You must have an inline swr meter, which can be purchased online or from a truck stop. The ones at truck stops are cheap ones, but will do the trick for the most part.
You connect your antenna 18ft coax to the antenna plug of the swr meter, and a jumper coax (any length) to the transmitter plug of the swr meter and then to the radio.
Close all doors and make sure no one is messing around with the vehicle or antenna. You must be set up as you would normally be transmitting.
Now set your cb radio to channel 40 and your swr meter to fwd. Key up your microphone
and at the same time turn the set knob on the swr meter until the needle is at the line that reads set. Unkey your mic and set the the swr meter to ref. Key up again and note what your reading is. Now leave the swr meter in ref and turn the cb to channel 1. Key up and take your reading. If the reading on ch 1 is higher than ch 40 you must raise the stinger on your antenna. If ch 1 is lower than 40, you lower your stinger. You are trying to get lower than a reading of 3 and as close to 1.5 as possible. If you lower your stinger as far into the antenna as it will go and you need it shorter, you cut the bottom of your stinger no more than 1/2" at a time, and recheck your swr reading after each cut.
Once you have gotten the best reading you can, connect your antenna directly back to the radio.
The setting of your swrs is to make your antenna as efficient as possible, by trying to get it as close as you can to a 50ohm impedance. THE ONLY PART OF YOUR SYSTEM THAT CAN CHANGE YOUR SWR IS YOUR ANTENNA, not your coax and not your radio. Your radio and coax can give you false readings, but only the antenna can actually change the swr.
On the swr meter, the fwd/ref switch stands for forward (power that is being transmitted out) and reflected (power that is reflected back into the radio.
Just for information sake, the swr cal switch on your radio is used to set the meter to reflect the swr that your antenna is set at. The meter on your radio is like a dummy light on your car. ONCE AGAIN, YOU CAN NOT SET YOUR SWR ON YOUR RADIO, only the antenna.
SOURCE: I installed a browning br-51 cb antenna on my cb radio.
You need to shorten the antenna,adjust the whip all the way down and see what you have and then cut off 1/4" at a time remember this low on 1 high on 40 it needs to be lengthened high on 1 low on 40 it needs to be shortened . I hope this helps and good luck.
SOURCE: I am getting high swr readings on my base station
what i would do is go and buy a real cb antenna mount like a mirror mount and get a peice of sheet metal and screw the mount to the metal and screw that to the roof or side of the house and you should buy a spring that will also help with the swr and if you by the mount you can just screw on a standard pl259 connector
SOURCE: my cobra 29 i can not set the swr on the antenna,new swr meter
then there may be prob with antenna system or radio has too low of dead key to operate the meter.
SOURCE: how to set SWR readings to my K40 Antenna without
If you have a cobra 29 then you have a meter. There is no way to Tune an antenna without a meter. You need a device that can read the reflect, or Standing Wave Ratio.That is a standing wave of RF energy that instead of leaving the antenna, is going back down the feed line to the radio and in time hurting the radio.
If you have a cobra 29 LTD, it has a build in SWR meter. It is not as accurate as an in line meter, but it will get it close enough not to hurt the radio. Here is how to do it.
Turn on the radio, with the antenna hooked up. Never key with out an antenna hooked up.
Set the switch all the way to the left(S/RF SWR CAL) to CAL. this stands for calibrate.
You will notice there is a knob right next to the channel selector knob marked SWR CAL as well. Start with the knob turned all the way to the left.
Put the radio on Channel 20. This is just about the middle of the band.
Key the radio and hold it. While holding the key on the mic, turn the SWR CAL knob up until the needle on the meter hits the mark "CAL". there is a triangle, and a gap in the line. The needle needs to be at the point of the triangle in the gap.
NOW, while still holding the mic key, flip the switch from CAL to SWR. You should see the needle immediately swing back. What ever the needle is on at this point is your SWR reading. use the set of numbers on the top of the meter, that's for SWR measurement.
If the needle does not swing back, and is in the rad, the antenna is WAY off. There are some reference points on the scale. The first gap in the line is 1.5 SWR. if the needle is there or less that is fine. then you have 2 and 3. 2 is not so great, but not extremely bad, but you should try to get it lower. 3 is really bad. Anything past 3 is considered infinity, and is really really bad.
If its high, then your antenna is either too long or too short. So how do you know which?
Here is how.
Turn to channel one and repeat the SWR process from above. Make note of the reading.
Then turn it to channel 40. Repeat the process again and take note of the reading.
Now, if the SWR is higher on channel 40 then 1, then your antenna is too long and you must shorten it. If the reading is higher on 1 then 40, then your antenna is too short, and you must lengthen it.
Make adjustments in length about an 1/8th inch at a time until you have either the same reading on 1 and 40 or real close, and or the reading on channel 20 is really low.
If you get it so that the reading on 1 and 40 are the same, then the SWR reading on 20 will most likely be almost nothing, unless there is either something wrong with the antenna, coax, or its just a crappy antenna.
K40 should be able to get a nice low SWR.
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