How To Lower Swr On Antenna

The MFJ-945D will reduce the SWR of most antenna systems to 1:1. Set the radio to minimum power and to FM or CW mode. Now back to the process of radio transmission. If the SWR is higher on channel 40 than channel 1: This indicates that the antenna is too long. The G5RV work in certain bands in harmonics, so you cannot expect very low SWR readings. You can consult meters which can tell you all about the antenna, but it may be too much information. The SWR plot for an 80 meter broadband dipole is shown below. In some cases, a perfect 1:1 SWR may not be obtainable. In a perfect world, this is the best way. Measure SWR of first channel (No. Swr problems and solutions ( example #1 ). • An antenna operated at its resonant frequency doesn’t need a coupler. The SWR, or Standing Wave Ratio, is a measure of how well the impedance of the transmitter (or receiver) matches the impedance of the antenna system. The net gain of antenna is 8. Wideband SWR meter Everyone involved with radio transmitters needs some instruments to assess basic antenna functionality. Key the radio and adjust the SWR meter for a full scale reading. It is a ratio of maximum voltage or current to minimum voltage or current. SWR is the ratio of the impedance of your coax to the impedance of the antenna. **If the SWR reading is higher on Channel 1 than Channel 40, the antenna needs to be tuned. 3 dBi, STILL VERY GOOD *CALCULATION OF MISMATCH ATTENUATION: Formulae. Hence, antenna impedance is a simple concept. In any case, the forward voltage drop becomes lower as the current decreases. 5:1 (14dB return loss). The SWR Antenna Analyzer MFJ-259C is a unique antenna analyzer that evaluates an antenna's performance almost instantly. Why do we need to tune the Classic Hexbeam ? We saw from the Classic Hexbeam - In depth page that the antenna is relatively narrow-band; for example our 20m benchmark antenna delivers >10dB F/B performance over a bandwidth of about 200KHz - that's 1. Testing on GMRS repeater frequencies. 0' of coax is 0. When you put your amp in line and check the SWR with it on high it should read slightly higher , no more then 1. Precision DDS signal generator (AD9851) used as signal source. Swr problems and solutions ( example #1 ). The higher frequency is more a function of the feedpoint gap between the disc and the cone. I assume this is acceptable for the time being with the antenna. If channel 1 is higher than 40, raise something on your antenna. As the real part of that impedance (38 ohms) is close to 50 ohms, a series inductance could be used to simply cancel out the capacitive reactance and still give a reasonable SWR. With a broadband antenna, there's really not much point making such adjustments. As it is, on CB alone, there are 40 channels to contend with. A lower SWR means that the antenna is better impedance matched to the receiver, and so less of the received signal will be reflected and wasted. The team in this video discusses how to design, build, and use an improved variant of Varney's original antenna known as the ZS6BKW. Which means the antenna needs to be the correct length for it to work properly. The lower SWR the better, ideally it should be around 0 to 1. You can put your hand around the antenna and the reading may increase slightly, and if you put the antenna in something like a metal box or foil paper it may even go up to something like 16 or higher. Since the SWR is a function of the antenna system, changing radios will not affect the SWR. The effect of the ATU is to reduce the VSWR as seen by the transmitter. One at 144 MHz, one at 146 MHz and one at 148 MHz. 2 ghz design. With different local site conditions, your SWR and resonant frequency may vary, which is normal. Setting your antennas SWR will reduce the restriction of radiated power. Basics of SWR. A good quality antenna and proper installation (location very important) should easily result in an SWR of less than 1. As real old timers will tell you forget resonance forget SWR you need to tune for maximum antenna current. 0:1* Most transceivers start to reduce power at this SWR level Using an swr reading of 1. This not a problem on hf, a minor problem on 2 meters , very noticeable on 440 mhz and can destroy a 1. How To Modify A Military Antenna Base For CB Use (pics) I have recently been working on modifying military antenna bases for CB and had a friend asking how and asking me to "show" it here. Now, you are reading SWR. Meters like the Daiwa CN-801S are expensive and need a minimum of 500mW (27dBm). This is why the very best tiny antennas will all be motor driven. Pet (N6PET) found a high SWR on his Comet SBB 15 6M triband mobile antenna. Oh and don't get super hung up with low SWR. 0, is this ok to use? Or should I scrap my antenna I worked so hard on. If you tune the antenna badly, it can turn your CB radio into a useless brick. RigExpert AA-600, AA-1000 and AA-1400 are powerful antenna analyzers designed for testing, checking, tuning or repairing antennas and antenna feedlines. 3 dBi, STILL VERY GOOD *CALCULATION OF MISMATCH ATTENUATION: Formulae. If you really want to spend some money, consider purchasing an antenna analyzer that covers the 2m band. so i was thinking to at this on the forum The specific dual ring "Adjust-A-Match" makes alignment for optimum SWR very easy. The DC port in mini60 shared with bluetooth antennna. First, it measures the SWR of the line by using a tandem match coupler. 000 MHz the SWR is over 3(the red zone) and on 144. Reduce SWR, RFI, and pattern distortion with our leading-brand baluns, ununs, and chokes! Whether you have a balanced antenna/unbalanced coax setup or you're matching an unbalanced antenna to unbalanced feedline, our baluns and ununs will help you operate at maximum efficiency with minimal noise. It is always best to reduce SWR well below 2:1 7. My name is Michael, KB9VBR, and I carry a full line of VHF and UHF antennas for sale. A deep dip in SWR occurs near 10. Warning When attaching cables with staples or thumbtacks, be careful to only attach through the insulation and not have the metal touch any bare wire. antenna with negligible amount being reflected back. Raise or lower whip so both SWR's are equal. – No, resonance only means the feed point is resistive and does not mean a low SWR. If the SWR is better at the lower edge of the band than the top end this means it is too long. It is uncommon to see values lower/better than about 1. Use SWR meter to adjust all-thread and position of bracket on conduit for lowest SWR at 146. To initiate antenna tuning, press and hold the TUNER/CALL button on the radio for one second. It is always best to reduce SWR well below 2:1 7. Measuring SWR. Inexpensive and Simple Mono- or Multi-Band HF Ham Radio Antennas, by PrepperDoc Hugh James Latimer July 7, 2015 May 30, 2019 One of the distinguishing features of traditional Ham radio, particularly shortwave (high frequency or "HF") Ham radio, was that you generally had to literally make your own antenna. " Therefore SWR is concerned with matching the antenna to the signal being transmitted through it. 4 to 1, you have a problem. The OCFD ( Off Center Fed Dipole ) decent SWR on all bands, decent performance on lower bands, lots of little lobes on higher bands, the guy directly south of you might be "S9" while the guy 10 degrees west of him might be "S2". Data signals may “just” be voltage levels corresponding to 0 and 1, but it takes very high frequency components to make the sharp edges and narrow pulses our designs require. You have multiple styles to choose from (beam, omni-directional, wire) and materials (fiberglass, aluminum) as well as mounting possibilities (mast, tower, tripod, roof). Install 6-inch all-thread and hand-tighten nuts. The end fed antenna is essentially half a dipole, it uses a good earth connection to complete the arraignment. On the other hand, by switching to REFlected, an antenna can be tuned by simply finding the minimum reading. Back to Basics: Impedance Matching (Part 1) Lou and the standing wave ratio (SWR). SWR stands for Standing wave ratio, which indicates how much energy outputted by the transmitter is actually delivered to the load (antenna). 219 foot jumper from the radio to the SWR meter, and a 71. SWR TESTING OF MOBILE TRANSMIT ANTENNAS. A Hawaii-based Amateur Radio Antenna Blog focusing on the theory, design, and use of homemade antennas. BUILD A 2 METER YAGI AND 6 METER. If your swr is lowest at the lower end of the band, that's an indication that your antenna is too long. A simple 1/4 wave ground plane with copper wire and a SO239 connecter. When we first installed the antenna the best SWR we could achieve was about 4:1--and that required the use of the grounding wire (impedance transformer) on the Silver Load. So the SWR is a measurement of how much signal is going out the antenna, versus how much signal is reflected back into the transceiver. Follow along as we take a quick look at an off-road driver's guide to CB radios as we teach you all the things you need to know about choosing and setting up the best CB radio for your 4x4. So I chatted with one of the members of the group that I talk with on 40 meters at nightly and he had encountered the very same problem with his antenna. What can be done to reduce RF in the shack (riding back along the coax) when using a vertical 10M antenna (without radials due to space constraints)? The antenna is an IMax-2000 at 32' elevation (20' over roof) with a 125' coax LMR-400, SWR is under 1. This antenna turned out about as well as I had hoped it would. Make smaller adjustments on shorter antennas. • Resonant antennas radiate better than non-resonant antennas. This will place the radio in “Tune” mode. When you put your amp in line and check the SWR with it on high it should read slightly higher , no more then 1. Swr problems and solutions ( example #1 ). 3; the same amount removed from a 2 foot antenna may move the SWR by 1. The readings you get from the SWR meter will tell you what needs to be adjusted. In January 1977 there appeared in RADCOM an article by G6XN extolling the virtues of the Smith Chart. You can adjust the physical length of the antenna by sliding the tubing that goes into the bottom section up or down. Adjust your antenna: If your SWR reading is higher on channel 40 than it is on channel 1, lower something on your antenna. Now, you are reading SWR. antenna's superior pertormance & low SWR compared to industry leading competitors. You can probably live with the problem, but you need to know the antenna is not as good as it can be. I needed to take about 2 feet off the horizontal section to get mine resonant at 1830. I bought a Cobra 25 LTD Classic CB Radio and a Little Wil Wilson Antenna. How to check swr with a swr meter, mobile Antenna or homebase. AW07A HF/VHF/UHF Antenna Analyzer Instruction Manual. Follow along as we take a quick look at an off-road driver's guide to CB radios as we teach you all the things you need to know about choosing and setting up the best CB radio for your 4x4. But the antenna behaves like it should, front to back ok on both bands, better than 25 dB, also when it was longer and at low altitude. The antenna lead from the tuner "longwire" terminal to the antenna should parallel and be reasonably close to the outside ground lead, if possible. After some time the SWR back to normal. 5 across 10M band. Use an antenna analyzer if you have one; if not, then apply a low amount of power (5 to 10w). Always measure the antenna VSWR at the antenna feedpoint. If it is too long don’t cut it – just fold the ends back on themselves and either twist the wires. A low SWR indicates little power reflection and efficient power transfer to the antenna, while higher SWR values indicate greater reflection and less efficient power transfer. If all radios only transmitted on one channel, it would be a much easier task to design antennas. At full scale deflection on this meter the forward drop across a BAT 81 is about. The Spiderbeam is broadbanded so it won't really matter much if you move the SWR up or down the band, unless you have a transceiver that begins folding back power even at low SWR levels. The SWR is 72 / 50 = 1. The Antron 99 EXPOSED! (By Tech 833) Have you ever wondered what was inside the Antron 99 antenna? A long time ago, I purchased a Solarcon Antron 99 antenna for my propagation beacon. Conclusions. Portability was a game changer, since antennas are usually adjusted to minimize the SWR and it's simply faster and easier when you can bring an SWR meter. Ham Radio and Amateur Radio online equipment sales. The net gain of antenna is 10. Antennas that have an easy, often mechanical, tuning device are referred to as a “tunable antenna”. Adjusting the SWR on this antenna can be accomplished in two ways. FIBERGLASS WHIPS. Power handling 20 W. Here's a simple way to lower the SWR and increase the performance of any HF/VHF/UHF vertical antenna. Automated antenna SWR analyzer. If the SWR remains unacceptably high (greater than 2:1) at the lowest point, it means the antenna is resonant in the band of interest but the impedance of the antenna is not near 50 Ohms. 6 mile distance fl I notice that you use only one output of the wifi extender to boost up. SWR stands for "standing wave ratio". any help is appreciated. According to my research, if your SWR reading on Channel 40 is higher than t. The lower the SWR,the better the match, so you tune an antenna but varying (mechanically or electrically) it's length relative to the desired frequency. Instead of feeding the antenna in the middle, we can lower the antenna onto the ground near the feepoint by connecting the earth (braid of the coax) to the ground (or the sea, for instance) and the centre conductor to the vertical bit of the antenna that goes straight up. Anyway it´s performance is pretty good for its price, size and simple setup. In that case, the SWR is probably too high for your transmitter. It does no real good IMO to have on-ground radials longer than the vertical. Adjust your antenna: If your SWR reading is higher on channel 40 than it is on channel 1, lower something on your antenna. Both antennas are similar in that they use a J style matching system consisting of a 1/4 wave stub, but the difference between the two is that the Slim Jim is a half wave folded dipole antenna. Wavelength: The wavelength is the distance between repeating units of a wave pattern. Conclusion #4 : Always use an antenna tuner when operating. Workman SWR Meter for CB Radio Antennas SWR2T. And found that all this did was make the SWR even lower around 1. Now switch to channel 20 and make your adjustments to either lengthen or shorten the stinger. Ideally a good antenna will transmit all of the power with nothing coming back. In the beginning I entered 30 m as a value into the above "Wires" table, without having calculated the actual length with the known formula. Next move the capacitor adjustment first one direction, then the other direction until a minimum SWR reading is obtained. As I wanted to reduce the SWR value in the lower bands I now tried to connect a radial roughly in the 40 m band area, hoping that it may effect the curve. Use it to get the lowest SWR you can. 5 across 10M band. To alleviate this, keep at least the top 12 inches of the antenna above the roof line, and position the antenna as high as possible on the vehicle. Tuning can be done somewhat independently on each of the bands. 0 will damage the transmitter. Then, based on your SWR readings, length or shorten BOTH antennas the same amount each time. After looking over this site I’ve seen a lot of posts asking about using military bases for CB radios and 10 meter export radios. The red dots represent the measured values of the SWR with the antenna mounted in the attic. A conventional coax-fed, half-wave dipole doesn't provide a low SWR over the entire 80-meter band - an inconvenience for those of us who like to operate phone and CW on that band. 2:1 is brilliant. Low Cost KC 901H/E/S Antenna Analyzer (1hz ~ 3ghz) A low cost VNA for FPV antenna builders? Some time ago, I reviewed on YouTube, the "Red Dot" ebay digital SWR meter for 2. Although there two things to consider with SWR. Sold by CRS Communications and ships from Amazon Fulfillment. Reprinted from Echelford Amateur Radio Society Newsletter for November 1978. 15 volts and less at the lowest readings. Loading Unsubscribe from jlmoo1 #456? Laird 450-470MHz 5/8 over 5/8 wave no ground plane antenna. If your swr is lowest at the lower end of the band, that's an indication that your antenna is too long. The reflector is designed to be "square". 000 MHz the SWR is over 3(the red zone) and on 144. Start your antenna trimming with the top dipole attach your coax to. When adjusting the antenna tip, you should move it a very small amount, about 1/8", and then check the SWR again. Many excellent examples are highlighted in Chapter 9 of the 21st Edition of the ARRL Antenna Book[1]. Connect the antenna cable plug to the standard receptacle on the rear panel. As the real part of that impedance (38 ohms) is close to 50 ohms, a series inductance could be used to simply cancel out the capacitive reactance and still give a reasonable SWR. Tighten mast set screw and again read SWR. Replace the cap and test the SWR. You can probably dial it in a little more, at least, by trimming equal lengths from each side. Its center load design features a 3. Mobile antennas with the lowest unmatched SWR perform best 11. Basics of SWR. Don’t get overly obsessed with SWR if your antenna is fairly well matched. To do this, simply remove the tip of the Antenna and cut off 1/4" at a time until the reading is acceptable. You can also adjust the SWR somewhat by changing the dangle-angle of the coax. 0:1* Most transceivers start to reduce power at this SWR level Using an swr reading of 1. The real part of the antenna impedance represents power that is either radiated away or absorbed within the antenna. Key the radio and adjust the SWR meter for a full scale reading. If the whip is fully lowered into mast and the SWR is still high, remove the whip from mast. Dave - Your comments were received and thought about; "However, isn't the opposite true with respect to SWR? Most SWR curves are steeper on the low end, so that an antenna that is adjusted for CW has a lower SWR at the top of the band than the SWR would be at the bottom of the band for an antenna that is adjusted for Phone. 5:1 right where I use it most on 80 meters (after some trimming). One experiment will be my brothers 10 wheeler. In some cases, a perfect 1:1 SWR may not be obtainable. 89 feet can be used with the the multiband antenna. Solarcon GPK-1 Ground Plane Kit For A-99 Antenna (1290) Solarcon GPK-1 Ground Plane Kit For A-99 Antenna The Solarcon GPK1 ground plane kit used with the Antron 99 (A-99) base cb antenna is intended to lower the angle of radiation for a slight increase in range. Adjusting the SWR on this antenna can be accomplished in two ways. A perfect antenna would have an SWR reading of 1:1 - meaning that all the power transmitted up the. When the impedance (effective resistance at a given frequency) of each are the same it results in the most efficient transfer of power from the transmitter to the antenna. This results in a 27:9 = 3:1 voltage ratio. During testing, using an ALD ATU, the antenna tuned in to 40m, 20m, 17m, 15m,12M and 10m!. Consider this; An unmatched HF mobile antenna, of reasonable quality, will have a measured input impedance of ≈25 ohms at resonance, and will therefore exhibit a 2:1 SWR. As it is, on CB alone, there are 40 channels to contend with. The Workman HP201S is an excellent SWR meter which takes up little space (just 6 inches). The great thing about J-Pole antennas is their simple design and excellent performance. No such luck on 20m; 7:1 was the lowest I could obtain and there was no time to fiddle with reducing the length of the wire. 2kΩ) so a 1:1 SWR was obtained on my chosen frequency of 21. Antennas for all radios need to have the SWR set, STANDING WAVE RATIO. A standing wave ratio of 1. 6 :1 in the example above, our percentage of reflected power would be 5 % with 95 % of transmitter power usable or 95 watts to the antenna assuming no other loses in your feed line or antenna. However, always trim your antenna for the lowest SWR first! A SWR higher than 2, directly connected to most radios will cause the radios protective circuit to reduce power. Antenna Analyzer Notes 2 CTU, Dayton, 2011 transmitter, were common inside stations for decades, the main feature of the antenna analyzer was the ability to take it outside to the antenna. Dipoles need to be half a wavelength long, locating these long antennas can be an issue, especially when we are aiming for the 80 metre band or lower. As I wanted to reduce the SWR value in the lower bands I now tried to connect a radial roughly in the 40 m band area, hoping that it may effect the curve. Tuning the Band. Automatic scanning results displayed as frequencies of lowest SWR and complex impedance. If the reflection coefficient is given by , then the VSWR is defined by the following formula:. What can be done to reduce RF in the shack (riding back along the coax) when using a vertical 10M antenna (without radials due to space constraints)? The antenna is an IMax-2000 at 32' elevation (20' over roof) with a 125' coax LMR-400, SWR is under 1. To alleviate this, keep at least the top 12 inches of the antenna above the roof line, and position the antenna as high as possible on the vehicle. 2kΩ) so a 1:1 SWR was obtained on my chosen frequency of 21. If channel 1 is higher than 40, raise something on your antenna. It was back before the internet so you had to wait for the license to come in the mail to find out what your call sign was and get on the air. From 102 Inch Whip. There is no relationship between SWR and receive performance. Repeat until lowest SWR is obtained. 5 of all the radio channels. Here, see the article How to install CB Radio Antenna. If you can find a friend with an antenna analyzer, check where the resonant frequency (and hopefully, the lowest SWR) occurs. The SWR at the transmitter can be improved by changing the length of the transmission line 10. It is uncommon to see values lower/better than about 1. The traditional measure of antenna bandwidth in terms of impedance is the standing wave ratio or SWR in the feed line. What is SWR ? SWR (Standing Wave Ratio) is a measure of the antenna efficiency. I think something in the range 300-500 mm is more likely to be acceptable SWR < 2:1. The boom adds negative reactance to the elements. High VSWR Lockout. Additional Info on Feedline Length with Multi-band Dipoles: Feedline length is critical to antenna tuning and performance. If SWR on channel 40 comes out to be higher than that of circuit 1, your CB antenna is too long. Inexpensive and Simple Mono- or Multi-Band HF Ham Radio Antennas, by PrepperDoc Hugh James Latimer July 7, 2015 May 30, 2019 One of the distinguishing features of traditional Ham radio, particularly shortwave (high frequency or "HF") Ham radio, was that you generally had to literally make your own antenna. Amplifiers do not like high SWR’s. The team in this video discusses how to design, build, and use an improved variant of Varney's original antenna known as the ZS6BKW. It is often used in association with meters used to detect the standing wave ratio. 3 MHz to 50. Tighten mast set screw and again read SWR. The effect of the ATU is to reduce the VSWR as seen by the transmitter. Automated antenna SWR analyzer. This is more than good enough to test an antenna. I don't use leaf antennas on drones anymore as sleeve antenna works amazing (if well tuned), is much harder to damage it and weights less. SWR (standing wave ratio) is a term every CB'er should know. W1TR 80 Meter Vertical Loop. transform the impedance at the antenna feed output at the radio to a value that your transceiver can handle, (typically 50 Ohms). The Spiderbeam is broadbanded so it won't really matter much if you move the SWR up or down the band, unless you have a transceiver that begins folding back power even at low SWR levels. I always felt end-fed antennas had low angle radiation, but at lower heights (3 ft off my roof for part of it), it would have a lot of high angle radiation. Since the SWR is a function of the antenna system, changing radios will not affect the SWR. CAL Control: adjust to the ANTENNA TUNER CAL line CAL FWD POWER CAL 20W REF Figure 3-3. In some cases, a 1:1 SWR is not achievable. 2:1 or 1:1 even. 6 dBi at 15 deg. You could also use an inexpensive HF SWR meter to make this measurement. After minimum SWR is achieved, transmitter power may be increased up to 300 Watts. Here is how to check the swr. To alleviate this, keep at least the top 12 inches of the antenna above the roof line, and position the antenna as high as possible on the vehicle. Remove the cap and a small amount of the heat shrink to expose the last few turns of the wire. There is one condition for this simplification to be true: the received RF noise floor must be above your receiver's noise floor. With it lower, as shown above, the SWR was around 2. 0 resistance circle in the inductive susceptance (lower half of the chart) region of the chart. The level adjust slider must be on the left. If you tune the antenna badly, it can turn your CB radio into a useless brick. When the impedance (effective resistance at a given frequency) of each are the same it results in the most efficient transfer of power from the transmitter to the antenna. Trimming the length of your coax will trick your SWR meter and you in to believing your SWR is lower. Generally, you should strive for a low SWR in your antenna system. 5:1 is better, 1. After looking over this site I’ve seen a lot of posts asking about using military bases for CB radios and 10 meter export radios. Consider a half-wave dipole designed to work with signals 1 m wavelength, meaning the antenna would be approximately 50 cm across. Any transmission line with high SWR produces unwanted radiation 8. A nonresonant antenna will work--even with sky-high SWR--if the feed-line loss is low enough. The first step is to install an SWR meter in line with your antenna, and take a couple of readings for a starting point (follow the manufacture's instructions on calibrating the unit first). SWR stands for Standing Wave Ratio. antenna's superior pertormance & low SWR compared to industry leading competitors. EFLW tunes most bands but is 15% less efficient. This is where the field strength meter comes in handy. The DC port in mini60 shared with bluetooth antennna. How to lower my SWR on my Mobile CB? Alright, so i just bought a Cobra LTD 25 classic, a new 102'' steel antenna and a ball mount. 85 Only 5 left in stock - order soon. If the SWR is higher on ch 40 slide the whip down, If the SWR is higher on ch 1 raise the whip. My 8214 cable should certainly offer low loss. Use an antenna analyzer if you have one; if not, then apply a low amount of power (5 to 10w). What is SWR ? SWR (Standing Wave Ratio) is a measure of the antenna efficiency. For a more fitted and stable antenna, buy antenna mounts from a local electronics outlet or they are available online. Poor SWR is not caused by the radio. First you need a SWR meter for the freq of the dipole you are working with. Use the antenna tuner to make SWR less than 1. Remember, we cut the antenna to 16. The lower the number, the lower the impedance. Please read the SWR section in this web site. The antenna could be scaled for other bands. I like to use a sheet of PC-. Meaning you will use a piece of square material to shape the curve. Knowing only the swr does not really tell you a lot about the antenna. Given time, many approaches in the Antenna Book would be well worth a try. If your SWR is above 2. An SWR of lower than 2:1 is barely acceptable, 1. ZS6BKW antenna is derived by the popular G5RV dipole antenna, but offer more bands a lower SWR on most bands and radiation angle making suitable for DX About The DXZone The DXZone is the largest human created and maintained library of web sites dedicated to Amateur Radio, currently lists 20. the single wire feeder should be kept away from the operator and RF sensitive equipment. Having conceded that the SWR may not be ideal the aim was simple to get to as lower value as was possible given the installation constraints and use an ATU to correct any less than ideal SWR figure in so far as the transceiver was concerned. the SWR is not 1:1 because of the reactance. 5 across 10M band. 1 dB (see calculations below). After some time the SWR back to normal. A typical quarter wave antenna should actually show an SWR of around 1. RG59 (Beldon 8241) is a good choice. It could be that the antenna is designed in free space, and you had to mount the elements to a boom to make it. This will be shown by the SWR increasing as you move up in frequency across the band. Because I was tuning/trimming the antenna with the MFJ 259 at only 6ft above the ground I had to take the risk of setting each of the elements to tune a little lower than the freq I wanted to operate on, the theory being that once raised the SWR would rise slightly from the tuning at ground level. 5 meters below it. The lower the number, the better the antenna is. If it is too long don’t cut it – just fold the ends back on themselves and either twist the wires. 24 ft x12 = 2. The real part of the antenna impedance represents power that is either radiated away or absorbed within the antenna. Thus, my measured lower SWR frequency sometimes extended below the lower band edge. It can be fed with ladder line from the center insulator to tuner or it can use an impedance. 8:1 just under 2:1. A poor performing antenna reduces range and damage the transceiver. You could also use an inexpensive HF SWR meter to make this measurement. SWR should not be the only meaning given to how an antenna “works”. So if you're running an antenna/transmission line which is 1:1 perfect, then theoretically 100% power goes out the wire (in practice some is lost and dissipated by the PA because in this house we obey the laws of thermodynamics). VSWR stands for Voltage Standing Wave Ratio, and is also referred to as Standing Wave Ratio (SWR). Replace the cap and test the SWR. If this is true shorten both ends of the antenna in stages until the lowest SWR point is at the center frequency of the band or the frequency you will use it at the most. Procedure: The SWR meter needs to be placed in line between the antenna and the CB. matching box, HOW TO REDUCE THE POWER REFLECTED IN A HIGH AMP POWER, rf reflected power high. As it is, on CB alone, there are 40 channels to contend with. The lower the number, the lower the impedance. off too much of the antenna, you might need to replace the antenna's top section to receive some lower frequency.