Measure out 8 separate pieces that are 17 inches (43 cm) long and mark the lengths with a marker. Cut the overall length of the wire to 125 feet or more to include the extra length for tuning. I also had to buy some coaxial cable so I bought two lengths of 50 foot cable and a splicing connector so I could splice them together if I needed to. Align the bottom of the antenna with the bottom of the cutting diagram. Must be 52 mm from the thread to the tip, so add some more for wrapping it around the thread This is how mine is updated. Still, many old-time technicians will tell you that when it comes to designing the length of an antenna, the best procedure is to perform all calculations and try out the antenna. 5:1 with a 50 ohm impedance. Hello, i have several questions regarding the antenna whitch is supplied with the DVB-T Dongle and the optimization of it: 1. 4 435 MHz 14 1/2 36. 2 cm), thick wall PVC sewer, or water pipe, and a way to cut it in either 1⁄4 or 1⁄2 inch (0. The idea is to run the antenna as high as possible around the perimeter of a house lot or just the backyard. Half waves have a specific length, depending on frequency. The measurements below are for building a simple Dipole Antenna. HD TV Antenna O. Welcome to the home of the #1 rated Indoor HDTV Antenna! Mohu Basic 50 Indoor HDTV Antenna (with Risk-Free TV guarantee) 2 Review(s) Add Your Review. 254mm above the ground plane. How to Determine Coaxial Cable Length Correctly for Your Antenna? Why dipole antennas. The Effective Radiated Power (ERP) of an antenna is the multiplication of the input power fed to the antenna and its power gain. For base antennas refer to the length chart that comes with the antenna. Then I put replacement 2. 2 Meter 5 Element Quad. 999 MHz), you must consider the-- Type of antenna. The dipole gives much better performance than you may expect from such a simple antenna. Example : For a 160 meter loop, 1005 divided by 1. LENGTH- To find out how long the antenna should be all you have to do is fill in a simple formula: 468 divided by FREQUENCY IN MHZ = LENGTH IN FEET. The next longest length of ladder-line that would be good for 40m would be 98 feet. Cutting Larsen NMO 40. Due to the fact that one turn equals 5696/8=712mm the diameter must be 712/π=226mm aprox. The 1" pipe needs to be cut to 86" A pipe cutter or hacksaw will work fine. antenna dimension chart note: all measurements on the chart is per leg click on the photo for a lager image an antenna that works read the eham reviews. Start by cutting off a 50mm length of copper pipe, and cut some slots in one end, making the length of the slots as close as possible to 30. Some radio signals are very strong and will not require much of an antenna, but a larger antenna may be required to pick up weak radio signals. The full size cutting template is used to cut the length of the whip for a particular frequency. The 39" and 19. unless of course there's only one possible matching condition that can exist between the line and the load. Antenna design calculators is a curation of 82 resources about , Magnetic Loop Excel sheet, Parallel Square Conductor Transmission Line Calculator, Analysis Of Antenna Mast Strength and Bending Stress, Full Wave Loop Antenna Calculator, Vertical Antenna Calculator. extend the length of the non-radiating edge into the interiors of the patch without increasing the overall antenna dimension. Coaxial myth one: The coax feed line must be a specific length. MOBILE ANTENNA SUPERIOR MOBILE ANTENNA Frequency 136-960 MHz With Cutting Chart 17-7 PH Stainless Steel Whip NMO Connection, Length: 21. The simplest multiband antenna is a random length of #12 or #14 wire. 4Ghz antenna pigtail on it without cutting, about 33mm length (not measured perfectly) the failsafe triggered at 310meters range. ; may be installed as a dipole, inverted-vee, or full sloper. Their antenna pattern non-compliance is masked by the specific elevation and azimuth antenna pattern cut directions. Depending on the size of your vessel, you can have a shorter one for portability or a longer one for better communication. I have the exact same antenna as pictured but mine is 122mm in lengYesth and so cutting it at 67mm isn't 1/4 length. For this, you will need either 4 or 6 inch (10. Tried a vise-grip with its close-in pinchers, and also tried a heavy duty pair of wire cutters, but no go. Dipole Antenna Length. Channel 7 wavelength should be about 66. " there isn't one. You'll need about 435 feet of wire for this antenna plus appropriate length of coaxial cable. Inches (w/o spring) Cm 406 MHz. Your question is incomplete. Wanted: antenna cutting chart for ASP mobile antenna's. 3 on channel 40, your antenna is too short. If you need assistance ordering the correct. Four wire clothes hangers became the radials. 5:1 was selected as an acceptable match, and corresponds with 96% of the incident power doing useful work. And so can mobile antennas be brought back to this principle. (should be 425-490) 8. I got a length of 2", schedule 80, black pipe (comes 21'), and cut off four 2. So simply cutting the antenna mast - and therefore the antenna wire - to a length that suits your eye or so it won't bang on your garage door will. The Effective Radiated Power (ERP) of an antenna is the multiplication of the input power fed to the antenna and its power gain. Measure and cut the remaining rods into get two 550mm lengths. If coiling the antenna wire is required do not create sharp bends in the wire, a coil should make a smooth. I tried that antenna (have it sitting in my garage), the problem is the threads are not the same. If the antenna is a quarter wave monopole antenna, then its length should be a quarter of the signal wavelength. 005 Siemens/ meter and relative permittivity = 13). The 1 1/2" pipe will be cut to 68". The antenna is easy to set up since it. Initially, I wanted to make the QFH antenna and the construction seemed to be a little complicated so I opted to build the DCA, also known as the Double Cross Antenna. I noticed not very big, but noticeable improvement in performance. I cut the trace on the PCB antenna leaving about 5mm and attaching about a 4mm length of the bare wire to it. Coupling between nearby antennas is a measure of the power delivered or received by one when the other transmits a given. It allows you to test the resonant frequency of the antenna for lowest SWR and zero reactance, and adjust the length to the exact frequency you want, in just one step, rather than a lengthy process of cut and try. 16 feet by 2 gives 61. It is supported by posts or ropes from trees. A minimum length for an efficient antenna is a half wavelength. 999 MHz), you must consider the-- Type of antenna. Different manufacturers may use different wires of different lengths. Take the quotient from the last problem and multiply it by 12, the product is the length of element in inches. When I raised the antenna and used a Rig Expert to tune the length I found the 40 m measurement was good for a less than 2:1 SWR across the phone portion of the band. 300 MHz it will match at 435 MHz which is outside the 70cm repeater band. Efficiency drops rapidly with antennas shorter than 0. Assembly instructions: Measure out the exact wire lengths you will need and cut the wire. The problem is that there are several factors that affect the antenna. I used to cut to length according to a chart depending on the given frequency for different two way radios I've owned over the years. For example, Firestik and Firestik II antennas between 2 foot and 5 foot have a radiation pattern similar to a 5/8 wave reference antenna. Wideband design of E-shape microstrip antenna is discussed, which yields bandwidth of 213 MHz (19. The chart provides an approximate cutting length for the antenna when mounted with the antenna base supplied. For a single resonant element, such as the common half-wavelength dipole antenna, @FaisalKhan's an. You're absolutely right about the length being excessively long =] More concerning than the convenience of such a thing, though, I'd be concerned about the relatively high resistivity of nitinol wire; at the length that a HT antenna is the resistivity is acceptable, but when you make it that long I'd be concerned that it may be too high. The length of the antenna would start after the shielded portion of the RG-58 ends. A Broadband 80/160 Meter Dipole An easy to build single wire antenna for 160 and 80 meters with a better than 2 to 1 swr across the 80 meter band. This calculator is also simple enough. line width and length for the aperture. customary length to diameter (I/D) ratio of wire antennas for the HF bands that varies from a few thousands to 20,000 or more. You will need 8 half wave lengths (9. Personally I would just sew the flag around the ant. 125 meters (or 125mm. A big screw is placed in the tree, and a 16 cm length of gray PVC pipe was used as an insulator. All I could do in that case was to design the antenna longer as you suggested and watched an RSSI reading at the other end as I tuned the antenna by moving my finger along the length of the antenna until I got a good strong reading. height above ground, proximity to large, especially metalic, objects, and proximity to other resonnant antennas. A Broadband 80/160 Meter Dipole An easy to build single wire antenna for 160 and 80 meters with a better than 2 to 1 swr across the 80 meter band. The large hole is where the rubber-duckie antenna goes. The simplest wire antenna for ham radio is a dipole, which is a piece of wire cut in the middle and attached to a feed line. Reference Diagram of a Small Loop Antenna. Measure twice, cut once. If your ground plane is good, your mount grounded and, your antenna favorably located, coax length rarely becomes an issue. Don’t worry too much about the total length of the antenna. single antenna, the picture is a bit different. I tried that antenna (have it sitting in my garage), the problem is the threads are not the same. A, OTA, Over the Air Antenna Reference chart for OTA over the air accessories no monthly bill cut the cord free HDTV. The antenna should be cut to 1/4 of wavelength, and NOT 1/4 of antenna's. The spreadsheet does its calculations in inches, but the user will find the conversion to feet and inches more practical when cutting wire to length. By finding the best antenna for your needs, you can access live major-network broadcasts and watch local TV, local news. Calculate the length of the antenna. One of the easiest antennas to build is a traditional half-wave dipole. When I raised the antenna and used a Rig Expert to tune the length I found the 40 m measurement was good for a less than 2:1 SWR across the phone portion of the band. 3/8″ rod elements cut and attached to the bracket using two self-locking nuts on the short element, and one on the long element to tighten it down after threading it into the antenna mount. The problem is that the Antenna I have fitted this onto is not a Glomex Antenna and I am wondering if the distance to be cut of would be the same if this Antenna is different. Circularly polarized microstrip antenna is frequently realized by cutting the slot inside the patch and feeding it along the diagonal axis. Note that only three bands line up with a ladder-line length of 98 feet, 40m, 20m, and 10m. Some suppiers think the cable should be cut to a wavelength of the frequency. The quotient from above divided by 2 gives you the quarter-wave element length in feet. If you suspect your wire is stretched call or e-mail us and we will help you send it back to get it cut to the proper length again. The results are conveniently displayed in inches, centimeters, feet and meters. 3, this could mean that antenna was not tunned good and the cable. So simply cutting the antenna mast - and therefore the antenna wire - to a length that suits your eye or so it won't bang on your garage door will. 6 on channel 1 and 1. If you put 4 watts into a 3-foot antenna you will get the same power out as if you wre putting about 1. Align the bottom of the antenna with the bottom of the cutting diagram. I noticed not very big, but noticeable improvement in performance. Strip the wires. One of the easiest antennas to build is a traditional half-wave dipole. 2 Meter 5 Element Quad. For example, if you are getting RF problems on 20m (14MHz), a PVC-coated wire or counterpoise cut to a length of 5m may resolve many of the EMC issues. But recently an RF engineer told me, that you could sometimes get the same radiated power, by matching the impedance without trimming the antenna to resonance. Assembly instructions: Measure out the exact wire lengths you will need and cut the wire. Yes, I know, 468 divided by the frequency divided by 2 gives a quarter wavelength, but this chart helps the non-technical people and those of us who want to check our math. Example : For a 160 meter loop, 1005 divided by 1. Antenna SourceBook Volume 11 - Hutton Communications Antenna SourceBook Volume 11. At 14,300 kc. This will give you the length of each leg of the antenna. ) For VHF Applications, an antenna anywhere from 14–18 inches is perfectly appropriate as a 1/4-wave antenna. Which brings us to… 5. PKW Wolf This antenna is the basic. The overall length of the antenna is shortened a total of 20 inches. The cable length is 16-feet. It comes with. 9 425 MHz 15 3/4 40. 1 440 MHz 14 35. (The half wave dipole cutting formula is: Length in feet = 468 divided by the Frequency in Mhz. Is a longer Wi-Fi antenna better? Why do Wi-Fi antennas have different lengths? The question is about the usual (stick-shaped) antennas used in consumer routers and adapters. 4mm hollow square) stock. Of course it is possible to exactly measure lengths, impedances and even the VF, but we need an antenna analyzer and a bit of math. Fortunately there is a starting formula for these types of antennas. To that end, here are 5 of the coolest DIY TV antenna plans we found. The antenna best suited for your location that truly receives both VHF and UHF signals is the EZ HD antenna. Measure twice, cut once. It can be mounted either on a roof or roof peak. 32 / frequency in Mhz: Cut wire slightly longer for connecting insulators and pruning. 0 Inches for one side. " Well, I cut the antenna down to 75 cm expecting better gain and the oscillator stopped oscillating!. The place that the GSM must be installed due to several reasons is in a basement with no signal at all. where Xo and Yo refer to the unknown position of the origin. 4 inches but most antennas use 1/2 or 1/4 wavelength for elements. We provide antenna solutions for Cellular, Two-Way Radio, Wi-Fi, Bluetooth, GPS, RFID, LPWAN, ISM, and a wide range of IoT/M2M applications. In the picture notice the longer elements (rods) protruding from the EZ HD antenna boom? There are four of them on each side spaced and cut to length to receive the VHF frequency wave pattern. An antenna's efficiency is measured by the Standing Wave Ratio, or SWR, which represents how much of the radio's power is being turned into radio signals by the antenna. A longer whip will allow better performance at the lower frequencies. The loss per connector at 2 meters is about. In this case remove it and place a copper cable (or any other metal) of a length of 52 mm instead of the tip. The Length of the Feedline; The Velocity Factor (VF) of the feedline It is not always easy to know the exact values of of of this so often we can only make a rough estimate. Wideband design of E-shape microstrip antenna is discussed, which yields bandwidth of 213 MHz (19. The larger the wire, the wider the bandwidth. Use an SWR meter or antenna analyzer to adjust the antenna for best (lowest) SWR at the desired operating frequency. single antenna, the picture is a bit different. The unit “HZ” stands for “Hertz” and was named to honer Heinrich Rudolf Hertz, who did research in Electromagnetic waves. Measure and cut a piece of wire that is 1. If you cut the antenna too short, you can just add a loop of wire [JUMPER] and leave it hanging from the insulator. line width and length for the aperture. 81 compared to a normal 5/4 wave 146 Mhz antenna. This length is a 1/4 λ on 144 MHz and 3 x 1/4 λ on 432 MHz. For channels 14 and above f(in MHz) = (6 x channel_number) + 389. Therefore cutting the length of the antenna will affect reception. Diamond MC101 commercial mobile antenna with cutting chart VHF MC-101, , China, Diamond, MC101. If I solder, say, a banana plug on the end and use 0. Note: If you select a waveguide size from the dropdown below, the broad wall width will be automatically calculated along with the other results. Why are Dipole Antennas so Popular? For almost any kind of MF/HF opera-. For example, if you are getting RF problems on 20m (14MHz), a PVC-coated wire or counterpoise cut to a length of 5m may resolve many of the EMC issues. 80m overall length - 134' or 67' per side. Divide the this number by your design frequency. I always use the water method to put it in the ground, no need to push hard with that method!) To use this antenna you MUST set it to the correct length for the band you wish to operate on. Find your local depth of the water table and get your antennae height using multiples of 36 feet from the water table. This works best with #12, #14 or #16 gauge copper house wire. The best length for a vertical antenna to achieve long distance communications is 5/8 wavelength, and for all practical purposes a backstay antenna is a vertical antenna, only with a slope to it. This calculator will help you to calculate the different wavelength of antennas based on the frequency. number of half-wave lengths. The antenna should be cut to 1/4 of wavelength, and NOT 1/4 of antenna's. As with any antenna, lengths should be cut longer than formula results and then trim as needed for best swr. PCTEL engineers external and embedded antennas and RF ancillary products, including LTE, Wi-Fi, GNSS/GPS, 5G, LMR, and multi-band antennas. Whether you're in the market for fully functional or purely decorative, we've got you covered. most of the time the longer cable is used to keep SWR lower because of the poor placement of the antenna or a poor antenna. a 10 ft length. If it's a random length, then it's probably not a half-wave but could be on a specific frequency. The dual band equilateral triangular microstrip antennas are realized by cutting the slots of either quarter wave or half wave in length, inside the patch. Even these 50 ohm antennas can be a little “off” at times, so you may need to tune them by physically cutting or adjusting the antenna to the correct length, as we discussed earlier, or by adjusting a matching section at the antenna. Modern auto antenna masts are wound round and round with the antenna wire itself, so the effective length of the antenna is the length of the wire winding not the length of the antenna mast. For channels 14 and above f(in MHz) = (6 x channel_number) + 389. Sleeve Dipoles are realized by the addition of a metallic tube on a coaxial structure. 5 meters long. Where your main coax line from the antenna ends inside your home, cut off 6 feet of the coax, and put antenna connectors on each side that was cut, and add your new equipment at that point. Cut the vertical wire to the length necessary to extend from the stereo to the location of the top section of the antenna. 40 inches is a compromise between the two higher frequencies 72 and 75 mhz. Obviously, an EFHW antenna has a "half-wave" length only at one specific frequency: there is absolutely no such thing as a "multi-band end-fed half-wave" antenna. Antenna theory and antenna terminology can seem complicated to the uninitiated. Example — 80 meters: If you are operating on 3. Dipoles are the most common wire antenna. You can buy a replacement antenna that is shorter, or you can save a few bucks and shorten your existing one. 5:1 VSWR for at least 2 MHz above and below center. The whip when purchased from Radio Shack is 102" in length and made for 27 Mhz Class "D" Citizen's Band use. The "KW" antennas are compatible with autos, trucks, vans, motorcycles and ATV's in a single antenna configuration when metallic ground plane is available. Electrical length is the "operating" length of the antenna, as the result of its electrical construction. Properly aligned and phased, a collinear array can provide a 3 dB or more increase in signal strength. 0 Inches in overall length and 0 Foot 0. If SWR on 148 MHz is more than 144 MHz, your will need to trim your antenna. If the antenna were to be a single band antenna with the wire cut to a ¼ wave length at the desire frequency this would produce a feed impedance somewhere between about 30 ohms to 80 ohms and would therefore be relatively easy to achieve a useful match. In proposed work, circularly polarized slot cut circular micro-strip antenna at 900 MHz is discussed. Further enhancement in E-shape antenna bandwidth is obtained by embedding pairs of rectangular slots on the ground plane. SWR - Standing Wave Ratio. These are going to be the two halves of your dipole (di pole = “two poles”). Most antennas are based on a dipole, Yagi's use a dipole antenna as the radiating element, vertical half wave antennas are "end-fed" dipole antenna. We are therefore delighted to almost double the length of the festival, a decision that reflects Antenna’s growth in recent years. The antenna is designed to operate between 150 MHz to 174 MHz unless otherwise specified. The phase difference arising between the antenna elements are added to the whole length of the antenna to values that can no longer be tolerated. Even quite short pieces of wire will radiate a signal and receive strong signals, but when the antenna is cut carefully to slightly less than a half wavelength long, the antenna becomes resonant and can be fed in the middle to work well as a transmitting or receiving antenna. SWR Range Explanations:. Cut the wires to length. RG-8X is recommended for runs in excess of 20’. 47 free space wavelength) was determined by modeling the length required to obtain resonance (jX = 0) when the “counterpoise” was the same length. antenna design theory I'd suggest you find a friend who is into ham radio. Yes, I know, 468 divided by the frequency divided by 2 gives a quarter wavelength, but this chart helps the non-technical people and those of us who want to check our math. There are many methods, from baluns, to coax wound around a form, or a straight line feed. The length of the antenna would start after the shielded portion of the RG-58 ends. Cut to Measure. DB-212 Folded Dipole. Radial length effects When the antenna is not ideal, i. Your question is incomplete. Aerial Masts: the Canadians produced 20-ft and 34-ft telescopic masts that could be used as vertical aerials or as supports for wire aerials. 2) The charts list the rod length in inches. You did measure the SWR before, now this means that from point you have measured it was a factor 1. Ground radials should be at least this long (1/4 wave): or or. The goal of antenna tuning is to match the antenna's physical length with that of the radio frequency being used, so as to ensure optimal performance and transmission efficiency. 8 megahertz will be about 123 feet long, or each leg will be about 61 feet 6 inches. An EZNEC antenna model was used to simulate cut-ting the dipole lengths until the SWR on the line reached 2. Divide by 2 for each leg length. In any case an antenna must be raised in relation to background to work well. 8mm to 32mm for a 1/4 wavelength on the 2. Antenna Suggestions? (ICOM 2700/Larsen Antenna) 7. For the better quality, use the 5/8 wave Ham radio antenna, for $39 at Radio Shack, with four inches cut off the whip for the RR frequencies, is your best bet. The results are conveniently displayed in inches, centimeters, feet and meters. Coupling between nearby antennas is a measure of the power delivered or received by one when the other transmits a given. The benefits of a Z-Matcher over precise cable lengths: (more from WB6FLY) You can (effectively) transform one impedance to another by cutting the interconnecting cable to a specific length (or multiples thereof) through a process of cutting, reterminating, testing, cutting some more, reterminating, testing, etc. ANTENNA SWITCH. When cutting your antenna lengths, keep in mind that if it's an End-Fed Half wave, it's not a randon length. To find the quarter wave, dividing 123. 4 db no ground plane antenna will get you more range than a badly placed 3db gain antenna. single antenna, the picture is a bit different. The cable length is 16-feet. This same antenna can have the ends of each of the two legs (or poles) pulled away from straight or flat so that it resembles a V shape until the impedance changes to match your 50 Ohm coax/radio and you have an antenna that has a 1. At Stubby Antenna, we prefer it short and sweet. Now for construction. on Alibaba. VHF and UHF antennas, especially beams, often have balanced feed points. and raised to the top of second mast and tied off. 4 inches but most antennas use 1/2 or 1/4 wavelength for elements. Cord Cutting Options: The Best TV antennas. Even these 50 ohm antennas can be a little “off” at times, so you may need to tune them by physically cutting or adjusting the antenna to the correct length, as we discussed earlier, or by adjusting a matching section at the antenna. My KX2 Owner's Manual, page 10, says "A length of about 25 feet for each wire, matched to the KX2's output using an antenna tuner (see ATU, pg. The exposed whip lengths shown are only approximate. The cable length with this antenna is a little bit longer than the antennas above. 75 feet (32 feet, 9 inches). You will need 8 half wave lengths (9. SWR for all lengths. Enter one (only one) value, the desired frequency or the antenna length in any length field. If it doesn't work right, use a cut-and-try method until it does. We must subtract 4% of the total full wave length if we are using insulated wire. The absolute minimum antenna which will work for you is a dipole cut to the frequency of interest. FULL SIZE WHIP CUTTING CHART. Antenna is already in your area of interest on receive. Recommended Wire Lengths (in feet) for Coverage of 160m through 10m 53 59 72 88. Cutting Larsen NMO 40. A short piece of feed line, cut to the correct length and connected in conjunction with the television receiver's antenna feed line, displays surprising characteristics. Yes - just hanging a vertical length of wire, fed in the center, to act as a dipole would be easier to handle than the 1/4 wave ground plane I have now. Actual lengths will depend on several factors including mounting position, coax length, other antennas in the area and matching method. Use tape on the floor to mark the lengths for each of the different cuts. In other words, the wires for each antenna should be identical in type and length. 2) The charts list the rod length in inches. Put the antenna back together, hooked up the coax, and my neighbor and I raised the antenna once again. In this design, however these simpler approximations of slot length against the frequency do not give closer results for different slot lengths. Mark a centreline onto the reflector and director rods, then made a further two marks at 5mm on both sides of the centre, this is where it will align with the boom. The W3EDP end-fed antenna is a cheap way of getting multi-band operation, especially if you are a newcomer and restricted to 10W. Make sure the signal of your camera is the strongest as possible even if you’re in the middle of the wood. CUTTING THE ROD PRODUCT WARRANTY - Antenna PCTEL antenna products furnished herewith shall be free from de- SELECT THE CORRECT CUTTING CHART FOR YOUR ANTENNA! (ADDITIONAL CHARTS AND CUTTING INSTRUCTIONS ON BACK) the length given is for the total length of the rod. Radial length effects When the antenna is not ideal, i. It is simple to make and cost can be nearly nothing. The 90 degree turn is what separates(de-couples) the radiator from the feedline. 0 Inches for one side. They are available in a wide range of. Welcome to the home of the #1 rated Indoor HDTV Antenna! Mohu Basic 50 Indoor HDTV Antenna (with Risk-Free TV guarantee) 2 Review(s) Add Your Review. 5ghz, it's about. Use a field strength meter when cutting the length of your coax. Use of a compound mitre saw makes this job easy. Solder the antenna wire (That you measured and cut in step 1) to the center conductor of the coaxial cable. Unfortunately, most neighborhoods seem to want an unobstructed view of utility poles, power lines and other people's houses, so they cut down most of the trees. A minimum length for an efficient antenna is a half wavelength. Dipole Antenna Length. We are also a custom cable maker, which means we can provide you with any wire or cable in multiple configurations. Source from Quanzhou Kingtone Optics & Electronics Technology Co. Is it a metal rod, as the metal ones are usually a bit shorter. 145 if you want the center freq to be the same ratio relative to 137 as it is to 118 MHz. Cut 8 pieces of copper wire that are each 17 inches (43 cm). Total Wire Optimum Number Optimum Length Peak Gain. The overall length of the antenna assembly is 77 3/4 inches. It allows you to test the resonant frequency of the antenna for lowest SWR and zero reactance, and adjust the length to the exact frequency you want, in just one step, rather than a lengthy process of cut and try. First, your antenna is now a combination of an inverted vee and a vertical running down the center of the vee. ( The 80 meter version was used for Field Day 2006 in Olympia, WA by the Olympia Amateur Radio Society) If it really has 11. Lower antenna and cut leg to. Of course it is possible to exactly measure lengths, impedances and even the VF, but we need an antenna analyzer and a bit of math. As most of you know, the key to antenna efficiency is length. Have a Yaesu FT-2500M ham radio set up to shift between my car and indoors. The model showed that. The resonant frequency happens to be a quarter of the signal wavelength, where the inductance and capacitance in the antenna are equal and cancel each other out. An antenna having a reconfigurable length, comprising: an enclosed composition capable of forming a plasma; an energy source configured for applying variable energy levels to the composition to thereby form a plasma operable as an antenna; and an enclosure containing the composition, said enclosure having a proximal end, wherein upon. 3, this could mean that antenna was not tunned good and the cable. Constructional tips. Cutting Instructions TOPA-AN-201 Helical Antenna Tuning Range: 136-340MHz For optimum. 3/8″ rod elements cut and attached to the bracket using two self-locking nuts on the short element, and one on the long element to tighten it down after threading it into the antenna mount. It is simple to make and cost can be nearly nothing. Before I bought this antenna , I simply put up a piece of scrap PVC pipe with a balun at the Tee in the middle, and stripped twelve gauge copper, cut to the length of channel 7 half wave. you can cheat a little by cutting. Few days ago I cut 3 mm off the top of whip, making it 66 mm long. Quarter-wave matching coaxial cable. Standard CB (11 meter) or 10 meter ham wire sets are available. We need only 5 ft of EMT conduit for a single Yagi antenna, but you'll pay about the same price for a 5 ft length vs.