- For 40 or 30 meters, use 12 turns of RG-213 on 4 inch PVC sewer pipe. 2m Slim Jim antenna made for under £10. Antenna projects for 144 MHz category is a curation of 148 web resources on , Magnetic Loop for the 2m band, Feed line Dipole for 2 Meters, OCF 2 Meter Sleeve Dipole Antenna. AUTHENTIC N9TAX VHF/UHF Slim Jim J-Pole For HT 2m 70cm Antenna 10' Coax - $36. It exhibits 1. Center is connected to the 3/8” 1/2λ aluminum element braid (ground) is connected to 1” 1/4λ aluminum element Use the Wavelength formula to compute for the element length in reference to your target. 25 results for folded dipole Save folded dipole to get e-mail alerts and updates on your eBay Feed. Many hams’ first choice of antenna is a half-wave dipole. Good for packing for a business trip where there are repeaters around. Measurement results for the S11 (or SWR) a. The difference with the short OCF is that it is less than λ/2 overall, and the feed is offset below the centre (and tube 8 is omitted, a different support is used) all of which results in the s/c stub being just λ/70 in length. This length plus the tiny amount of coax exposed makes this a perfect 1/2 wave dipole for 2M and a good 440 antenna too. The elements are colour coded with heatshrink to identify where they are to be screwed in. 0 (0 votes) Store: XZ-Car Store US $4. 64 – Dual-Band Sloper Antenna. Take out the screws attaching the dipole half to the tee and attach the coax to the antenna using the dipole half screws. Adjustable cable ties will help to position each center connector on the pole. 2m/70cm 24 Watt Dual Band Mobile $139. The 2 meter square loop is a folded Dipole around itself. 5 Speakers,2x Amp, 100ft Wire,2x Antenna,usb Aux Interface Mount. A center-fed wire dipole impedance is Z dipole=72 W, increasing off-center toward the ends. Plus, it would be nice if it were omnidirectional. I ended up with D1 & D2 = 0. The same ground definition was used in each case. In our ISO-9001 certified production facility for. 1dBi 1/4 wave + 5/8 wave. It is fitted with 4m of 50 Ohm coax cable with a BNC male connector as standard, but can be supplied with PL259. Slide three FT50-43 or almost any similar sized toroids over the bottom end of the coax as shown in Figure 3. Minimum SWR for the 2m band is 1. The feed impeadance is achieved by making one side out of a thinner conductor (2. I'd looked at a number of the loops and squared-off dipoles, even came close to buying a Delbert Loop at HamCom. I pulled the braid over the outside of the coax, which isolates the rf from the transmision line and keeps it from being a verticle half wave dipole. It is packaged to be turnkey, providing everything you need for best outdoor or attic-mount NWS broadcast reception with coax and weather radio. 0db at 145mhz. the same length dipole (doublet) with optimized tuning. Since then we have become the largest manufacturer of Amateur, CB, and Scanner antennas and accessories in the UK We are also the largest local authorised dealer for Alinco, Kenwood, Icom, Yaesu and Wouxun. If you want. A 1:1 balun has the widest operating frequency range, lowest core stress, and provides the best overall balance of any balun for given cost, size, and weight. 08 - Quarter Wavelength Vertical Antenna 09 - Folded Marconi Tee Antenna. Portable 2m 144 MHz vertical 1/2 wave Coaxial Dipole antenna for QTH, SOTA & portable field operations/WICEN exercises. The Fan dipole for 40/20/6m performs well. com in a single category. An Attic Coaxial-Cable Trap Dipole for 10, 15, 20, 30, 40, and 80 Meters John DeGood, NU3E [email protected] Mount it to a thin wood stick. The Coaxial Dipole lacks the self-balancing behavior. Changing the able to RG-8X drops the loss to 4. I am trying to tune a coaxial dipole antenna that I built from some RG58A as a portable 2m antenna for my HT. Secure with 1-1/2" U-bolts. If your putting in an HF rig and need 20-50 feet then that same coax would not work very good and you would need to go to 213 or even LMR400. One of the members commented to me that I should write an article about collinear arrays so that we could all build our own. The short end was placed at about 40 feet off the ground, tied to a tree limb, using about 10 feet of insulated rope. When tested on my Analyzer It achieves resonance @ 50 ohms with a " flat 1. However, these antennas are quite complex to build, being made up of numerous short lengths of coax which must be accurately cut to length. 1:1 • Loss < 0. deemed mandatory. One of the antennas Bob discussed was the HF wire fan dipole. Tuning is carried out in the same way that you would tune a standard 40 meter dipole. This is a common site limitation for any HF antenna. We offer site. 62 – Dual-band Loop Antenna for 30m – 40m. Transmitting or receiving. Work with 146 MHz, middle of 2m. Fiori Films Presents Ham Radio TV: How to Build a Dipole Antenna In this video Kevin, N6VLF walk you through the theory on how to build a good working Dipole Antenna. Changing the able to RG-8X drops the loss to 4. 20 meter dipole kit Glass Mount 2m/440 Antenna - No Drilling, No Holes! Includes 14 feet of coax/RG58u, PL-259 Whip Length: 28. 2 ft for 1/2 wavelength, total length of dipole. Tuning help for a 2m coaxial dipole antenna Forums. Ending Feb 16 at 1:15PM PST. 2M + 70cm Open Sleeve Vertical Dipole; I have to add something for context. This was found to be quieter and made the antenna less sensitive to frequency changes. The antenna I used was a Cushcraft 17B3 up about 50 feet, fed with a chunk of 9913 coax. One of the members commented to me that I should write an article about collinear arrays so that we could all build our own. 69 – Linear Loaded Sloper Antenna for 160m. Also at the junction between Balanced Feeder (ladder-line) and Coax - eg: G5RV. Home-built VE3SQB Coaxial Dipole antenna (aka Double Bazooka) The first HF antenna I put up was a coaxial dipole, the concept was developed by MIT. Finally, the coax was pulled out so the cable tie was against the inside of the sewer pipe, the choke balun coils were formed tight against each other, and the coax slack was pushed through into the tube and out the bottom. 15 MHz traps 0. Below is another simple type of covert receive-only antenna. This is a multi-band antenna. A 1:1 balun has the widest operating frequency range, lowest core stress, and provides the best overall balance of any balun for given cost, size, and weight. The long end was tied to a tree, again, using insulated rope, and with maybe five. The radiating element is a quarter wave (λ/4) and the radials are 12% longer. Don't discard that old mobile antenna--recycle it as a new antenna. I found the plans on the following site. The feed impedance is several times higher than the cylindrical dipole's. How Common Mode Current Chokes Work •Differential Mode signal only sees the coax •Coiling the coax has no effect •Typical: • SWR < 1. The other method might be to use a gamma match similar to the ones used on yagi and other 1/2 wave driven element antennas (like beams and such). Geometriy is not that critical. It also ruins the continuity and context of the thread. I make this new deluxe with a ferrite bead installed at the antenna feed point to eliminate rf feed-back through the coax. org and guerrilla. It requires a balun and works very well. However, these antennas are quite complex to build, being made up of numerous short lengths of coax which must be accurately cut to length. You will need. 25in or 6mm, up to 3/8-in or 8-9mm. Half-Wave Flower Pot Antenna. 5 dB loss corresponds to 36% of the power makes it through. Centerfire Antenna, LLC PO BOX 8305 South Bend,IN 46660. They tuned up a treat! and are both flat (vswr) across the bands, too. 5:1 across the entire 2 meter band. 080 m) makes 360 degr. com in a single category. 365 m (x2) if the first is too short. Double Bazooka Antenna 10 meter band. Type 1: alu or copper tubing of 1 meter 15mm tube and 1 meter 12 mm diameter tube. But we can accomplish the same thing with ordinary 75 Ω, RG-59 TV type coax if we run the cable with an intentional impedance mismatch. I have issues with J-poles, and while easy to build, I think they interact with their feedlines way to much. To help support the coax and choke. Dipole Antenna Length. all band dipole mk3 The Mk3 All Band HF Doublet is the same as the Mk2 version with the inclusion of a balun at the interface from the coax to the open wire feed-line. Page 8 Keep plate at least 1/2" from elements. In their simplest form, dipole antennas for 2m and 70cm can be constructed from 2mm diameter enamelled copper wire and. I used 1″ thin-wall PVC pipe, aluminum tape, and RG-8X coax. Resonant mid-band. I was looking to build an easy to breakdown 2 meter antenna for an event I was helping with. 4 and an Assumed Dipole Impedance = 50 Ohms. Split 1 1/4" PVC -T lenghtwise to slide over support mast. The upper grey box is a 144 MHz preamplifier, and the other box houses a coax-relay. The 4-Band antennas are OCF (off-center-fed), with a 23 foot leg and a 45 foot leg, totaling 68 feet. Being the crafty maker type, I wanted to build my own antenna. Yet both antennas have the same performance. However, coaxial cable is unbalanced! When feeding a balanced load, such as a dipole, with an unbalanced transmission line, the antenna will induce RF currents on the outer shield of the coax. DX Engineering receive antenna systems feature the best designs available for HF DXing, as well as for “AM DXing” on the MW Broadcast Band and for the Short Wave Listening bands (SWL). This antenna is for vertical polarization via ground wave and long-haul ionospheric propagation, and requires just one point of suspension. The dipoles attach to the mast using two hose clamps per dipole as shown below. A dipole is basically a length of conductor (wire) split into two portions and signal is taken off at the split. Build a multiband HF antenna using multiple dipoles and single coax feed. The SWR is very low across the band. It is waterproof to protect it for a lifetime. 2m/70cm 24 Watt Dual Band Mobile $139. One may argue that 560 feet is ridiculous for a 40 meter dipole, but keep in mind that the data can be scaled down to a 10 meter dipole with similar results. 7 dBi gain and 18° Vertical Beamwidth. 2 meters, 70cm, MURS, GMRS, ham. My operation is mainly working locals, the occasional. Comparison with Dipole. A Simple 2 m/70 cm Vertical Dipole Antenna This easy to build dual band VHF/UHF antenna makes a great project for the new ham that is ready to get on the 2 meter and 70 centimeter amateur radio bands. This is a fairly big 2m Yagi with 13 elements on a six metre boom. I proceeded to make a very heavy dipole from copper pipe, akin to the type used for J-poles. The construction is very easy to handle. 10-80 Meter Alpha Loop, 100W 10-40M, 20W 40-80 magnetic. Cut the coax segment 7/8" longer than the brass tube. 2M + 70cm Open Sleeve Vertical Dipole; I have to add something for context. Trust me when I tell you that The 6db of gain you get with this antenna over a typical 5/8 wave antenna more than makes up for the 1db loss in the coax. The SWR is very low across the band. TV Antenna. This is the length of coax being prepared. This folded dipole has a 200 ohm feedpoint providing a good match for 50ohm coax through the 4:1 coaxial balun shown. Loss is a length multiplier, so a 200 ft length would have twice the loss shown above and a 50 ft length would have half the loss. 23 + EUR 114. For VHF 2M, the center frequency is about 146MHz. It was incredibly heavy and very quickly became a sagging and corroded eyesore on the corner of my house. Electrically it is very different to a conventional dipole; it incorporates a balun and is almost like having two quarter-wave dipoles connected side by side. Since then we have become the largest manufacturer of Amateur, CB, and Scanner antennas and accessories in the UK We are also the largest local authorised dealer for Alinco, Kenwood, Icom, Yaesu and Wouxun. Homebrew 2m 144 MHz vertical 1/2 wave Coaxial Dipole antenna for QTH, SOTA & portable field operations/WICEN exercises. • The antenna shall be reasonably inexpensive compared to the cost of a similar size wire dipole antenna. First, only the 10-meter dipole is built and brought to the desired resonant frequency by the 20-mm tubes which are displaced on both sides by the same amount. 2m/70cm Slim Jim ladderline antenna 10 mts of coax. 95 Until 06/30/20: YAESU FT818ND Portable HF/VHF/UHF $549. Dissadvantage: needs a matching device at the base to match it to the coax, it cannot be attached directly. I have issues with J-poles, and while easy to build, I think they interact with their feedlines way to much. I like to tinker, so when I finish one project, I go on to another, even if it works well. Half-Wave Flower Pot Antenna. Introduction. Straight Horizontal For the best in DX (Distant Communications) we suggest these Antennas be installed in a straight Horizontal Mode. The Double Bazooka Dipole The double bazooka is claimed by its users to be broad-banded, a quality especially interesting for those hams operating on 75/80 meters. 2m Folded Dipole. This is an easy antenna to build and the materials cost about $15-20. The Folded Dipole exhibits the self-balancing behavior. Radio frequency (RF) current in dipoles is at its maximum at the centers of the dipole and at its minimum at ends of the element, and vice versa for RF voltages. Coaxial Length Calculator Version 5. is a homebrew coaxial dipole built from a small stainless whip, a length of threaded table-lamp tubing and some 3⁄ 4 inch cop-per and PVC fittings. Here's a model of a 20m dipole with a severe example of this problem. 1”copper tubing) •Portable loops (e. (The actual impedance depends on the height of the antenna above ground and many other factors. 6 watts for the ferrite beads. If you still want to make one, just use some television twin lead cut to length using the info in #2. 2-meter vertical dipole array copper dipole array details rev. which gives the amateur the capability of utilizing several radio bands with only one feed line. 70 shipping. For VHF 2M, the center frequency is about 146MHz. 22 - Wideband Dipole Antenna. 13 - Multiband Dipole Antenna. This antenna has about 1. What I came up with was a trapped end fed folded dipole. 10m/2m/440 10m, 2m and 440 MHz Antenna: 20m/2m/440 20m, 2m and 440 MHz Antenna: HamR-7 40m, 20, 10m, 6m, 2m, 220 and 440 MHz Antenna: Cushcraft: Beam Antenna Chart & Index: Vertical Antenna Chart & Index: Diamond: A502HB Yagi Beam 6m: F 22A Vertical 2m: F 23H Vertical 2m: V2000A Vertical 6m/2m/70cm: X 30A Vertical 2m/70cm: X 50A Vertical 2m. Many hams connect the center conductor of the coaxial cable to one side of the dipole, and the shield to the other. A 4:1 coax balun is easy to make and, using this tool, I worked out the size of the coax loop for my balun centred on 434. This will affect the radiation pattern. 5mm square building wire). It makes a great SWL antenna as well, along with being able to transmit directionally. This is a fairly big 2m Yagi with 13 elements on a six metre boom. To help secure the coax put another wire tie an inch or two below the tie at the bottom of the choke. MFJ-347 Dipole Mount. Shop for 2 Meter Antennas here. For want of a better name, lets call it a ‘half folded dipole’. Center is connected to the 3/8” 1/2λ aluminum element braid (ground) is connected to 1” 1/4λ aluminum element Use the Wavelength formula to compute for the element length in reference to your target. DBJ-2 VHF UHF Dual Band Roll Up portable Antenna. This horizontal "slot" antenna, cut into the reflector of a TV dish, is both the master of disguise and high in performance. This dipole is made for NOAA weather radio and EAS reception from 162. The feed impedance is several times higher than the cylindrical dipole’s. No performance advantage over a dipole unless you proceed to make a beam with some gain and use some sort of impedence matching system from 300 to 50 ohms coax. I think that the weight of the balun & feeder cable. This dipole is made for NOAA weather radio and EAS reception from 162. the Double Bazooka Dipole is a very efficient single band antenna which is very quite,and does not require the use of a balun. It has a 7-turn choke before coax splits to aluminum tube. The SWR is very low across the band. 20 - Multiband Tuned Doublet Antenna. A length of Coaxial Cable, preferably RG-8X or RG-213U to keep losses low. 13 - Multiband Dipole Antenna. Sleeve Dipole / Flowerpot Antenna. the dipole on 20m, to the 50ohm's of your coax, will not happen if you stick the balun/choke in the feedpoint of the antenna like you would on a normal dipole antenna. The actual feedpoint would be at either a standard split in the radiator with the center of coax to one side and shield to other, just as you would do a normal dipole. Figure 1 The Balun is hung at a right angle. [The wire dipole and slot dipole are complementary structures. Posted here as might help others better picture of support On 26/07/2015 20:36, Dominic Baines wrote: Hi, At a pie and pint someon. TV Antenna. Don't discard that old mobile antenna--recycle it as a new antenna. Fixing the Folded Dipole to the Boom 6. Supporting the Folded Dipole 7. When determining how long to make each leg of a Dipole antenna, dividing the frequency in MHz into 468 will give the overall length. The radiator is a stretched dipole with 10-12mm insulation between the two parts. This calculator is designed to give the horizontal length of a particular dipole (including Tees) antenna, or one side of it, for the frequency chosen. but in my experience this is only true if you solder a larger coax direct to the antenna (like LMR400/RG8). This antenna is normally used with a T-Match Antenna Tuning Unit. HDTV/UHF Digital Outdoor. After many requests for a dual band version of this antenna. Buy the Sandpiper WSJ-144 Folded 2m Dipole from Radioworld. 6 watts for the ferrite beads. For example, to make a 150MHz dipole: 147/150 = 98cm so each element of the dipole should be 49cm. An End-Center-Fed Vertical Dipole Behaves like a center-fed vertical dipole - ZO ~ 70 ohms, so 75 ohm coax is the best match Top half is λ/4 wire Outside of coax shield is the bottom λ/4 - Use Vf ~ 0. I was thinking of putting a horizontal fibreglass pole on my mast, just above my roof line, to fix the legs to then attaching the center slightly higher and having it as an inverted v formation to avoid the need for long ropes. 706 m shorter than the coaxes # 1, 4 feeding the outer dipoles. 18 - Bow-Tie Dipole Antenna. RG8 Coax 9 Turns for 145Mhz SO239 OR PL259 to feedline SLEEVE DIPOLE for 2m VHF Antenna Note: For coax with 9 turns feedpoint connection. We suggest using high test fishing line or rope. Coiled-Coax Balun. 97 for a PVC insulated 0. To find the half wave, divide that number by two. seal feedpoint terminations with coax-seal. The main category is Antennas for 2 meters band that is about Antenna projects for 144 MHz. I just got done building a dual band dipole tonight. , a 2-meter vertical, a 40-10 Meter Off Center Fed (OC F) Dipole, and a 10-meter rotatable aluminum dipole. A vertical dipole needs to be a few feet off the ground to tune properly; It is vitally important that the coax feed line in a vertical dipole come out at at 90° angle for several feet to avoid common mode currents. The coil forms are cut from the PVC pipe. 6kg Note that photo shows the. with whatever connector you need for your radio, gently cut the outer insulation about 19. the dipole on 20m, to the 50ohm's of your coax, will not happen if you stick the balun/choke in the feedpoint of the antenna like you would on a normal dipole antenna. Past week I have created simple 2m band half-wave dipole antenna. The wife has me moving furniture tomorrow. Quick View Workman GRK-8 Ground Plane Kit For Base Antennas. The measurements below are for building a simple Dipole Antenna. Details HAM We get wire for the coils when we strip the shield from the RG-58 coaxial cable. 2 ft for 1/2 wavelength, total length of dipole. note the shortest possible wires during adjustment. 21 - G5RV Antenna. The coil forms are cut from the PVC pipe. In the first two columns, the. Cut & cap copper, 20" for each half of dipole. Your first antenna - the half-wave dipole. I decided to go back to the drawing board and starting from scratch, designed an entirely new, much lighter, 2 meter vertical dipole. Using CB Antennas on 10 Meters! By N4UJW. Looks like you used good coax, so it should. The Antenna Farm : VHF 108-174 MHz Dipole Antennas - VHF & UHF Mobile Radios Radio Accessories VHF & UHF Hand Held Radios Antennas Mobile Antenna Mounts SWR/Power Meters Adapters Coaxial Cable Two Way Accessories Antenna Accessories DC Power Supplies Coax Cable Accessories Connectors Aviation Radios Repeater Systems Towers & Accessories Duplexers Diplexers & Triplexers VHF & UHF Base Stations. the dipole on 20m, to the 50ohm's of your coax, will not happen if you stick the balun/choke in the feedpoint of the antenna like you would on a normal dipole antenna. The same ground definition was used in each case. My J design dimensioned here is really great for single feed dual band operations!!!. "Subject: Plumbers' Dipole Antenna Date: Fri, 13 Sep 2002 13:39:21 -0500. To achieve these design considerations, I concluded my 6 m dipole antenna shall be be made from rigid aluminum elements, supported at its center on a single mast, utilizing a strong, light. 30 Amp Power Supply $99. DBJ-2 VHF UHF Dual Band Roll Up portable Antenna. Closer View of the Ogden Receiving Site Tower Shows various antennas mounted on the tower that supports the 80-meter inverted-v dipole normally used by JimAndLeah's Online Tuner. 68 – Two-Bands Half Sloper for 80m – 40m. But if you want an antenna your neighbors can't see, or recognize as an antenna, then the ATAS-120 may be the answer to your prayers. All Antennas, Magnetic Loops, Portable. Measurements and simulation confirm the quarter-wave stub modifies the circular H-plane pattern shape increasing the gain slightly on the side of the J stub element and reducing the gain slightly on the side opposite the J stub element. All you need is: speaker wire soldering iron and solder coax cable wire cutters. and raises the feed point resistance, or so they say. RG8 Coax 9 Turns for 145Mhz SO239 OR PL259 to feedline SLEEVE DIPOLE for 2m VHF Antenna Note: For coax with 9 turns feedpoint connection. This folded dipole has a 200 ohm feedpoint providing a good match for 50ohm coax through the 4:1 coaxial balun shown. 95 Until 06/30/20: YAESU FT818ND Portable HF/VHF/UHF $549. Take a look at the first drawing. Coaxial dipoles on 2m - 70cm. What I posted today is right after your great artical. Optimum Coax Coiled Turns Choke Baluns for Antennas (1/1) K1JJ: Here's an interesting piece written by WA2SQR. YAESU STEALTH ANTENNA. Many hams’ first choice of antenna is a half-wave dipole. It can produce similar results to a commercial version and be made from scraps of coax. The antenna is constructed from a single length of 50 or 75 Ohm. Detailed instruction of the correct position are included and a banana plug system is used for quick tap changes. 1:1 • Loss < 0. 65 - Inverted-V Beam Antenna for 30m. The coax to the receiver and transmitter must also be 100 percent shielded in multiples of one half wave lengths of coax. instructions and tuning tool included. The difference with the short OCF is that it is less than λ/2 overall, and the feed is offset below the centre (and tube 8 is omitted, a different support is used) all of which results in the s/c stub being just λ/70 in length. The radiating element is a quarter wave (λ/4) and the radials are 12% longer. HF Flagpole antenna for 10-80 Meters. The basic design for the FM dipole antenna is shown below. In the first two columns, the. Tuning is carried out in the same way that you would tune a standard 40 meter dipole. Keep in mind that the antenna dipole starts at the point that the inner and outer core of the coax split and therefore, this 5-10mm of each should finish where the coax is whole again (see picture). Each half of that (1/4 wl) is ~ 19. Dipole Antenna Length. Because a collinear antenna is hot with RF along the shield of the coax, it is necessary to prevent the RF from coming back through the coax. The principle corresponds to the sleeve dipole or the coaxial dipole. 22 - Wideband Dipole Antenna. If you use RG 58 or equivalent for a few feet, you should have. I wound a choke, 6 turns of coax, before running the cable inside the PVC. A phasing harness is basically (2) sections of 75-ohm cable cut to odd quarter wavelengths X velocity factor, transitioning to a 50-ohm cable, which is usually the transmission line. This antenna has a much wider bandwidth than a Jpole, and is a little smaller too. Parts list. The same ground definition was used in each case. Detailed instruction of the correct position are included and a banana plug system is used for quick tap changes. Primarily a dipole, the J-pole antenna exhibits a mostly circular pattern in the H plane with an average free-space gain near 2. 2m long, 3m from trap to end, and the capacity loads have a radius of 0. I hope this makes sense. 21 - G5RV Antenna. Half Wave Dipole. The Coaxial Dipole lacks the self-balancing behavior. Antenna HLP-2 144MHz 2M Halo Loop Folded Dipole Antenna Frequency: 144-146MHz. Page 8 Keep plate at least 1/2" from elements. Assembles and disassembles quickly. 50 (+/- 10) Ohms, mostly resistive, for the entire 2m band. OH2FTG instruction's are clear and easy to follow. Description: The Hextenna™ system is packable and deployment can be achieved using the included Top of Mast Mount, which can be affixed to any sized pipe between 1 to. 2 ft for 1/2 wavelength, total length of dipole. Finally solder and secure the coax to the crimp connectors, insulating as appropriate and form the balun of 4-8 turns of coax if required using cable ties. Don't discard that old mobile antenna--recycle it as a new antenna. Parts list. I pulled the braid over the outside of the coax, which isolates the rf from the transmision line and keeps it from being a verticle half wave dipole. The other method might be to use a gamma match similar to the ones used on yagi and other 1/2 wave driven element antennas (like beams and such). Yes, this is a balanced antenna, and coax is unbalanced, but I still recommend you solder the coax directly to the antenna. have shown the double bazooka is only slightly more broad-banded than a regular dipole, probably due to the use of a large conductor (coax) for the center. Whereas a Dipole is a half-wavelength long radiator, fed in the Center of two equal length legs, the Off-Center-Fed Dipole (which I prefer to call a WINDOM) is a Dipole whose feedpoint is at a point removed from the center of the antenna. For VHF 2M, the center frequency is about 146MHz. So the measurements are based on a 40 meter 1/2 wave dipole. Because a collinear antenna is hot with RF along the shield of the coax, it is necessary to prevent the RF from coming back through the coax. Two pieces of single strand 12-gauge wire that were 19. Context: I am working on an impedance matching section (1/2 wave length of coax) for a folded dipole antenna (VHF 2m amateur radio band). This antenna will be used specifically for 2m (144-146mhz). Most terrestrial DX activity on 144MHz uses SSB, CW or digital modes and horizontal antennas. GB 430MHz Yagi Antennas; GB 144-453MHz verticals; GB Broadcast Antennas; Wire Antennas; GB Special Antennas; GB Log-Per Antennas; HF Mini Beams MQ Yagi; GB Combi 4m/6m Yagi/Quad Antenna; GB 430MHz/144MHz Quad; HF Yagi Antennas; GB 144MHz Quad Antennas; HF Quads; GB 27MHz Yagi/Quad Parts; GB Combi 6m/144MHz Quad; GB HF Verticals; GB Combi 2m/6m. I kept the tree in a bucket of water to keep the tree moist. The basic design for the FM dipole antenna is shown below. Half Wave Dipole. 1/4 wave ground planes work well, but will have half the signal of a dipole. So in doing this, we’ve built a homebrew antenna with just a couple cheap parts and a little know-how, as well as building our capabilities and our skills. Buddipole Compact Portable Dipole 40m-2m with coax Feeder. 05 wavelengths (7 feet) to 4 wavelengths (560 feet) above good ground. 10m/2m/440 10m, 2m and 440 MHz Antenna: 20m/2m/440 20m, 2m and 440 MHz Antenna: HamR-7 40m, 20, 10m, 6m, 2m, 220 and 440 MHz Antenna: Cushcraft: Beam Antenna Chart & Index: Vertical Antenna Chart & Index: Diamond: A502HB Yagi Beam 6m: F 22A Vertical 2m: F 23H Vertical 2m: V2000A Vertical 6m/2m/70cm: X 30A Vertical 2m/70cm: X 50A Vertical 2m. 4GHz wireless networking, including wireless. My favourite magnetic loop for HF pedestrian mobil Work the AO91 amateur radio satellite with cheap h Ham Radio 2m Backpack Quad Antenna. All the current RG-58 is going to be replaced by Aircell-7 coax and high quality (=low loss) connectors. This will give you the length of each leg of the antenna. "This Old Dipole" or Dipole 101 An antenna construction workshop conducted at Marshall N1FN's QTH on Sunday, 8/2/98 Mission: Replace an old co-ax fed 40M dipole with a new one, fed with 300 Ohm ladder line and in doing so provide a "workshop" for the necessary techniques, and document the process for "posterity. The End Wire Size can range from 16 AWG to 12 AWG. Two-meter Vertical Dipole Larry Nelson - K5IJB. I have been giving thought to setting up a six meter antenna with horizontal polarization. Transmitting or receiving. T2lt /coax dipole antenna For cb radiosPre on tx if needed comes with verticall stand off mounting kit. org and guerrilla. I later changed this by feeding the dipole twin feeder via a remote balun. php 7032 Bytes 08-11-2019 17:10:52. 20m band End-Fed Choked Coax Dipoles (T2LT) 75 ohm to 50 ohm transmission line matching coax stub; JT65 UK Band Plan and how to stay within; 40m compact fan dipole for 40, 30 and 20m bands; Introduction to the 60m Band Plan (5 MHz) 5. Detailed instruction of the correct position are included and a banana plug system is used for quick tap changes. Description. 365 m (x2) if the first is too short. Here is a view of the antenna: Here is the SWR plot: Will run 1W WSPR for 24 hours and compare data with the 1/4 Wave vertical. 5 metre length RG-178 terminated in an SMA plug for direct connect to a portable 2m radio. 2 meters, 70cm, MURS, GMRS, ham. With separate coax feedlines both bands are useable at the same time!. For operation on 70cm my advice is to use low loss 50 ohm coax fitted with N connectors. Just waiting for the glue to dry and then it goes on the side of the house tomorroe. 300 Ohm Twin Lead with the ends shorted is an option for even greater bandwidth. 50 Amp Power Supply $149. 2m/70cm vertical dipole antenna. Overall length 116″. About VHF Coax Dipole The resource is currently listed in dxzone. Efficient 2 meter Disguise Antenna. has been producing industry leading RF management products for the communications industry for over 30 years. 17 - Delta Fed Dipole Antenna. I'll frequently dig through a free bin of part, hoping to scavenge something for the next project. Many would be familiar with the traditional folded dipole made from tubing or wire, and possibly the lightweight version made from 300 ohm ribbon cable. Making it a resonant antenna for all bands from 80m to 6m (except WARC bands). If you want. For VHF 2M, the center frequency is about 146MHz. How to use this Catalog Browse by ITEM # Wire Accessories, Insulators, Mobile CB Antennas, Mobile Ham Antennas, Base Station Antennas, Fixed Station Antennas, 2 Meter Antennas, Two-Meter Antennas, Dual Band Antennas, HF Antennas, Dipole Antennas, Wire Antennas, Vertical Antennas, AM. doc (kh6htv, 3/5/14) p. When tested on my Analyzer It achieves resonance @ 50 ohms with a " flat 1. 92m from feedpoint to trap, 7. Both being full wave loops, this difference in behavior of the Folded vs. It is a 2m copper pipe dipole encased in PVC tubing. My operation is mainly working locals, the occasional. Comparing it against a 20m coax Dipole at the same height and, with the Doublet “tuned”, it was typically 1 S-point down on the resonant Dipole. My original packing included a 10m length of coax, my analyser, some antenna weights, wire, rope, power leads, BNC adaptors, barrel connectors and a balun. 2metre and 70cm Coaxial Dipoles (Double Bazooka type) What an easy way to set up some temporary antennas for 2m and 70 cm! I made both antennas with RG58 coax and slipped the into some electrical conduit. I have been in commercial and private radio broadcasting for 25 years, and it's time to dispel the myths about SWR and coax. Folded Dipole Calculator. 62 - Dual-band Loop Antenna for 30m - 40m. This folded dipole has a 200 ohm feedpoint providing a good match for 50ohm coax through the 4:1 coaxial balun shown. 23 - Wideband. Resonant Feedline Dipoles for 4m and 2m The resonant feedline dipole (which is a halfwave end fed antenna), has been in existence for many years and is capable of excellent performance. Adjustments was made on-site with MFJ-269 antenna analyzer. Again we are trying to help but not knowing your application it's hard to tell you what would be a good choice. Ham Radio Dipole Transmission Line. WBØTGE’s Mighty Woof 2m/440 Fan Dipole. Finally, the coax was pulled out so the cable tie was against the inside of the sewer pipe, the choke balun coils were formed tight against each other, and the coax slack was pushed through into the tube and out the bottom. It has a nominal 3 dB gain over an isotropic source and is directional, tending to favor signals broadside to the wire. Coaxial Folded Dipole Antenna. net Abstract A coaxial-cable trap dipole antenna installed in the attic provides a surprisingly effective solution to HF operation on the 10, 15, 20, 30, 40, and 80 meter amateur bands at a QTH with restrictive covenants that prohibit outside antennas. Examples where this may be necessary are small dipole antennas such as Force 12 vertical dipoles, shortened or loaded antennas using the coaxial cable as a counterpoise, verticals with few or shortened radials, full-size dipoles using the feedline shield as the "other leg" of a dipole, so-called 'end-fed' dipoles which use the feedline as the. It works great! It is temporarily mounted at 19ft on 2 sections of Rohn 15G tower that is bracketed to my garage. The KL3JM 80 40 20 “SRI” Fan Dipole Build a 3 band reduced space multibander THE DIPOLE ANTENNA What is a dipole antenna? KL7JR END FED ANTENNA. Except for the connector at the end of the feedline, the 2 m QHA is now finished. Detailed instruction of the correct position are included and a banana plug system is used for quick tap changes. The coax feed uses a 1. The same ground definition was used in each case. Context: I am working on an impedance matching section (1/2 wave length of coax) for a folded dipole antenna (VHF 2m amateur radio band). You will need. This means most preassembled coax cables will need to be shortened. 300 Ohm Twin Lead with the ends shorted is an option for even greater bandwidth. Moonraker was established in 1978. All you need is: speaker wire soldering iron and solder coax cable wire cutters. Basic half wave dipole antenna. Drill two 3/8" holes and insert coax cable, soldier lugs, bolt, lock washers, and 3/8-24 coupling nuts. The first item on the list is a 10 m Mobile antenna, or more specifically 2 of them. Nowadays with all those 2m repeaters and many used vertical radiators, this omni directional horizontally polarized antenna probably will not be interesting anymore. This antenna has a much wider bandwidth than a Jpole, and is a little smaller too. That's because the center. 2m/70cm vertical dipole antenna. 2m 1/2wave center fed dipole. Page 7 DIMENSION SHEET KLM 2M-14C ELEMENT SPACING - FEET/INCHES FROM ELEMENT LENGTHS IN INCHES: BOOM REAR: X X = FEEDPOINTS. Dipole antennas are oriented vertically, horizontally or in slants. The main part of the antenna is all one piece. With a simple antenna tuner (MFJ-945E) at my transceiver and 25 m (80 ft) of RG58A/U coax to the Slinky dipole, I could easily load & match the antenna system from 80 to 6 m. In Massachusetts the 47. A dipole is basically a length of conductor (wire) split into two portions and signal is taken off at the split. Detailed instruction of the correct position are included and a banana plug system is used for quick tap changes. The SIMPLE 2m/440 Copper pipe "J" by Dale “Kuby 3” pieces of coax in the HAM shack to bring the VSWR back to the 1:1 tuning the antenna was setup at. Secure with 1-1/2" U-bolts. This was okay but appeared noisy. Materials: 7m length of 50 ohm RG58AU/CU Mil Spec coax 1 * 50 ohm BNC connector 2 * 1 metre lengths of 27 mm water pipe (Bunnings) 1 * End Cap 2 * T-piece connectors 1 * […]. It is an ideal resonant choke at the base of the dipole. The so-called " OCF windom " is also a misnomer, for the same reasons. 2 Meter Whip Dipole Antenna By Jose B Rivera - N2LRB. Some commercial CB antennas are also made this way. The real practical advantage of the small loop compared to say a short vertical whip tuned. 2 of 2 have as high gain as a wire dipole strung really high in the air, or a yaggi beam antenna on a really tall (and very visible) tower. It will fit inside a 1 1/2" PVC to look like a vent. The RFI range of dipole arrays provide expanded bandwidth, high power ratings and unequalled. 080 m) makes 360 degr. Don't forget to ground the RF-socket at the boom to avoid currents on the braid of the coax cable ! A close look at the feed (early stage). The Folded Dipole antenna is 5% smaller than the standard, to generate -jX in the complex impedance. I want to add dipoles for 80m, 15m and 10m. 10m/2m/440 10m, 2m and 440 MHz Antenna: 20m/2m/440 20m, 2m and 440 MHz Antenna: HamR-7 40m, 20, 10m, 6m, 2m, 220 and 440 MHz Antenna: Cushcraft: Beam Antenna Chart & Index: Vertical Antenna Chart & Index: Diamond: A502HB Yagi Beam 6m: F 22A Vertical 2m: F 23H Vertical 2m: V2000A Vertical 6m/2m/70cm: X 30A Vertical 2m/70cm: X 50A Vertical 2m. 25in or 6mm, up to 3/8-in or 8-9mm. Depending on where you put the thing, it'd work as well as any other 2 meter dipole antenna in the same place. 1MHz and 147. Coaxial dipoles on 2m & 70cm. For VHF 2M, the center frequency is about 146MHz. If your putting in an HF rig and need 20-50 feet then that same coax would not work very good and you would need to go to 213 or even LMR400. 2 db gain over the dipole antenna and 1/2 vertical. The first item on the list is a 10 m Mobile antenna, or more specifically 2 of them. How to build a J-pole antenna for the 2-meter amateur radio band using zip cord, vinyl electrical tape, solder, a 6-foot bicycle safety flag pole and a length of coaxial cable to connect to the transceiver. The UHF ever increasing costs and site density requirements are reducing availability of antenna positions on prime sites. This double extended version provides 3 db gain over a dipole on the band it is designed for and each side or leg is about 5/8 wavelength long. Awkward you say? I would agree! What if I told you can make a 50 ohm version directly from RG-58 or RG-8 / RG-213 cable?. Coaxial dipoles on 2m - 70cm. Ferrite is made in different formulas, called mixes. If your putting a 2m or cb in your vehicle and need like 12 feet then RG58 would work fine. This multiplier factor is why you should keep cable installation lengths between radios and antennas as short as practical!. I am hoping I am able to make a wire dipole for 2m fed with rg213 coax. Call or Text: 574-575-6787. A balun is a MUST for dipoles or similar antennas when they are feed with coaxial cables. impedance, the losses are under 5 watts for the coaxial baluns and 53. The Antenna Farm : VHF 108-174 MHz Dipole Antennas - VHF & UHF Mobile Radios Radio Accessories VHF & UHF Hand Held Radios Antennas Mobile Antenna Mounts SWR/Power Meters Adapters Coaxial Cable Two Way Accessories Antenna Accessories DC Power Supplies Coax Cable Accessories Connectors Aviation Radios Repeater Systems Towers & Accessories Duplexers Diplexers & Triplexers VHF & UHF Base Stations. Making a Coaxial Dipole If you start with a common half wave (λ/2) stainless whip and extend it all the way down through a λ/2 long support tubing,. I was looking to build an easy to breakdown 2 meter antenna for an event I was helping with. It gave me 40, 20 and 15 with a push because although a 40 meter dipole should give you a resonant 15 meter antenna, in this case – with the coils. They tuned up a treat! and are both flat (vswr) across the bands, too. The so-called " OCF windom " is also a misnomer, for the same reasons. 1MHz and 147. To construct this antenna you will need a length of at least 130 cm RG58 coax. The dipole elements are threaded on the outside. HYS TCJ-N1 VHF NMO 136-174 Mhz Mhz Mobile Vehicle FM Tranceiver 2M Antenna with 13 ft RG58 Coax Cable NMO to UHF PL259 Connector for Yaesu Kenwood HYT Vertex Icom Mobile Radios 4. He is credited with original article in QST magazine. I like to tinker, so when I finish one project, I go on to another, even if it works well. Authentic Dual Band N9TAX Slim Jim antenna! The N9TAX Slim Jim antenna is the highest quality roll up antenna available today. Past week I have created simple 2m band half-wave dipole antenna. 64 – Dual-Band Sloper Antenna. My problem is that is preforms very badly and has worse range than stock dual-band whip antenna. (See mounting to mast below) Trim coax end & solder connectors on each conductor of coax Slide copper element ends into center insulator T and screw coax leads to copper antenna elements. FM Radio Dipole Aerial. The SWR is very low across the band. The Times Microwave Systems attenuation & Power Handling Calculator is a convenient online tool for comparing coaxial cable options. Sleeve baluns are normally used at VHF and higher. has been producing industry leading RF management products for the communications industry for over 30 years. Strip 1/2 inch of insulation from both ends of each wire. If the best SWR is at the high end of the band the antenna is too short. Now you are ready to attach the coax to the antenna (Image C). 2m Folded Dipole. Typical tubing diameters for the 2m and 70cm bands are from 0. Buddipole Compact Portable Dipole 40m-2m with coax Feeder. Call or Text: 574-575-6787. – Dipole antennas, twin lead, ladder line are (dipoles) fed with coax – RF on outside of coax and into shack. I like to tinker, so when I finish one project, I go on to another, even if it works well. A basic or folded dipole antenna picks up equally well in front of or behind its poles, but poorly at each end. - For 40 or 30 meters, use 12 turns of RG-213 on 4 inch PVC sewer pipe. Figure 1 The Balun is hung at a right angle. #N#Dipole_folded. this is important. The Phasing Harness. One 40 foot RG-58C/U coax feedline with PL-259 connectors. On a rare calm day on Mt Wellington (VK7/SC-001) we setup both the VK7JJ vertical and the linked dipole and did a test thanks to Robbie VK3EK. mast which holds three other antennas, viz. You can feed your dipole with coax, as already mentioned above. Further, the E-field only has one vector component and consequently the fields are linearly polarized. The sloping dipole antenna (fig. It requires a balun and works very well. Dipole antenna made from the rtl-sdr stock antenna cable. Split 1 1/4" PVC -T lenghtwise to slide over support mast. 97 for a PVC insulated. ☜Return☜ Short Leads. Length is measured from connector tip to connector tip with the 'T' connector in place (see below). All pages are hosted on this site so visitors will not have to search thru many broken links. That is a pattern which has low side lobes in relation to the main lobe. For want of a better name, lets call it a ‘half folded dipole’. There is a general lack of measured data comparing small transmitting loop antennas to some sort of standard antenna. Using an antenna analyzer and about 9 feet of coax I drive the nail into the tree until I get a 1. If you have a requirement for more than we are showing in-stock, perhaps for a club-build or group project - please get in touch. Made out of coax, it matches closely to 50 ohms and can be set up horizontally or in an inverted V. This type of trap construction of- fers several electrical advantages arid is. It does not have any theoretic gain, but it can be tuned PERFECTLY. 62 postage 2m 70cm BOXX TB-2x. Resources listed under Antenna for 2 meters category belongs to Antennas main collection, and get reviewed and rated by amateur radio operators. It is best to cut the antenna for the center of the band in question. Center is connected to the 3/8” 1/2λ aluminum element braid (ground) is connected to 1” 1/4λ aluminum element Use the Wavelength formula to compute for the element length in reference to your target. 00 Ex Tax: £34. I want to add dipoles for 80m, 15m and 10m. The feed impeadance is achieved by making one side out of a thinner conductor (2. No matter what type of antenna or antenna system you need, you'll find it at DX Engineering. Coaxial dipole is a surprise. The antenna was created for the 40 meter band and above. The coax should see the full 200-300 ohm impedance of the folded dipole, so a bad match without further work. Follow us on Facebook KENWOOD TS990S Best HF Base Made! $7099. You can feed your dipole with coax, as already mentioned above. Coaxial dipoles on 2m & 70cm. of runtime on coax be equivalent to a length of 1. W3JlP 0th the coil and capacitor of a parallel-resonant antenna trap can be made from the same length of coaxial cable. 9) connected with the mounting brackets. If you're a ham, that's got to sound interesting! By Robert H. TV Antennas have been around for many years - and people have tried all sorts of unsightly things to "fix" them or make. Pull the coax snug and secure it with a wire tie. 62 - Dual-band Loop Antenna for 30m - 40m. Consider this, I have a 2 meter ground plane antenna tuned for 146 Mhz and matched to 50 ohms at the feed point. This double extended version provides 3 db gain over a dipole on the band it is designed for and each side or leg is about 5/8 wavelength long. 65 – Inverted-V Beam Antenna for 30m. Made From a TV Satellite Dish. Coverage 40m - 2m. The "Cylinder" - Center Connector for Dipole Antenna: This is another alternative home-brew center connector for a dipole. This will also prevent water getting onto the joint. The loaded dipole (V2) is not as good as a full size antenna but it can be used in limited spaces and even indoors. It was incredibly heavy and very quickly became a sagging and corroded eyesore on the corner of my house. So the measurements are based on a 40 meter 1/2 wave dipole. The cable /in the shack/ was cut in small portions until the SWR as at the antenna feed point was obtained. It can be fastened to the side of a house and painted the same color or painted dark brown/black and fastened to a tree. Enter the desired frequency and select the desired calculation from the drop box. Ver2cal'Wire'Antenna' • Actually'a'ver2cally'orientated' resonate'1/2'wave'dipole'with' the'earth'being'the' return ' half' • Due'to'poor'ground' conduc2vity'a. EU & World tracking £5. My thought is to use the shield and center conductor of the coax to make the radiators - strip the insulation off the outside for a length, fold the shield back along the length of still insulated coax, exposing the center. I then remembered a chapter in the 18. My problem is that is preforms very badly and has worse range than stock dual-band whip antenna. 13 - Multiband Dipole Antenna. It is strongly suggest that you put a 1:1 Current Balun at this point. The other method might be to use a gamma match similar to the ones used on yagi and other 1/2 wave driven element antennas (like beams and such). • The antenna shall be reasonably inexpensive compared to the cost of a similar size wire dipole antenna. This was found to be quieter and made the antenna less sensitive to frequency changes. And a decent SWR. My thought is to use the shield and center conductor of the coax to make the radiators - strip the insulation off the outside for a length, fold the shield back along the length of still insulated coax, exposing the center conductor. It is made to be hung in the rafters or from the ceilings. The BOOM of antenna its a piece of square aluminium 15x15 mm. 14 Gauge Wire. 2m/70cm vertical dipole antenna. Gain & Wave: 2M: 1. 2m is the target band. Every Day new 3D Models from all over the World. mast which holds three other antennas, viz. This is a tried and true method and it works. 4GHz is shown in the photo below. This was found to be quieter and made the antenna less sensitive to frequency changes. If you still want to make one, just use some television twin lead cut to length using the info in #2. 293 "coax" 3D Models. M-24B (coax terminates in a BNC-male conn) M-24S (coax terminates in an SMA-male conn) M-24SJ (coax terminates in an SMA-female conn for the new Chinese made HT’s) 2M/440MHz DualBand antenna on a small magnet, 12 ft of coax included terminating in the most common connectors. "Subject: Plumbers' Dipole Antenna Date: Fri, 13 Sep 2002 13:39:21 -0500. The elements are colour coded with heatshrink to identify where they are to be screwed in. Making it a resonant antenna for all bands from 80m to 6m (except WARC bands). Centerfire Antenna, LLC PO BOX 8305 South Bend,IN 46660. Description. A crossed-dipole turnstile antenna for 2-meter ARDF I came up with this antenna design for use with hidden transmitters on international-rules ARDF events.