frequencies for your country or favorite modes. 3 0 obj You are using an out of date browser. 80m up, W3EDP's 84' antenna, 17' counterpoise is probably the way to go. End Fed Half Wave Antenna Coupler Schematic - 7-30MHz. 32.00. stream We are working every day to make sure our community is the best Radio Hobbyist's site. Here Is a 250 Watt Home-Brew That I Made In about an Hour. Our newdesign isperfect for matching both long and short length wire antennas for multiband use. SWR will vary based on topography, wire orientation and use of ground or counterpoise. %%EOF A VSWR sweep of the unun after adding a 100pF capacitor shows an SWR <5:1 from 160M to 10M. A 50 foot run of RG-8X coax connected the antenna into the LDG Z100-plus tuner and then a Yaesu FT-891A transceiver. This type of antenna is very easy to install because there is no need . When you're 1/2w long you're around 2k ohms or more where the balun won't under or over xform; as you approach 3/4w your z is going to drop to where a coax match can be made just by soldering the wire to the center conductor sans balun - more or less the principle of the windom and ocf dipole. Use with other lengths can potentially damage the transformer depending on power level in use. If the transformer is used with an externaltuner in conjunction with a single wireantenna typically 130-135 feet in length, power should be reduced on those bands that show an SWR above 1.6 to2:5 withoutthe tuner. Because I had some spare Cu-Wire I wound another 1:49 Unun on a smaller FT-140-43 toroid and tried different capacitors between feedline and ground (to compensate for the 10m band). rig, often with no feedline, and the other end in the air attached to The "Super Bullet" End Fed Long Wire Antenna Matcher - 1500/3000 watt rated for Super-Punch of your signal! Thus a 1/4 wave for 20m@16ft, 40m@33ft as examples are not going to work. Usually any wire length that is non resonant on the band or bands desired will work with the 4:1 ratio. An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). At multiples of half wavelengths of the A png image named g.png will be created. /CropBox [0 0 748 752] is that for a given ham band there are min and max frequencies which Then verify it with your installed antenna and SWR measurements. 2. google_ad_height = 600; The Nelson antenna 9 to 1 unun did the trick. wire lengths less than 1/4 wavelength of the lowest desired frequency Tune Around! SSTV 2 0 obj We do not encourage any radio operations contrary to regulations. For typical tuners built into a rig, I connected the free twisted end of the short and long wires (the ground) the chassis wire (ground) of my homemade testing jig with alligator clip. I sent him the link to the 49:1 unit to get his feedback. <>>> 6 Screws/ Nuts/ Washers/Wing Nuts And Ring Connectors, 1 X Mica Capacitors 100pF 500V 5%(Mouser Electronics), 1 x 4 in. 22.00 + 5.00 Postage. hbbd```b``^ "Cs;D2 I*`0D;+EVUHy`qml0{YVw`b0i DvkAh |"w I2% ?W%@Fg`` 6 You have to stay away from a half wavelength on any frequency. If you would like to use high power up to legal limit with a single end fed wire antenna (not necessarily a half wave) consider using our Model 9135 along with one of the wire lengths shown in the Installation Notes. The popular End-Fed Half-Wave (EFHW) Antenna is an easily portable, high-impedance (2,000-4,000 ohm) wire antenna that resonates on its fundamental frequency and all harmonics above. Antenna Design Picture Information. 75/80 METER RESONATOR KIT FOR THE UJM-EFHW-40-10 200W 40-10m ANTENNA Odds are that most lengths are fine though, so the easiest solution is to pick a length based on something else (like, the room you have available) and if you get unlucky, roll the dice again. gnuplot var sc_security="1df091cc". Turns 1 through 14 are secondary windings (the long wire). 0 x@ The length should be calculated based on the lowest frequency to be worked. The "9:1 UNUN" are for random length wire antennas fed at the end. The kit includes the parts needed to construct a 49:1 impedance matching network, which will transform the impedance to 50 Ohms, which will suit most transceivers. For instance, to work 40m be sure the antenna is at least 10m or 33' long. Lengths of a half-wave or multiple must be avoided. I say run what you got and don't worry about it. Both were on 20 meters at 97 watts, Icom 7300. unavailable, a random wire can save the day, but it is important to <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Jack, VE3EED, hopefully has solved a major headache we all have when we attempt to go thru the trial and error and frustration with getting the random wire to work where WE want it to work. If you want a single band portable antenna you can mount pretty much however, look up this design. So, if you connect a length of wire that presents an impedance of about 450 to the input, you'll get an impedance of about 50 on the output. I have not done this yet. This Balun Designs unit is replacing an MFj 1982 HP EFHW balun that was DOA when it arrived last May. End fed 9:1 58ft wire and 17ft counterpose wire touching ground. /Subtype /Image /ProcSet 7 0 R >> >> My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about . 10C) for the 10-80 m bands, or even 6-160 m: 17 ft (5.2 m) of twin-lead and 68 ft (20.7 m) of antenna wire (i.e., standard dimensions). That meant calculating all the way to 32 multiples of a half wave on 10 meters. Several ways exist to bring the wire's high impedance feedpoint closer to the desired 50 ohms, including use of a 49:1 or 64:1 unun, which eliminates the need . >> Privacy Policy /ColorSpace 11 0 R At this point, Ive only used the 49:1 tap, but plan to take the 64131 whenever I operate portable. STORE Jack, VE3EED, used center frequencies of thebands described in the article above, and I thought it would be nice to use band edges. You will also need a half-wavelength length of wire (14 or 12 gauge typically) in order to construct an antenna radiator for whichever ham band you choose. To summarise the results WRT to reference antenna consisting of 30ft wire vertical fed with auto- bands you're intested in in a vector like the example below, by typing. InJack's own words. The WorldwideDX Radio Forum was originally established in 2001. When on the trail, at Field Day, or whenever a good antenna is I purchased a MFJ-16010 Random Wire Tuner and an LDG RU 1:1 unun. While I have not done so yet, I plan on gluing the test cap to the back of the junction box. Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. HF & Shortwave For instance, to work 40m be sure the antenna is at least >> Upon further research, I remade it tightly twisting those two separate wires together, just as it shows in archjeb's picture, and it worked surprisingly well. Cut the center conductor wire (free untwisted end of short wire) of the unun to the correct size, scrape the enamel insulation off of the free end with a box cutter, and solder it to the SO239 connector. A Balun is used to match a balanced line to an unbalanced line. Y &lD30. 2 eyehooks with washers and nuts (I used #8 diameter, but size is up to you.) This undesired reflection of RF power back toward the transceiver is identified as a high voltage standing wave ratio (VSWR or SWR). % Re: 9:1 or 49:1 unun for end-fed long/random wire? &nb A good place to start is the formula 468 / f (MHz) for a 1/2 wavelength wire antenna. results. http://udel.edu/~mm/ham/randomWire/. 40-30-20-15m bands for my 4 band Elecraft K1 qrp rig. I actually did this first and before the connector was bolted to the box. The transformer usually used with an end fed wire is a 9:1 transformer. N4UJW. I used 2000 and 1000 ohm resistors in series connected to the proper unun wires with alligator clips for a total of 3000 ohms. 1863 1.49 swr 3915 2.50 7200 1.80 14.332 1.29 18.130 1.07 21.300 1.40 24.950 1.30 28.400 1.37 This is a great antenna that is . https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. Ham Radio News! You can take one of these 49:1 transformers and use the 468/freq (Mhz) formula to calculate the length you need in feet. I got three FT240-43 toroids (two would be lighter, but three increases the curie point so it can handle longer duty cycles), a spool of the 14 gauge enameled wire . 40-10m with a 49:1 Unun. /Type /Page Balun Designs. uR5ucE`_aksLjYT=hzRa]JucX7d}|'}`XRa>X google_ad_client = "ca-pub-9377297764300878"; They just saved you and I loads of time and frustration. random wire page. << The short piece is for the primary winding of the transformer, and the long piece is for the secondary winding of the transformer. It is not a good choice for working lower bands from a too short wire, that is, if you have cut your wire to a 20m halfwave, it ain't much punkin' for 40m, 80m, or 160m. I'm consistently pleased with the quality and ease of use of Balun Designs products and look forward to my next purchase in the future. 9:1 or 49:1 unun for end-fed long/random wire? Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. /Parent 3 0 R Ham Hints << In the first year using this unun with a random length endfed wire (Aluminum Elec fence wire at that) I managed to confirm WAS via LoTW on 10m, 15, 17, 20, 30, 40, 80. . Post Reviews which got me thinking. /Title (Wire-Lengths-for-9-1-ununs.pdf) This may not be relevant to HF stuff, but the antenna I use for NDB reception has a 400:1 transformer (20:1) turns ratio. The ratio doesn't need to be 49:1 2,400 ohm either, other ratios will transform to other impedance. You will also need a half-wavelength length of wire (14 or 12 gauge typically) in order to construct an antenna radiator for whichever ham band you choose. 3 0 obj random wire should use 423/f. . Box cutter (for scraping enamel off of wire ends), (Helpful) Step drill bit for SO-239 connector, Paracord (for simulating and measuring lengths of windings on toroid), Antenna analyzer for HF frequencies (I use the RigExpert Zoom AA-55), Resistor(s) totaling about 3000 ohms (I used 1K and 2K ohm resistors in series). Do what works best! . 20/40/17m. Ask Elmer Power Handling (CW/SSB): 100 W/200 W Enclosure Width: 2.500 in. Let's have a look at a few details on how to build a 49:1 impedance . Cannon". Hope it's clear now, if not. want the antenna to be at least 1/4 wavelength long for each band you I have used the 49.2 ft (15 Meter) length of wire on vacation with both automatic tuners and an MFJ Model 16010 tuner with good results for 40, 20, 17, and 15 Meter operation. Anyway, an old friend mentioned 'MyAntenna.com' but they were closed for the summer. 59 0 obj <>/Filter/FlateDecode/ID[<81C501BAF3AD19DF6B2122F37F15AF84>]/Index[25 50]/Info 24 0 R/Length 149/Prev 898971/Root 26 0 R/Size 75/Type/XRef/W[1 3 1]>>stream The Short Answer Would Be That an UnUn Is a "UN balanced to UN balanced" matching transformer. Well, I didn't think it would make any difference at that many multiples. The 30 day return period lapsed before I could get the antenna deployed to test it. The QRP End-Fed Half-Wave Antenna 49:1 Transformer Building a great impedance transformer for Ham Radio end-fed wire antennas. are easily converted to half wavelengths by the famous 468/f generally This is not exactly a 1/2 wavelength in free space, but works for wire as it has a different velocity factor than "air". Designed for use with single wire unbalanced antennas, this new addition is small, compact and perfect for quick portable/emergency installations. The fewer bands, the fewer high impedance regions to avoid. For best results, use the Wire Length Feet 1.8 MHz 3.7 MHz 5.3 MHz 7.1 MHz 10.1 MHz 14.2 MHz 18.1 MHz 21.2 MHz 24.9 MHz 28.5 MHz 50.1 MHz stream Theme designed by Papathemes. endobj SO-239 (UHF female) chassis mount with screws, nuts, lock washers. The magic lengths to use with the End Fed longwire is 29, 35.5, 41, 58, 71 and 84 feet I use a 29 foot wire with my PackTenna 9:1 balun for 40m-10m and then add a 28 foot length for better coverage on 80m when needed. Here are the final numbers (in my opinion) in green below that would be good for a long-wire antenna: (You may want to make a note of them), REVISED: 29 35.5 41 58 71 84 107 119 148 203 347 407 423, REVISION NOTE: We had a note from James, KB5YN, pointing out that one of my so-called GOOD numbers was 220 feet. Use only the white gaps for your antenna lengths, and if About Hamuniverse 1 0 obj 2 0 obj %PDF-1.5 9 0 obj /Kids [ 4 0 R ] /XObject << /Im0 9 0 R >> All you need for a random wire antenna is some wire, your tuner, one or more supports up as high as you can get them to string the wire from the supports to the tuner, at least one or two insulatorsand a little time. So for 80 meters (say 3.525 MHz) this gives you about 133' of wire. Click to enlarge. | 5 0 obj "Can you please recommend schematics that are designed to tune setups like these? <> Theme: Newsup by Themeansar. <> Start winding the toroid with the twisted wires at loop #1 (see schematic below). That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at . SBULLET-9U-1500. I connected the free untwisted end of the short wire to the center conductor of my homemade testing jig (see tools list) with an alligator clip. Each vertical blue line represents an amateur radio band. endstream endobj startxref The following wire connections do not need to be made in the order I described. x][~ XwiH:99gn`1-wz;n[VbW7JH4D]>}>y/D_^7,yyx}s*nveo>mn|6k7GMY4%" M)?O|'opw8o1\5JNe:9hTc5@Ik~aE%O^0$ 0E 'BX2?R!t&^E"3oqbW |${boEU>jU:]bQW?4, u1'^`oQ_4E 0~y L^'y}-RHV8L KSZ?mF4lTv'r^mF|":e}?VdTm7bGR]PchDpb*{*HGJ-m)bC!EX"iM%8L7O7-=jcn+D{_' I HH~v70J^9$.7m]knq)L(UQ%OrK:nn!8*EP << Suggested wire lengths for 1-61 MHz operation (measured from Bullet wire point): Bands Covered (meters) Wire Length (feet) Minimum Coax Length (feet) 40-30-20-15. <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> As typically 7 0 obj An end fed antenna consists of a wire fed on its end, the length of that wire is not resonant with any frequency or frequencies you will be using it on. There are so many new frequencies to stay away from, that it gets pretty tricky for the longer wires. [ /PDF /Text /ImageI ] %PDF-1.4 % K1S Valentines Are (Almost) Out The Door! //-->, The "Best" Random Wire Antenna Lengths NEMA rated 4x marine grade junction box for outdoor installations. hb```YloD@(aKI V!}g@~}%Q/[[~_=Wy-:O)x[~hs/~SGeG _QE C6q %r As an example, a 28-31 foot wire will typically allow 40 thru 10 meter coverage and a 43-50 foot wire will provide access to 80 thru 10 meters. and experiment. endobj 748 0 0 752 0 0 cm In stock . A level of 500-600 watts is the maximum with a further reduction onany band measuringabove 3:1. V#X~[Z?\ZcX:-Y?&Y?IqTnayZ{jTZOub}=UTWu1G>o.,RaT c=W>:sECXTkc=X I made one without doing this and it didn't work so well. The novel thing was that I only built it the day before and it uses a Coghlan camping washing line spool with the string taken off and about 21m of wire wound onto it. the C code, in Matlab or Octave get a plot by simply putting the (Also check out AB3AP'Swebsite and say thanks for sharing his skills. The length should be calculated based on the lowest frequency to be worked. End Fed Antennas. An Unun is used to match an unbalanced line to another unbalanced line. document.getElementById("copyright_year").innerHTML = new Date().getFullYear(); Vacation Closure - See Homepage for Next Availability. Wire lengths for the 4:1 ratio in models 4130, 4132, 4134, 4932 and 4935. Each winding is counted when the wire enters through the center hole of the toroid. all US ham bands. "Just received my new 64131 yesterday and was anxious to see how well it performed. If the choices are. The unun was floating at about 15 feet above ground. The bandwidth where SWR was below 2:1 was about one MHz. The idea What these lengths are depend on your tuner and also the wire's surroundings and also the ground system. First, it is important to understand the difference between the end fed half wave and a random wire (or "long wire") antenna: the random wire is just a piece of wire that is matched to 50 Ohm impedance using an antenna coupler, sometimes adding a 9:1 unun. endobj A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. 31 doing the initial 468/f on C and D scales. The WSPR map is so dense it looks like the US and Europe are just big blobs of color. If you plan on stringing up a dipole you use 2 equal lengths of wire with the Balun in the middle. End fed 49:1 60ft wire (using coax as the counter poise. multiples, and of course different band combinations yield different endobj >> I only used two screws instead of four. It's an efficient way to get all the multiples CQ-Calling All Hams! Proudly powered by WordPress 4 x 4 x 2 electrical junction box (available at big box hardware stores), One PVC DWV Test Cap (available at big box hardware stores in plumbing). Clansman End Fed Long Wire Antenna Used. Turns 1 & 2 are primary windings (the short wire).