(Also note that here may be instances where the suggested lengths may not work exactly due to the many variables in the surroundings of the antenna, wire length variances, your tuner, it's height above ground, it's construction, etc. I'm looking forward to getting off work and hitting 40 & 20 meters again!! Placing 3000 to 4000 ohms of resistance between the free end of the twisted portion of wires (the gound) and the free end of the long wire (the wire that connects with the antenna radiator after the 14th winding), can simulate adding an antenna radiator wire to the unun impedance transformer. Lengths of a half-wave or multiple must be avoided. Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. About Batteries /XObject << /Im0 9 0 R >> N4UJW. Prescott Hamfest 2023 Saturday - May 13, 2023 - 0800 to 1200 MST Granville Elementary School 5250 Stover Drive, Prescott Valley, AZ 86314 The 2023 Prescott Hamfest is co-sponsored by the Yavapai Amateur Radio Club (YARC) and the Amateur Radio Council of Arizona (ARCA). So you have the freq range of interest and the total length of the wire, figuring out wich balun will be a better match for 50ohm coax should be easy. 1 0 obj Contact 6 0 obj I only used two screws instead of four. var sc_security="1df091cc". The WorldwideDX Radio Forum was originally established in 2001. multiples, and of course different band combinations yield different You also , Most matching problems occur when the antenna system >> var sc_invisible=1; I made just a touch over 100 QSOs today with the new unit. One is for the top of the box so that it can be hung up. He had heard good things about 'Balun Designs' so he recommended you. This calculates to 4.2 m or 14 ft for an 80m end-fed. 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 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. Continue twisting the entire length of the short wire. document.getElementById("copyright_year").innerHTML = new Date().getFullYear(); The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? This unit is a Balun Designs, in collaboration with Fair Rite products, has developed what we consider to be the best single core 1:1 feedline isolation balun available today. To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. 9:1 Unun EF Random Long wire matching Transformer with BNC or SO-239. In another life, I could have been a telephone engineer. Our newdesign isperfect for matching both long and short length wire antennas for multiband use. but instead of the Jaycar core, we used an Amidon FT-240-43; anyhow, we also followed the UnUn with a 1:1 guanella choke and boxed everything, at that point, we . 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. /CreationDate (D:20221212112042) 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 . often can't match it. The "Super Bullet" End Fed Long Wire Antenna Matcher - 1500/3000 watt rated for Super-Punch of your signal! x[q;`&z`uAlo#V@;hvOYt, @*Ys~_W_~W_aw_ p[N+}[t-^oLy}xz>7/~c|ZZt75;kN^=>Y+_~|b~"m*tw>xG=x6Qwz|xvz- | VSWR analysis of the antenna in the field showed that VSWRs between 3-5.5 from 40M to 10M. I did not want to put the transformer in the housing until I tested it. Stacked coreswithwinding configured as 49:1auto transformer. Click to enlarge. Because I'm more visually oriented I then plotted the many overlapping "red zones" and ended up with the page at: u?X`f0&/Ri;W0Tn_*TX:ug Legal Stuff understand its properties. Multiples are on C and installed, it is a compromise antenna but great for portable use because If you plan on stringing up a dipole you use 2 equal lengths of wire with the Balun in the middle. Use a slide rule! frequencies for your country or favorite modes. >> In total 29 contacts were made from British Columbia to Texas to Florida in 40 minutes on 20M. Use only the white gaps for your antenna lengths, and if In stock . SO-239 (UHF female) chassis mount with screws, nuts, lock washers. You will note that when comparing my results with VE3EED that some of the results are a bit different. >> Technical specification : Type : 49:1 Unun Frequency : 1.81 MHz - 30MHz Impedance ratio: 1:49 Input Impedance: 50 Output Impedance: 2500 Power Handling (CW/SSB) : 250W Core Type : 1x FT240-43 by Fair-rite Co. Capacitor 100pF 3KV Assembled and tested. 31 The counterpoise wire does not have to be similar in length to the main radiator wire and just a short wire is all that is needed, about 0.05 . /* Ad banner 160 x 600 */ So for example 80m could range in length from 120 to 133 feet. hb```YloD@(aKI V!}g@~}%Q/[[~_=Wy-:O)x[~hs/~SGeG _QE C6q %r This is to avoid the antenna radiator from acting like a resistor, and thus instead of radiating radiofrequency energy produced by the transmitter, sending it back down the coax toward the transmitter. Lengths to avoid are not always the same as This transformer is designed to be used with an end fed half wavelength of wire only. 35. Proudly powered by WordPress STORE here are values for CW portions of the USA /Type /Catalog Care to buy us a beer? Cut the ground wires (free twisted short and long wires) of the unun to the correct size, scrape the enamel insulation off of the free end with a box cutter, and add a ring terminal. shown in the column e. var sc_project=8077274; For those that enjoy the LNR and Hy Endfed antennas, but want to run more power, We have also installed an additionalstud which can be used for a separate counterpoise wire rather than forcing the use of the feedline's coax shield, ttaching a counterpoise wire to the common point of the auto-transformer, provides the antenna radiator something to push against rather than the coax shield. Wire lengths for the 4:1 ratio in models 4130, 4132, 4134, 4932 and 4935. google_ad_height = 600; you're using different ham bands than in these examples, modify and rerun What these lengths are depend on your tuner and also the wire's surroundings and also the ground system. For example a 32 foot length is actually a half wave on 20m with an impedance of about 3500 ohms and requires a 50:1 balun. It is optimized for 3.5/7/10/14 MHz but will work reasonably well on all amateur bands from 80 meters thru 10 meters with a 135 foot length of wire and a short connection to ground. $119.95. 3 0 obj 32.00. The major point of this message is to tell you that approximately 20 minutes after I connected the balun unit to the antenna, I made contact with a gentleman in Italy-my first European contact!! Post Reviews To summarise the results WRT to reference antenna consisting of 30ft wire vertical fed with auto- JC[ d8O[UKKQ{yZ{G 'Upno_*~8uo a@G`' zxUHXW&`}mEp`?i0 oE:N0-/t"t.-? This will be for an eyehook in order to provide strain relief for the radiator wire. ", KiwiSDR Online Radio - 500 ft Northeast Beverage, KiwiSDR Online Radio - 400 ft South Beverage, KiwiSDR Online Radio - 10/11m dipole up 20 meters high. >> Tools I imported my spools from the US, but I have seen them on Ebay in the UK. Typically unbalanced = 50/75 ohms too unbalanced = 450/675 ohms. http://udel.edu/~mm/ham/randomWire/. this used by hams for dipole lengths. config file by typing gnuplot rw.gnu. /MediaBox [0 0 748 752] Superglue 2 toroids together. Ultimately, this housing works fine, but it is heavy and clunky.). Then verify it with your installed antenna and SWR measurements. Wire-Lengths-for-9-1-ununs.pdf Created Date: 12/12/2022 11:20:42 AM . This design is excellent for matching both long and short length wire antennas for multiband use. 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. Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. About Hamuniverse That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at . Each vertical blue line represents an amateur radio band. wire lengths less than 1/4 wavelength of the lowest desired frequency Reading Room Recommended wire lengths for Unun models 9130, 9132 & 9135 Table shows typical SWR relative to installed wire length. At multiples of half wavelengths of the There probably should be some holes for ventilation. 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. /Width 748 AndWhat Is It Used For In Antennas? The second smallest number I measured was 2.7pF, derived from the self resonance at 2.72 MHz with the magnetizing inductance (measured at 25.8 H) with the secondary open and the output wire folded to a small 1/2 length. Picture 1 of 9. Alternate connectors and Mounting Options are available in the. The graph below shows lengths to avoid for different collections of bands. For instance, to work 40m be sure the antenna is at least 10m or 33' long. I attached the toroids to a PVC DWV test cap with 3 cable ties. << The trick, therefore, is either google_ad_client = "ca-pub-9377297764300878"; Just add or subtract as needed a little at a time toget the best compromise. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. SO-239 connectors are silver plated with Teflon insulation. Generally an EFHW will be in the range of 2,000 to 5,000 ohms at the very end of the dipole when resonant. are blocked out because an antenna should be at least that long. The free end of the untwisted portion of the long wire (past the 14th winding) will be secured to this bolt as well on the inside of the box, while the radiator will be secured to it on the outside. . An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). Q It may not display this or other websites correctly. The First Thing New Hams Often Ask:What Is An UnUn? It is used fornon-resonant verticals like 43 foot or 33 foot Or Wire antennas like an End-Fed1/2 Wave Multiple Length Wire Antenna. endstream Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. 9:1 Unun 1.5-54MHz 2kW 9132S. 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 . endobj 2 0 obj Coverutilizes integralneoprene gasket for weatherproof integrity. EFHW unun Resonant Long Wire 49:1 Transformer With BNC or SO-239 | Mobile Phones & Communication, Radio Communication Equipment, Antennas | eBay! The bandwidth where SWR was below 2:1 was about one MHz. For reasons that I do not understand, adding a capacitor between the coax conductor wire (untwisted free end of short wire) and the ground (twisted free ends of long and short wire) can increase the functional bandwidth of the antenna on the higher HF frequencies. 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. <>>> (The numbers aboveare a great start, thanks to Jack and Mike! Following the directions exactly as specified (0.47wl / 0.05wl matching counterpoise) and drilling two weep holes in the appropriate position, I had a 10 meter EFHW antenna up in less than ten minutes. wire to the UnUn "-" connector and then down to ground there it connects with the two other wires but neither the counterpoise nor the two other wires are connected to ground.
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