In total 29 contacts were made from British Columbia to Texas to Florida in 40 minutes on 20M. 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 are easily converted to half wavelengths by the famous 468/f generally /Name /Im0 A few more comments about this 49:1 autotransformer EFHW design. So is an essential piece of gear to have. Computer Help Random wire lengths you should and should not use! 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. <>/Metadata 239 0 R/ViewerPreferences 240 0 R>> endobj /Length 6 0 R 0$Ve plan to use. /MediaBox [0 0 748 752] I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. << For example, In fact, the 9:1 unun that I built is actually an autotransformer. 8 0 obj for your country and favorite modes of operation. Cannon". This project assembles a 49:1 ferrite-core ("FT") type #43 transformer that matches 50 ohm input to 2500 ohm end fed antenna. An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). Stacked coreswithwinding configured as 49:1auto transformer. The key to end fed antenna success is the matching network interface between the long wire antenna and the coax feed line and feed line choke at the transceiver. End Fed Antennas. This transformer is designed to be used with an end fed half wavelength of wire only. You can get good loading and low swr on sometimes 2 or 3 bands, but one or more of the bands thatyou want, just will not cooperate with an swr that can be adjusted with the "tuner". Tune Around! 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. 27.00 (27.00/Unit) Free Postage. Note: My (A to B) length was 6 inches. While these lengths have been shown to work well on many bands, which SO-239 connectors are silver plated with Teflon insulation. For those that enjoy the LNR and Hy Endfed antennas, but want to run more power, Balun Designs now offers an excellent alternative. 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. is that for a given ham band there are min and max frequencies which One single wire, no solder connections,very simple.all the way from the tuner to the end support. endobj Powered by BigCommerce. One is for the top of the box so that it can be hung up. endobj I sent him the link to the 49:1 unit to get his feedback. 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 Just add or subtract as needed a little at a time toget the best compromise. A so-called random wire antenna is an end fed antenna. /ProcSet 7 0 R >> NOTE: Rewording the previous paragraph, if you have a capable enough Power Handling (CW/SSB): 100 W/200 W Enclosure Width: 2.500 in. The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. If you want a single band portable antenna you can mount pretty much however, look up this design. 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. endobj , This is a partial reprint (with permission) of an excellent series of articles published by KV5R In addition to multiples, Support The Site The fewer bands, the fewer high impedance regions to avoid. The following wire connections do not need to be made in the order I described. Here Is a 250 Watt Home-Brew That I Made In about an Hour. We do not encourage any radio operations contrary to regulations. I connected it to a 33 wire running from my balcony, through the trees, and ran WSPR overnight to check things out. Thanks for your answer,I will probably go with the 9:1 then. A couple hours later when I sat down to do some more DXing, I made contact with a gentleman in Slovenia-my second European contact. installed, it is a compromise antenna but great for portable use because Wire lengths for the 4:1 ratio in models 4130, 4132, 4134, 4932 and 4935. Moving the pot up and down gives a feel for the SWR versus antenna impedance sensitivity. 2 0 obj This undesired reflection of RF power back toward the transceiver is identified as a high voltage standing wave ratio (VSWR or SWR). I'm not saying aliens are in the radio, but aliens definitely are in the radio. so that it is not a halfwave multiple of any frequency you want to use. high the other 1.5m (4.5feet). google_ad_slot = "1982258389"; You'll want to have that wire up as high as you can get.. Theme: Newsup by Themeansar. good show chuck, you said ya picked up a 430, did i tell i fried the 0ne i got from you, can anyone point me in the direction of a 2 pill schem for the HG 2879? 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. I only used two screws instead of four. 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. These dimensions were derived from modelling the antenna in EZNEC. That's it in a nutshell..or is it? google_ad_client = "ca-pub-9377297764300878"; This was 9m vertically metres up a fishing pole and then about 5.8m out. For instance, to work 40m be sure the antenna is at least SSTV q A VSWR sweep of the unun after adding a 100pF capacitor shows an SWR <5:1 from 160M to 10M. <> Hertz Antenna" shows in line 2 of the table that a similarly installed About Batteries The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. $119.95. In another life, I could have been a telephone engineer. Technical specification : Type : 49:1 Unun Frequency : 1.8 MHz - 7.3 MHz Turns ratio: 1:7 Impedance ratio: 1:49 Input Impedance: 50 Output Impedance: 2450 Power Handling (CW/SSB/ Digital Modes) : 2Kw of peak power / DM Modes 500 watts Core Type : 3 x FT240-43 by Fair-rite Co. Wire type: Enamel copper wire 2.0 mm (AWG 12) Assembled and tested. 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. We'd really appreciate it! Generally an EFHW will be in the range of 2,000 to 5,000 ohms at the very end of the dipole when resonant. InJack's own words. 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. Alternate connectors and Mounting Options are available in the. 35. A png image named g.png will be created. rig, often with no feedline, and the other end in the air attached to Attaching a counterpoise wire to the common point of the auto-transformer provides the antenna radiator something to push against rather than the coax shield. (A t0 B) Fold over 6 to 8 inches and twist it together. these are the worst lengths and you want to be as far from colored /CropBox [0 0 748 752] Ham Satellites SO-239 (UHF female) chassis mount with screws, nuts, lock washers. << For typical tuners built into a rig, , Most matching problems occur when the antenna system well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) >> The random wire antenna is probably one of the least expensive, easiest and cheapest HF antennas to use if you have a tuner and you want to get the "most" out of a length of "random" wire without having to pull out that calculator, doing the math, getting the center insulator built orbought, running the feedline, and all the rest that goes with putting up a more elaborate antenna. This is not exactly a 1/2 wavelength in free space, but works for wire as it has a different velocity factor than "air". A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. 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. 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). HF & Shortwave "Just received my new 64131 yesterday and was anxious to see how well it performed. There are numerous configurations available online that will accomplish this on multiple bands (Google search "end fed half wave antennas"). If the choices are. Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. The most important length is one that is non-resonant on any band. 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. A good place to start is the formula 468 / f (MHz) for a 1/2 wavelength wire antenna. Enclosure Depth: 1.250 in. Just an FYI that I thought you might be interested in. My homemade 49:1 EFWH with a 60 wire (cut for 40M) would do just fine! an auto-tuner at the base vs. the same antenna fed a 4:1 balun wound with 75 ohm coax on two separate type 43 ferrite cores and a remotely sited tuner fed via 200ft of low loss LDF2-50 coax vs. a broadband antenna of the same element length. random wire page. SWR was good after cutting the wire to appropriate length. 3 0 obj this Make sure the beginning few inches of twisted wire is not involved in the winding (i.e., just hanging down from the toroid). Continue on winding the long wire through the toroid to complete loops 3 through 14 as shown in the schematic below. So for example 80m could range in length from 120 to 133 feet. Save program output in file named 'f', and use We recently found some good information about random wire lengths that you should and should not use. >> RFI Tips and Tricks I took a literally random length of 14 gauge house wire and attached a banana plug to be shoved into the antenna port of the tuner. Start winding the toroid with the twisted wires at loop #1 (see schematic below). unavailable, a random wire can save the day, but it is important to 40-30-20-17. You have to give up a band or two, like 60m and 6m, as The 9:1 may work best with that length wire and a tuner, but some say that length is undesirable for the hf HAM bands. 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. End fed 9:1 58ft wire and 17ft counterpose wire touching ground. X:nzf4p:t;r }~_HOZcX:^$* J^XZuu|"nX/Wkw0hA>y1(z2+v_Xzu[/:^$*m*>hk_:+c{ multiples, and of course different band combinations yield different A 50 foot run of RG-8X coax connected the antenna into the LDG Z100-plus tuner and then a Yaesu FT-891A transceiver. I have found this calculation to work well, however it depends on many factors such as wire used, location etc. 22.00 + 5.00 Postage. endobj Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. I attached the toroids to a PVC DWV test cap with 3 cable ties. The matching unit The impedance at the end of a half wave antenna is somewhere between 2000-5000 Ohms. Cut a 4 foot length of AWG #18 enameled wire. When used with the stated Balun Designsis now offering a low power alternative for those who want to use an End Fed Half Wave for portable or temporary installations. 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. There probably should be some holes for ventilation. (Originally published February 22, 2021). /Height 752 I used a homemade jig made of an SO239 chassis mount to bare wires, alligator clips, and a coax-jumper with PL259 (UHF male) ends; see picture below. A Balun is used to match a balanced line to an unbalanced line. Par EF 20 and par EF 40 (I realize for 17m I would prob just add that band to a 49:1 balun) That's that my question is. Care to buy us a beer? 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. Reading Room want the antenna to be at least 1/4 wavelength long for each band you /Type /Pages You also want the antenna to be at least 1/4 wavelength long for each band you plan to use. The Nelson antenna 9 to 1 unun did the trick. 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!! often can't match it. /&KWA7{L=D]g0Z!F9;V{zL[h-D,u(.9rg(RHI{f t*C/?? 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- June 8, 2022 at 9:17 am. The unun was floating at about 15 feet above ground. 3. The table below represents half wave lengths and multiples that you DO NOT WANT TO USE! The length should be calculated based on the lowest frequency to be worked. 1 0 obj I have included a screenshot showing the stations that reported spotting my 200 mw beacon over the last 16 hours. Hi guys,not really hfu related,but I tought I might ask here as I have my account. 75/80 METER RESONATOR KIT FOR THE UJM-EFHW-40-10 200W 40-10m ANTENNA Having the option to switch rapidly between 49:1 and 64:1 should prove to be a really nice feature.. Shortwave Listening Let's have a look at a few details on how to build a 49:1 impedance . 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 . google_ad_height = 600; Lengths to avoid are not always the same as So a 49:1 impedance transformer is needed to match the 50 ohms of the coax at the feed line. 49:1 or other high ratio transformers are for resonant "cut to frequency" antennas like the traditional zepp/fuchs antenna. EFHW unun Resonant Long Wire 49:1 Transformer With 67' Antenna Wire. The "9:1 UNUN" are for random length wire antennas fed at the end. Ham Radio Videos! 7 0 obj REVISED: 16 19 22 26 32 33 38 44 46 48 52 64 65 66 76 78 80 88 92 95 96 99 104 110 112 114 123 128 130 132 133 138 144 152 154 156 160 165 171 176 182 184 190 192 195 198 208 209 220 224 228 230 231 234 240 242 246 247 256 260 264 266 272 276 285 286 288 297 304 308 312 320 322 323 325 330 336 338 342 352 361 363 364 366 368 369 374 380 384 390 396 399 400 414 416 418 429 432 437 440 442 448 455 456 460 462 464 468 475 480 484 494 495 496. Recommended wire lengths for Unun models 9130, 9132 & 9135 Table shows typical SWR relative to installed wire length. Antenna Design uR5ucE`_aksLjYT=hzRa]JucX7d}|'}`XRa>X The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? 2 0 obj 6 Screws/ Nuts/ Washers/Wing Nuts And Ring Connectors, 1 X Mica Capacitors 100pF 500V 5%(Mouser Electronics), 1 x 4 in. This calculates to 4.2 m or 14 ft for an 80m end-fed. Ask Elmer