748 0 0 752 0 0 cm >> plan to use. AndWhat Is It Used For In Antennas? EFHW unun Resonant Long Wire 49:1 Transformer With 67' Antenna Wire. is helpful if you're in a hurry to get on the air, read up on the topic % Our newdesign isperfect for matching both long and short length wire antennas for multiband use. SO-239 (UHF female) chassis mount with screws, nuts, lock washers. (The numbers aboveare a great start, thanks to Jack and Mike! My homemade 49:1 EFWH with a 60 wire (cut for 40M) would do just fine! (wlSR9dJ_x%+VHX4FRr 3>;g^x%g'wkJu,i~#Q"2|WGf[!_m]#&1$)R.{--" 'dGO;=_B$T}". bands you're intested in in a vector like the example below, by typing. Just add or subtract as needed a little at a time toget the best compromise. End Fed Antennas. 7 0 obj He was so impressed that he purchased a 9:1 unit from you, his will be delivered Saturday. I used 2000 and 1000 ohm resistors in series connected to the proper unun wires with alligator clips for a total of 3000 ohms. My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about . (QST, Oct 1926, "The Length of the $119.95. 1 0 obj recommended on VE3EED's page because I use all halfwave /Pages 3 0 R Jack, VE3EED, used center frequencies of thebands described in the article above, and I thought it would be nice to use band edges. << Work all bands from 80 through 10 on it. SSTV The length should be calculated based on the lowest frequency to be worked. /Title (Wire-Lengths-for-9-1-ununs.pdf) Wire lengths for the 4:1 ratio in models 4130, 4132, 4134, 4932 and 4935. << Update guys:made the unun,the antenna was extended to about 37m length,and I added a counterpoise which is about 10m.The whole thing is much higher in the air,compared to where it was before. A way of connecting the analyzer to the transformer. 3 to31 MHz - up to 1kW intermittent (50% duty cycle). /Length 10 0 R HF & Shortwave >> 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 . Thus a 1/4 wave for 20m@16ft, 40m@33ft as examples are not going to work. %PDF-1.5 % Antenna Safety! A 49:1 would match 50 ohms to about 2,450 ohms and a 64:1 matches to 3,200 ohms, typical of a 1/2 wave end fed. Quantity: Sold individually. CQ-Calling All Hams! Yes, with the recent surge in popularity of the end-fed half-wave antenna, the 49:1 balun has also become the defacto ratio for use with them. 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!! He used 300 ohm twin-lead and a 4:1 UNUN, with a 1:1 current choke between the UNUN and the coax to the tuner and transceiver: The full-size "flimsy" (ref. Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. http://udel.edu/~mm/ham/randomWire/. The Nelson antenna 9 to 1 unun did the trick. $1YacO5Q}YC\>qZ } program or two to do all the dirty work. Turns 1 through 14 are secondary windings (the long wire). << I'll get a 9:1 unun,and use a suggested random wire length to avoid half-wave and it's multiples then,that sounds like the best things I can get out of this setup. Enclosure Depth: 1.250 in. The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. Start winding the toroid with the twisted wires at loop #1 (see schematic below). Click to enlarge. In theory, my LDG Z100 Plus autotuner should be capable of matching the impedance of this 49:1 transformer with a end-fed half wave length antenna radiator across all amateur HF bands. 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). %PDF-1.7 ", KiwiSDR Online Radio - 500 ft Northeast Beverage, KiwiSDR Online Radio - 400 ft South Beverage, KiwiSDR Online Radio - 10/11m dipole up 20 meters high. /* Ad banner 160 x 600 */ "I received my third balun from Balun Designs this afternoon. 32.00. The counterpoise wire, This transformer is designed to be used with an end fed, Approx. Thank you so much for such a great product! Liquidtight NM 90-Degree Connector(Home Depot). END FED "RANDOM WIRE" HF DIPOLE 9:1 ANTENNA RELACEMENT ELEMENT ONLY $28.99 Save up to 6% when you buy more. I won't bore you with all that so the first portion of this still only shows up to the 4th multiple. The length of a half wave antenna is calculated using the following formula: L (ft) = 468 / f (freq in mhz). /Width 748 are easily converted to half wavelengths by the famous 468/f generally Power handling is 100 watts CW / SSB & 25W Data modes. /CreationDate (D:20221212112042) We'd really appreciate it! 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. Kj8~q7c? Use with other lengths can potentially damage the transformer depending on power level in use. Many hams have tried till they are blue in the face to install the random wire antenna that works on most; if not all of the HF bands with terrible results. Ham Radio News! Solder a the 100pF capacitor between the center conductor wire and ground wires. 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. About Batteries /Im0 Do 9:1 Unun 1.5-54MHz 2kW 9132S. 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. Feeling a bit too lazy to calculate that by hand, however, I wrote a I say run what you got and don't worry about it. 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 made just a touch over 100 QSOs today with the new unit. Here is an ARRL Reading Room This transformer is designed to be used with an end fed half wavelength of wire only. Humor endobj . Links x 2 in. I made one without doing this and it didn't work so well. An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). 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. 2 0 obj Presented for your consideration by Jack, VE3EED. SO-239 connectors are silver plated with Teflon insulation. This calculates to 4.2 m or 14 ft for an 80m end-fed. Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. Let the now free end of the short wire hang down from the toroid. << The following wire connections do not need to be made in the order I described. the C code, in Matlab or Octave get a plot by simply putting the We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. EFHW unun Resonant Long Wire 49:1 Transformer With BNC or SO-239 | Mobile Phones & Communication, Radio Communication Equipment, Antennas | eBay! Typically unbalanced = 50/75 ohms too unbalanced = 450/675 ohms. You will note that when comparing my results with VE3EED that some of the results are a bit different. So after much frustration..down it comes and you go on to a totally different type of antenna.all that time just wasted inyour opinion..until now! In addition to multiples, 73. JACK, VE3EED As typically % I included the tools I used to analyze the transformer as well; this is only necessary if you are interested in analyzing your project. %PDF-1.5 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). If you want all the bands from In total 29 contacts were made from British Columbia to Texas to Florida in 40 minutes on 20M. 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 . A level of 500-600 watts is the maximum with a further reduction onany band measuringabove 3:1. 1 X FT240-43 Ferrite Toroid Core 43 Material(Mouser Electronics), 1 X SO-239 UHF PANEL JACK S/CUP SO-239(Mouser Electronics), No. RFI Tips and Tricks "Can you please recommend schematics that are designed to tune setups like these? 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. 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. He had heard good things about 'Balun Designs' so he recommended you. 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. 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. Superglue 2 toroids together. gnuplot The QRP End-Fed Half-Wave Antenna 49:1 Transformer Building a great impedance transformer for Ham Radio end-fed wire antennas. 73, Usually any wire length that is non resonant on the band or bands desired will work with the 4:1 ratio. 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. This project assembles a 49:1 ferrite-core ("FT") type #43 transformer that matches 50 ohm input to 2500 ohm end fed antenna. /&KWA7{L=D]g0Z!F9;V{zL[h-D,u(.9rg(RHI{f t*C/?? The 30 day return period lapsed before I could get the antenna deployed to test it. Therefore, we came up with the following numbers to avoid (IN FEET): These lengths in the table beloware the culprits that cause all of the trouble when using random lengths. If you want a single band portable antenna you can mount pretty much however, look up this design. <> (A t0 B) Fold over 6 to 8 inches and twist it together. The graph below shows lengths to avoid for different collections of bands. HF Underground wiki Radio Hobbyist technical blogHFU Discord EuroPirate ChatPropagation DataTeamspeak Server, TDK CXA-2090 LCD Inverter Module New Old Stock USA Seller $19.99, Shortwave Pirate Radio In North America And Around The World, And Other Signals That Go Bump In The Night, Login with username, password and session length. The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. 49:1 or other high ratio transformers are for resonant "cut to frequency" antennas like the traditional zepp/fuchs antenna. For instance, to work 40m be sure the antenna is at least Lengths of a half-wave or multiple must be avoided. Performance is ASTOUNDING, far exceeding my expectations. This transformer is designed to be used with an end fed half wavelength of wire only. Part List: If the choices are. something as high as you can find. The "9:1 UNUN" are for random length wire antennas fed at the end. I have included a screenshot showing the stations that reported spotting my 200 mw beacon over the last 16 hours. 2 0 obj var sc_security="1df091cc". 33 ft #18 insulated copper wire (20m half wave), Counterpoise: 1 meter coax (0.05 x wavelength) connected between 64131 and Balun Designs 1115d Isolation /Choking balun, 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. Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. 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. <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Beginning from the 3rd band from the left, the vertical blue lines are: 160M, 80M, 60M, 40M, 30M, 20M, 17M, 15M, 12M, (11M), and 10M bands. I sent him the link to the 49:1 unit to get his feedback. 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. Code Practice which got me thinking. 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. (Also check out AB3AP'Swebsite and say thanks for sharing his skills. JC[ d8O[UKKQ{yZ{G 'Upno_*~8uo a@G`' zxUHXW&`}mEp`?i0 oE:N0-/t"t.-? 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. document.getElementById("copyright_year").innerHTML = new Date().getFullYear(); Built with the same craftsmanship as all our other units, this new model will allow you to either replace your current matching unit or construct a new higher powerend fed half wave antenna.
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