"Can you please recommend schematics that are designed to tune setups like these? 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. . 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.
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If the choices are.
var sc_invisible=1; SWR was good after cutting the wire to appropriate length. high the other 1.5m (4.5feet). <>
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). A small ring terminal for 14ga wire that fits these screws would be helpful too. The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. You have to give up a band or two, like 60m and 6m, as Here is an ARRL 40-30-20-15m bands for my 4 band Elecraft K1 qrp rig. Repeater Builders 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. %%EOF
(wlSR9dJ_x%+VHX4FRr 3>;g^x%g'wkJu,i~#Q"2|WGf[!_m]#&1$)R.{--" 'dGO;=_B$T}". My homemade 49:1 EFWH with a 60 wire (cut for 40M) would do just fine! Moving the pot up and down gives a feel for the SWR versus antenna impedance sensitivity. That is the 10th multiple of a half wave on 15 meters. 10m or 33' long. Drill a hole in one side for the antenna radiator wire mount (for a #8 bolt in my build). 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. V#X~[Z?\ZcX:-Y?&Y?IqTnayZ{jTZOub}=UTWu1G>o.,RaT
c=W>:sECXTkc=X Do what works best! for your country and favorite modes of operation. wire is at least 1/4 wavelength.
DIY 49:1 Unun Impedance Transformer For End-Fed Half Wave (EFWH He was so impressed that he purchased a 9:1 unit from you, his will be delivered Saturday. << For example, when adding a 1/4w tiger tail to a 2m ht with a halfwave for antenna will likely show no improvement at all in tx or rx strengths. I only used two screws instead of four. endobj
You'll want to have that wire up as high as you can get.. 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. 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. The graph below shows lengths to avoid for different collections of bands. W3EDP's results in the above referenced 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 . Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. %PDF-1.4 So, having nothing better to do one day, I re-did the calculations going out to 500 feet. Use only the white gaps for your antenna lengths, and if This is the latest and greatest transformer design for End Fed Half Wave (EFHW) antennas. $1YacO5Q}YC\>qZ } I imported my spools from the US, but I have seen them on Ebay in the UK. /Producer (XnView, http://www.xnview.com) 6 0 obj Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. In total 29 contacts were made from British Columbia to Texas to Florida in 40 minutes on 20M.
This will be for an eyehook in order to provide strain relief for the radiator wire. /Pages 3 0 R >> /CreationDate (D:20221212112042) Picture 1 of 9. A good place to start is the formula 468 / f (MHz) for a 1/2 wavelength wire antenna. This was 9m vertically metres up a fishing pole and then about 5.8m out. >> About Batteries 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. There are so many new frequencies to stay away from, that it gets pretty tricky for the longer wires. Enclosure Height: 5.000 in. END FED "RANDOM WIRE" HF DIPOLE 9:1 ANTENNA RELACEMENT ELEMENT ONLY $28.99 Save up to 6% when you buy more. Save program output in file named 'f', and use SO-239 (UHF female) chassis mount with screws, nuts, lock washers.
Re: 49:1 transformer for EFHW antenna - groups.io are easily converted to half wavelengths by the famous 468/f generally 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). Product Reviews Just an FYI that I thought you might be interested in. The most important length is one that is non-resonant on any band. recommended on VE3EED's page because I use all halfwave Start winding the toroid with the twisted wires at loop #1 (see schematic below). Thanks for your answer,I will probably go with the 9:1 then. installed, it is a compromise antenna but great for portable use because That meant calculating all the way to 32 multiples of a half wave on 10 meters. 35. Antenna Design
Balun One Nine v1 - Tiny Low-Cost 1:9 HF Antenna Balun and Unun with u?X`f0&/Ri;W0Tn_*TX:ug 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. 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). . You also want the antenna to be at least 1/4 wavelength long for each band you plan to use.
Single Wire/End Fed Antenna - K7MEM I use this 8010 EFHW at home, too. The First Thing New Hams Often Ask:What Is An UnUn? 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. 75/80 METER RESONATOR KIT FOR THE UJM-EFHW-40-10 200W 40-10m ANTENNA /Name /Im0 x@ >> 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 . I will also find some sort of heat resistant packing material to help hold the transformer in place. multiples, and of course different band combinations yield different The WorldwideDX Radio Forum was originally established in 2001. Step 1: Drill holes for and install the SO-239 or BNC connector, the stainless steel machine screw antenna connector and the ss machine screw ground connector. I actually did this first and before the connector was bolted to the box. << Just add or subtract as needed a little at a time to get the best compromise. Caution: When used atfull power rating of 1kW, the antenna must have a low SWRon the band selected and be used on a 50% duty cycle. (The numbers aboveare a great start, thanks to Jack and Mike! Jack, VE3EED, used center frequencies of thebands described in the article above, and I thought it would be nice to use band edges. Usually any wire length that is non resonant, like those shown above, will work with the 4:1 ratio. 80m up, W3EDP's 84' antenna, 17' counterpoise is probably the way to go. 27.00 (27.00/Unit) Free Postage. FCC Information The unun was floating at about 15 feet above ground. something as high as you can find. The fewer bands, the fewer high impedance regions to avoid. 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. Alternate connectors and Mounting Options are available in the. WwS`8o}=n,pjhzRa]Ju/Ru ni4=UvZ:u9*@ Xz+zZcXm}i[Z;Z>.u!*eQVjucXeqYZnSJu)U[n>>KXzZ.Lz sqxcGj]%q}i6=-?YTlnZXV6}=U >5`ZNxChzRa]JU.6TVr6a] endobj program or two to do all the dirty work. I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. 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. Liquidtight NM 90-Degree Connector(Home Depot). The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? On our next windy free day, AA1F and . 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. An end fed half wave antenna is one of a specific length depending on the frequency that it is to be used on, for example, an end fed half wave antenna for 80 meters is about 130 long. The vertical (y-) axis shows the VSWR and the horizontal (x-) axis shows the frequencies. uR5I5z G^u2`j[}+sy9 %
End Fed Half Wave Antenna Coupler Schematic - 7-30MHz. Theme: Newsup by Themeansar. bands you're intested in in a vector like the example below, by typing. A 50 foot run of RG-8X coax connected the antenna into the LDG Z100-plus tuner and then a Yaesu FT-891A transceiver. /BitsPerComponent 8 Powered by BigCommerce. 59 0 obj
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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. 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 . 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!! You need to use these lengths and the longer ones . 32.00.
1:64 vs 1:49 balun for an end fed?? : r/amateurradio - reddit Typically unbalanced = 50/75 ohms too unbalanced = 450/675 ohms. EFHW unun Resonant Long Wire 49:1 Transformer With 67' Antenna Wire. /ModDate (D:20221212112042) >> This transformer is designed to be used with an end fed half wavelength of wire only. 9:1 UnUn End Fed Long Wire Lengths - Pretty Simple. 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. However, the list has been revised and is good for wires as long as 500 feet.