9:1 Unun EF Random Long wire matching Transformer with BNC or SO-239. . /Pages 3 0 R are easily converted to half wavelengths by the famous 468/f generally Usually any wire length that is non resonant, like those shown above, will work with the 4:1 ratio. document.getElementById("copyright_year").innerHTML = new Date().getFullYear(); 73. JACK, VE3EED Tools 49:1 End Fed Half Wave Antenna 40-10M 100W Version Bands of operation 40,20,15 & 10m using 67 feet of our UV, Ozone resistant Antenna wire. This is a followup video to #344 where I assembled the 49:1 UNUN kit from HF-Kits / ARRL. >> The "9:1 UNUN" are for random length wire antennas fed at the end. 7 0 obj 73, So is an essential piece of gear to have. What these lengths are depend on your tuner and also the wire's surroundings and also the ground system. Coverutilizes integralneoprene gasket for weatherproof integrity. 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). Here Is a 250 Watt Home-Brew That I Made In about an Hour. This calculates to 4.2 m or 14 ft for an 80m end-fed. Clansman End Fed Long Wire Antenna Used. 10m or 33' long. 9 0 obj 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. 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. Drill a hole in one side for the antenna radiator wire mount (for a #8 bolt in my build). Even easier than Repeater Builders /Width 748 A few more comments about this 49:1 autotransformer EFHW design. well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) /&KWA7{L=D]g0Z!F9;V{zL[h-D,u(.9rg(RHI{f t*C/?? Electronics Start winding the toroid with the twisted wires at loop #1 (see schematic below). 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. often can't match it. A so-called random wire antenna is an end fed antenna. While I have not done so yet, I plan on gluing the test cap to the back of the junction box. EFHW unun Resonant Long Wire 49:1 Transformer With BNC or SO-239 | Mobile Phones & Communication, Radio Communication Equipment, Antennas | eBay! high the other 1.5m (4.5feet). endobj For a better experience, please enable JavaScript in your browser before proceeding. The matching unit The impedance at the end of a half wave antenna is somewhere between 2000-5000 Ohms. endobj 3 0 obj $1YacO5Q}YC\>qZ } This was 9m vertically metres up a fishing pole and then about 5.8m out. A way of connecting the analyzer to the transformer. Moving the pot up and down gives a feel for the SWR versus antenna impedance sensitivity. Re: 9:1 or 49:1 unun for end-fed long/random wire? %PDF-1.5 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 png image named g.png will be created. bands as possible. I usually go with a 3.2k transformation wire winding ratio of 8:1 which is a final impedance conversion of 64:1 (50ohm * 64 = 3.2k ohm). >> 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. You also want the antenna to be at least 1/4 wavelength long for each band you plan to use. 25 0 obj <> endobj which got me thinking. var sc_security="1df091cc". Performance is ASTOUNDING, far exceeding my expectations. Code Practice 3 0 obj We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. The Nelson antenna 9 to 1 unun did the trick. 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. Work all bands from 80 through 10 on it. 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. . 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". 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. transmit frequency the impedance is so high that tuners in most rigs Lengths for Long-wire Antennas Jack - VE3EED Recommended lengths: 29 - 35.5 - 41 - 58 - 71 - 84 - 107 - 119 - 148 - 203 - 347 - 407 - 423 Not recommended lengths: 16 - 19 - 22 - 26 - 32 - 33 - 38 - 44 - 46 - 48 - 52 - 64 - 65 - 66 - 76 The 49:1 unun with 3000 ohms of resistance shows a VSWR under 10:1 from 160M to 15M, and less than 3:1 from 80M to 20M. Drill out holes in the designated bottom of the electrical junction box for the SO239 chassis mount. all US ham bands. W3EDP's results in the above referenced Some of these numbers are too close to squeeze in between them. rig, often with no feedline, and the other end in the air attached to Just a note, if you make one of these yourself, you need to twist together the first two wraps of the 14 winding wire with both wraps of the two winding 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. Dimensional Drawing of Standard Enclosure, 1:1 Common Mode Choke / Noise Suppression, Core Material Selecton for Baluns and Ununs, Antenna Matching Problems When Using Ladder Line or Open Wire Feedlines, Model 4932 - 4 & 9:1 Unun 1.5 - 54MHz - 2kW, Model 49130 - 49:1 - 80-10m EFHW - 200 watts, Model 64131e - 64:1 & 49:1 - 80-10m EFHW - Up to 1kW, Model 4116 - 4:1 Hybrid Balun 1.5 - 54MHz 3kW, Model 9130sw - QRP 9:1 Unun 1.5 - 54 MHz - 300 watts, Model 1115d - Max Choking 1:1 Balun, 1.5-54 MHz, 5kW. Wait a few minutes for glue to set. I included the tools I used to analyze the transformer as well; this is only necessary if you are interested in analyzing your project. On our next windy free day, AA1F and . This transformer converts the impedance at the end . Wire lengths for the 4:1 ratio in models 4932 and 4935. Use with other lengths can potentially damage the transformer depending on power level in use. An Unun is used to match an unbalanced line to another unbalanced line. June 8, 2022 at 9:17 am. 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. Wire-Lengths-for-9-1-ununs.pdf Created Date: 12/12/2022 11:20:42 AM . /Resources << /ProcSet 7 0 R >> My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about . . Solder a the 100pF capacitor between the center conductor wire and ground wires. UJM-49-1 $56.99 Save up to 6% when you buy more. 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. (Center fed is so appealing because you avoid this.). 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. 2 0 obj endobj 1 0 obj Care to buy us a beer? var sc_invisible=1; $119.95. Theme designed by Papathemes. 3 0 obj Click to enlarge. 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. This design is excellent for matching both long and short length wire antennas for multiband use. It may not display this or other websites correctly. I made just a touch over 100 QSOs today with the new unit. In stock . In addition to multiples, /Filter [ /FlateDecode ] ), Note that Jack, VE3EED,went SK several years agohe will be missed. <> So for example 80m could range in length from 120 to 133 feet. Site Map This is not exactly a 1/2 wavelength in free space, but works for wire as it has a different velocity factor than "air". 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. 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. want the antenna to be at least 1/4 wavelength long for each band you I've made contact with several folks across North America in my 6 months as an amateur but getting to Europe flipped a switch and I'm afraid this amateur radio thing is going to be addicting. Turns 1 & 2 are primary windings (the short wire). This design is excellent for matching both long and short length wire antennas for multiband use. Two pieces of 14 gauge enameled wire (e.g., Thermalese), one short piece (about 1 foot in length) and one long piece (about 7 feet in length). % 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. /ModDate (D:20221212112042) Humor Designed for use with single wire unbalanced antennas, this new addition is small, compact and perfect for quick portable/emergency installations. /CreationDate (D:20221212112042) It is used for non-resonant verticals like 43 foot or 33 foot Or Wire antennas like an End-Fed 1/2 Wave Multiple Length Wire Antenna. "Here's the word on random-wire antennae.". This article details the construction of the transformer. Proudly powered by WordPress IMG_2.jpg Step 2: Take the 6 feet of 18 gauge enameled copper wire, measure 11" from one end and fold it back. The beauty of the halfwave antenna is it's a complete antenna in the sense it needs no counterpoise. SO-239 (UHF female) chassis mount with screws, nuts, lock washers. google_ad_client = "ca-pub-9377297764300878"; The graph below shows lengths to avoid for different collections of bands. We recently found some good information about random wire lengths that you should and should not use. So, having nothing better to do one day, I re-did the calculations going out to 500 feet. stream 35. He had heard good things about 'Balun Designs' so he recommended you. uR5I5z G^u2`j[}+sy9 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. I'm looking forward to getting off work and hitting 40 & 20 meters again!! Midi Music . 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. 35. 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. End Fed Half Wave Antenna Coupler Schematic - 7-30MHz. random wire page. 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. Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. Hope it's clear now, if not. 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. /Length 6 0 R About Batteries Best SWR was . The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. 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? Continue on winding the long wire through the toroid to complete loops 3 through 14 as shown in the schematic below. Its really an impedance transformer (9:1) to feed a high impedance, end fed (unbalanced) random wire which is likely to be a few hundred ohms, and transform it into something closer to a 50 (unbalanced) coaxial input, hence UnUn. You have to give up a band or two, like 60m and 6m, as Palomar Engineers employs a dual core matching system that offers wide bandwidth (1-61 MHz), 500 watt PEP rating, and a connection for a counterpoise or ground if desired. Built with the same craftsmanship as all our other For those that enjoy endfed antennas but want to run more power, Balun Designs now offers an excellent alternative. is that for a given ham band there are min and max frequencies which It is important to use a counterpoise. The transformer usually used with an end fed wire is a 9:1 transformer. 2 0 obj >> Tune Around! 40-30-20 . 2 eyehooks with washers and nuts (I used #8 diameter, but size is up to you.) A 9:1 matches 50 ohms to 450 ohms and that turns out to be an ok compromise for feeding 50-100ft of wire for general purpose SW receive. The following wire connections do not need to be made in the order I described. Support The Site End fed 49:1 60ft wire (using coax as the counter poise. Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. (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 connected it to a 33 wire running from my balcony, through the trees, and ran WSPR overnight to check things out. 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. 31 uR5ucE`_aksLjYT=hzRa]JucX7d}|'}`XRa>X There are numerous configurations available online that will accomplish this on multiple bands (Google search "end fed half wave antennas"). 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. it is easy to pack and easy to install. You also Each vertical blue line represents an amateur radio band. This homebrew 49:1 impedance transformer is the heart of any EFHW antenna you will build, most of the time. I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. /Length 10 0 R https://www.kb6nu.com/playing-end-fed-wire-antennas-91-ununs/, http://www.hamuniverse.com/randomwireantennalengths.html, https://www.youtube.com/watch?v=sty7RlXQoJI, https://www.youtube.com/watch?v=WwJnXTVUrgI, Quote from: refmo on October 15, 2019, 2036 UTC, Quote from: joczo on October 16, 2019, 0815 UTC, http://www.w3pga.org/Antenna%20Books/Reflections%20III.pdf, http://www.arrl.org/files/file/Technology/tis/info/pdf/7007024.pdf, http://www.tasrt.ca/AntennaTips/AntennaTips.htm, http://www.wb2rcb.com/documents/balunlin.pdf. Power handling is 100 watts CW / SSB & 25W Data modes. 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 This transformer is designed to be used with an end fed half wavelength of wire only. NEMA rated 4x marine grade junction box for outdoor installations. excellent page for EFHW info - or, addressed below, to cut the wire thank you. plan to use. %PDF-1.4 Ask Elmer << That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at . I have included a screenshot showing the stations that reported spotting my 200 mw beacon over the last 16 hours. x {avla[g#+yt]Mk"B` xp[AO8;c=\b}|8p4cSmzgU7be,+i5ci6uq.x T/s@9uk-oZX;u`=U >8rsIXW B:uUVr6a] 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] Antenna Design /Title (Wire-Lengths-for-9-1-ununs.pdf) 1. Winding 1:64 Matching Auto Transformer on the FT240-43 core. Just add or subtract as needed a little at a time to get the best compromise. j#f5(fk0?P[polEo5b2-/oVZu1Qo-I6C/M@TbddPc#cdZZ|7+|o{}!F#?Go7ju|?wwgow/c2/W-m~~hn[S29OU}}r7lc]wsw[shS[#qbrrK[7*0,Xv{k+o {=*vo S__O~*=y/zk75O?yjCnXS{`~Ii'c_GxN. Cut a 4 foot length of AWG #18 enameled wire. To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. JC[ d8O[UKKQ{yZ{G 'Upno_*~8uo a@G`' zxUHXW&`}mEp`?i0 oE:N0-/t"t.-? hb```YloD@(aKI V!}g@~}%Q/[[~_=Wy-:O)x[~hs/~SGeG _QE C6q %r The 30 day return period lapsed before I could get the antenna deployed to test it. Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. answers on D - one setting. wire is at least 1/4 wavelength. Free Postage. Hertz Antenna" shows in line 2 of the table that a similarly installed <>/Metadata 239 0 R/ViewerPreferences 240 0 R>> Hopefully these random wire length calculations will help us all make this "easy" antenna work better! This is the latest and greatest transformer design for End Fed Half Wave (EFHW) antennas. 80m up, W3EDP's 84' antenna, 17' counterpoise is probably the way to go. While these lengths have been shown to work well on many bands, which They just saved you and I loads of time and frustration. <> Vacation Closure - See Homepage for Next Availability. 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. License Study Reading Room FCC Information 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. As typically Ham Hints Vhf and Up /Kids [ 4 0 R ] "Just received my new 64131 yesterday and was anxious to see how well it performed. 5 0 obj The ratio doesn't need to be 49:1 2,400 ohm either, other ratios will transform to other impedance. AndWhat Is It Used For In Antennas? I have not done this yet. q 35-45, 54-64, 67-77. Ham Radio Videos! endstream Anyway, an old friend mentioned 'MyAntenna.com' but they were closed for the summer. 22.00 + 5.00 Postage. I did not want to put the transformer in the housing until I tested it. /BitsPerComponent 8 SEARCH A VSWR sweep of the unun after adding a 100pF capacitor shows an SWR <5:1 from 160M to 10M. 3 to31 MHz - up to 1kW intermittent (50% duty cycle). . 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 . A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. The graph below shows lengths to avoid for different collections of bands. ", KiwiSDR Online Radio - 500 ft Northeast Beverage, KiwiSDR Online Radio - 400 ft South Beverage, KiwiSDR Online Radio - 10/11m dipole up 20 meters high. SWR will vary based on topography, wire orientation and use of ground or counterpoise. u?X`f0&/Ri;W0Tn_*TX:ug When on the trail, at Field Day, or whenever a good antenna is The length should be calculated based on the lowest frequency to be worked. I attached the toroids to a PVC DWV test cap with 3 cable ties. Feeling a bit too lazy to calculate that by hand, however, I wrote a Save program output in file named 'f', and use 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. Part List: endobj Be sure to review the various lengths in the link below to obtain the lowest SWR across most if not all HF bands. InJack's own words. The length of a half wave antenna is calculated using the following formula: L (ft) = 468 / f (freq in mhz). 40-10m with a 49:1 Unun. This antenna, which works on 10, 15, 20, and 40 meters, has a very high impedance of around 2,500 Ohms. x 2 in. 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 . and leave the unun on the ground. Presented for your consideration by Jack, VE3EED. config file by typing gnuplot rw.gnu. The Short Answer Would Be That an UnUn Is a UN balanced to UN balancedmatching transformer. For typical tuners built into a rig, You can take one of these 49:1 transformers and use the 468/freq (Mhz) formula to calculate the length you need in feet. A level of 500-600 watts is the maximum with a further reduction onany band measuringabove 3:1. Hi guys,not really hfu related,but I tought I might ask here as I have my account. %PDF-1.5 % 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. However, the radio didn't tune up very well on 15 meters. A Balun is used to match a balanced line to an unbalanced line. . Repeater Basics and experiment. understand its properties. 49:1 UNUN IMPEDANCE XFORMER FOR END FED HALF WAVE ANTENNA. 1 bolt for antenna hook up (with nuts, washers, lock washers, and possibly thumb screw; I used #8 diameter, about an inch or so in length.). 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). Continue twisting the entire length of the short wire. 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. >> For instance, to work 40m be sure the antenna is at least 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. x@ Twist the short and long wires together starting at an end of each wire. Cannon". <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> I will also find some sort of heat resistant packing material to help hold the transformer in place. In another life, I could have been a telephone engineer. https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. I say run what you got and don't worry about it. Change the program to use 423 if desired.) Having the option to switch rapidly between 49:1 and 64:1 should prove to be a really nice feature.. The idea used by hams for dipole lengths. Note: My (A to B) length was 6 inches. Experimenting by slightly changing the wire length (+ or-) is encouraged to provide best overall performance. PVC Junction Box(Home Depot), 1 x 1/2 in. 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. a more capable tuner - see AA5TB's 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. Random wire lengths you should and should not use! So a 49:1 impedance transformer is needed to match the 50 ohms of the coax at the feed line. For those that enjoy the LNR and Hy Endfed antennas, but want to run more power, Balun Designs now offers an excellent alternative. I plotted the results for the U.S. CW band edges for use with my4 band Elecraft K1 qrp rig. Privacy Policy This will be for an eyehook in order to provide strain relief for the radiator wire. Ham Radio News! stream I actually did this first and before the connector was bolted to the box. % I used 2000 and 1000 ohm resistors in series connected to the proper unun wires with alligator clips for a total of 3000 ohms. 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. 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 . These are sometimes known as a Magnetic Longwire Balun. Again, the bands are USA, so change them Use a slide rule! Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 1500 Watts, End Fed Antennas. , This is a partial reprint (with permission) of an excellent series of articles published by KV5R (The numbers aboveare a great start, thanks to Jack and Mike! 4 0 obj 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. Antenna Safety! The WSPR map is so dense it looks like the US and Europe are just big blobs of color. 8 0 obj Tweak the antenna length if necessary and then maybe adjust the turns ratio again. This is considered a random wire end fed antenna, not to be confused with a half wave end fed antenna which uses a 49:1 or 64:1 unun and a wire that is a half wave length. the C code, in Matlab or Octave get a plot by simply putting the for your country and favorite modes of operation. Computer Help Weight: 0.380 lbs. Powered by BigCommerce. /Type /Catalog In total 29 contacts were made from British Columbia to Texas to Florida in 40 minutes on 20M. , Most matching problems occur when the antenna system doing the initial 468/f on C and D scales. I imported my spools from the US, but I have seen them on Ebay in the UK. EFHW unun Resonant Long Wire 49:1 Transformer With 67' Antenna Wire. results. 9:1 UnUn End Fed Long Wire Lengths - Pretty Simple. <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> The length should be calculated based on the lowest frequency to be worked. 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. x 4 in. 3. If you want all the bands from Legal Stuff You will note that when comparing my results with VE3EED that some of the results are a bit different. An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). these are the worst lengths and you want to be as far from colored stream Longer wire is always more 1 0 obj shown in the column e. var sc_project=8077274; Just add or subtract as needed a little at a time toget the best compromise. Y &lD30. multiples, and of course different band combinations yield different (Note: I am not satisfied with this part of the project, so I will describe it here briefly. Gil Gruson 1 Campaign | Comines, France $0 USD 0 backers 0% of $3,450 Flexible Goal Follow Story FAQ Updates 0 Comments 0 Prototype The project team has a working demo, not the final product. 27.00 (27.00/Unit) Free Postage. Shortwave Listening endobj Alternate connectors and Mounting Options are available in the. However, the list has been revised and is good for wires as long as 500 feet. Windings are inserted into Teflon tubes increasingtotal breakdown to 10,000 volts.
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