Privacy Policy A Balun is used to match a balanced line to an unbalanced line. 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. The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. 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. Cut a 4 foot length of AWG #18 enameled wire. The QRP End-Fed Half-Wave Antenna 49:1 Transformer Building a great impedance transformer for Ham Radio end-fed wire antennas. <> Legal Stuff 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. endobj 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 . 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. Best SWR was . Shortwave Listening 40-10m with a 49:1 Unun. presents an extremely high impedance to the tu 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 . 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. . Allows the internal tuner of most rigs to tune remotely mounted single wire antennas. In fact, the 9:1 unun that I built is actually an autotransformer. At multiples of half wavelengths of the Because I'm more visually oriented I then plotted the many overlapping "red zones" and ended up with the page at: 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. Coverutilizes integralneoprene gasket for weatherproof integrity. << (A t0 B) Fold over 6 to 8 inches and twist it together. 40-30-20-17. unavailable, a random wire can save the day, but it is important to a more capable tuner - see AA5TB's There probably should be some holes for ventilation. I attached the toroids to a PVC DWV test cap with 3 cable ties. <> 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. 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. Work all bands from 80 through 10 on 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. /Producer (XnView, http://www.xnview.com) /Type /Page The 49:1, shown in my previous message, is meant for the EFHW that are fed close to or on the half wave (highest impedance) point. That's it in a nutshell..or is it? CQ-Calling All Hams! "Here's the word on random-wire antennae.". In addition to multiples, x][~ XwiH:99gn`1-wz;n[VbW7JH4D]>}>y/D_^7,yyx}s*nveo>mn|6k7GMY4%" M)?O|'opw8o1\5JNe:9hTc5@Ik~aE%O^0$ 0E 'BX2?R!t&^E"3oqbW |${boEU>jU:]bQW?4, u1'^`oQ_4E 0~y L^'y}-RHV8L KSZ?mF4lTv'r^mF|":e}?VdTm7bGR]PchDpb*{*HGJ-m)bC!EX"iM%8L7O7-=jcn+D{_' I HH~v70J^9$.7m]knq)L(UQ%OrK:nn!8*EP Longer wire is always more This is the latest and greatest transformer design for End Fed Half Wave (EFHW) antennas. Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. 35. A standard recommendation (see QST, March 1936, p. 32, "An Unorthodox 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. JavaScript is disabled. End Fed Antennas. Here is an ARRL Solder a the 100pF capacitor between the center conductor wire and ground wires. The trick, therefore, is either If you want all the bands from I'm not saying aliens are in the radio, but aliens definitely are in the radio. << 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 bands as possible. EFHW unun Resonant Long Wire 49:1 Transformer With 67' Antenna Wire. This transformer converts the impedance at the end . A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. Re: 9:1 or 49:1 unun for end-fed long/random wire? This is a 4:1 Current Balun.That means it can match a 200ohm antenna to a 50 feed line. A so-called random wire antenna is an end fed antenna. /ModDate (D:20221212112042) Be sure to review the various lengths in the link below to obtain the lowest SWR across most if not all HF bands. IMG_2.jpg Step 2: Take the 6 feet of 18 gauge enameled copper wire, measure 11" from one end and fold it back. thank you. 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 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. endstream The length of enamelled copper wire per winding for the T-200-2 powdered iron toroid core is determined by length per winding = 50mm per turn plus 250mm tails. Tune Around! 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. is that for a given ham band there are min and max frequencies which Lengths to avoid are not always the same as 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. Hopefully these random wire length calculations will help us all make this "easy" antenna work better! document.getElementById("copyright_year").innerHTML = new Date().getFullYear(); /Parent 3 0 R You also /Length 10 0 R 3 0 obj Picture 1 of 9. To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. endobj There are numerous configurations available online that will accomplish this on multiple bands (Google search "end fed half wave antennas"). PVC Junction Box(Home Depot), 1 x 1/2 in. This may not be relevant to HF stuff, but the antenna I use for NDB reception has a 400:1 transformer (20:1) turns ratio. 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. 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. W3EDP's results in the above referenced 748 0 0 752 0 0 cm Hertz Antenna" shows in line 2 of the table that a similarly installed Feeling a bit too lazy to calculate that by hand, however, I wrote a This was 9m vertically metres up a fishing pole and then about 5.8m out. . You have to give up a band or two, like 60m and 6m, as (Also check out AB3AP'Swebsite and say thanks for sharing his skills. 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? 49:1 or other high ratio transformers are for resonant "cut to frequency" antennas like the traditional zepp/fuchs antenna. 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. << 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. Links 9 0 obj 2 eyehooks with washers and nuts (I used #8 diameter, but size is up to you.) After winding #2 is made and extends down the backside of the toroid, untwist the wires. V#X~[Z?\ZcX:-Y?&Y?IqTnayZ{jTZOub}=UTWu1G>o.,RaT c=W>:sECXTkc=X /&KWA7{L=D]g0Z!F9;V{zL[h-D,u(.9rg(RHI{f t*C/?? 74 0 obj <>stream ?7{*. Turns 1 through 14 are secondary windings (the long wire). << A success! Power Handling (CW/SSB): 100 W/200 W Enclosure Width: 2.500 in. Tweak the antenna length if necessary and then maybe adjust the turns ratio again. wire is at least 1/4 wavelength. June 8, 2022 at 9:17 am. Please note that I will not be describing the construction of the antenna wire radiator here. I used the RigExpert Zoom AA-55 to test VSWR of the 49:1 unun impedance transformer. Again, the bands are USA, so change them It uses an FT140-43 or FT240-43 toroid in a 49:1 impedance matching unit at the base and a 110 micro Henry (H) coil to act as a loading coil for 80m and a choke to stop higher frequencies using the last 2m of wire. 1 0 obj Here they are in order: Ultimately, this housing works fine, but it is heavy and clunky.). $1YacO5Q}YC\>qZ } 35-45, 54-64, 67-77. http://udel.edu/~mm/ham/randomWire/. I did not want to put the transformer in the housing until I tested it. To summarise the results WRT to reference antenna consisting of 30ft wire vertical fed with auto- 3 to31 MHz - up to 1kW intermittent (50% duty cycle). About Hamuniverse Usually any wire length that is non resonant, like those shown above, will work with the 4:1 ratio. these are the worst lengths and you want to be as far from colored Drill another hole in the same side as the antenna radiator wire mount hole. 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 management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. answers on D - one setting. This article details the construction of the transformer. JC[ d8O[UKKQ{yZ{G 'Upno_*~8uo a@G`' zxUHXW&`}mEp`?i0 oE:N0-/t"t.-? Liquidtight NM 90-Degree Connector(Home Depot). In other The most important length is one that is non-resonant on any band. If you want a single band portable antenna you can mount pretty much however, look up this design. the C code, in Matlab or Octave get a plot by simply putting the 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. The key is you want to stay at least 1/2w long but not near 3/4w for any band of interest. Swr usually is all over the place and the tuner will just not do it's job. 6 0 obj The First Thing New Hams Often Ask:What Is An UnUn? 40-30-20 . endobj Picture Information. You will note that when comparing my results with VE3EED that some of the results are a bit different. That meant calculating all the way to 32 multiples of a half wave on 10 meters. Continue twisting the entire length of the short wire. Contact Hope it's clear now, if not. /Width 748 This design is excellent for matching both long and short length wire antennas for multiband use. Reading Room 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). The 49:1 impedance transformer will help you bring down the high impedance of your resonant EFHW antenna to almost 50 Ohm. /Resources << You also want the antenna to be at least 1/4 wavelength long for each band you plan to use. As typically /Contents 5 0 R Repeater Builders Twist the short and long wires together starting at an end of each wire. Thank you so much for such a great product! you're using different ham bands than in these examples, modify and rerun While I have not done so yet, I plan on gluing the test cap to the back of the junction box. 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. My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about . The beauty of the halfwave antenna is it's a complete antenna in the sense it needs no counterpoise. A 50 foot run of RG-8X coax connected the antenna into the LDG Z100-plus tuner and then a Yaesu FT-891A transceiver. Ham Hints 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. UJM-49-1 $56.99 Save up to 6% when you buy more. Windings are inserted into Teflon tubes increasingtotal breakdown to 10,000 volts. stream I got three FT240-43 toroids (two would be lighter, but three increases the curie point so it can handle longer duty cycles), a spool of the 14 gauge enameled wire . For reasons that I do not understand, adding a capacitor between the coax conductor wire (untwisted free end of short wire) and the ground (twisted free ends of long and short wire) can increase the functional bandwidth of the antenna on the higher HF frequencies. K1S Valentines Are (Almost) Out The Door! Just add or subtract as needed a little at a time toget the best compromise. Free Postage. are blocked out because an antenna should be at least that long. X:nzf4p:t;r }~_HOZcX:^$* J^XZuu|"nX/Wkw0hA>y1(z2+v_Xzu[/:^$*m*>hk_:+c{ The Short Answer Would Be That an UnUn Is a "UN balanced to UN balanced" matching transformer. >> See the picture below. SWR was good after cutting the wire to appropriate length. endobj 5 0 obj The matching unit The impedance at the end of a half wave antenna is somewhere between 2000-5000 Ohms. NOTE: Rewording the previous paragraph, if you have a capable enough Theme: Newsup by Themeansar. /* Ad banner 160 x 600 */ The bandwidth where SWR was below 2:1 was about one MHz. We are working every day to make sure our community is the best Radio Hobbyist's site. <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> 7 0 obj Here's a list of recommended lengths of wire to use with a 9:1 unun. recommended on VE3EED's page because I use all halfwave multiples, and of course different band combinations yield different (Also note that here may be instances where the suggested lengths may not work exactly due tothe many variablesin the surroundings of the antenna, wire length variances,your tuner, it's height above ground, it's construction,etc. Use only the white gaps for your antenna lengths, and if 20/40/17m. 3 0 obj 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-1.5 SSTV One is for the top of the box so that it can be hung up. The graph below shows lengths to avoid for different collections of bands. 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. For instance, to work 40m be sure the antenna is at least frequencies for your country or favorite modes. 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!! Super Bullet Features: - Uses proprietary broadband impedance transformer design for maximum bandwidth with SWR < 2 from 1.8-61 MHz for 1500 Watt model and 1.8-30 MHz for 3000 watt model Well then you need to choose a wire length that is at least 1/4 on 40 meters, and doesn't fall on any of the 1/2 multiples for ALL the bands between 40 to 10 meters While you could certainly calculate the lengths to avoid using the standard formulas, and then make a chart, the section below may be what you are looking for. something as high as you can find. 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. /Kids [ 4 0 R ] I imported my spools from the US, but I have seen them on Ebay in the UK. 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. random wire page. End Fed Half Wave Antenna Coupler Schematic - 7-30MHz. At this point, Ive only used the 49:1 tap, but plan to take the 64131 whenever I operate portable. 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. q He was so impressed that he purchased a 9:1 unit from you, his will be delivered Saturday. endobj 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. Cannon". Click to enlarge. So for example 80m could range in length from 120 to 133 feet. 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. On our next windy free day, AA1F and . Figure 2 Schematic of the 9:1 voltage unun . This homebrew 49:1 impedance transformer is the heart of any EFHW antenna you will build, most of the time. The fewer bands, the fewer high impedance regions to avoid. I say run what you got and don't worry about it. So I just wanna say thank-you!! Having the option to switch rapidly between 49:1 and 64:1 should prove to be a really nice feature.. . While these lengths have been shown to work well on many bands, which 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. I only used two screws instead of four. License Study 1 0 obj so that it is not a halfwave multiple of any frequency you want to use. 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. Performance is ASTOUNDING, far exceeding my expectations. Typically unbalanced = 50/75 ohms too unbalanced = 450/675 ohms. SBULLET-9U-1500. x {avla[g#+yt]Mk"B` xp[AO8;c=\b}|8p4cSmzgU7be,+i5ci6uq.x T/s@9uk-oZX;u`=U >8rsIXW B:uUVr6a] VSWR analysis of the antenna in the field showed that VSWRs between 3-5.5 from 40M to 10M. bands you're intested in in a vector like the example below, by typing. Lengths of a half-wave or multiple must be avoided. Ask Elmer Even better would be shortening to 53'. Turns 1 & 2 are primary windings (the short wire). Lowest Band of Operation: 160 meters Highest Band of Operation: 10 meters Additional Information LDG Electronics RU-9:1 Unun >> Meet 'Balun One Nine', a small, cost-effective balun. 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. 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. 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 . You can add your own wire or get the complete product from this link EFLW-3K antennas. 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 can take one of these 49:1 transformers and use the 468/freq (Mhz) formula to calculate the length you need in feet. The Nelson antenna 9 to 1 unun did the trick. 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. 10m or 33' long. and experiment. So is an essential piece of gear to have. The fewer bands, the fewer high impedance regions to avoid. Usually any wire length that is non resonant on the band or bands desired will work with the 4:1 ratio. Start winding the Matching Auto Transformer, each pass through the center of the core equals one turn. tuner the colored bands below are the best lengths as long as your When do you use a 1:1, 9:1 or a 49:1 balun? are easily converted to half wavelengths by the famous 468/f generally 1 0 obj Both were on 20 meters at 97 watts, Icom 7300. endobj often can't match it. 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". excellent page for EFHW info - or, addressed below, to cut the wire So for example 80m could range in length from 120 to 133 feet. Here are the final numbers (in my opinion) in green below that would be good for a long-wire antenna: (You may want to make a note of them), REVISED: 29 35.5 41 58 71 84 107 119 148 203 347 407 423, REVISION NOTE: We had a note from James, KB5YN, pointing out that one of my so-called GOOD numbers was 220 feet. stream /Name /Im0 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. Figure 3 Wiring of the 9:1 voltage unun. About Batteries Use a slide rule! The goal of the impedance transformer is match the 50 ohm impedance of the feedline (coaxial cable) with the potential 3000 to 4000 ohm impedance expected from an end-fed half wave antenna wire radiator. 9:1 Unun EF Random Long wire matching Transformer with BNC or SO-239. In stock . The vertical (y-) axis shows the VSWR and the horizontal (x-) axis shows the frequencies. 25 0 obj <> endobj FCC Information Designed for use with single wire unbalanced antennas, this new addition is small, compact and perfect for quick portable/emergency installations. Jack, VE3EED - SK. "Can you please recommend schematics that are designed to tune setups like these? Drill a hole in the top for an eyehook (to be used to secure the unun to whatever it is you want to hang it from.). endobj Quantity: Sold individually. /Subtype /Image I plotted the results for the U.S. CW band edges for use with my4 band Elecraft K1 qrp rig. <>>> What these lengths are depend on your tuner and also the wire's surroundings and also the ground system. (The numbers aboveare a great start, thanks to Jack and Mike! 10C) for the 10-80 m bands, or even 6-160 m: 17 ft (5.2 m) of twin-lead and 68 ft (20.7 m) of antenna wire (i.e., standard dimensions). , Most matching problems occur when the antenna system 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). Wire lengths for the 4:1 ratio in models 4130, 4132, 4134, 4932 and 4935. Each vertical blue line represents an amateur radio band. END FED "RANDOM WIRE" HF DIPOLE 9:1 ANTENNA RELACEMENT ELEMENT ONLY $28.99 Save up to 6% when you buy more. 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. "Just received my new 64131 yesterday and was anxious to see how well it performed. I won't bore you with all that so the first portion of this still only shows up to the 4th multiple. understand its properties. google_ad_height = 600; >> Building on the original 1:1 design by Dr. Jerry Sevick, this balun has two (2) cores in a stacked Model 49131 - 49:1 - 80-10m EFHW - Up to 1kW, Decrease Quantity of Model 49131 - 49:1 - 80-10m EFHW - Up to 1kW, Increase Quantity of Model 49131 - 49:1 - 80-10m EFHW - Up to 1kW. Presented for your consideration by Jack, VE3EED. I connected it to a 33 wire running from my balcony, through the trees, and ran WSPR overnight to check things out. 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. I sent him the link to the 49:1 unit to get his feedback. Drill a hole in one side for the antenna radiator wire mount (for a #8 bolt in my build). /ColorSpace 11 0 R &nb Thus a 1/4 wave for 20m@16ft, 40m@33ft as examples are not going to work. It is important to use a counterpoise. I will also find some sort of heat resistant packing material to help hold the transformer in place. This is not exactly a 1/2 wavelength in free space, but works for wire as it has a different velocity factor than "air". 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. config file by typing gnuplot rw.gnu. %%EOF Thanks for your answer,I will probably go with the 9:1 then. Just an FYI that I thought you might be interested in. Notice from column f that there is no length giving low impendance for 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 another life, I could have been a telephone engineer. 27.00 (27.00/Unit) Free Postage. Change the program to use 423 if desired.) The other is to provide strain relief for the antenna wire). 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. 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. Post Reviews The "9:1 UNUN" are for random length wire antennas fed at the end. 73. JACK, VE3EED | endobj Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. For instance, to work 40m be sure the antenna is at least 10m or 33' long. 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- That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at . Do what works best! That is the 10th multiple of a half wave on 15 meters. You have to stay away from a half wavelength on any frequency. This article explains why the use of mix 43 for HF applications is almost always a mistake. all US ham bands. Some of these numbers are too close to squeeze in between them. 4 0 obj 40-30-20-15m bands for my 4 band Elecraft K1 qrp rig. The "Super Bullet" End Fed Long Wire Antenna Matcher - 1500/3000 watt rated for Super-Punch of your signal! Designed for those who want the maximum isolation and choking across the full HF spectrum. 8 0 obj