If you plan on stringing up a dipole you use 2 equal lengths of wire with the Balun in the middle. The table below represents half wave lengths and multiples that you DO NOT WANT TO USE! 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. Let the now free end of the short wire hang down from the toroid. config file by typing gnuplot rw.gnu. An excellent way to attach a long wire antenna to the Ham It Up, this 1:9 balun has an SMA output port and high-quality spring-type terminal block input for your coax. 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. Hope it's clear now, if not. There probably should be some holes for ventilation. For example a 32 foot length is actually a half wave on 20m with an impedance of about 3500 ohms and requires a 50:1 balun. 4 0 obj
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. Shortwave Listening Each winding is counted when the wire enters through the center hole of the toroid. high the other 1.5m (4.5feet). 6 Screws/ Nuts/ Washers/Wing Nuts And Ring Connectors, 1 X Mica Capacitors 100pF 500V 5%(Mouser Electronics), 1 x 4 in. 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. However, the radio didn't tune up very well on 15 meters. Performance is ASTOUNDING, far exceeding my expectations. 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. Hopefully these random wire length calculations will help us all make this "easy" antenna work better! These are sometimes known as a Magnetic Longwire Balun. PVC Junction Box(Home Depot), 1 x 1/2 in. 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. Feeling a bit too lazy to calculate that by hand, however, I wrote a https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. 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. 27.00 (27.00/Unit) Free Postage. 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 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. Antenna Safety! After winding #2 is made and extends down the backside of the toroid, untwist the wires. these are the worst lengths and you want to be as far from colored %
https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. 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). The Short Answer Would Be That an UnUn Is a "UN balanced to UN balanced" matching transformer. doing the initial 468/f on C and D scales. <>
To summarise the results WRT to reference antenna consisting of 30ft wire vertical fed with auto- To DB's point of a single band antenna, this 49:1 transformer is a good choice for a single band matcher. /Width 748 Here is an ARRL Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 1500 Watts, End Fed Antennas. A png image named g.png will be created. 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.
80m up, W3EDP's 84' antenna, 17' counterpoise is probably the way to go. The 30 day return period lapsed before I could get the antenna deployed to test it. . SO-239 (UHF female) chassis mount with screws, nuts, lock washers. are blocked out because an antenna should be at least that long. This article details the construction of the transformer. endobj 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. (wlSR9dJ_x%+VHX4FRr 3>;g^x%g'wkJu,i~#Q"2|WGf[!_m]#&1$)R.{--" 'dGO;=_B$T}". This is the latest and greatest transformer design for End Fed Half Wave (EFHW) antennas. which got me thinking. Tweak the antenna length if necessary and then maybe adjust the turns ratio again. 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. 35. Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. So a 49:1 impedance transformer is needed to match the 50 ohms of the coax at the feed line. You need to use these lengths and the longer ones . Windings are inserted into Teflon tubes increasingtotal breakdown to 10,000 volts. is that for a given ham band there are min and max frequencies which 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. 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. Post Reviews Care to buy us a beer? recommended on VE3EED's page because I use all halfwave /BitsPerComponent 8 5 0 obj %PDF-1.7
frequencies for your country or favorite modes. 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". transmit frequency the impedance is so high that tuners in most rigs Liquidtight NM 90-Degree Connector(Home Depot). Figure 3 Wiring of the 9:1 voltage unun. Repeater Basics Again, the bands are USA, so change them 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. (Center fed is so appealing because you avoid this.). 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 small ring terminal for 14ga wire that fits these screws would be helpful too. . 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. Stacked coreswithwinding configured as 49:1auto transformer. The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. An Unun is used to match an unbalanced line to another unbalanced line. I will also find some sort of heat resistant packing material to help hold the transformer in place. Meet 'Balun One Nine', a small, cost-effective balun. 25 0 obj
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This article explains why the use of mix 43 for HF applications is almost always a mistake. Just add or subtract as needed a little at a time to get the best compromise. google_ad_client = "ca-pub-9377297764300878"; Picture 1 of 9. The trick, therefore, is either 6 0 obj /Kids [ 4 0 R ] well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) Hi guys,not really hfu related,but I tought I might ask here as I have my account. X:nzf4p:t;r }~_HOZcX:^$* J^XZuu|"nX/Wkw0hA>y1(z2+v_Xzu[/:^$*m*>hk_:+c{ $1YacO5Q}YC\>qZ } It is important to use a counterpoise. Change the program to use 423 if desired.) 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). Even easier than , Most matching problems occur when the antenna system
The beauty of the halfwave antenna is it's a complete antenna in the sense it needs no counterpoise. /Height 752 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. We hoisted the free end of the antenna wire approximately 30 feet into a tree. They just saved you and I loads of time and frustration. A success! The QRP End-Fed Half-Wave Antenna 49:1 Transformer Building a great impedance transformer for Ham Radio end-fed wire antennas. the program as I did, above, for my K1. 3 0 obj
It's an efficient way to get all the multiples Best SWR was . /* Ad banner 160 x 600 */ Ham Satellites 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. This is a followup video to #344 where I assembled the 49:1 UNUN kit from HF-Kits / ARRL. The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? We are working every day to make sure our community is the best Radio Hobbyist's site. Ask Elmer This design is excellent for matching both long and short length wire antennas for multiband use. stream
There are numerous configurations available online that will accomplish this on multiple bands (Google search "end fed half wave antennas"). Site Map In stock . stream
You'll want to have that wire up as high as you can get.. BUILD INSTRUCTIONS FOR 49:1 UNUN IMPEDEDENCE TRANSFORMER: WX1MAR and I brought the DIY 49:1 unun with a borrowed antenna radiator wire cut for 20M half-wavelength to Ashland State Park K-2417 in Massachusetts for a Parks-on-the-Air (POTA) activation. Presented for your consideration by Jack, VE3EED. Use with other lengths can potentially damage the transformer depending on power level in use. Thus a 1/4 wave for 20m@16ft, 40m@33ft as examples are not going to work. Hertz Antenna" shows in line 2 of the table that a similarly installed random wire page. 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. understand its properties. For instance, to work 40m be sure the antenna is at least Product Reviews You can add your own wire or get the complete product from this link EFLW-3K antennas. Wait a few minutes for glue to set. 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). >> A level of 500-600 watts is the maximum with a further reduction onany band measuringabove 3:1. Even better would be shortening to 53'. Jack, VE3EED - SK. 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. 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. endstream
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and experiment. W3EDP's results in the above referenced are easily converted to half wavelengths by the famous 468/f generally something as high as you can find. all US ham bands. EFHW unun Resonant Long Wire 49:1 Transformer With BNC or SO-239 | Mobile Phones & Communication, Radio Communication Equipment, Antennas | eBay! excellent page for EFHW info - or, addressed below, to cut the wire ?7{*. is helpful if you're in a hurry to get on the air, read up on the topic An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). SEARCH You are using an out of date browser. /Creator (XnView) While these lengths have been shown to work well on many bands, which <>
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. . 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 . 1. I swept the VSWR of the unun and resistors as described from <1 to 55MHz. 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 endobj Privacy Policy You can take one of these 49:1 transformers and use the 468/freq (Mhz) formula to calculate the length you need in feet. 1 0 obj and leave the unun on the ground. Let's have a look at a few details on how to build a 49:1 impedance . FCC Information Antenna Design It may not display this or other websites correctly. Turns 1 through 14 are secondary windings (the long wire). So for 80 meters (say 3.525 MHz) this gives you about 133' of wire. 31 Quantity: Sold individually. 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!! Do what works best! Drill out holes in the designated bottom of the electrical junction box for the SO239 chassis mount. 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. (Note: I am not satisfied with this part of the project, so I will describe it here briefly. used by hams for dipole lengths. endobj The length should be calculated based on the lowest frequency to be worked. Figure 2 Schematic of the 9:1 voltage unun . stream Here's a list of recommended lengths of wire to use with a 9:1 unun. The ratio doesn't need to be 49:1 2,400 ohm either, other ratios will transform to other impedance. 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 A so-called random wire antenna is an end fed antenna. 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. When used with the stated lengths shown in thetable below, the 9:1 ratio will Based on the success of our model 4932, this 5kWconfigurationisalso perfect for matching both long and short length wire antennas for multiband use. Re: 9:1 or 49:1 unun for end-fed long/random wire? hb```YloD@(aKI V!}g@~}%Q/[[~_=Wy-:O)x[~hs/~SGeG _QE C6q %r For those that enjoy the LNR and Hy Endfed antennas, but want to run more power, Balun Designs now offers an excellent alternative. On our next windy free day, AA1F and . The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. . Our Ask An Elmer panel discuss this question - what's the difference between matching units?Please consider using. This is a 4:1 Current Balun.That means it can match a 200ohm antenna to a 50 feed line. 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? x
{avla[g#+yt]Mk"B` xp[AO8;c=\b}|8p4cSmzgU7be,+i5ci6uq.x T/s@9uk-oZX;u`=U >8rsIXW B:uUVr6a] JC[
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a@G`' zxUHXW&`}mEp`?i0 oE:N0-/t"t.-? you're using different ham bands than in these examples, modify and rerun << 9:1 or 49:1 unun for end-fed long/random wire? Recommended wire lengths for Unun models 9130, 9132 & 9135 Table shows typical SWR relative to installed wire length. This was 9m vertically metres up a fishing pole and then about 5.8m out. Wire lengths for the 4:1 ratio in models 4932 and 4935. Lengths of a half-wave or multiple must be avoided. Experimenting by slightly changing the wire length (+ or-) is encouraged to provide best overall performance. 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). Theme designed by Papathemes. VSWR analysis of the antenna in the field showed that VSWRs between 3-5.5 from 40M to 10M. << 3 0 obj uR5ucE`_aksLjYT=hzRa]JucX7d}|'}`XRa>X The key is you want to stay at least 1/2w long but not near 3/4w for any band of interest. //-->, The "Best" Random Wire Antenna Lengths This project assembles a 49:1 ferrite-core ("FT") type #43 transformer that matches 50 ohm input to 2500 ohm end fed antenna. %%EOF
Vhf and Up He had heard good things about 'Balun Designs' so he recommended you. Advertising Info 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. tuner the colored bands below are the best lengths as long as your installed, it is a compromise antenna but great for portable use because %
Usually any wire length that is non resonant on the band or bands desired will work with the 4:1 ratio. One single wire, no solder connections,very simple.all the way from the tuner to the end support. 2. SWR will vary based on topography, wire orientation and use of ground or counterpoise. [ /PDF /Text /ImageI ] HF & Shortwave A standard recommendation (see QST, March 1936, p. 32, "An Unorthodox =======================, More on Random Wire Lengths from Mike, AB3AP (06-29-2012), I was surfing around Hamuniverse.com and found thIs page on random wire antennas: <>
NOTE: Rewording the previous paragraph, if you have a capable enough %PDF-1.5
Drill another hole in the same side as the antenna radiator wire mount hole. 9:1 Unun 1.5-54MHz 2kW 9132S. google_ad_height = 600; It will be good for 15m, and 10m. Cut the antenna radiator wire (free untwisted end of long wire) of the unun to the correct size, scrape the enamel insulation off of the free end with a box cutter, add a ring terminal, and secure to antenna radiator bolt with washers and lock washers. 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. 2 0 obj
. << In another life, I could have been a telephone engineer. 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). One end goes straight into the Please note that I will not be describing the construction of the antenna wire radiator here. The graph below shows lengths to avoid for different collections of bands. One is for the top of the box so that it can be hung up. Designed for use with single wire unbalanced antennas, this new addition is small, compact and perfect for quick portable/emergency installations. The bandwidth where SWR was below 2:1 was about one MHz. /ProcSet 7 0 R >> <>>>
In other Our newdesign isperfect for matching both long and short length wire antennas for multiband use. This calculates to 4.2 m or 14 ft for an 80m end-fed. endobj Placing 3000 to 4000 ohms of resistance between the free end of the twisted portion of wires (the gound) and the free end of the long wire (the wire that connects with the antenna radiator after the 14th winding), can simulate adding an antenna radiator wire to the unun impedance transformer. This design is excellent for matching both long and short length wire antennas for multiband use. presents an extremely high impedance to the tu Vacation Closure - See Homepage for Next Availability. 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. I won't bore you with all that so the first portion of this still only shows up to the 4th multiple. Enclosure Depth: 1.250 in. /Resources << UJM-49-1 $56.99 Save up to 6% when you buy more. (Also check out AB3AP'Swebsite and say thanks for sharing his skills. Balun Designs. Tune Around! Typically unbalanced = 50/75 ohms too unbalanced = 450/675 ohms. SO-239 connectors are silver plated with Teflon insulation. I attached the toroids to a PVC DWV test cap with 3 cable ties. >> >> 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. (Originally published February 22, 2021). A few more comments about this 49:1 autotransformer EFHW design. Powered by BigCommerce. 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. You have to give up a band or two, like 60m and 6m, as 748 0 0 752 0 0 cm 73, /Type /Page program or two to do all the dirty work. Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. The First Thing New Hams Often Ask:What Is An UnUn? endobj
This type of antenna is very easy to install because there is no need . 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. Anyway, an old friend mentioned 'MyAntenna.com' but they were closed for the summer. My homemade 49:1 EFWH with a 60 wire (cut for 40M) would do just fine! The length should be calculated based on the lowest frequency to be worked. I have not done this yet. SBULLET-9U-1500. The other is to provide strain relief for the antenna wire). the C code, in Matlab or Octave get a plot by simply putting the Each vertical blue line represents an amateur radio band. endobj The "9:1 UNUN" are for random length wire antennas fed at the end. My commercial EFHW is 130 feet long for 80 and up, and my 40 meter homebrew antenna is about .
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