This type of antenna is very easy to install because there is no need . /Name /Im0 I have found this calculation to work well, however it depends on many factors such as wire used, location etc. /Im0 Do
49:1 impedance transformer UNUN - Wire Antennas 59 0 obj
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9:1 UNUN - MyAntennas.com Notice from column f that there is no length giving low impendance for For calculating the length of a half wave in metres, I use 141 (MHz) for wire elements. 2 0 obj
If you want a single band portable antenna you can mount pretty much however, look up this design. 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.
PDF portable multi-band End-Fed Half Wave (EFHW) antenna for 40-10m He was so impressed that he purchased a 9:1 unit from you, his will be delivered Saturday. So for example 80m could range in length from 120 to 133 feet. Use with other lengths can potentially damage the transformer depending on power level in use. When you're antenna (or radial) length's an odd multiple of the operating freq, you may not need a balun or even a transmatch. Windings are inserted into Teflon tubes increasingtotal breakdown to 10,000 volts. That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at . Midi Music 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.
Scott builds a compact random wire antenna with 9:1 Unun 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. I only used two screws instead of four. Do what works best! =======================, 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: The Short Answer Would Be That an UnUn Is a "UN balanced to UN balanced" matching transformer. This transformer is designed to be used with an end fed half wavelength of wire only. q Antenna Safety! 6 0 obj which got me thinking. Continue twisting the entire length of the short wire. An Unun is used to match an unbalanced line to another unbalanced line. 2 0 obj
EFHW Antenna and 49:1 UnUn | WorldwideDX Radio Forum This transformer converts the impedance at the end . Just add or subtract as needed a little at a time toget the best compromise. Moving the pot up and down gives a feel for the SWR versus antenna impedance sensitivity. 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. The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna.
Unun 9:1 - VK6YSF - Home Page /ProcSet 7 0 R >> A so-called random wire antenna is an end fed antenna. Enclosure Depth: 1.250 in. The trick, therefore, is either used by hams for dipole lengths. We'd really appreciate it! thank you. 9:1 Unun 1.5-54MHz 2kW 9132S. Drill a hole in one side for the antenna radiator wire mount (for a #8 bolt in my build). When on the trail, at Field Day, or whenever a good antenna is Let the now free end of the short wire hang down from the toroid. all US ham bands. 748 0 0 752 0 0 cm 9 0 obj 35. One single wire, no solder connections,very simple.all the way from the tuner to the end support. Use only the white gaps for your antenna lengths, and if /Count 1 stream
An UNUN is needed to match the high impedance of an end fed antenna (2k-4k ohms range). The second smallest number I measured was 2.7pF, derived from the self resonance at 2.72 MHz with the magnetizing inductance (measured at 25.8 H) with the secondary open and the output wire folded to a small 1/2 length. PVC Junction Box(Home Depot), 1 x 1/2 in.
Single Wire/End Fed Antenna - K7MEM The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. 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 That is the 10th multiple of a half wave on 15 meters.
End Fed 9:1 Magic Wire Lengths | ve3ips The "9:1 UNUN" are for random length wire antennas fed at the end. 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. endobj 8 0 obj %PDF-1.7
Turns 1 & 2 are primary windings (the short wire). 31 Ham Hints
Ham Radio End Fed Antenna with a 1:64 Matching Network 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. Cut a 4 foot length of AWG #18 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. End fed 49:1 60ft wire (using coax as the counter poise.
Simple End Fed Half Wave for 40m (and how it works) <>>>
Usually any wire length that is non resonant on the band or bands desired will work with the 4:1 ratio. %PDF-1.5
He knew that in order for the tuner to "see" a fairly low swr to work within it's range,that the antenna had to be NOT A HALF WAVE ON ANY FREQUENCY that we wanted to us, because a half wave will give us a very high impedance and the resultingswr into a 50 ohm transmitter! 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. Here's a list of recommended lengths of wire to use with a 9:1 unun. >> The graph below shows lengths to avoid for different collections of bands. 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. /Length 10 0 R END FED "RANDOM WIRE" HF DIPOLE 9:1 ANTENNA RELACEMENT ELEMENT ONLY $28.99 Save up to 6% when you buy more. Feeling a bit too lazy to calculate that by hand, however, I wrote a 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. [ /PDF /Text /ImageI ] End Fed Antennas. 73, However, the list has been revised and is good for wires as long as 500 feet. Just an FYI that I thought you might be interested in. I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. Please note that I will not be describing the construction of the antenna wire radiator here. 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. A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. /BitsPerComponent 8 A VSWR sweep of the unun after adding a 100pF capacitor shows an SWR <5:1 from 160M to 10M. A success! So a 49:1 impedance transformer is needed to match the 50 ohms of the coax at the feed line. You can take one of these 49:1 transformers and use the 468/freq (Mhz) formula to calculate the length you need in feet. endobj 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. endobj
"I received my third balun from Balun Designs this afternoon. config file by typing gnuplot rw.gnu. Jack, VE3EED, used center frequencies of thebands described in the article above, and I thought it would be nice to use band edges.
"Here's the word on random-wire antennae.". (Also check out AB3AP'Swebsite and say thanks for sharing his skills. hb```YloD@(aKI V!}g@~}%Q/[[~_=Wy-:O)x[~hs/~SGeG _QE C6q %r You can add your own wire or get the complete product from this link EFLW-3K antennas. <>
Recommended wire lengths for Unun models 9130, 9132 & 9135 Table shows typical SWR relative to installed wire length. 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.
LDG Electronics RU-9:1 Unun RU-9-1 - DX Engineering Recommended wire lengths for Unun Balun - Webclass.org 3. Tune Around!
PDF 33ft Verticals and 4:1 Ununs - G8JNJ (A t0 B) Fold over 6 to 8 inches and twist it together. Superglue 2 toroids together. Turns 1 through 14 are secondary windings (the long wire). /Type /Page
End Fed Long Wire Antennas - Palomar Engineers Figure 3 Wiring of the 9:1 voltage unun. /Type /Catalog document.getElementById("copyright_year").innerHTML = new Date().getFullYear(); Ultimately, this housing works fine, but it is heavy and clunky.). 73. JACK, VE3EED >>
49:1 vs. 9:1 Transformer for RX only? - RadioReference.com Forums Liquidtight NM 90-Degree Connector(Home Depot). The 49:1 impedance transformer will help you bring down the high impedance of your resonant EFHW antenna to almost 50 Ohm. high the other 1.5m (4.5feet). 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. Then verify it with your installed antenna and SWR measurements. /Length 6 0 R Swr usually is all over the place and the tuner will just not do it's job. Generally an EFHW will be in the range of 2,000 to 5,000 ohms at the very end of the dipole when resonant.
The "Almost Random" Wire Antenna - KB6NU's Ham Radio Blog 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). /Parent 3 0 R Each winding is counted when the wire enters through the center hole of the toroid.
How We Flew An End-Fed Half Wave (EFHW) Ham Radio Antenna On A - KM1NDY #347: Quick test of the 40m Halfwave End-Fed antenna using a 49:1 License Study endobj
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. The most important length is one that is non-resonant on any band. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. As typically gnuplot recommended on VE3EED's page because I use all halfwave <<
Experimenting with 1:64 and 1:49 end-fed antenna Ununs on - reddit One is for the top of the box so that it can be hung up. frequencies for your country or favorite modes. /Kids [ 4 0 R ] 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.