#188 . Put a dummy load or an antenna that shows a good match to it, and put some power through the unun. Ideal for high power Windom design antenna . There was quite a discussion on the 49:1 transformer for the EFHW antenna a few weeks ago. It may be used with many of your antenna projects where a 4:1 Unun is typically recommended. To celebrate our 20th Anniversary in the year 2020 we have developed a new line of Baluns and Feedline Chokes. 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. Install November 2016. It is a conventional transformer. This may explain the impedance transformation disparity you're observing. 9:1 UnUn Feeding a random/long wire or at the base of a multi-band vertical. for a 9:1 UNUN its better to choose a "random length". Winding Material : 14 gauge Superior Essex Heavy build polyamideimide Allex 240 Winding Wire. The SWR varied from a low of 5.9:1 on 10m to a high of 49:1 on 30m. 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. 49:1 or other high ratio transformers are for resonant "cut to frequency" antennas like the traditional zepp/fuchs antenna. My question is the 9:1 unun used with a random wire antenna considered to be as lossy as the 49:1 transfomer? Requiring a balun to feed a balanced antenna from an un-balanced load with an impedance step up from 50ohms to 450ohms, a 1:9 Voltage balun design using an L15 ferrite toroid cores was selected. Dâoù un ROS de 50 : 4 = 12,5 => 12,5:1 ! The tuner was connected directly to the transceiver, and all cables were kept the same during the series of tests. Add to Cart. 49:1 UNUN Transformer 2 Kw. SWR will vary based on topography, proximity of nearby structures, configuration of the antenna wire and choice of ground or counterpoise. I have never tried to transmit through it, but it proved the optimal ratio for receiving with my setup. 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 think this violates the Terms of Service. Recommended Wire Lengths for 9:1 ratio (in feet) for Coverage of 160m through 10m 53 59 72 88.5 98.5 124.5 146 162 175 Values in color are best overall lengths to use for optimum HF spectrum coverage. A 4 to1 balun can also match 50 Ohm to 12 Ohms, and a 9 to 1 can match 50 Ohm to 5 ohms. The 132-foot half-wave radiating element presents about an 1800 ohm (at 10 meters) to 5000 ohm (at 80 meters) impedance to an end-fed feed point. These are sometimes known as a Magnetic Longwire Balun. The "9:1 UNUN" are for random length wire antennas fed at the end. Windings are inserted into Teflon tubes increasing total breakdown to 10,000 volts. HF Underground wiki Radio Hobbyist technical blogHFU Rocket Chat EuroPirate ChatPropagation DataTeamspeak Server, Shortwave Pirate Radio In North America And Around The World, And Other Things That Go Bump In The Night, Login with username, password and session length. All hardware is stainless steel and housing has ground connector for ground rod or grounding to mast or tower. terminal in the UNUN goes to the COLD side of both the input and the output. Introducing DX Engineering "Maxi-Core® 20" Baluns and Feedline Chokes. It wasn't as hard as I thought it would be. Are you sure you wish to repost this message? In this two-part tutorial, Paul (OM0ET) show us his new design of a compact 9:1 UnUn for portable QRP Random Wire Antennas. 49:1 or other high ratio transformers are for resonant "cut to frequency" antennas like the traditional zepp/fuchs antenna. Add to Cart. 49:1 IMPEDANCE TRANSFORMERThe End Fed antenna is very popular especially for field work. Typically, performance is better with no ground at the antenna, but you can try both ways. Delta Loop Antennas (10) Double Bazooka (6) End-Fed Wire Antenna 9:1 Non Resonant (5) G5RV Antenna (2) Half Wave End Fed (19) Marconi Inverted L G7FEK (3) OCF Dipoles (Windom) (2) ZS6BKW (3) 2M (3) 4M (3) 6M (8) 10M (32) 12M (29) 15M (32) 17M (31) 20M (38) 30M (29) 40M (39) 60M (8) 11 M (CB) (7) 80M ⦠The coax is connected to the SO-239 and fed to your radio. 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 50Ω (unbalanced) coaxial input, hence UnUn. 20 m, câest un quart dâonde sur 80 m. Lâextrémité présente donc, lorsque le fil est bien accordé, une impédance de 36 Ω (fois 2 pour un dipôle = 72 Ω). Organic Greens Powder,
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