These are sometimes known as a Magnetic Longwire Balun. 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. They are not a half-wavelength long, meaning that, if you choose the length of the radiator wisely, the impedance at the end of the wire will not be as high as the impedance of a half wavelength long wire. In many cases, the impedance can be transformed with the help of a 9:1 unun (unbalanced input to unbalanced output). See the figure at right.
Part One RF Man Discusses Long Wire Antennas, Unun's, RF Chokes, and Antenna Tuners YouTube
1. How long should a 9:1 counterpoise be? A typical length for a 9:1 counterpoise is between 20 to 40 feet (6 to 12 meters). It should be resonant or non-resonant depending on your antenna setup. 2. What is the best length for a random wire antenna? Figure 1 Typical 9:1 voltage unun and long wire antenna configuration. Construction PVC covered 1mm diameter copper wire was used with the view that the thicker insulation may reduce the possibility of insulation puncture due to the higher nominal impedance. This is part 1 of a 4 part video that discussed how to build and test a Multiband Long Wire Antenna, a 9:1 Unun, a 1:1 RF choke, and an Antenna Tuner. Please visit my web site at:. The feed point of a long-wire antenna is nothing more than a broadband impedance transformer. In the case of a 1:9 UnUn, the power line (coax) impedance of 50 ohm will be transformed up to an impedance of 450 Ohm. After all 50 x 9 = 450.
Balun 9a1 UnUn 91 Antenna LONG Wire i6ibe
Installation Notes and Recommended Wire Lengths. This unun should be used with the wire lengths listed in the table shown in the above link. Use of the 9135 for "random" wire lengths, other than shown, can potentially create an impedance that is too low for an ATU to match.. 4:1 unun designed for use with wire verticals, long wires and. I have recommended this balun to many hams and I have 2 in my antenna toolbox (actually I have the whole line of them). They are not waterproof so not ideal for winter use unless you mount it into another box (grey electrical plastic box works well). Try 53 feet for better 80m coverage. You need at least 25 ft of coax with it or add about 10 ft. Overview Brand: LDG Electronics Manufacturer's Part Number: RU-9-1 Part Type: Baluns, UNUNs and Chokes Product Line: LDG Electronics RU-9:1 Unun DXE Part Number: LDG-RU-9-1 Frequency Range: 1.8-30 MHz Ratio: 9:1 Termination Impedance (Ohms): 450 Termination Location: This is part 4 of a 4 part video that discussed how to build and test a multiband long wire antenna, a 9:1 Unun, a 1:1 RF choke, and an antenna tuner. Part 4.
Balun 9a1 UnUn 91 Antenna LONG Wire i6ibe
Your balun or unun is built to provide a very long service life by following a few simple installation procedures. Please be sure to read through both this section and the second section titled "Recommended wire lengths and Configuration Notes for Unun models 4130, 4132, 4134, 4932, 4935, 9130, 9132 & 9135". 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. 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.
Core is coated and sealed for long term durability. Winding Type: Single core with trifilar wire winding configured as 9:1 unun Downward impedance transformation by factor of 9. i.e. 450 ohms to 50 ohms. Winding Material: 14 gauge Superior Essex Heavy build polyamideimide Allex 240 Winding Wire. Technically a true "longwire" needs to be at least one wavelength long. but Hams commonly call any end-fed wire a longwire or more correctly random wire antenna. Figure 1 Typical ATU and long wire antenna configuration with an earth or earth plus counterpoise.
91 UNUN for the long wire radio antenna YouTube
I made the HF multiband Random Long Wire Antenna with UNUN 9:1 (my toroid T130-26 from an old PC PSU) publicated by VK6YSF on his website here:https://vk6ysf. 9:1 Ununs are useful between coax and long wires with load impedances near 450 ohms. Shortwave listener antennas also can benefit with the 9:1 unun and it will provide a better match than 4:1 ununs - this means quieter noise levels and stronger signals so you can hear distance stations easier.
