This design is excellent for matching both long and short length unbalanced wire antennas for multiband use and will allow the internal tuner of most rigs to match remotely mounted single wire antennas. This unit utilizes stacked cores for increased power handling and added inductance for the lower frequencies. Be sure to review the various lengths in the link below to obtain the lowest SWR across most if not all HF bands.
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. If a wire length not shown in the table is installed, an antenna analyzer should used to determine the actual feedpoint impedance that will require matching for each band of operation.
"I would like to thank you for the prompt service and excellent condition in which the item was received. I have since erected a wire antenna at 40', using the installation-chart. I used the 53 ft lgth to start with and found the SWR-specs according to the chart to be almost dead-on. I worked the T32C expedition this past week-end on 9-bands with the single wire antenna and was very pleased with the ability of the #-9135 Unun, didn't need to use more than 100wts but if needed I knew the Unun could handle the added 'HorsePower". Thanks again for a great product, and I might soon be in the market for another one of your stout products, but will enjoy using the one I now have. 73..Alex"
Please note that short antenna lengths will not be capable of performing as a highly efficient antenna, especially on lower bands. The intent of this unun is to allow HF coverage in restricted installations such as HOA managed communities. Longer wire lengths will always be more efficient and provide better performance.
Ununs are intended for use with unbalanced antennas such as verticals and long wires.
They will not work with balanced designs such as dipoles or loops and use with a balanced antenna may cause erratic operation and/or damage to the unit.
|Core Material|| Custom mix low permeability ferrite by Fair Rite Products for maximum bandwidth.
Cores are coated and sealed for long term durability.
|Winding Type|| Stacked cores with trifilar 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.
Windings are inserted into Teflon tubes increasing total breakdown to 10,000 volts.
|Power Rating||1 to 35 MHz - 5kW, 35-54 MHz - 4kW|
|Useable Frequency||1 to 54 MHz|
|Insertion Loss||Less than .02db|
|Connectors|| SO-239 connectors are silver plated with Teflon insulation.
Studs and eyebolts are 1/4 inch.
Alternate connectors and Mounting Options are available in the Accessories section.
|Hardware||All Stainless Steel|
| Enclosure Type
|| NEMA rated 4x marine grade junction box for outdoor installations.
Cover utilizes integral neoprene gasket for weatherproof integrity.
|Dimensions|| 4x4x2 inches for main body of unit
Dimensional Drawing of Standard Enclosure
|Additional Info|| Very high efficiency.
Weight 1lb 6oz