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Max Choking 1:1 Isolation Balun 1 - 54 MHz 5kw - #1115d
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Manufacturer:
Balun Designs | | SKU: |
1115d
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Price: $79.95
$81.25 1115det - Eyebolts on sides & Top
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Designed for those who want the maximum isolation and choking across the full HF spectrum. Building on the original 1:1 design by Dr. Jerry Sevick, this balun has two (2) cores in a stacked configuration to maximize choking impedance on HF bands from 1- 54MHz. By utilizing Mil-Spec coax, the SWR, Transformation and power handling are excellent while providing a choking impedance that exceeds 10,000 ohms. Even on 80m the choking impedance is over 3,500 ohms. If you operate primarily on the low bands (160 thru 40m) you should also consider the model 1116d for your needs.
Sometimes called a choke balun or common mode choke, this 1:1 ratio current balun is the best for feedline isolation and choking. It has the widest operating frequency range, lowest core stress and provides the best overall balance of any balun for given cost, size, and weight. Please click on the graph shown below to see the complete results.
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Tests performed with AIM-4170c Network Analyzer and precision 50 ohm non inductive load.
Design features:
- Utilizes specifications of Jerry Sevick, W2FMI, the authority on baluns. This is his Guanella current balun design which he modified to provide higher efficiency. By utilizing a new toroid mix, the bandwidth of his design has been increased.
- Custom mix low permeability toroids in a stacked configuration provide broad frequency coverage and high choking impedance. Toroid is coated with epoxy paint for added durability.
- This Isolation balun has significantly higher common-mode impedance which exceeds 10,000 ohms. The larger core area is much more effective than types with ferrite beads, ferrite bars or wound air-core coax.
- Windings are Mil Spec 50 ohm coax rated 19kw @ 1mhz, 9kw @ 10 Mhz and 3.5kw @ 50 Mhz. Silver coated braid and center conductor. Solid Teflon dielectric.
- Typical insertion loss is less than 0.2 dB
- Power handling of 5kw continuous - 10kw intermittent up to 35 MHz. From 35MHz to 54MHz power limit is 4kw.
- SO-239 connectors are silver plated with teflon insulation.
- All hardware is stainless steel
- N connectors and Alternate Mounting Options are available in the Accessories section.
- Very high efficiency. Will not heat up or saturate like many of the typical cheap current baluns.
- Balun is installed in weatherproof 4" X 4" X 2" Nema Box which makes an excellent outdoor weatherproof enclosure.
Regardless of the antenna you're using, an isolation balun can provide numerous advantages
- Prevents unwanted RFI by eliminating feedline common mode currents and radiation
- All power goes to the antenna, improving efficiency
- Reduces noise or EMI picked-up by your coax shield
- Power is balanced between driven elements of antenna
- Can help overcome a less than optimal ground
Noise Reduction
While the most common advice is to improve the station's RF ground, the root of the problem is in the poor isolation of the feedline from antenna currents. If your goal is to reduce feedline radiation and improve reception by reducing noise, feedline isolation baluns are an excellent choice. Adding an additonal isolation balun at the point where the feedline exits the near field area of the antenna will substantially reduce unwanted feedline radiation and reception of EMI without the need for improved station grounding.
***ONE EXCEPTION!***
It must be pointed out that a 1:1 balun should never be used on the second harmonic of a half-wave center-fed dipole fed with coax (like an 80 meter dipole being used on 40 meters). The impedance can be as great as 10,000 ohms creating very high voltages which can bring about voltage breakdown and/or excessive heating. This exception ONLY applies to Coax Fed HALF WAVE CENTER FED DIPOLES WHEN USING A 1:1 BALUN AT THE FEEDPOINT.
This balun will handle continuous power and tolerate high SWR for extended periods.
It will not heat up or saturate at rated power, under extended duty cycles or stressing load conditions.
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