Model 1115z - 1:1 Balun, 3kW

Balun Designs, in collaboration with Fair Rite products, has developed what we consider to be the best single core 1:1 feedline isolation balun available and designed for space constrained environments. By reviewing the scans shown below you can see what we're referring to.  Notice how the level of choking impedance ramps up very quickly developing 3100 ohms on 160m and continues at high levels across the full HF spectrum. This is a difficult to achieve and maintain for a single core balun and comes with near perfect transformation, SWR and return loss. 

N connectors and mounting options are available in "Accessories & Connectors" section of the website

This balun is more than just high power. Tests show SWR is below 1.04 across the entire HF band, transformation is perfectly flat, return loss is typically 65-85 dbmw. Please click on the graphs shown below to view the complete test results.

   
Tests completed utilizing AIM-4170c Network Analyzer and precision 50 ohm non inductive load.

 Hello Bob,

I want to share how happy I am with the new 1115i balun I purchased from you recently. I was able to complete some antenna repairs last weekend and finally attached the 1115i balun to my inverted V fan dipole. I clearly hear more stations now than I have in at least a year ! The noise floor for me is lower now than it ever has been. Another bonus, I can now happily run my ALS-600 with no problems.

Can't wait to install the other 1115t balun I purchased to my A3S.

Thank you for another great product !!

Windings of Mil Spec coax allow this balun to provide a very high power rating across all HF frequencies while also providing a uniform impedance, excellent transformation and high levels of RF choking / feedline isolation. By utilizing one of our mounts in Accessories, the balun can be securely installed on a mast, boom or where ever you need it. 

Sometimes called a choke balun or common mode choke, this 1:1 ratio current balun is the best for feedline isolation. 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. If you have a yagi you should be using one to balance the power to the driven elements and prevent the coax feedline from distorting your radiated pattern. If you have a vertical you should be using one to prevent the vertical element from using your coax as a radial and to decouple the feedline for reduced noise.

Tests carried out in an anechoic chamber to determine the affects of imbalance on radiation patterns of a half wave dipole (published April, 1980 in QST) show just how serious this can be and how important the function of the balun is in achieving predictable patterns. Notice how the pattern is distorted when the feedline is not being isolated with a balun.

Click to Enlarge

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

***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 5,000 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 caution does not apply to fan dipoles or any dipole that utilizes loading coils to create resonance on the bands in use.

Specifications

Installation Notes