Broad Band Terminated Dipoles (BBTD), Tilted Terminated Fold Dipoles (T2FD) and Balanced Termination Folded Dipole BTFD) antennas can be designed to cover a large range of frequencies between 1.8 30 MHz. Longer length antennas generally provide better low frequency efficiency but take up a larger footprint of land. One BBTD that has worked well at the AK6R antenna farm is shown below. Many other designs are available and can be found at www.HFLINK.COM as well as other internet sites. Your mileage may vary using this antenna, but as a general coverage antenna for ham and shortwave broadcast, the simplicity can’t be beat even though an individual dipole on a specific band may out perform this broad band dipole. Palomar Engineers has all the parts you need to build this antenna, so why not give it a try?
Depending on the source of the antenna design, different value baluns are specified. Our Bullet(TM) baluns in ratios of 9:1, 12:1 and 16:1 are excellent for this type of antenna as they are broadband from 1.8-61 MHz and will take up to 500 watts PEP.
SPECIAL ORDER SABRE 2:1 CUBE Balun™ – (1.8-30 MHz)
(Original product part # was 770013S - circa 1999)
Model SABRE-2-2000 is a 2:1 (100:50) quad core balun used to translate a 50 ohm input to 100 ohms at RF power levels up to 2000 watts PEP when used with a matched load. This assembled balun features a quad core configuration for increased power handling and flatter frequency response to 31 MHz. With a matched 100 ohm load the SWR over the frequency range 1.8 to 30 MHz is shown in the following table measured with an AIM 4170 network analyzer. Notice that the conversion from 100 to 50 ohms is very consistent from 1.8-31 Mhz and SWR is less than 1.5:1 over the range allowing easy tuning by most radio internal antenna tuners or an external tuner. Graph is for a 2:1 balun often used with delta loop, log periodic, horizontal loop antennas and HF Radar.
Input connector is 50 ohm type N (SO-239 also available - inquire).SABRE-2-2000 is in a NEMA 4x4x2 weatherproof box with mounting flanges at bottom to attach to fixed location (mast, wall, beam antenna, etc.).
Eye bolts and studs are all stainless steel for long life.
Likewise Termination Resistor values vary from 500-1250 ohms and we have a good selection shown HERE: