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.
5000 Watt rated 1:1 CUBE UNUN™
This higher power UNUN utilizes mil-spec coax cable for the windings on a extra large core toroid with coax silver shield and silver braid for low loss. The dielectric is Teflon® insulation for high voltage ratings of 1,900 volts. (A typical 5KW signal at 50 ohms impedance will have a voltage of 500 volts at 1:1 SWR). Wired as a UNUN (CU-1-5000) with SO-239 input and output connectors. Rated 5KW PEP/1500 Watts AM/RTTY/CW from 1.8-30 Mhz, less at 50 Mhz.
If you run RTTY contests or FT8 at 1500 watts output, this is the balun/unun you need – it won’t burn out at heavy 1500 watt duty cycles like other brands rated at 1500 watts (or more). We use these same chokes in our own RTTY station at full 1500 watts output and they have never failed. We use one at the amplifier output and another at each antenna feed point. Works very well on OCF antennas below the 4:1 balun to keep RF current on the antenna and off the feed line. Built like a tank, works like a charm, and priced under the competition – what more can you ask for? THIS IS OUR MOST POPULAR HIGH POWER UNUN!
Choose optional ground lug (on input connector shield) and static bleeder (on input connector center conductor) to bleed off static charges on a continuous basis. (Not a lightening arrestor)
Likewise Termination Resistor values vary from 500-1250 ohms and we have a good selection shown HERE: