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.
Model CB-9-1500 is a 9:1 multi-core, balanced output balun housed in a water resistant enclosure with top stud/wingnuts (TS) or Eye bolts (halyard top hoist, side eye bolts/outputs) used to translate a 50 ohm input up to 450 ohms at RF power levels up to 1500 watts PEP when used with a matched load. With matched 450 ohm load the SWR over the frequency range 1.8 to 61 MHz is less than 2:1 on the coax feed side. Actual SWR is under 1.25:1 from 1.8-180 MHz so very useful for 30-150 MHz also - see graphs for specific details
Features
* Wide Frequency Range 1.8-161 MHz, usable to 180 MHz < 1.25:1 into resistive load
* High Power, 1500 watts PEP (up to 61 MHz)
* Convenient side tab mounting feet
Many designs for BBTD antennas using 9:1 baluns at HFLINK.COM
We also have the 9:1 with the built-in 1:1 choke/balun in part# CB-9-1-1500EB
Likewise Termination Resistor values vary from 500-1250 ohms and we have a good selection shown HERE: