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.
Feed Line Chokes for Vertical Antenna with radials/counterpoise
Feed line chokes for verticals require a special arrangement to isolate the coax feed line from the radials and ground system. Schematically, a good feed line choke for verticals with radials should be built as follows:
Our CUV-1-1500 and CUV-1-5000 feed line chokes are all internally connected to isolate the coax feed line as shown above.
Th CUV-1-1500 unun is a common mode feed line choke for vertical antennas with radials that need to be isolated from the coaxial feed line to keep common mode current from using the coaxial braid as another radial. Very effective with high choking of 1K-5K from 1.8-61 MHz and also incorporates two side studs/wingnut terminals for radial or ground connection at the antenna while isolating the coax feed line braid from the radials via the internal common mode feed line choke. Top terminal with stud/wingnut for vertical connection enclosed in a 4″ x 4″ x 2″ box..
To reduce receiver common mode noise for long runs of coax to your antenna, use a MC-1-1500 or CU-1-1500 feed line choke at the station end of the coax.
Likewise Termination Resistor values vary from 500-1250 ohms and we have a good selection shown HERE: