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.
Coax antenna switches generally only switch the center conductor of the coax and all the coax braids remain connected in parallel summing the common mode noise off ALL coax lines onto the coax selected - this means you may be picking up common mode noise from coax lines that are not even connected to the coax antenna selected. The only practical solution is to isolate the coax braids from each other BEFORE they connect to the antenna switch as shown in the picture for a FLEX RADIO Antenna Genius 8 port switch or just a simple 2 position antenna switch.
This product listing is for antenna switches from 2 - 8 antennas. Each switched line needs a common mode noise filter prior to being connected to the switch. In some cases you can use a double male barrel connector to attach the filter to the switch or you may need a short jumper cable.
We offer a low power filter (CMNF-500-50 up to 500 watts PEP and up to 46 dB of common mode noise suppression per line) or a high power (Maxi-Choker, MC-1-1500 up to 1.5KW PEP and up to 42 dB of common mode noise suppression per line) and 2-8 ports of antenna switch. If you use a dummy load for one of the switched ports you do not need a filter for that port. Each filter has a range of 1.8 to 61 MHz (see individual listing on this website for specifics).
Picture shown is 8 port FLEX RADIO Antenna Genius at AK6R with one dummy load and 7 antennas. Inputs to Antenna Genius is from TUNER GENIUS with SO2R option.
This kit also includes 1/2 snap on filters for the ethernet line and the 12 volt power supply and two 1" snap on filters for the RF input lines (1/2" ID RG-213 shown and also works with 1/4" ID RG8-X/RG400, etc.).
Likewise Termination Resistor values vary from 500-1250 ohms and we have a good selection shown HERE: