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.
Exercise Equipment RFI Kits
Does the operation of a treadmill or your exercise equipment wipe out your radio receiver reception? We have heard cases where the treadmill from a neighbor’s house wiped out the ham radio receiver reception from 2-30 Mhz! The treadmill source was finally isolated to a variable speed motor power supply that was injecting RFI into the AC wiring of the house and the AC wiring was acting as a transmitting antenna broadcasting the signal to the entire neighborhood. The case was difficult to track down since the broadband RFI interference only occurred at 7-8 pm each nite when the neighbor used the treadmill. As with all RFI cases the sequence is similar: Find the Source, Choke the Path, Protect the Victim.
Once the source was identified, a simple solution was to choke off the transmitting antenna with a AC line choke shown below which eliminated the interference problem to the ham receiver:
Testimonials
F400-31 AC Power Cord Choke completely cured the RFI problem I had with my wife’s treadmill. Now I can hear the weak signals!
Likewise Termination Resistor values vary from 500-1250 ohms and we have a good selection shown HERE: