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.
New improved version now goes down to 100 KHz and up to 61 MHz < 2:1 SWR!
The Bullet-2B is a multi-core balun with a compact enclosure (looks like a bullet) enclosure that is lightweight and easy to transport for your portable loop antenna solution. Halyard hoist at top of balun for convenient attachment point. Input is via SO-239 coax connector and output with side eye bolt output. Rated 500 Watts PEP Watts from .1-61 MHz. DC grounded to coax shield for static bleed off.
This transformer requires a feed line choke at the balun to isolate the coax feed line from the antenna. A coax noise filter is also recommended at the radio end of the coax..
Loop Antennas
Loop antennas are some of the best radiating and receiving antennas you can make. They can be in a triangle (called a delta loop), square or rectangle or even a circle. Horizontal loops can be fed anywhere that is convenient. Vertical delta loops(circumference length=1005/f(Mhz) are best fed 1/4 wavelength (length=246/f(Mhz)) from the top point down one side.
We offer pre-configured loop wire kits for your antenna building convenience. Just choose the band you need - see related products.
Want multiple bands from a loop antenna, consider the 4;1 Bullet (Bullet-4BEB in 500 or 1500 watts versions).
NOTE: We rate our Bullet baluns (and ununs) VERY conservatively at 500 watts PEP with a 50% duty cycle. Some manufacturers selling low cost baluns may use a 5% duty cycle for their PEP rating to make it appear you get a higher rated balun for a lower price, but you may in fact be getting be getting less. Their 1500 watts PEP really means 75 watts continuous or 150 watts at a 50% duty cycle compared to our 250 watts at 50% duty cycle. Our baluns typically cover a larger frequency range under 2:1 SWR which make your transceiver happy and probably will last longer with less electrical stress.
Remember we over engineer our products, to out perform our competition - just compare the weight of our baluns to theirs and you will know we put much more into our products so you don't have to worry about failure at a critical moment.
Likewise Termination Resistor values vary from 500-1250 ohms and we have a good selection shown HERE: