Broad Band Terminated Dipoles (BBTD, T2FD)

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?

BBTD at AK6R 1024x726 - Broad Band Terminated Dipoles (BBTD, T2FD)

 

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.

50:200 (4:1) CUBE™ Current Balun, 1.8-61 MHz, 1.5KW - Loop, OCF, Folded Dipole useful to 200 MHz

CB-4-1500EB
$124.95
In stock
1
Product Details
MPN: CB-4-1500
Country/Region of Manufacture: USA
Type: Balun
Input ohms/Output ohms: 50 in, 200 out
Frequency Range < 2:1 SWR (MHz): 1-31
PEP Power Rating (watts): 1500
Enclosure Size: 4" x4" x 2"
Weight (pounds): 2
Antenna Compatability: Dipoles: Extended double zepp, folded 2 wire, off center fed (OCF); Loops: Horizontal, vertical - coax fed

The CB-4-1500 balun is a multi-core current balun with an enclosure box. Input is via SO-239 coax connector and output can be top studs (for ladder line) or side eye hooks (2) and top eye hook used as a halyard hoist for supporting your wire antenna. Rated 1500 Watts PEP Watts from 1.8-61 MHz (see SWR graph).

This transformer requires a feed line choke to isolate the coax feed line from the antenna. A coax noise filter at the radio end of the coax is also recommended to reduce coax cable common mode noise.is also recommended.

Useful on these type of antennas:

Dipole, double extended
Dipole, linear load, ladder line fed
Dipole, long, non-resonant
Dipole, off-center fed (OCF)
Dipole, snake type, ladder line fed
Long wire with ground system
Multi-band, remote balun


Useful out to 200 MHZ under 2:1 SWR (see swr graph)

Need a 4:1 and 1:1 HYBRID balun? Check out our CB-4-1-1500/5000 with feedline choke built into same box as impedance transformer for ease of installation!


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Likewise Termination Resistor values vary from 500-1250 ohms and we have a good selection shown HERE: