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.

439679433 - Broad Band Terminated Dipoles (BBTD, T2FD)
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Shortwave Listener Antenna - with MLB-2 Magnetic Longwire unun, 50 foot antenna wire, 25' support cord, end insulator

PA-SWL-1
$109.95
In stock
1
Product Details
Brand: Palomar Engineers

Model # PA-SWL-1 includes MLB-2 Long Wire antenna matcher, 50 feet of insulated wire and 25 feet of support cord and a end insulator for the antenna. Great for short wave listening and works as a bent antenna, sloper, inverted “L” antenna (Vertical and horizontal) or as a straight vertical antenna. For best results use a counterpoise for the lower frequencies.

Palomar Engineers Magnetic Longwire Balun has been redesigned for shortwave listeners and others needing to match a long wire antenna to 50/75 ohm coax feed line cable.

Specifications: Frequency: 100 KHz – 30 MHz. Input: 50/75 ohms for coaxial cable. Output: High impedance. Connector: SO-239 (for cable) wingnut/solder lug for wire lead (for antenna). Mounting: Stainless steel eyebolt. Size: 2.5” diameter. Case: White PVC sealed weatherproof. External ground bolt with wing nut for external counterpoise or separate ground.

The long wire antenna often has a high impedance in the 500-1000 ohm range and the MLB-2 transforms this high impedance close to 50/75 ohms efficiently coupling the received signal to the receiver. A long wire antenna with a matching unit such as the MLB-2 often has a 12 db (2 “S” units) better signal than a long wire without a matching unit.

For best results use a coax noise filter at the receiver end of the coax to reduce common mode noise picked up by the coax braid. Model # CMNF-500-50 is best suited for this antenna.


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