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.
CMNF-5000HF for transmitter/receiver coax lines up to 5000 watts PEP - 1.8-60 MHz!
For coax feed lines with receive and transmit signals, you will love the small size, wide frequency range and excellent attenuation of common mode noise interference
- Reduces broadband common mode receiver noise* picked up on the outside of the antenna coax feed line.
- Wide frequency range works on all brands of radios and coax fed antennas from 1.8-60 MHz
- Common mode noise rejection up to 15-38 DB (2-5 "S" units) depending on frequency
- Simple plug & play installation: plug a short jumper from the CMNF-5000HF to your amplifier output and plug the feed line (or a jumper to your antenna tuner) into the other SO-239 CMNF-5000HF input. Either connector can be input or output. Rated at 5000 watts PEP.
- will work with Bias-T antenna switches and will pass DC voltage from input to output with no attenuation
* not effective for noise from AC power lines or noise received directly by antenna
Installation Note: For best results, and to reduce co-interference between choked and unchoked coax feed lines with multiple antennas, ALL antenna feed lines entering the radio room need to have a separate feed line choke particularly if they are at a different frequency then HF, like VHF or UHF.
if you use a antenna switch for multiple antennas in the 1.8-61 MHz range, place the CMNF-5000HF in the "common" line of the antenna coax switch and the antenna tuner/amplifier.
For additional common mode noise reduction, consider the CMNF-500HF (500 watts PEP) placed between the receiver and the amplifier.
Got Common Mode Noise? Not Sure - Find out now by clicking link below:
Likewise Termination Resistor values vary from 500-1250 ohms and we have a good selection shown HERE: