The simplest, most cost effective feed line choke is a ferrite ring installed as shown in the picture (at the antenna feed point) to stop feed line radiation or at the radio end of the coax to suppress common mode coax noise current on the coax braid.
Great choke for log periodics, HF beams, Transceiver/Amp isolation
Improves antenna pattern by preventing your dipole from becoming a tripole
Suppresses pesky coax braid radiation and RFI
Reduces coax braid common mode current up to -40 dB ( 6 “S” units) on receive
Use one choke for each antenna feed line
Add a double female barrel connector to act as an “extension” of the existing coax.
50:600 ohm, (12:1) CUBE™ Balun/Unun, 1.8-31 MHz Balun/Unun, RX Only/1KW/2KW/3KW PEP, T2FD, Rhombic, End Fed, Flagpole
| Quantity | Price per item | Discount |
| 2 items | $111.95 | 7% off |
| 10 items | $103.95 | 13% off |
| 50 items | $99.95 | 17% off |
HF 12:1 Impedance Transformers
12:1 Baluns are useful transformers for 600 ohm balanced loads the impedance at the end of the feed line is 600 ohms (1/2 wavelength feed line), or high impedance feeds for rhombic, T2FD and traveling wave antennas.
12:1 Ununs are useful between coax and long wires with a load impedance near 600 ohms like a beverage antenna. Shortwave listener antennas also can benefit with the 12:1 unun and it may provide a better match than 9:1 ununs – this means quieter noise levels and stronger signals so you can hear distance stations easier.
For end fed antennas, use a 9:1 unun or 12:1 unun - also available in the "Bullet" antenna end fed style (Bullet-12U-500)
Receive only baluns/ununs are rated for 100 watts PEP
All enclosure boxes have 2 side flanges with 1/4" holes.
All of these products are made to order and typical production time is 10 days depending on quantity.