1:1 Baluns/Ununs/Chokes

Bullet 50:200 (4:1) HF Balun, 1.8-61 MHz, 500/1500 Watts PEP, Loop, OCF, ZEPP

SKU Bullet-4B-500EB
$89.95
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PEP Power Rating
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Bullet 50:200 (4:1) HF Balun, 1.8-61 MHz, 500/1500 Watts PEP, Loop, OCF, ZEPP
Product Details
Country/Region of Manufacture: USA
Type: NEW
Input ohms/Output ohms: 50 in, 200 out
Frequency Range < 2:1 SWR (MHz): 1.8-61
PEP Power Rating (watts): 500/1500
Input Connector: UHF SO-239
Output Connector(s): Eyebolt/Wingnut
Transformer Topology: Broadband
Hardware Type: Stainless - 1/4"
Antenna Compatability: OCF, Zepp, Folded Dipole, Loop

The Bullet-4B-500 and SBullet-4B-1500 are multi-core core baluns with a compact enclosure (looks like a bullet) enclosure that is physically lightweight but electrically robust and easy to transport for your portable loop antenna solution or permanent installation. Halyard hoist at top of balun for convenient attachment point. Input is via SO-239 coax connector and output with side eye bolt output. Choose your model rated 500 or 1500 Watts PEP from 1.8-61 MHz.

This transformer requires a feed line choke (see related products) to isolate the coax feed line from the antenna. A coax noise filter at the radio end of the coax is also recommended for best results.

Vertical Delta Loops

Multi-band vertical delta loops can be oriented several way but the most popular is to have the “pointy” end at the top (usually a single support) and the lower horizontal ends just out of reach of humans and animals. Best feed point at the top for multi-band use with a 4;1 balun. CUt total wire length to 1005/F (MHz) where F is lowest band frequency of use..

Single band vertical delta loops are best fed 1/4 wavelength (246/f(MHz)) from the top point down one side. Vertical delta loops use the same 2:1 baluns as the horizontal loops.

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.


HF 1-61 MHz coax feed line common mode chokes

1:1 feed line Chokes (also known as feed line current chokes, common mode chokes, line isolators, current mode chokes, and 1:1 baluns/ununs) are available in kit form or assembled form in a weatherproof Current Unun and Balun Enclosure which we call a CUBE™. All 1:1 chokes are ferrite based and are designed for 50 ohm coaxial cable input and 50 ohm output. 1:1 Ferrite toroidal or bead chokes have a higher choking impedance than our popular Sleeve Chokes and various models are available for specific frequency ranges and power levels.

1:1 Chokes are useful for choking common mode currents that may flow on the exterior of the coax cable shield while allowing the signals on the interior of the shield and the center conductor to flow unaffected and keeping the common mode current on the antenna. They isolate the coax shield and prevent it from becoming part of the antenna system.  

1:1 Chokes are useful between balanced lines for center fed dipoles at their fundamental frequency (468/f (MHz), beam antennas with a 50 ohm balanced driven element, G5RV, loops, yagis, NVIS antennas, mobile installations, portable antennas and anywhere common mode current (or RFI) is a problem.  They are also helpful between transmitter and linear amplifier or between linear amp and antenna tuner or as isolation chokes where higher choking impedance is needed (in the range of 2K-7K ohms). 

1:1 Chokes are also very useful as feed line current chokes at the “radio end” of the antenna (we call them coax noise filters) where they choke/filter common mode current induced onto the coax shield from radiated waves (from your antenna, and other sources such as DSL routers, computer devices, plasma TVs, etc. originating in your house or your neighbor’s house).  For RFI issues see RFI/EMI Solutions for general use or for specific radios and devices.  

For best results we recommend a 1:1 choke at the “antenna end” of the coax and a coax noise filter at the “radio end” of the coax. (A side benefit is a reduction in noise level caused by common mode currents). 1:1 chokes are also available as Sleeve Chokes (Slip on or Snap on) for ease of installation and light weight on the antenna.