AM Broadcast RFI Kits

Bullet 50:100 (2:1) HF Balun, .1-61 MHz, 500/1500 Watts PEP, Loop Antenna

SKU Bullet-2B-500EB
$89.95
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Bullet 50:100 (2:1) HF Balun, .1-61 MHz, 500/1500 Watts PEP, Loop Antenna
Product Details
MPN: Bullet-2B-500/Bullet-2B-1500
Country/Region of Manufacture: USA
Type: NEW
Input ohms/Output ohms: 50 in, 100 out
Frequency Range < 2:1 SWR (MHz): .1-61 MHz < 2 SWR
PEP Power Rating (watts): 500/1500
Input Connector: SO-239
Output Connector(s): Side Eyebolts
Hardware Type: Stainless Steel
Weight (pounds): 1
Antenna Compatability: Full Wave Loop

New improved version now goes down to 100 KHz and up to 61 MHz < 2:1 SWR!

The Bullet-2B is a multi-core balun with a compact enclosure (looks like a bullet) enclosure that is lightweight and easy to transport for your portable loop antenna solution. Halyard hoist at top of balun for convenient attachment point. Input is via SO-239 coax connector and output with side eye bolt output. Rated 500 Watts PEP Watts from .1-61 MHz. DC grounded to coax shield for static bleed off.

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

Loop Antennas

Loop antennas are some of the best radiating and receiving antennas you can make. They can be in a triangle (called a delta loop), square or rectangle or even a circle. Horizontal loops can be fed anywhere that is convenient. Vertical delta loops(circumference length=1005/f(Mhz) are best fed 1/4 wavelength (length=246/f(Mhz)) from the top point down one side.

We offer pre-configured loop wire kits for your antenna building convenience. Just choose the band you need - see related products.

Want multiple bands from a loop antenna, consider the 4;1 Bullet (Bullet-4BEB in 500 or 1500 watts versions).

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.


When considering solutions for AM broadcast (550 Khz – 1.8 Mhz) you should consider Mix 77 ferrites available in a variety of shapes and sizes.  Choose a size to give the maximum number of turns of the affected wire or cable.

AM broadcast transmits on a low frequency with large antennas.  Consequently it takes a large antenna to receive the signals.  Typical “antennas” are AC house wiring, phone lines, long satellite or cable TV cables, DSL/CAT5 lines running between rooms, etc.  The device wires that connect to these  “antennas” need to be choked with as many turns through the ferrite as possible.  Some installation examples are shown below on this page.

For AC/ DC power cords and coax cables the F240-77 (2.4″ OD, 1.4″ ID) “Donut” toroid is the most popular.  Also available are smaller toroid donuts and Mix 77 beads. Shown below is a graph with 8, 10, and 12 turns through the toroid – obviously more turns has higher choking impedance.  Mix 77 toroid products are HERE and Mix 77 small beads (for small wires) are HERE

F240 77 Turns Comparison 1024x648 - AM Broadcast RFI Kits

F240-77 Turns Comparison from .1 – 8.1 Mhz

Shown below is a graph of frequency response verses choking magnitude for a F240-77 in the AM Broadcast band for a 12 turn coil around the toroid. (Same info as above but different frequency range).

AM Band Choking Graph F240 77 1024x648 - AM Broadcast RFI Kits

F240-77 Choking Impedance in AM Broadcast Band

 

 

Typical Installations for Donut/Ring Toroids

20131210 114716 150x150 - AM Broadcast RFI Kits

AC Cable on F-240 Toroid – 6 turns

20131210 115137 150x150 - AM Broadcast RFI Kits

Ethernet Cable on F-240 Toroid – 7 turns

20131222 125533 150x150 - AM Broadcast RFI Kits

Audio or Mic cable on F240- 12 turns

 

 Extra Mix 75 Snap On Beads  HERE – VERY effective for AM Broadcast RFI