AM Broadcast RFI Kits

Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 500/1500 Watts, End Fed Long Wire Antennas

SKU Bullet-9U-500
$79.95
Power Rating (PEP)
1
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Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 500/1500 Watts, End Fed Long Wire Antennas
Product Details
Brand: Palomar Enginees
UPC: Does not apply
MPN: Bullet-9U-500/SBULLET-9U-1500
Type: NEW
Country/Region of Manufacture: USA

The “Bullet” End Fed Antenna Matcher

The key to end fed antenna success is the matching network interface between the long wire antenna and the coax feed line and feed line choke at the transceiver. Palomar Engineers employs a dual core matching system that offers wide bandwidth (1.8-61 MHz), 500 watt PEP rating, and a connection for a counterpoise or ground if desired.

The antenna can be used as a sloper, “L” with a vertical section and a longer horizontal section, or as a random horizontal antenna between two trees or supports.

Our network matching network is called the “Bullet” because of it shape and its effectiveness at taking down or contacting distant (DX)

stations all over the world under the right conditions. The Bullet uses all stainless steel connectors and a dual core ferrite 9:1 unun for higher power rating then many competitive products.

We sell the Bullet separately so you can add you own wire type and length (see table of suggested lengths below) or you can purchase a complete antenna system including wire and end insulator.

For best results we recommend that the coax feed line be at least 1/4 wavelength on the lowest operating frequency since the coax braid is used as a counterpoise if you don’t use the external counterpoise terminal on the matching unit. We also recommend a feed line choke at the end of the coax feed line near the radio to prevent RFI common mode current from interfering with the radio.

Suggested wire lengths (measured from Bullet feed point):

Bands Covered (meters)


Wire Length (feet)

Minimum Coax Length (feet)

40-6


41

25 (16' to choke)

80-40-30-20-17-15-12-10-6


71

50 (42' to choke)

80-60-40-30-20-17-15-12-10


111

50 (37' to choke)

160-80-60-40-30-20-17-15-12-10-6


155

100 (95' to choke)

AM, 160-80-60-40-30-20-17-15-12-10-6


173

100 (80-90' to choke)

If you run more than 500 watts PEP and need a high power 9:1 unun for your end fed antenna, check out the BULLET-9U-1500 or square box CU-9-1500 (1500 watts PEP) or CU-9-5000 (5000 watts PEP)

Installation

For best results raise the Bullet matching unit as high as possible (use a tree or vertical support) and then extend the antenna wire horizontally or as an “L” (horizontal with vertical end drop). The antenna may also be deployed as a sloper with the Bullet matching unit at the top (best) with the wire sloping toward the ground (with the end high enough to avoid contact by humans or animals), or at the bottom of the sloper with the antenna wire rising to a higher point (see typical configurations below).

Antenna Length Modifications: For best results, chose a length from the table above as these lengths will form a non-resonant antenna for the amateur bands indicated.The antenna length should NOT be ¼, ½ wavelength on any frequency that you transmit as the impedance will be very high (or low) and will not transfer through the matching unit at a favorable impedance to your antenna tuner.The theory of the antenna length is to make the antenna non-resonant on any amateur band so that the impedance at the antenna side of the matching unit is in the range of 200-600 ohms and when divided by 9 will be in the range of your transceiver antenna tuner.

Any length of 50/75 ohm feed line ok (over 35 feet minimum) but longer feed lines over 50 feet may show reduced SWR on some bands due to soil conductivity, nearby objects, etc. Due to local ground conditions, antenna height and feed line length, SWR may vary and an antenna tuner may be required or some bands to bring SWR at end of feed line to acceptable levels.Use of one or more ¼ wavelength counterpoise(s) connected to the ground post of the matching unit may also improve antenna efficiency and reduce SWR on certain bands.The first counterpoise should be installed under the horizontal portion of the antenna for best results

Use a good quality 50 ohm cable adequate for the power level of your station.The Bullet-80 matching unit is rated for 500 watts PEP for SSB and 150 watts continuous carrier for AM, FM, digital modes, or 375 watts CW. If the matching unit becomes warm to the touch after transmitting at high power, reduce the power output or the internal matching unit may become damaged.

Testimonial

Hello, Bob:

I am e-mailing to tell you how impressed I am with the Bullet-9U I received on 3/11/19. I immediately threw a 44 foot wire across my tile roof (in Florida) and began to tune up on 20 meters CW. I was running only about 15 watts to tune the wire and immediately, a station in Ontario came back with "579".) I got down to a 1.5:1 match and increased power to 100 watts. I heard a ham in Croatia calling CQ and got a "599" from him. Switched to 40 meters and before I could tune up, with about a 5:1 SWR, I was called by a ham in Cuba with a 579! And this with the bands in "poor" condition. I never expected such fantastic results. Thank you for a great product.

Dennis Lazar
W4DNN

Note: See Dennis's QST article in February 2020 QST Magazine for more details.

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