Loop Antennas

Loop antennas may be constructed in many forms including horizontal full wave loops in square, rectangle or triangle (delta) shapes.  They can also be in the vertical plane and are most often in the same shapes with the delta being very popular as it has both vertical and horizontal polarization.  The impedance at the loop resonant frequency is approximately 100 ohms but will very slightly on harmonics.  Loops are “quiet” antennas compared to verticals and dipoles and are omni-directional.  The also exhibit gain on harmonic bands.  Once you try a loop antenna you will know why they are so popular with old timers but still a secret to newcomers.  Shown below are some typical designs:


Full Wave Horizontal Loop Antenna (a.k.a Skyloop)

Palomar Horizontal Loop Config 2022 300x202 - Loop Antennas

This antenna is horizontally polarized and should be mounted as high as possible but works well at low heights of 10-30 feet.  They are quieter than a dipole or a vertical, have a broader bandwidth and will usually out perform a dipole antenna.To determine the approximate circumference in feet of a full wave loop antenna use the formula:

1005/Freq in Mhz = length in feet.

The feed point impedance of a full wave loop antenna is theoretically in the vicinity of 120 ohms and requires a 2:1 impedance transformer (for single band loops or a 4:1 balun to match on multiple bands) with 50 ohm line.  You will also need a feed line choke or better yet, just get the Hybrid 4:1+1:1 in a single box.

Vertical Delta Loops

Palomar Vertical Loop Config 300x198 - Loop Antennas

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 is 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 or 4:1 for multi-band operation.


MAXI-CHOKER Coax Line Isolator/Choke, 1-61 MHz, 1.5/3KW/5KW, up to -60 Db Common Mode Rejection, Static Bleeder Option

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Product Details
Brand: Palomar Engineers
MPN: MC-1-3000/MC-1-5000
Country/Region of Manufacture: United States
Effective Frequency Range (MHz): 1-61 (1.5KW, 3KW, 5KW)
PEP Power Rating (watts): 1500/3000/5000 to 61 MHz
Common Mode Attenuation (db): 15-42 (1.5KW), 20-48 dB (3KW), up to 60 dB (5KW)
Estimated Insertion Loss (db): .25 db
Input Connector Type: SO-239 female/N (option)
Output Connector Connector Type: SO-239 female/ N (option)
Ground Connector (Y/N): optional with static bleeder
Enclosure Size (LxWxH inches): 12" long, 2" diameter (3KW)/11" x 2-3/4" (5KW)


- Uses proprietary Multi-Mix, Multi-Core, Multi-Turn(TM) ferrite technology for maximum choking (up to -48 dB common mode noise rejection) and maximum bandwidth

- Choose 1.5 KW, 3 KW PEP or 5KW PEP for heavy duty digital modes up to legal limit, 50 ohm SO-239 connectors In/Out, 1-61 MHz, usable to 100 MHz

- Suppresses transmitter coax feed line radiation when installed at antenna feed point or reduces common mode receiver "noise" when installed at radio end of coax.

- Available with ground stud/static bleeder option for solving tough RFI issues

- Available with dual stud/wingnut output for ladder line interface

- Works for all coax fed antennas from 1.8-61 MHz (160-6 meters) - excellent for multi-band beams, verticals, dipoles and highly unbalanced off center fed antennas.

- 2-5 times more common mode noise rejection, wider bandwidth and higher power then competing filters

MAXI-CHOKER feed line chokes are used to suppress common mode current carried on the outside of the coax braid which is often responsible for receiver noise and RFI in the receiver/transmitter. These chokes are very useful for suppressing RFI common mode current at the antenna feed point, at 1/2 wavelength intervals along the coax feed line and also at the entrance to the radio station. This choke is available with a SO-239 input/output and ground/static bleeder stud (optional) for attachment to a ground rod. Use an isolator every 1/2 wavelength for the antenna operating frequency (include velocity factor in calculation). Use the ground lug option for long coax antenna feed lines (over 1/2 wavelength at the operating frequency of any antenna system in the near field of the coax).

Need a smaller power rating but with same, great common mode suppression? Try our 500 watt PEP rated Mini-Choker HERE

Production Note: Maxi-Choker may be in Black or White color depending upon available inventory at time of shipment.

Production Note: "N" connector models are custom made per order - please allow 2 weeks for manufacturing prior to shipment. You can also get the regular SO-239 version and the optional UHF PL-259 PL259 Male Plug to N Female Jack Straight RF Connector Adapter : UHFMTONF

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