Half Wave Square Loop Antenna for 20-6 Meters
Model SL-20-10
$249.00 including shipping to lower 48





About the black Acetal Delrin blocks used on these loops as well as our Moxon antennas:

Acetal provides high strength and stiffness coupled with enhanced dimensional stability and ease of machining. As a semi-crystalline material, acetal is also characterized by a low coefficient of friction and good wear properties -- especially in wet environments. Because acetal absorbs minimal amounts of moisture, its physical properties remain constant in a variety of environments. Low moisture absorption results in excellent dimensional stability for close-tolerance machined parts. In high moisture or submerged applications, acetal bearings outperform nylon 4 to 1. Acetal is ideally suited for close tolerance mechanical parts and electrical insulators which require strength and stiffness. It also offers resistance to a wide range of chemicals including many solvents.

Specifications:
Size-7 1/2 feet per side
Element Material- 3/8" dia. solid aluminum rod
Cross boom- 1" square aluminum with boom to mast assembly
Maximum Mast Size- 2 " nominal
Element Fastening Clamps- Acetal (Delrin) UV stabilized
Bolt Sizes- On element clamps, 1/4-20 and Delrin Clamps, 5/16-18 Stainless Steel
Feed Point Connector- SO-239 in die cast aluminum box. Feed with 50 ohm coax for strictly 20 meter operation or feed with 450 ohm window line or 600 ohm open wire line for five band operation.
Matching System for 20 meter operation- Beta match with adjustable shorting bar. No tuner required when used only on 20 meters with coax feed.
Weight-12 lbs.
Measured SWR-@14.00mhz-1:8 to 1, 14.10mhz-1.4 to 1, 14.20mhz,1.2 to 1, 14.30mhz, 1:0 to 1, 14.35mhz, 1:1 to 1 using coax feed and no tuner.
Freq. Range-20,17,15,12,10 and 6 meters using 450 ohm window line and tuner, 20 meters using 50 ohm coax feed and no tuner.Will tune on 6 meters if you have a radio with a built in tuner. Use good low loss coax for this such as LMR 400.

Description:
Antenna is basically a 20 meter full half wave dipole formed into a square using 3/8" dia. solid rod as the radiating elements. Has some unique characteristics, for example it has a low take off angle on all bands from 20-10 meters making it an ideal DX ing antenna. In addition the Azimuth pattern is semi omnidirectionl so it does not require a rotor as a rotatable dipole would. Elevation patterns are also cleaner with less lobes than an equivilant straight flat top dipole on the bands 17-10 meters. At only 7 1/2 feet per side it is fairly compact and easy to mount not requiring two or more supports as a standard dipole. The radiation patterns are very similiar to a 33 foot vertical dipole but in the horizontal mounting it is a much quieter antenna than any vertical. The transmission line does not have to extend straight out from the center (for a half wave length) as a vertical dipole's transmission line. Being a full half wave length on the lowerst band, it is not a compromised antenna as many of the other limited space antennas.

This square loop can be fed with 450 ohm window line for 5 band operation. The window line runs from the antenna to a tuner balun fixed as close as possible to your radio with a built in tuner or your outboard tuner. Then coax (a short of run as possible) from the balun to radio or tuner.
The antenna can also be used for 20 meter operation only with 50 ohm coax feed and no tuner is required. Adjust Beta match shorting bar for lowest SWR.