Shared Apex Loop - SAL- Antenna

Shared Apex Loop Antenna (SAL) 

An eight direction, highly directional array in a small space. No control cable needed"

Introducing the Shared Apex Loop ArrayTM!

Now, you have a new interference fighting weapon in your receiving arsenal. The Shared Apex Loop ArrayTM is a revolutionary receiving antenna that will change the way that you listen to the radio! The patented design provides performance in a size and over a range of frequencies that will please both the rag-chewer and DX’er alike.
The antenna is a true time-delay array with four identical wire loops supported by a single non-conductive mast. Signals from each loop are transferred through a ferrite coupler to a short balanced line that connects to the switch/ combiner/amp/BCB filter (bypassable filter) enclosure mounted at the base of the antenna. Within this enclosure, signals from each loop are routed either directly to a combiner or through a delay line and then to the combiner, where they are amplified by a dual stage balanced broadband amplifier and sent out to the feedline to the controller located in the shack. The controller connects directly to your receiver, and sends power and control signals over the feedline to the antenna.

Three models to chose from:

  • AS-SAL-30 - optimized for VLF, BCB, 160/80/40m DXing, 32 feet (9.75 m) tall and approximately 50 x 50 foot (15.24 m x 15.24 m) square footprint
  • AS-SAL-20 - optimized  for LF, BCB and shortwave to 15 MHz, 24 feet (7.31 m) tall and approximately 36 x 36 foot (11 m x 11 m) footprint
  • AS-SAL-12- optimized for BCB, and 3 to 30 MHz, 16 feet (4.88 m) tall, and approximately 25 x 25 foot (7.62 m x 7.62 m) square footprint


SAL-30 installed at WX0B since August 2013

"Shared Apex Loop Array: A Wideband Directional Receiving Antenna for 500 KHz - 30 MHz"

Effective communication on the LW, MW, and SW bands requires more than just a careful ear. You need the right gear to navigate through the jungle of interference that can be as close as your computer, or as distant as a thunderstorm on the other side of the globe. Interference, though isn't just a challenge for DX'ers - it's a challenge for net operators, rag chewers and county hunters too, military operations - in other words, it is a challenge to all of us!

We have developed a new type of receiving antenna that delivers exceptional directivity in a small package and is useable over a wide range of frequencies without need for adjustment. This new antenna is called the Shared Apex Loop Array antenna and it opens the door to a new class of compact, high performance, wideband receiving antennas developed for both amateur and professional users.

The antenna operates on the true-time-delay principle rather than the more traditional phased array methods. This method of operation enables outstanding bandwidth. For example, a 18 foot tall, 18 foot radius array can provide outstanding front-to-side and good front-to-back performance for continuous frequency coverage below 500 KHz to 16 MHz with good sensitivity above 1.8 MHz! Ten foot tall loops, ten foot radius array provides continuous frequency coverage between 500 KHz to 22 MHz with good sensitivity above 5 MHz.

The patented and additional patent pending designs provides the following benefits:

  • Compact Size, light weight
  • Wideband operation without need for adjustment
  • Ground independent operation
  • Outstanding front-to-side and front-to-back ratio
  • Ease of Construction, and simple single feed line control for data and RF
  • Modular design
  • Portability for DX-peditions, quick deploy operations, field day operations, emergency operations
  • Easily remote controlled with the Shacklan - 4 USB interface to your PC or a Ethernet Everywhere device
  • Control commands sent through the 75 ohm transmission line
Front and rear views of the SAL controller.
Combiner, delay line and TX line at the mast lower section.
Typical Pattern

Handout download, pdf file
Presentation Notebook,  pdf file

QEX OCT 2012 Article - pdf file, with permission from QEX and ARRL
Videos and other technical info
Frequently Asked Questions

AS-SAL Manual

AS-SAL Manual-Japanese translation by Katsuhiro "Don" Kondou - JH5GHM(日本語バージョンのマニュアルはこちらをクリックしてください)

SAL antenna users Yahoo Group


Pictures, Videos and Testimonials from users.

Palmyra 2016 DXPEDITION - K5P



SAL-30 Set up at Palmyra - K5P

We had a SAL-30 receive array, which we initially put up near the Dry Lab, but there was a lot of desense and noise picked up from laboratory equipment.   We were able to move this 800 feet away and found this location extremely quiet!   Without this antenna we would not have had the success we had on 160 and 80 meters.   We had the usual tropical QRN, but surprisingly little in the way of local thunderstorms.   We only heard one clap of thunder while we were there. The SAL-30 really helped with this noise!

 Noise on the middle of the 160 m band and noise on 160 m with the SAL-30 antenna.
In the first few days we were plagued with noise right in the middle of our 160 m operating area.  We eventually tracked down the source to be the solar inverters.   The SAL-30 made a huge dent in the noise, making the band quite usable!

Jay, THANK YOU SO MUCH for your support of the K5P Palmyra DXpedition!!!!
Glenn W0GJ


Performance Videos
See this video of the SAL-30 F/B at 1.70 MHz
SAL vs. Hi-Z (4 el) comparison
FT5ZM on 80 m via Long Path with the SAL-30

Showing SAL-30 antenna F/B at W5PR


Other links on the Shared Apex Loops Antenna

Video of the SAL antenna presentation at the Dayton Hamvention 2014