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Array Solutions

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AS-AYL-4  4 direction Low Band Receiving Antenna

Wolf RF Systems




Improved robust design of controller and outdoor box upgraded to  NEMA- 4X


Upgraded controller, adds more flexibility and easier use


Mast /Antenna Kit is military grade hardware


Mast/Antenna Kit is rugged enough for permanent installations but also quickly deployed for DX-Peditions or Emcomm.


The Best Preamp/bandpass filter on the market. See specs and plots here


Termination of loop is done with temperature stable resistors vs a Vactrol, since Vactrols are unstable, easily damaged by surges and they drift with temperature changes. We reviewed using Vactrol terminations and rejected it as a poor design. See what Gary, K9AY says about Vactrol terminations in the FAQ.

The AS-AYL-4 Loop antenna consists of

1. Controller, the blue box above.  It includes the pre-amplifier and bandpass filter.

2. Outdoor relay box that mounts on the antenna mast


3. AYL-4 Mast/Antenna kit, which includes a mast, wire loops, stakes and ground rod fixture.

or if you supply your own mast, we have

4. Wire Kit which has everything that the Mast/Antenna kit has except the mast.  Very desirable for overseas shipments.

The AYL-4 Mast/Antenna Kit includes the following parts

 Easy but secure installation portable, DX-Peditions or Permanent QTH.



















Specifications AS-AYL-4  Loop System

bulletAntenna type:                          Terminated loop
bulletPattern:                                   Cardioid, switched in four directions
bulletPeak front-to-back:                 Greater than 20 dB, typically 30 dB

Feedpoint impedance:             50 ohms nominal; low-loss transformer matching to the antenna


Frequency range:                    Very low frequencies to  8 MHz, using published dimensions. With preamp on, bandpass is limited to 1.8-5 MHz

bulletDirection change:                   Feedpoint/termination switching relays
bulletDirection control:                    Connected with a 6-conductor control cable

RF connection (antenna):       SO-239 (UHF) connectors at control box and outdoor relay box


RF connection (radio):            Phono connector output to receiver external antenna input


Termination Adjustment:         Eight resistances from 340 to 680 ohms, selected by front-panel rotary switch


Power requirements:               +12 to 15 VDC, 400 mA max., (provided by customer, to be fused at 0.5 A)

bulletPreamplifier:                           15 dB gain, feedback type, using a silicon NPN transistor
bulletFilter passband:                      2 dB from 1.80 to 4.5 MHz
bulletFilter stopband:                       55 dB at 7 MHz, 50 dB below 1450 kHz (typical)

Required Area

The AYL-4 K9AY Loop System requires approximately 18 feet in four directions from the center of the antenna, plus additional distance depending on the guying method.  The base of the supporting pole and the ground rod are located at the center. With the AYL-WM kit, 18 feet in each of the four directions is required. The center support is 24 feet high, and must clear any objects above.


Plot of the K9AY loop Antenna Response.  

Measured Plot of the AS-AYL-4 Control Box -
Amplifier and Filter Response

Preamp Switched On


Measured Plot of the AS-AYL-4 Relay Box

Matching Balun Transformer

Top Plot is the S11 Response with the Antenna terminated into 450 Ohms

Bottom Plot Shows a Return Loss of 25 dB into the Balun with 450 Ohms Termination




bullet BUY THE AS-AYL-4 - go to pricelist


bulletAS-AYL-4 Manual for serial numbers 100 to 112


bulletAS-AYL-4 Manual for serial number 112 and above


bulletAS-AYL-4 MW Manual for the mast / wire loop antennas / complete kit


bulletK9AY Loop Antenna FAQ


bulletDemo Video of the loop system in the AM BC Band showing 32 dB of Front to Back!


bulletVideo of Customers AS-AYL-4 showing 8 S units of Front to Back!! customer comments




ZD8UW .wma audio files 160 metersFirst recording is a comparison between the dipole & then loop -- first part of the recording is the dipole, ZD8UW is just barely perceptual in the noise --  at the edit point (15 secs)  is ZD8UW on the AS-AYL-4  loop .. second recording is the station on the loop with no QSB .. signals are very solid & have been for the past 45 minutes .. TNX Vic, WB4SLM

Dipole vs Loop switch over occurs about 15 seconds into the audio

Solid copy on Loop



Attached is a short movie clip (poor quality to control the size of the file).   I am receiving CHU Canada at 3330.0. The station is a hair stronger on the S-meter on the loop compared to the vertical.  This might mean it is doing better on the high angle stuff since the vertical probably is a better low angle receive antenna.  The two antennas are about 350 feet apart.  As you watch the video clip, note the s-meter dropping back and forth by about 7 to 8 s-units.  I am switching the AY loop from the NE to the SW.  It is really impressive. 

.I am having fun and Array Solutions (Bob and Jay) have been a great help.

de Jerry   K8RA





bulletHear a K9AY in action with S. Orkney Island AY1ZA (wav file)  vs Inverted Vee



 I received my AYL-4 and got it installed just in time for the CQ160 CW contest. What a great product! It works like a charm, reducing atmospheric noise so I can copy weak DX signals.

It almost works too well in fact, because I had stateside stations calling me off the back of the loops and barely copied them. Switching the direction usually brought them up several S-units.

In comparison, my inverted L is almost useless as a receive
antenna for DX because the noise often overpowers the

Thanks for getting this unit to me in a timely manner. I'm
thoroughly enjoying operating 160m.

Tom N2CU <><



Thanks for the info Jay  ...by the way, my K9AY loop I purchased from you last October is working great...it holds its own against my 500 ft beverage into Europe. the f/b is very good on 80 and 160  ...great product !!

Todd / W4WTB

What makes the K9AY pre-amps better then the rest?

Reliability and a spec you can trust.  Many low band "premium" preamp products you see on the market are not what they are made out to be. For instance they may use MMIC amplifier devices.  These devices are attractive to the designer since they are easy to use and inexpensive.  But they are not well understood and they are easily damaged. For instance, it is attractive to take the MMIC spec of +35 dBm and say your pre-amp design will have this impressive IP3 point. But looking closer at the MMIC spec you see it also has a +15dBm input IP3.  This is nothing special.  Gary's preamps use what he calls his "old fashioned" circuit using a discrete 2N3866 transistor. It has a 12-15 dB higher input intercept point then the GaAs FET MMIC devices and also doesn't have the fragility of a 5-volt GaAs FET MMICs which have drain breakdown voltages of 8 volts. The old 2N3866 has a max collector voltage of 40 volts!  Giving this a much higher chance of surviving a nearby lightning strike. Coupled with his RF filters in the front end you truly have a "premium" pre-amp circuit.  Read more about them on the data pages.


Picture of the base of the Loop system