K9ay loop switch and preamplifier
W7iuv Loop. No Interference Reported. Part Type: HF Preamplifiers. It is of utmost importance to decouple the coax shield wire from the antenna! The shield must act only as a shield and not as an antenna allowing pick up of noise along the feed-line otherwise the radiation pattern of the.
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80m Loop Antenna
Here are the instructions for constructing the loop itself. If you don't want to make the loop using 'homebrew' construction, we also offer the AYL-M kit that includes a mast, wire and all the hardware needed to construct the antenna. Terminated Loop Basics The K9AY Loop is one of several published designs that use a terminated loop to get a directional pattern in a small space. In simplest terms, these antennas are very small phased arrays, with the vertical or mostly vertical portions being the main elements.
The termination resistance balances the currents to provide the best possible null. It is also possible to explain the loop's behavior in terms of its response to the E-field and H-field components of the arriving wave, but this is more complicated than necessary! The main advantage of the K9AY Loop is that the feedpoint and termination are at the same location. Simple switching lets you instantly reverse the pattern direction by exchanging the feed and termination.
Using the AYL-4 unit and two crossed loops, 4 different directions can be selected, giving you the greatest flexibility in reducing interference and hearing the signal you want. Switching from one direction to another can mean the difference between solid copy and a signal covered up by interfering stations! Horizontal and vertical radiation patterns of the K9AY Loop over average ground:. Construction Details A single loop that will cover the and 80 meter ham bands requires one foot high support and 85 feet of wire.
The basic layout is shown here:. Construction of a single K9AY Loop:. The matching transformer and terminating resistor are located in the AYL-4 relay box, so you only need to install the basic wire loop, its support and insulators, plus the ground rod. The support can be a tree limb, a strong mast, or anything else that will hold the loop in place. The AYL-4 4-way loop control system uses two of these loops, sharing the same central support, but oriented at right angles to one another.
The relay box changes pattern by switching the feedpoint and termination connections-front-to-back by reversing the ends of a loop; degrees by switching from one loop to the other. Locating Your K9AY Loops Since you have chosen a small receiving antenna, it is likely that your transmitting antenna will be nearby. Transmitting antennas, power lines, towers and other nearby large conducting objects can re-radiate signals that are coupled to the receiving antenna. To avoid this problem, locate the K9AY Loop as far from the transmitting antenna as possible.
Because the loop is small, it is often possible to place it among trees or shrubs in a front or side yard, while the transmitting antenna is in back. Another way to minimize the interaction is to locate the loop toward the most important direction you want to hear. For example, if you are most interested in hearing Europe from the US, locate the loop Northeast of the transmitting antenna.
When pointed toward Europe, the null will be in the direction of the transmitting antenna, reducing the pickup of re-radiated signals. If the earth is very dry, a longer ground rod is advised, to reach permanently moist earth-or you may install four or more to foot long radial wires for better coupling to ground. The grounded design of the K9AY Loop has several advantages over ground-independent versions of the terminated loop Pennant and Flag , including simpler switching, no feedline isolation problems, and greater signal capture for the same size loops.
Preamplifier All terminated loop antennas are inefficient, which means that signal levels are low. A preamplifier providing this gain, along with excellent bandpass filtering for 1.
At and 80 meters, coax loss is very low, so a preamp located at the receiver is usually sufficient. In normal installations, we recommend against an outdoor preamp, since it is exposed to greater risk of damage from static discharge lightning or RF from nearby transmitting antennas.
The most common exception is with extremely long feedlines, where a preamp at the antenna will boost the signal level to overcome coax losses and to increase the signal relative to any common-mode noise and signals picked up by the long feedline.
Feedline and Control Line Routing As with all small receiving antennas, the low signal levels from the K9AY Loop require careful routing of the coax feedline and control cables. The best solution is to bury the cables and take advantage of the natural RF shielding of earth. Second best is to simply lay them on the ground, which is often done when receiving antennas are only connected during the Fall and Winter lowband DX season.
We strongly recommend against above-ground installation, but we know it is sometimes unavoidable. If you believe that your feedline is affecting the pattern of the loop, it probably indicates that your grounding is insufficient. In this case, refer to the previous notes and other published data on grounding. Many Broadcast Band DXers marvel at the way switching the pattern lets you hear different stations on the same frequency. In some installations, the antenna may retain some directivity above 5 MHz, but this should not be expected.
The preamplifier provided includes a bandpass filter that limits its use to approximately 1. A preamp is rarely needed for Broadcast listening or for frequencies above 5 MHz. For Low Frequency DXers, we can provide the AYL-4 without the highpass filter no extra charge for this special order , which allows the preamp to operate down to kHz or lower. Installation Checklist Problems experienced by some users :.
The two loops in the 4-way system are completely separate--not connected at the top 2. The control cable is wired properly between the indoor control unit and the outdoor relay unit 3. The antenna is properly connected to the ground rod 4. Proper control relay voltage. Enjoy your K9AY Loops!
K9AY 80/160 Meter Switchable Loop Antenna System
After finishing the SMCTL v1 we stumbled upon the problem of having complete control over the 1x10 antenna switches and over the K9AY switching system with different resistors. SMTCL v2 is an universal controller and it works as:. The circuit lets you connect 10 push button switches and a PTT interlock active when grounded. Pressing one of the push buttons will select the active outputs. The circuitry and software are designed with 5 different programs which enable the controller to be used for other switching purposes, such as a 10x1 antenna switch.
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I used a single center mast made from three fiberglass windsurfer masts I had obtained as surplus and made the loops out of 18 enameled wire. The dimensions and orientation of the loops were as described in the K9AY instruction sheets they also appear on the web. At times I felt I had a beam operating on meters. This is not a report on the loops and the loop performance I and will say nothing more about them here. Because I had looked at the effect of of an ARR 0. See Effect of band pass filter on K9AY signals. The spectrum analyzer was set so that the top of the display was 0 dBm. The tracking generator output was set for dBm. The analyzer bandwidth was 3 kHz and except for Figure 4 following, the display is set for 0.
W7iuv Loop
Basically, after looking at the currently available commercial version , I figured I could make a better unit for less money and be happy. The basis for the K9AY antenna is that it has a steerable null. The gain around the antenna is close to unity, except for the terminated side of the loop, which has a deep null. This can be switched around using a combination of relays that change the loops and termination.
K9AY Loop antenna (40), 80 and 160 meter.
Here are the instructions for constructing the loop itself. If you don't want to make the loop using 'homebrew' construction, we also offer the AYL-M kit that includes a mast, wire and all the hardware needed to construct the antenna. Terminated Loop Basics The K9AY Loop is one of several published designs that use a terminated loop to get a directional pattern in a small space. In simplest terms, these antennas are very small phased arrays, with the vertical or mostly vertical portions being the main elements. The termination resistance balances the currents to provide the best possible null. It is also possible to explain the loop's behavior in terms of its response to the E-field and H-field components of the arriving wave, but this is more complicated than necessary!
K9AY Loop at VE1ZAC, Finally
It was apparent that many stations were copying me much better than I could hear them, so something needed to be done. I knew Beverage antennas were the hot ticket, but I did not have anywhere near the real estate required for these antennas. Looking around the Net, I came across several articles about the K9AY Loop System , which seemed to be a good alternative, and required much less space. A complete set of chip capacitors is included with the boards. I ordered the circuit boards from Far Circuits, and the rest of the parts from Mouser electronics. This was easy, because Far Circuits provided a list of the necessary Mouser part numbers. System , Loops , Meters , Antenna , Switchable , meter switchable loop antenna system.
4-way K9AY Loop System - Array Solutions
I was also hoping that I could use it for phasing purpose against my wire antennas and that it could be a nice performer for Latin America notably. I soon discovered that the overall gain wasn't as high as the Beverages making it almost useless for phasing and the performance for DXing was lower that I've expected. I was really wondering why this antenna was so praised?
A receiving antenna for the low bands. For our contest group PA6Z we needed some good receiving antennas for the low bands m, 80m and 40m. A lot of info can be found on internet, and especially in the must read "low band dxing" by ON4UN. There are also some discussion groups that can help. After having enough info, we decided to build the so called K9AY loop. This antenna is easy to set up, it has a small footprint 10x10 m and it provides four directions for receiving.
You don't have the space to put up a 4 beverage antenna's, an EWE or a 4-square and want 'good ears' on and 80m? No problems The K9AY only needs about 10m of space The V-radiation pattern. As with all small loop antenna's, it is recommended to boost the signal by inserting a preamplifier with a gain of at least 15 dB. I found a good schematic of preamplifier, offering up to 20 dB gain, a high 3rd order intercept point, and a bandpass filter at the input rejecting signals from the AM broadcast band and above 4MHz.
Enter your e-mail address below and we will notify you when the product is available! Your e-mail address will be stored up to days. It attenuates unwanted signals with up to 30 dB. It comes with a control box se photo and an external rely box that is mounted at the mast.
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