AS-AYL-4 4 direction Low Band Receiving
Antenna
Wolf RF Systems
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Improved robust design of controller and
outdoor box upgraded to NEMA- 4X
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Upgraded controller, adds more flexibility and
easier use
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Mast /Antenna Kit is military grade hardware
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Mast/Antenna Kit is rugged enough for permanent
installations but also quickly deployed for DX-Peditions or Emcomm.
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The Best Preamp/bandpass filter on the market.
See specs and plots here
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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.
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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
Optional
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
| Antenna type: Terminated loop
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| Pattern: Cardioid, switched in
four directions |
| Peak front-to-back: Greater than 20 dB,
typically 30 dB |
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Feedpoint impedance:
50 ohms nominal; low-loss transformer matching to the antenna |
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Frequency range:
Very low frequencies to 8 MHz, using published dimensions. With preamp on,
bandpass is limited to 1.8-5 MHz |
| Direction change: Feedpoint/termination
switching relays |
| Direction control: Connected with a
6-conductor control cable |
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RF connection (antenna):
SO-239 (UHF) connectors at control box and outdoor relay box |
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RF connection (radio):
Phono connector output to receiver external antenna input |
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Termination Adjustment:
Eight resistances from 340 to 680 ohms, selected by front-panel rotary
switch |
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Power requirements:
+12 to 15 VDC, 400 mA max., (provided by customer, to be fused at 0.5 A)
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| Preamplifier: 15 dB gain, feedback
type, using a silicon NPN transistor |
| Filter passband: ±2 dB from 1.80 to 4.5 MHz
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| Filter 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.
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Measured Plot of the AS-AYL-4
Control Box -
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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
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
signal.
Thanks for getting this unit to me in a timely manner. I'm
thoroughly enjoying operating 160m.
73,
Tom N2CU <><
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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 !!
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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.
Email me WX0B for special needs
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