INTRODUCTION
W2IHY AUDIO EQUALIZER
AND
NOISE GATE
Analog and digital technology have for many years been used in the
audio industry to do audio equalization and noise reduction. Many
amateurs have purchased audio equalizers and other equipment with
the hope of improving their transmitted audio signal. The amateurs who
have succeeded have in many cases had to pay premium prices for
audio equipment that not only required modifying, to properly
interface with their amateur stations, but also had to be hardened to
tolerate R.F.
The W2IHY 8 Band Audio Equalizer and Noise Gate solves two basic
problems many hams experience. The Audio Equalizer allows the
user to change the transmitted audio frequency response without
changing microphones or microphone cartridges. Transmitted audio,
with substantial high frequency content, can be used to work DX or
communicate in band conditions where there is a significant amount
of noise. A balanced frequency response may be more desirable in
strong signal, full noise quieting environments. Many amateur operators
transmit audio in high ambient noise environments. Typical high noise
sources include linear amplifier fans, dehumidifiers, room air
conditioners, road and wind noise during mobile operation, etc..
The Noise Gate eliminates the aforementioned noise from being
transmitted. On the air tests in high ambient noise conditions have
shown the Noise Gate to be very effective. The removal of moderate
to very high levels of ambient noise, from the transmitted audio signal,
results in audio with increased clarity and presence.
Extensive testing was done of the Noise Gate and Equalizer. The unit
has been designed to work in high RF environments. We feel so
confident that you will be delighted with the unit
The W2IHY Audio
Equalizer and Noise Gate represents affordable audio technology
designed for amateur radio use.
we offer a 30 day
money back , no questions asked, guarantee.
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8 BAND EQ REAR CONNECTOR
PC BOARD LAYOUT AND PARTS
C41, C42 - .001 uf mylar
C40 - .01 mylar,
C7, C13, C37, C39 - .1 uF ceramic monolithic
C39 - 4.7 uf tantalum electrolytic
J2, J4, J5 - Male 5 Pin DIN
R33, R34 - 47K ohm ¼ watt 5% resistor
RFC2, RFC3 - 100 uh R.F. choke
RFC4, RFC5 - 470 uh R.F. choke
S4 - 4 pole 3 position rotary switch
S5 - 4PDT slide switch
T1 - 600 ohm: 600 ohm audio transformer
