W2IHY Dual Band Audio Equalizer and Noise Gate

•	You can adjust Bass and Treble of your transmit audio for rag chew, dx and contest style audio.
•	You can change Equalization settings instantly to switch from one audio "personality" to another.
•	You can boost low-output microphones to work great with your radio.
•	You can use the Noise Gate to get rid of background noise and give your signal more presence.
•	You can use the Noise Gate to improve VOX operation by reducing false triggers.
•	You can switch Equalization on or off.
•	You can switch the Noise Gate on or off.

Introduction
Finally, professional audio processing technology is applied to the unique requirements of amateur radio operators! The W2IHY Dual Band Audio Equalizer and Noise Gate is an easy-to-use, sophisticated unit loaded with high-performance features. This thoughtfully-designed, quality-constructed station accessory performs three important functions, all in one good looking, low-profile package:

•	The Audio Equalizer gives you bass and treble control of the tonal qualities of your microphone and, thus, of your transmit audio quality.
•	The Noise Gate is the long-needed solution for noisy operating environments. Background noises that used to make copy difficult or unpleasant on the other end of the QSO are eliminated or greatly reduced.
•	The microphone and radio matching capabilities are terrific. Adjust the wide-range input level for optimum drive to the built-in microphone amplifier. Adjust the output to give your radio the ideal signal level for best performance of microphone gain, alc, compression and smooth VOX operation. The 8 pin microphone jack with three position switch gives instant plug and play with Yaesu, Kenwood and Icom microphones; other radios and microphones, too.

Continue on to find out more about the transmit audio accessory that is delighting audio-conscious hams everywhere. Not responsible for drool on keyboards. But we are responsible for some of the most outstanding SSB, AM and FM audio on the amateur radio bands worldwide!

Product Specifications

Dual Band Audio Equalizer For Transmitter Microphones
•	Adjustable Treble and Bass
•	Treble boost/cut at 2300 Hz
•	Base boost/cut at 240 Hz
•	Smooth-action slide potentiometers
•	EQ settings can be changed instantly
•	Equalizer bypass switch (on/off)
Extremely Effective Noise Gate Eliminates Background Noise
•	Adjustable threshold (level control)
•	Adjustable decay for smooth trailing edge (delay control)
•	LED level indicator
•	Noise Gate bypass switch (on/off)
Microphone Input Connections
•	8-pin connector with 3-position switch selects ICOM, KENWOOD, YAESU microphones
•	Adapters available to support all other 4 and 8 pin microphone jacks
•	RCA phono connector
•	Microphone input impedance 600 ohms
Microphone Input Gain
•	Wide-range input level control adjusts internal microphone amplifier gain
•	LED indicator facilitates gain adjustment
•	When used with a Heil cartridge provides >20 times the output to better drive your transmitter
Microphone Phantom Power Voltage Jumper
•	For use with HM12, SM6 electrets and other microphones requiring phantom power
•	Provides 5VDC to the microphone cartridge
•	Accessible from the bottom of the case
Microphone Output
•	Adjustable output level control for ideal drive level to transmitter microphone input
•	LOW-Z balanced output
•	5-pin DIN connector, rear panel
PTT input (RCA jack)
•	Adds push to talk control for non-PTT microphones
•	Rear panel accessible independent PTT input. Can be used with foot switch, etc.
Operating Environment
•	Designed specifically for amateur radio use adjacent to transmitters and linear amplifiers
•	Extensive RFI protection
Physical
•	6" Wide x 3" High x 5" Deep
•	Grey finish with white lettering. Attractive in any shack
Power
•	7-14V (100ma) wall transformer provided
•	LED indicator and on/off switch
Guarantee/Warranty/Support
•	30 day no questions asked money back guarantee
•	3 year parts and labor warranty
•	Free technical support

Dual Band EQ and Noise Gate jacks and selection switch.

This switch lets you plug and play Icom, Kenwood and Yaesu 8-pin microphones. Optional adapters are available for all other 8-pin and 4-pin microphones.

Connecting to Microphones and Radios
The W2IHY Dual Band Audio Equalizer and Noise Gate interfaces between your microphone and your transmitter. And it does this intelligently. A 3 position switch on the rear panel lets you choose between Icom, Kenwood and Yaesu microphones. Simply plug in your microphone and set the rear panel switch. Now your microphone audio output is reaching the system's input stage. And at the same time, your microphone's push to talk control is passing through and will appear on the output.

But what if you like to use other types of microphones? The system will accommodate all 600 ohm microphones. Adapters are available for all 8 pin and 4 pin microphone connectors. There is also a simple RCA phono input to expand your microphone connection options. W2IHY even provides the 5 volt power requirements for models such as HM12 and SM6 and other microphones requiring phantom power.

Another thoughtful touch: Some microphones, especially professional studio models, do not include push to talk capability. W2IHY gives you a rear panel push to talk (PTT) jack. Use this to connect a foot switch or other control. The PTT control circuit will now reach the radio via the cable described below.

The output side of the system consists of a 5-pin DIN jack. To connect the output to your radio, you will need the correct cable for your radio. These are available for $30.00 each. Be sure to specify radio make and model when ordering.

Adjusting Input and Output Audio Levels
With your microphone connected to the W2IHY Dual Band Audio Equalizer and Noise Gate and the correct cable connected to your radio, you are now ready to adjust system input and output levels for optimum performance. While speaking into the microphone adjust the MIC IN GAIN control on the bottom panel until the red MIC LED on the front panel just barely lights up. This control has a wide range to accommodate microphones with high or low signal output.

Microphones that didn't properly drive your radio before will now!

Similarly, the MIC OUT LEVEL control on the bottom panel lets you adjust the audio signal level sent to your radio's microphone jack. Use this to provide your radio with the ideal microphone signal level. Now you have optimum performance of mic gain, alc and compression controls. This not only makes for better sounding transmit audio but often improves VOX operation. Already, you have improved operating performance of your microphone and your radio. And you haven't even started on the high-quality Equalization and Noise Gate features!

Equalization Overview
The W2IHY Dual Band Audio Equalizer and Noise Gate lets you increase (boost) or decrease (cut) the signal level at the bass frequency and the treble frequency. The frequency bands are 240 Hz (bass) and 2300 Hz (treble). Boosts or cuts are made to suite personal tastes of the user.

Broadcast engineers and recording studio technicians consider equalization (called EQ for short) to be one of the most important tools in achieving desired characteristics in a final audio product. Professionals use the signal-shaping power of EQ as both a creative tool to give audio a desired personality and as a corrective tool to overcome frequency response excesses or deficiencies in equipment such as microphones. Professional audio technology is now available for amateur radio applications and amateur radio budgets! Amateurs are using the W2IHY Dual Band Audio Equalizer and Noise Gate to do more good things with their transmit audio than ever before.

With the Treble and Bass controls, you can create a wide variety of audio personalities.

Equalization Adjustments
Here comes the magic! You've done this on your stereo to make it sound the way you want. Now do it with your transmitter to get the kind of on-air transmit audio you want! With the unit properly connected and Power on, turn the Equalizer Switch on. With the Treble control you will boost or cut the high frequency content in your transmit audio. Similarly, you will boost or cut the low frequency content with the Bass control. You can create a wide variety of audio personalities, feel free to experiment!

For the most critical EQ adjustments, nothing beats listening to your actual transmit signal on a second receiver in the shack, using good quality headphones. This lets you get "up close and personal" with how your transmit audio really sounds. You will notice that very small adjustments to the slide pots can make meaningful changes. Many of our users conduct on-air adjustments, relying on friends with good ears. Of course this is best done under low-noise, high signal conditions.

Our users don't settle for the "one size fits all" mentality. They transmit customized audio adjusted to their personal preference.

Microphones And Equalization
Well, okay let's get this out of the way. The microphone is a necessity. The W2IHY Dual Band Audio Equalizer and Noise Gate is an accessory. At least that's true at first. But it won't take long until you are so spoiled, you won't want to be without your W2IHY EQ system no matter what microphone or radio you use!.

For as long as there has been amateur radio there have been operators who never settle for the norm or stock configurations or default settings. Always pushing the envelope, adjusting and tweaking. Always in a quest to make something work better. That's a good description of W2IHY users. Our users don't settle for the "one size fits all" mentality. They transmit customized audio adjusted to their personal preference.

Audio guru Bob Heil recently wrote an article encouraging hams to pay much closer attention to their transmit audio and to not be shy about applying professional audio techniques wherever possible. We agree with Bob and it is clear that amateur interest in better transmit audio is at an all-time high and is growing.

So what about the relationship between microphones and equalization? No microphone manufacturer knows the characteristics of your voice ... or your favorite voice transmission mode ... or the acoustics of your shack. So, right out of the box, no microphone is fully optimized for you and your specific application. As mentioned earlier, you can use EQ as both a creative tool and a corrective tool. You'll need less correction on a good quality microphone since it has been designed to deliver wide, flat response. Here, EQ becomes a creative tool for satisfying your personal taste.

On the other end of the audio quality spectrum, there are a lot of poor microphones out there. Some manufacturers are more concerned with how their microphones look than how they sound. When microphones are marginal performers, EQ plays much more of a corrective role, compensating for poor response characteristics. It's amazing, but you can actually get a bad sounding mike to sound surprisingly good by experimenting with the various EQ possibilities. With its ability to work that kind of magic, imagine what the W2IHY Dual Band Audio Equalizer and Noise Gate can do with your existing microphone that already sounds "pretty good".

Once you have the Noise Gate adjusted, you will amaze your friends when you let them hear the difference by switching it on and off. They'll wonder where the noise went!

Noise Gate Overview
You've heard this a thousand times: Your friend on the other end of the QSO has a good signal but the noise in his shack makes copy difficult or unpleasant. One of the biggest noise makers in HF operating is the linear amplifier with blower or fan noise nearly as loud as the operator! Another biggie is the multi-operator contest or dx station with so many voices talking at once it's like they are QRM'ing themselves! In these cases, and in mobile operation too, reducing or eliminating background noises picked up by the microphone makes a BIG improvement in audio clarity, presence and effectiveness of the transmitted signal.

Once again W2IHY brings sophisticated audio processing technology into the ham shack affordably. The Noise Gate feature is proven to be very effective in high ambient noise conditions. The Noise Gate operates in conjunction with the LEVEL control which sets the threshold at which the circuitry responds. The Noise Gate function is to remove audio signals with energy levels lower than the value established by the threshold.

W2IHY users tell us the Noise Gate does more than get rid of background noise. It can make VOX operation smoother by reducing VOX trips from the radio's speaker and extraneous noises in the shack.

Noise Gate Adjustments
Once you have the Noise Gate adjusted, you will amaze your friends when you let them hear the difference by switching it on and off. They'll wonder where the noise went!

A front panel switch lets you select NOISE GATE on or off. There are 2 slide pot controls, LEVEL and DELAY. When you push the LEVEL control up, the system becomes less sensitive to background noise. Pushing the LEVEL control down makes the system more sensitive to background noise. To set the LEVEL, adjust the control while speaking into the microphone and observing the status of the green LED. When the LED just begins to go off you have established the correct threshold level. Keep in mind that this adjustment is sensitive to the noise environment. The best way to adjust is under your worst noise conditions.

The DELAY control is another thoughtful touch from W2IHY. It works between words and at the end of a transmission to smoothly taper the trailing edge of the system's audio output. This elegant design feature overcomes the choppy, harsh effect of previous noise reduction units. Your transmitted audio will be smooth and pleasing to the ear. The DELAY control set to maximum value will allow the audio to decay over a few seconds. As you move the control down into the white-marked calibration zone, the decay is reduced to fractions of a second. On-air testing shows this region to give very pleasing audio transitions. Experiment on your own to find the best settings for you.

Some experience in kit-building is recommended. Average assembly time is 8 hours; if you're a whiz you can do it in 5.

Kit Option
The W2IHY Dual Band Audio Equalizer and Noise Gate is available in kit form. You receive all components and easy-to-follow assembly instructions. Component placements are indicated on the printed circuit boards and all polarized capacitors and diodes are oriented the same way. The boards have solder masking to inhibit solder bridging. No test equipment is required. Some experience in kit-building is recommended. Average assembly time is 8 hours; if you're a whiz you can do it in 5.

Bottom line: If you enjoy building kits (and saving money) specify the kit version when you order.

Product Comparison Table

Feature	W2IHY 8 Band	W2IHY EQ Plus	W2IHY Dual Band
Bands of Equalization	8	2	2
Headphone Monitor	X	X
200 Ohm Microphone Input	X	X
High Impedance Microphone Input	X	X
Audio Outputs to Radio's	2	3	1
Mic Impedance	200 600 HI-Z	200 600 HI-Z	600
Noise Gate or Downward Expander	X	X	X
Kenwood, ICOM, Yaesu mic Compatable	X	X	X
Adjustable Mic Input Level	X	X	X
8 Pin Mic Connector	X	X	X
RCA Phono Mic Connector	X	X	X
XLR Mic Input	X
Phantom 5 vdc for eletrets	X	X	X
Output Impedances	600 HI-Z	600 HI-Z	600
PTT Input	X	X	X
Kit Available	X		X
Audio Compression		X
Audio Limiter		X
Effects		X
Bar Graph Audio Level Indcation		X