The goal here is to get the proper level to the input of the 222 and to the transmitter.

Input: Connect your audio source as explained below. You should be able to see some indication on the Peak limit and Pre - emphasis indicators as you adjust the input gain. Be sure they are on. If you cannot get any indication with the input gain all the way up then remove the cover (with the 222 unplugged) and set the (input range select (see figure 7)) to the low position (marked L on the board). You should be able to get an indication now, if not check to see if you have an input signal.

Once you have the audio material showing on the indicators, then try to connect the transmitter. Depending on where the audio gain is on the transmitter unit you may or may not be able to get good sound at this point. If you cannot get good sound in the entire range of the 222 output level control then check the transmitter audio gain, it should be 1/2 to fully clockwise, it is preferable not to have it lower then 1/2 way. If you are way over driven try turning the transmitter audio gain down a bit, if not enough gain turn it up.

If access to the transmitter is difficult and/or you are over driving the transmitter (distortion) even when the 222 output is all the way down (counterclockwise) then you can build the attenuator (see link below) to attenuate the signal. We keep some of these attenuators in stock. Build the 20Db attenuator. It is not hard to build, it is just 5 resistors in an "H" configuration. The resistors can be gotten at radio shack. The values are not critical, just get close.

If you have a balanced (twisted pair, no ground) signal simply connect it to the 222 input - and + terminals (the ground terminal is left unconnected).
If you have a unbalanced signal (hot and ground, single wire with shield) then connect the ground or shield of the input signal cable the the ground input, the + 222 input terminal goes to your center conductor.
Don't solve the gain problem by just turning down the input control, you will get good sound but the 222 will not operate properly. You should be able to see the lights come on as the music peaks if you have the limit and/or pre emphasis controls on.
Do not use the AM1000PR audio adapter when using the 222. Even though it will provide 6Db of attenuation, this may not be enough. You need about 20 Db of attenuation. Customers recommend the

Creative Labs/ SoundBlaster for use in driving the Inovonics 222 processor

Helpful Notes on connecting the Inovonics 222 AM Processor to the Hamilton Rangemaster AM1000 (From Dan)

The following scenarios should be helpful in getting a good “handshake” between the Rangemaster 1000 and the Inovonics 222 when using an unbalanced audio source.

Note: If you have a problem with not getting enough signal to the 222 check to be sure your 222 is set for low level range input

If needed, you can build an attenuator.

Rangemaster 1000 connected to the Inovonics 222 using an unbalanced audio source from a Behringer 602A audio mixer as an audio source.

1. Remove the top panel of the Inovonics 222 (5 screws) and set the jumpers (located at the lower left hand corner in the rear of the unit under the terminal strip) to the “LOW” position as per factory instructions. Re-install cover.
2. Connect balanced 600 ohm line from the Rangemaster 1000 to the OUT (+) and OUT (-) terminals on the rear of the Inovonics 222 (Make sure polarity is correct).
3. Place a jumper wire between the IN (-) terminal and the IN GND (Ground) terminal on the Inovonics 222.
4. Connect the audio source from the LINE OUT on the mixer to the Inovonics 222 with the positive (+) lead to the IN (+) and the shield or ground to the IN (-) terminal.
5. Set all “screw type” controls on Inovonics 222 to the full counter-clockwise position (a slight click will be felt when position is reached) and all switches to the “ON” position.
6. Turn on all units and send an audio signal (music, tone etc. with good gain) through the mixer to the Inovonics 222.
7. Adjust the INPUT GAIN on the Inovonics until the -2 light is almost always lit on the limiter with the -6 light occasionally flashing. This will give you a proper input signal.
8. With a AM radio tuner turned ON nearby (set to your frequency), slowly turn the OUTPUT GAIN on the Inovonics until you hear your signal at a good level without distortion. Note: If distortion seems to be present at any level you may need to adjust the audio control on the Rangemaster counterclockwise to compensate and get a clear signal. Be careful not to adjust down too much! Readjust the OUTPUT GAIN until a maximum, distortion free, level is reached.
9. After a good and clear audio signal is obtained with plenty of volume on the AM radio, turn the POS. PEAKS control fully clockwise (a slight click will be felt when that point is reached).
10. Everything is set to broadcast at this point. No additional adjustments should be necessary.

This is from Chip:

I added a Behringer PRO-XL MDX2600 to
my audio chain today and what a huge improvement.

I can now fully modulate the Rangemaster and use every bit of that
carrier.

The MDX2600 does:
1. Expander / enhancer / peak limiter
2. Voice adaptive De-esser (compensates for male / female voices)
3. Interactive dynamic enhancer with hard and soft knee
4. Tube simulation, adds warmth of tube gear (you can select or
deselect this feature)
5. Interactive knee adaptation
6. Interactive ratio expander
7. Safety relay (bypasses unit in event of power outage)
8. Self detecting balance or unbalanced inputs/ outputs - easy to
hook into audio chain (both XLR or 1/4 TRS jacks)
9. Selectable input range -10dbV or +4dbu
10. Dual channel (can be used for stereo)
11. Variable gain to allow user to set so audio chain stays constant
12. Inexpensive
13. Drives 222 to full spec
14. Manual or auto Attack and Release

It really makes the audio have lots of punch, makes quiet pieces
quiet, eliminates deep bass drum beat thumping (makes it sound like a
drum instead of a thump).

This is in addition to the Inovonics 222. The 222 is still
the "spectrum cop", but the MDX2600 adds fidelity which the 222
cannot.

Anyway, I highly recommend this unit.
If you drive the 222 hard enough and keep the Rangemaster driven hard
but not into distortion, that is the desired operating point. That
gets the maximum peak power out of the RangeMaster and hence range.
Note the the quiescent input power with zero modulation is still
within FCC spec of 100 milliwatts.


 

We here also recommend the MDX 1400. The trick here is that for it's low cost (comparative) the 222 does not have compression. This compression can be added by an inexpensive limiter/compressor like the Behringer models mentioned.