Freq Button Settings; Block 470/19 Frequency Overlap - Lectrosonics HMa Instruction Manual

nected to ground, then you will draw maximum current
from the power supply. The HM is fully protected against
such shorts but the batteries will be drained at twice the
normal rate.
The transmitter can supply 4 mA at 42 Volts, 8 mA at 15
Volts, and 8 mA at 5 Volts. The 42 Volts setting actually
supplies the same voltage to a 48 Volt microphone as
the DIN standard arrangement due to a dynamic bias-
ing scheme that does not have as much voltage drop as
the DIN standard. The 48 Volt DIN standard arrangement
protects against shorts and high fault current with high
resistance in the power supply feeds to pins 2 and 3.
This provides protection if the supply current is acciden-
tally shorted to ground and also keeps the microphone
from being attenuated by the power supply.
The HMa improves on those functions and is able to use
less power from the battery by using constant current
sources and current limiters. With this dynamic arrange-
ment the HMa can also supply more than twice the cur-
rent of competing 48 Volt plug on units and provide four
times the current for some very high end 15 Volt micro-
phones.

FREQ Button Settings

Press the FREQ button on the Control Panel to enter
this setup screen. The display will vary depending upon
which StepSize setting is selected. See Selecting Step
Size on page 9.
Note: The default display is in MHz. Pressing
the FREQ button again displays the operating
frequency as a two-digit hexadecimal number
that corresponds to legacy Lectrosonics
products that used two 16-position switches to
set the frequency.
While holding the FREQ button, use the UP or DOWN
arrow buttons to change the frequency.
Note: The operating frequency displayed on the
LCD wraps as it reaches the upper or lower end
of its range.

Block 470/19 Frequency Overlap

Frequencies 486.400 - 495.600 Overlap in Blocks 470 and 19
Block 470 and block 19 overlap each other in the fre-
quency range from 486.400 to 495.600 MHz. Since block
470 starts at a lower frequency than block 19, the hex
codes (and pilot tones) will not match even though the
frequencies are the same in the overlap zone. When
using a transmitter on the A1 band with a block 19
receiver, be sure the transmitter is set to block 19 and
check the hex code on the receiver to make sure it
matches the transmitter.
Call the factory for further questions on this issue.
Rio Rancho, NM
Wideband Digital Hybrid
Set Up in 100kHz Step Size
Frequency displayed
in MHz
Frequency displayed as
two-digit hexadecimal
number
Set Up in 25kHz Step Size
The hexadecimal display in the 25 kHz mode will ap-
pear with a decimal suffix to indicate the 25 kHz steps.
Standard Frequency
frequency in hex
block (20) code (F6)
Examples:
475.875 MHz
490.225 MHz
487.650 MHz
509.200 MHz
Lock/Unlock Screen
Simultaneously pressing and holding both the UP and
DOWN arrow buttons during normal operation starts
the LOCK timer. The timer starts at three and counts
down to zero. When the timer reaches zero, the keypad
controls are locked.
The LCD will display the locked condition as long as
the arrow buttons are held, then revert back to the pre-
vious screen when either button is released.
With the controls locked, the AUDIO and FREQ but-
tons can still be used to display current settings. Any
Plug-On Transmitter
®
The operating frequency can
be displayed either in MHz or
as a two-digit hexadecimal
number. The example of the
two-digit display shown here
indicates CH (channel) and 2C
as the frequency.
The frequency can be set with
the unit in standby mode or
when powered up for normal
operation.
Frequency expressed in MHz
Frequency in hex
Offset in
MHz (.25)
11