Frequency Blocks And Ranges - Lectrosonics UH400A Instruction Manual

Frequency Blocks and Ranges

Each UH400A transmitter is built to cover a pre-se-
lected range of frequencies (a "block"). The transmitter
will tune to any of 256 different frequencies within this
factory assigned block. (See Operating Frequencies
(MHz).)
The block number is determined by this formula:
25.6 × Freq. (MHz) = Lowest freq. (MHz) in the
block
To determine a block number from a frequency:
Freq. (MHz) divided by 25.6 = Block number
It is handy to remember these formulas, in case you do
not have a copy of the table. For example, suppose you
need to know which block covers 685.500 MHz, without
using the table:
685.500 divided by 25.6 = 26.77734375
The first two digits left of the decimal are the block
number. In this case, 685.500 MHz falls within block 26.
Part of block 23 is not used since it covers a 608 to 614
MHz band that is illegal for use with wireless micro-
phones.
Operating Frequencies (MHz):
Block 21
Block 22
Block 23
Block 24
Block 25
Block 26
Block 27
Block 28
Block 29
Block 30
Rio Rancho, NM
537.600 - 563.100
563.200 - 588.700
588.8 00- 607.900;
614.100 - 614.300
614.400 - 639.900
640.000 - 665.500
665.600 - 691.100
691.200 - 716.700
716.800 - 742.300
742.400 - 767.900
768.000 - 793.500 (export only)
Frequency Agile Plug-On UHF Transmitter
Use the two Frequency Switches to set the transmitter's
carrier frequency to match the associated receiver. For
example, assume that the transmitter and receiver are
both assigned Block 25 and the receiver's switches are
set to 658.400 MHz.
Subtract the lowest frequency for Block 25 from the
assigned frequency to determine the switch settings for
the transmitter.
658.400
-640.000
18.400
Divide the result by 1.6 and round down the nearest two
digits to determine the coarse Frequency Switch
setting.
18.4/1.6 = 11.5 or 11 (B on the switch dial)
Multiply the coarse Frequency Switch setting by 1.6 and
subtract that number from the original result to deter-
mine the setting for the fine Frequency Switch.
11 x 1.6 = 17.6
18.400
- 17.600
.800 or 8
Therefore, the Frequency Switch settings for this
transmitter would be B8.
9