Receiver Multicoupler
Rio Rancho, NM
11
Antenna Bandwidth and Requirements
The design of Lectrosonics wideband multicouplers
helps deal with a changing RF spectrum, however, it
also introduces the requirement for specific or more
advanced antennas to provide maximum operating
range. Simple whip antennas cut to a single frequency
block are inexpensive and effective at covering a 50 to
75 MHz band, but will not provide adequate coverage
for the entire range of a wideband antenna multicou-
pler. Following are the antenna options available from
Lectrosonics:
Lectrosonics Antennas:
Model Type Bandwidth
MHz
A500RA (xx)
Rt. angle whip
25.6
ACOAXBNC(xx)
Coaxial
25.6
SNA600
Tunable dipole
100
ALP500
Log-periodic
450 - 850
ALP620
Log-periodic
450 - 850
ALP650 (w/ amp)
Log-periodic
537 - 767
ALP650L (w/ amp)
Log-periodic
470 - 692
In the table, (xx) with the whip and coaxial antenna
model numbers refers to the specific frequency block
that the antenna is precut to use. The SNA600 model
is tunable to move the center frequency of its 100 MHz
bandwidth up and down from 550 to 800 MHz.
The greater the mismatch of frequencies between
the antenna and the receiver, the weaker the signal
will be, and the shorter the maximum operating range
of the wireless system. Experimentation and check-
ing the range before the production starts is always
a good idea, and is mandatory if the frequencies of
the antenna and receiver do not match exactly. On
many production sets, the short operating range that
is needed may allow the use of a slightly mismatched
whip antenna.
In general, using a whip antenna one block above or
below the receiver range will provide adequate range,
often with no noticeable difference from the correct
antenna.
Use the RF level meter on the receiver to check the
received signal strength. Keep in mind that the signal
level varies wildly as the system operates, so be sure
to conduct a walk test through the area to identify loca-
tions where the signal drops to very low levels.
There are also many antennas made by other compa-
nies, which are easily found by searching for their web
sites. Use search terms like “Log-periodic,” “directional,”
“broadband,” etc. A specialized type of omni-directional
antenna is called a “discone.” A DIY “hobby kit” instruc-
tion manual for building a discone is on this web site:
SNA600
ACOAXBNC
(precut to block)
A500RA
(precut to block)
ALP500
ALP620
ALP650
http://www.ramseyelectronics.com/downloads/manuals/DA25.pdf
* See Antenna/Block Reference
Chart on next page
