User's Manual
UHF Wireless Diversity Receiver  
Rio Rancho, NM
9
The receiver is supplied with two right angle BNC an-
tennas. In some circumstances remote antennas such 
as the SNA600 or ALP600 may be useful for improving 
reception. Position remote antennas at least three or 
four feet apart and not within three or four feet of large 
metal surfaces. If this is not possible, try to position the 
antennas so that they are as far away from the metal 
surface as is practical. It is also good to position the 
receiver so that there is a direct “line of sight” between 
the transmitter and the receiver’s antenna. In situations 
where the operating range is less than about 100 feet, 
the antenna positioning is much less critical. The an-
tennas can also be configured with one whip connected 
to one antenna input of the receiver, and a remote 
antenna connected to the other antenna input.
Be careful about the length of cabling from antenna 
to receiver. Long cable runs can have serious signal 
loss. Lectrosonics has in-line RF amplifiers suitable for 
compensating for long cable runs. Contact your dealer 
or the factory for more information.
A wireless transmitter sends a radio signal out in all di-
rections. This signal will often bounce off nearby walls, 
ceilings, etc. and a strong reflection can arrive at the re-
ceiver antenna along with the direct signal. If the direct 
and reflected signals are out of phase with each other 
a cancellation may occur. The result is a “dropout.” A 
dropout can sound like audible noise (hiss or swishing), 
or in severe cases, it may result in a complete loss of 
both the carrier and the sound. Moving the receiver’s 
antennas even a few inches will change the sound of 
the dropout, or often eliminate it. A dropout situation 
may also be either better or worse as a crowd fills or 
leaves the room, or when the transmitter or receiver is 
operated in a different location.
The R400A receiver offers a sophisticated diversity de-
sign which overcomes dropout problems in almost any 
situation. In the event, however, that you do encounter 
a dropout problem, try moving the receiver or antennas.
If the antennas are attached directly to the receiver, 
moving the receiver at least three to four feet from 
its current location. If dropouts are still a problem, 
try moving the receiver closer to the transmitter.
If remote antennas are used, try moving one or both 
of the remote antennas at least three or four feet from 
their current location. This may alleviate the dropout 
problem at that location. If dropouts are 
still a problem, try moving the remote an-
tennas to an entirely different location.
Lectrosonics transmitters radiate power 
very efficiently, and the receivers are very 
sensitive. This reduces dropouts to an 
insignificant level. If, however, you do 
encounter dropouts frequently, call the 
factory or consult your dealer. There is 
probably a simple solution.
Antenna Use and Placement
Better 
antenna 
placement
Good
antenna 
placement
Poor antenna 
placement
Front mounted whips with 
optional rack mount
Optimal antenna placement
with optional remote antennas










