Specifications

6
microphones
wired
TECH-TIPS
Which antenna cable is best for wireless microphone systems?
All coaxial antenna cables are inherently lossy. The amount of signal loss increases with frequency (higher frequencies = more loss), and length of the
cable (longer length = more loss). Given that the general concept is to minimise signal loss, the best option is to use the lowest loss cable possible, and
keep the cable runs as short as possible. However low loss cables are generally more expensive, and harder to work with. So a compromise is required.
Table 1. lists several 50 ohm coaxial cables commonly used with wireless microphone systems. The ‘normal’ cable supplied with most wireless systems is
RG-58/U, which has the highest loss of all. RG-58/U is only suitable for very short runs.
Table 1.
Cable Type
Diameter
(mm)
Loss
dB/30m @ 1GHz
% Loss
(per 30m @ 1GHz)
RG-58/U 4.9 16.7 98
RG-8/X 6.2 11.2 92
RG-8/U 10.3 8.8 87
RG-213/U 10.3 8.8 87
So what is the maximum length I can run?
There is no easy hard & fast answer to this question. If your system has plenty of head room, i.e. your transmitter is physically close to the receiving
antenna, you can afford to lose a fair bit of signal on the coax before system performance deteriorates. However if you do not have much system
headroom you need to minimise all losses.
As a general rule it is recommended that selecting a cable so that cable loss is maintained at less than 10dB. This translates to the following distances
at 1GHz:
RG-58/U = 17m / RG-8/X = 26m / RG-8/U or RG-213 = 33m
Distances beyond this require careful system design and possibly in-line amplification. But that is a topic for another day. Shure supply pre-terminated
coaxial cable assemblies in various lengths, conveniently utilising lower loss cable types for the longer runs. Shure part numbers are detailed in Table 2.
Table 2.
Stock Code Description
UA802 BNC-BNC, RG58C/U type, 2 foot (0.6m)
UA806 BNC-BNC, RG58C/U type 6 foot (2m).
UA825 BNC-BNC, RG8X/U type 25 foot (7.5m).
UA850 BNC-BNC, RG8X/U type, 50 foot (15 m)
UA8100 BNC-BNC, RG213 type, 100 foot (30m)
How do I install remote wireless microphone antennas?
Remote antennas; multi-coupling receivers; multi room wireless; it can all seem a bit daunting. Shure Microphones, one of the worlds leading manufacturers
of wireless systems, have put together an excellent publication on all things antenna related. Check out the “Shure Effective Antenna Setup” guide. It
should have all the answers you are looking for. You will find the document in the “Microphones” folder of the “Educational Information” section of our
companion CD located inside the front cover.
Industrial/Commercial Microphones
300Hz-5kHz•
Dynamic•
Omnidirectional•
Shure Handheld 527B
Handheld, push-to-talk for
communication, paging and PA
applications.
60Hz-11kHz•
Dynamic•
Cardioid•
Shure Desktop 522
Dual impedance, push-to
-talk for paging and talkback
applications.
100Hz-7kHz•
Dynamic•
Cardioid•
Shure Gooseneck
503BG
Compact, low background
noise for paging, talkback and
close-talk applications.
80Hz-15kHz•
Dynamic•
Cardioid•
Shure Handheld
515SDX
Rugged push-to-talk for radio
communications, dispatch and
paging.
Shure Wired Microphones
TECH-TIPS