Antenna amplifiers for U4D wireless system

FAQ #1185 Updated September 24, 2008

Question:

We have a Shure wireless system in our facility comprised of:
(4) U4D receivers
(1) UA845
(2) UA830 Amplifiers
(7) Beta 87A Mics
We would like to place the receivers in the Audio Control Room situated about 100 meters (300') away from the antennas.

The studio where the system is installed is of rectangular shape about 1800m2 (20.000 feet2)

In no noise condition without lighting or any other possible source of interference we can obtain a signal of -52 dBm. In the best case and after fiddling with the ground plane and moving the antenna around we can obtain a level as high as -44dB.

We obtain this level using low loss RF cable and 2 UA830 amplifiers roughly installed as suggested in the user's manual.

We estimate that a 30dB to 40dB amplifier would give us the sufficient gain to have a comfortable level and room to play with. However, we can not find an amplifier with those characteristics in your catalog.

If Shure has no such product available, could you direct us to a manufacturer that you would recommend? Could you give us any other suggestions?

Thank you very much for your help and any information you can send our way.

Answer:

We do not recommend amplifying the signal that much. If you amplify the signal that much, you are also amplifying the noise and your signal to noise ratio will be awful.

Instead, you should use better cable. RG-8/U (Belden 9913) has a loss of 3.9 dB/100 ft at 800 MHz. This means you could run 256 feet of cable and place a 10 dB amplifier on it to compensate for this 10 dB of loss.

You should be able to run 300 feet of RG-8/U and place a single 10 dB amplifier at the antenna end. The extra 2 dB of loss from that extra 50 feet of cable is not going to cause any problems.

Find an Answer

Related Product Types

Wireless Systems

Contact Information

Telephone: (800) 516-2525

Fax: (847) 600-8686

Additional Support

Ask a Question