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Testing a Channel for Outside Interference
Once a microphone and module have been successfully paired, turn the microphone OFF (leave the module ON). With the
microphone off, if the RF indicator still has bars showing, there exists interference. Note that RF interference can ebb and
flow. Sometimes it may appear as 4 steady bars on the RF indicator, other times, it may weakly occupy a single bar or two.
Generally, we recommend looking for another channel if ANY bars register.
Using the Frequency Scan
In some areas the scan feature may not select an interference-free channel . This is not because the system is
malfunctioning, but rather there are no interference-free channels available to choose from in that subgroup. If setting up in
this kind, and do not want to use manual frequency selection, we recommend you do the following:
1. Start a Scan (see Setting the Frequencies Automatically for instructions) on the left module (1) using the first group. If
there is no open channel in that group, repeat the Scan in the next group. Continue this process until an open channel is
selected. (see above for how to test a channel for interference)
2. Begin the Scan process on the second module, but this time start with next available subgroup.
3. Repeat this process with the rest of the modules.
Obtaining Local TV Tower Information
The most common source of RF interference to the UHF-8900 is TV broadcast towers. If the UHF-8900 is experiencing
dropouts, static, or other strange noises, it is likely RF interference at fault if within the threshold distance of 30 miles.
Follow the instructions below to obtain the information on your proximity to broadcasting TV towers.
(Applicable to the United States only)
1. Visit www.antennaweb.org (see note below)
2. Select “Click Here to Start”
3. Enter the Zip Code in which the UHF-8900 will be used and hit Submit.
4. The search results page that comes up will contain all the TV broadcasting stations within a 50 mile range.
A.) The information provided for each channel is:
I. Station Name
II . RF Channel -
This is the information to be interested in
III. Distance and Heading
5. Write down all of the RF Channel numbers for each of the search results.
Note: Only TV stations within 30 miles would cause issues with the microphones.
6. Refer to the TV Channel Frequency List (page 20) to determine which frequencies not to use.
7. Use the UHF-8900 Frequency List to determine which group and channels that are NOT being interfered with.
Please Note: antennaweb.org is a third party website and is not maintained by nor affiliated with Vocopro.
For example, let’s say you did a search in your area (this example shows zip code 05456) and received the following
information:
The only relevant channel is 43, therefore you would jot it down to cross-reference with TV frequency list (page 20)
After cross-referencing, you find that channel 43 uses the frequency range of 644 to 650 MHz. You would NOT choose a
frequency that falls in that range .
Advanced Operation
