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400Mhz Radio Problem

4206 Views 3 Replies 3 Participants Last post by  mbott
Granted, 400Mhz radios are fading into history, but here is a warning for anyone still carrying one.

Taser has issued a warning on allowing 400Mhz radios to get close to their X26 Taser unit. Seems that a 400Mhz radio can cause a X26 Taser to discharge IF within 1" of each other AND the X26 is armed / safety off. Don't remember the name of the department that encountered this, but Taser was able to reproduce the issue.

I don't believe that this was an issue with the older M26 Taser unit.


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Here is the text of the bulletin:

Training Bulletin 13–11:

Possible Radio Interference

TR-FORM-BUL-014 Rev: A September 7, 2007 Page: 1 of 1

Subject: Notification from Motorola regarding possible interference generated by police

radio transmissions that can adversely affect other electronic equipment including TASER


A police department recently notified TASER International of a possible interference issue between

their 400 MHz Motorola police radio and a TASER® X26 device that was located directly adjacent to

the radio. The interference from the Motorola police radio caused the TASER X26 device to

unexpectedly discharge when the TASER X26 device was within approximately 1 inch of the radio

antenna and the TASER device safety switch was in the up (ARMED) position. TASER

International immediately started an investigation into this issue to determine the probable cause of

the interference. As part of our investigation, we contacted Motorola, Inc. to obtain additional

information about all models of their police radios, including antennas, microphones, radio

accessories, power output and any interference issues they were aware of.

Motorola informed us that the Motorola police radio antenna transmits enough energy that any

electronic device (e.g., cell phone, walkie-talkie, or TASER device) that is within approximately 1

inch of the radio antenna is subject to possible interference up to and including permanent damage

to components in the other electronic device.

Motorola advised TASER International that all electronic devices, including TASER devices, should

be kept at least 1 inch away from the radio antenna, especially during radio transmission, in order to

avoid harmful interference and possible permanent damage to these electronic devices.

Based on this caution received from Motorola, and a complete analysis of the TASER X26 device in

question, TASER International has determined that the TASER X26 device was operating

according to factory specifications and in compliance with FCC requirements. The probable cause

of the interference was the transmission of the Motorola radio when the radio antenna was in close

proximity to the TASER X26 device and the TASER device safety is in the up (ARMED) position.

The only known incidences of this type of interference involve 400 MHz radios. TASER

International was able to duplicate the interference with a 400 MHz Motorola radio, but we were

unable to duplicate it with an 800 MHz Motorola radio. Motorola discontinued production of

400 MHz radios in 2004.

TASER International recommends that all departments advise their officers of this notification from

Motorola. As a precaution, all Motorola police radios should be kept several inches aware from any

electronic device, including a TASER device, and that the safety on a TASER device should be

placed in the down (SAFE) position whenever it is immediately adjacent to a Motorola police radio.

TASER International also recommends that if a department is using a radio manufactured by any

other company, that department should contact the radio manufacturer for recommended distances

for protection of other electronic devices.
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