User's Guide

ThingMagic M6e User Guide 63
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characteristic that attenuates discharge events. (This also makes the antenna compatible with the M6e
antenna detect methods.)
• Install a Minicircuits SHP600+ high pass filter in the cable run at the M6e (or Vega or other finished
reader) end. This additional component will reduce transmit power by 0.4 dB which may affect read
range in some critical applications. However the filter will significantly attenuate discharges and improve
the M6e ESD survival level.
NOTE: The SHP600+ is not rated for the full +31.5 dBm output of the M6e reader at +85°C. Operation at
reduced temperature is acceptable, but has not been fully qualified by JADAK.
• Install a Diode Clamp* circuit immediately outboard from the SHP600 filter. This will reduce transmit
power by an additional 0.4 dB, but in combination with the SHP600 will further improve the M6e ESD
survival level.
* Not yet productized. Needs DC power. Contact [e-mail] for details.
Further ESD Protection for Reduced RF Power Applications
In addition to the protective measures recommended above, for applications where reduced M6e RF power
is acceptable and ESD is suspected, the following protective measures can also be applied:
• Install a one watt attenuator with a decibel value of +30 dBm minus the dBm value needed for tag power
up. Then run the reader at +30 dBm instead of reduced transmit power. This will attenuate inbound ESD
pulses by the installed decibel value while keeping the tag operation generally unchanged. Attenuators
of 6 dB have been shown to not adversely affect read sensitivity. Position the attenuator as close to the
M6e as feasible.
• As described above, add the SHP600 filter immediately adjacent to the attenuator, on the antenna side.
• If required, add Diode Clamp adjacent to the SHP600, on the antenna side.
Variables Affecting Performance
Environmental
Reader performance may be affected by the following environmental conditions:
• Metal surfaces such as desks, filing cabinets, bookshelves, and wastebaskets may enhance or degrade
reader performance.
• Antennas should be mounted far away from metal surfaces that may adversely affect the system
performance.
• Devices that operate at 900 MHz, such as cordless phones and wireless LANs, can degrade reader
performance. The reader may also adversely affect the performance of these 900 MHz devices.
• Moving machinery can interfere with the reader performance. Test reader performance with moving
machinery turned off.
• Fluorescent lighting fixtures are a source of strong electromagnetic interference and, if possible, should
be replaced. If fluorescent lights cannot be replaced, keep the reader cables and antennas away from
them.
• Coaxial cables leading from the reader to antennas can be a strong source of electromagnetic radiation.
These cables should be laid flat and not coiled.
Tag Considerations
There are several variables associated with tags that can affect reader performance: