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Used Anechoic Chambers
Anechoic means "neither having nor producing echoes." In applications discussed here, the echoes typically refer to RF and/or microwave reflections. An anechoic chamber is usually a modular shielded room (or occasionally a welded room) that is lined inside with RF and/or microwave absorbing ("anechoic") material. It is essentially a "stealth room" that is invisible to the products or tests being conducted inside. Depending on the purpose of the room, anechoic material may be placed on the walls and ceiling (usually referred to as "semi-anechoic") or it can be placed on all six sides of the room (aka "fully anechoic").
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None at this time, but check back soon!
Note
Used anechoic chambers can offer a terrific savings over the price of a new room - typically 50% or more. However, be aware of the following cautions:
- DJM Electronics does not offer performance guarantees for any chambers. Most chambers can be made to achieve 80dB of shielding effectiveness and reflectivity characteristics that vary with the age and quality of the absorbers, but this is not always the case. Some chambers listed here may require considerable additional expense to repair or renovate before they will perform at an acceptable level. If you must have a performance guarantee, then you should consider a new chamber.
- Payment terms are 50% with the purchase order and 50% upon delivery of the room. No exceptions.
- Installing an anechoic chamber is not as easy as it might appear. We recommend enlisting the services of a shielding installer.
Typical Construction
Supporting Structure
An anechoic chamber is normally a modular shielded room with additional structural steel to provide the necessary support for the additional weight of the anechoic material. See the web page on used shielded rooms for more information about the construction of the shielded room. In most situations, we can refurbish or enlarge existing modular enclosures to accommodate new or additional anechoic absorber.
RF/Microwave Absorber
The RF and microwave absorbing material is chosen based on the customer requirements. We offer a wide selection of polyurethane, polystyrene, polyethylene and ferrite absorbers as well as various combinations to refurbish or augment existing absorber configurations. Please see our web page on rf absorber for more information about our selections.
Typical Models
Used Antenna Pattern Measurement
Anechoic Chambers
Antenna Pattern Measurement chambers come in many different designs and sizes and are often customized to the particular requirements of the original owner. An untreated modular shielded room is a resonant cavity with field variations up to 30dB. By incorporating anechoic material in specific designs and configurations, the same room can be controlled to within 3-8dB across a frequency range of 26MHz up to 1GHz, 18GHz or 40GHz (depending on the requirement) - a dramatic improvement on the reliability and consistency of test data acquired. The chambers are normally designed to provide specific performance in an area called the "Quiet Zone" located on the opposite end of the chamber from the transmit/recieve antenna. We cannot guarantee that used chambers will provide the same performance as when it was new, but will do our best to reconstruct the chamber to its original design.
Used Electromagnetic Compatibility (EMC)
Anechoic Chambers
EMC chambers are designed to create a controlled environment in accordance with published specifications. The Compact Anechoic Chamber and 3m Anechoic Chamber are the most popular EMC chambers.
Used Compact Anechoic Chambers
The compact anechoic chamber is the smallest anechoic test facility recommended for performing EMC testing from 26MHz to 1GHz (usually up to 18GHz). This style of anechoic chamber allows the user to carry out radiated immunity measurements in full compliance with IEC 61000-4-3 standards and pre-compliance emissions measurements for EN 50147-2, ANSI C63.4 and CISPR 22. The chamber is comprised of a standard modular shielded enclosure, additional structural support and ferrite tile absorber on five sides. Compact anechoic chambers are designed to provide a uniform field variation of less than 6dB across 75% of the test plane when measured in accordance with IEC-61000-4-3. We cannot guarantee that used chambers will provide the same performance as when it was new, but will do our best to reconstruct the chamber to its original design.
Used 3m Anechoic Chambers
3m anechoic chambers are ideally suited for performing both radiated emissions and radiated immunity EMC testing from 26MHz to 18GHz (with typical options to go to 40GHz or higher). Like the compact chamber, this style of anechoic chamber allows the user to carry out radiated immunity measurements in full compliance with the IEC 61000-4-3 standard, but the full-scan capability of the 3m chamber allows fully compliant emissions measurements for many (but not all!) International and United States specifications. The chamber is comprised of a standard modular shielded enclosure, additional structural support and a combination of foam and ferrite tile absorber on five sides. 3m anechoic chambers are designed to provide a uniform field variation of less than 6dB across 75% of the test plane when measured in accordance with IEC-61000-4-3 and to exhibit a normalized site attenuation within +/- 4dB of the theoretical normalized site attenuation. We cannot guarantee that used chambers will provide the same performance as when it was new, but will do our best to reconstruct the chamber to its original design.
Used Mil-Std 461E Anechoic Chambers
The Mil-Std-461E anechoic chamber is designed specifically for Mil-Std testing. The chamber is comprised of a standard modular shielded enclosure, additional structural support and ferrite tile absorber on five sides. Mil-Std-461E chambers are designed to provide 6dB reflectivity loss between 80MHz and 250MHz and 10dB above 250MHz. We cannot guarantee that used chambers will provide the same performance as when it was new, but will do our best to reconstruct the chamber to its original design.
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