Direct answer: A UHF RFID reader’s quoted dBm value is useful only after you know where it is measured and what antenna configuration it describes. A conducted output at a reader port is not the same as the radiated result of an antenna system; an integrated sled may publish an EIRP value for its finished configuration. Compare approved, region-specific configurations and then test the required tags and neighboring tags. Do not select the higher number as a substitute for a defined read zone.
This guide addresses the power evidence a buyer should request for RFID mobile computers, RFID sleds or a separately assembled reader and antenna system. Those AIDC GO category pages do not establish the RF output or antenna gain of an unspecified model.
Read the unit and reference point before comparing quotes
In a modular fixed-reader path, the configured transmit power may be the conducted power available at a particular RF port. Antenna cable loss reduces the power delivered to the antenna; antenna gain concentrates radiation in particular directions. A conceptual link budget in compatible dB units is EIRP (dBm) ≈ port power (dBm) − cable loss (dB) + antenna gain (dBi). This arithmetic does not replace the reader manufacturer’s approved configuration, measured emissions or applicable regional requirements. Also distinguish gain in dBi from gain in dBd; they are not interchangeable numbers.
ETSI’s TS 102 903 V1.1.1 discusses conducted measurements and antenna/cable corrections for RFID interrogators; it is a technical source for the distinction, not a statement of today’s permission in any country. Zebra’s FXR90 cable-loss tutorial for RFID SDK for Android 2.0.5.275 shows a model-specific get/set interface. Neither defines an AIDC GO device setting.
An integrated or sled reader may instead quote power for the complete antenna assembly. Zebra’s RFD40 Standard Sled Product Reference Guide lists regional RF output values explicitly as EIRP for that model. Do not add an imagined external antenna gain to an already stated EIRP value or compare it directly with another device’s port-power number. Confirm which regional SKU and radio configuration are actually in the quotation.
Use a constructed calculation only to expose missing fields
Editorial calculation, not a measured system or permitted power setting: suppose a modular reader is configured for 27 dBm at its port, its approved cable path loses 2 dB and its specified antenna has 6 dBi gain in the relevant direction. The illustrative arithmetic gives 27 − 2 + 6 = 31 dBm EIRP. If a quote gives only “27 dBm reader power,” you cannot reproduce this comparison without the cable, antenna, measurement point and regional configuration. The result is neither a legal limit nor a prediction of read distance.
For a handheld with an integrated antenna, request its documented output definition rather than applying the modular calculation to inaccessible internal components. For a sled attached to a host, identify the sled SKU, region, antenna design, firmware and host combination. A different host application may expose different controls, but a configuration screen is not evidence that an unapproved RF setting is available.
Keep compliance, coverage and business results separate
First establish that the proposed reader, antenna, cable and settings are approved for the deployment country. The region-selection guide addresses this gate. Do not copy a power value from another country or another reader family. This article does not give a universal regulatory maximum; the applicable documents and supplied configuration must be checked for the actual order.
Next test RF coverage. Port power or EIRP alone does not capture antenna pattern, polarization, tag orientation, tagged-item material, reader sensitivity, interference, dwell time or operator movement. The polarization guide addresses orientation, while the read-range guide covers misses and stray reads. This page adds the narrower decision of whether two quoted power figures describe equivalent reference points and complete configurations.
Finally check the application result. A tag that responds to the reader may be filtered, deduplicated or unmatched in the business record. Raising power cannot fix a wrong EPC mapping, an excluded population or a failed inventory transaction. The inventory-scope article separates the responding tag set from the accepted business count.
An editorial aisle comparison
Editorial scenario, not a customer trial: a warehouse wants a handheld to count tagged cases on one shelf without routinely collecting cases on the adjacent shelf. Candidate A is an integrated reader with a manufacturer-stated EIRP range. Candidate B is a reader plus a separately quoted antenna and cable. The buyer must not compare the top numbers as if both were port outputs.
- Record each exact reader SKU, regional variant, firmware, antenna and cable where applicable, approved power range, RF mode and application settings. Mark missing fields as unresolved rather than filling them from a different model’s datasheet.
- Prepare the same verified EPC list for expected shelf cases and a separate list of neighboring tagged cases. Keep item packaging, tag placement, shelf geometry, operator route and read window representative of the work.
- At documented, allowed settings, capture unique expected reads, misses and unwanted neighboring reads per run. Preserve the raw reader output and the application-accepted result separately.
- If increasing an approved setting reduces misses but increases neighbor reads, the purchase decision is a read-zone trade-off, not an automatic power upgrade. Consider antenna pattern, placement and workflow before changing the power again.
If neither candidate satisfies both the expected-read and unwanted-read rules, redesign the read point or test conditions. Do not claim that an arithmetic EIRP estimate proves a shelf boundary. A reader’s higher power setting may alter coverage, but it cannot provide a unique mapping from RSSI to distance; see the RSSI guide.
Specify an acceptance record, not a single maximum number
Ask the supplier to identify whether each RF value is conducted port power, EIRP or ERP, along with its measurement point, regional SKU, approved antenna, cable loss, operating mode and adjustable range. Require the application integrator to document who sets those values, how the configuration is backed up, and how an operator can verify the intended setting after service. Do not infer AIDC GO RF controls from Zebra or Impinj interfaces.
Acceptance should include the exact tagged population, adjacent population, settings and output from several normal-use runs. Record failures as well as the best case. Use the broader AIDC pilot checklist for business acceptance and send the tagged-item samples and target zone to Integration Support or Contact. An exact-model quotation and sample trial are needed before making a range or compliance claim.
Sources and scope
ETSI TS 102 903 V1.1.1 (2011-08), Zebra’s FXR90 cable-loss tutorial, RFID SDK for Android 2.0.5.275 and the RFD40 Standard Sled guide were checked on 2026-09-23. They describe different technical contexts and third-party products; no cited value is an AIDC GO specification or current universal regional permission. The numerical calculation and aisle trial are editorial examples only.