Issue 1
Fielding questions for Wireless
manufacturers is one of the many activities that we perform at ATCB. Packets
provides an overview of a small portion of the communiqués that run in and
out of our office.
Please note that the
following represents, in most cases, technical opinions with justification
in FCC Requirements, the particulars of the product must be considered.
Thus, we welcome a call or email if you have any special needs or questions.
Question:
Multiple Antennas for Low Power Device:
We have a project consisting of a PCMCIA card that uses up to 5 different
antennas in the same product, we propose to test all of the antennas of the
EUT, pre-testing all of them, but recording only the one showing the
greatest emissions. What RF exposure should we consider?
Response:
The FCC wants to see a representative antenna of EACH TYPE included in the
Test Report—not just the one with greatest gain. As an example, if two
Yagi antennas are offered by a manufacturer, test the highest and lowest
gain with each antenna family.
This would be true regardless
of the form factor of the device.
Since the issue is with respect
to a PCMCIA card, it becomes more complicated because you may have some configurations which will be "Mobile" and others
which may be "Portable" from the perspective of RF Exposure. The
inclusion of one antenna in the "Mobile" RF Exposure category may
prohibit it’s use in "Portable". To date, the Commission is
reluctant to allow one FCC ID to cover both "Mobile" and
"Portable" configurations of the same product.
Question:
The Worldwide 5 GHz Band:
Please provide a summary of the applicability for unlicensed devices in the
5 GHz band. Note in some countries a license maybe required for use of these
devices outdoors.
Response:
The US and EU have fairly regulated structures (FCC & R&TTE).
Most of South America - will
accept FCC report. Africa, Mid East, Eastern Europe, Russia, require ETSI/EN
report.
Market/Region: US
Applicability: 5150-5250
MHz, 5250-5350, MHz5725-5825 MHz
Market/Region: EU Applicability:
5150-5350 MHz & must also operate in 5470-5725 MHz. Hyperlan
standard—not 802.11a Now allows 802.11a without TPC or DFS on a
country–by–country basis
Market/Region: Eastern EU,
Africa, Mideast Applicability: Currently no 5 GHz allocated in some
countries- some awaiting results of WRC-03 conference next year
Market/Region: Japan Applicability:
4.9-5.025 GHz, 5250-5350 MHz Std 33a and 66
Market/Region: China Applicability:
No 5 GHz Band 5725-5825 MHz has been adopted 5150-5350 MHz under
consideration
Market/Region: Malaysia
Applicability: No 5 GHz Band 5150 – 5350 MHz under consideration
5725-5850 MHz under consideration
Market/Region: Korea
Applicability: 5725- 5825 MHz, 5150-5350 MHz under consideration
Market/Region: Hong Kong
Applicability: 5725-5850 MHz, 5150-5350 MHz under consideration
Question:
Portable Transmitter Cards:
Should all 15.247 PCMCIA cards with integral antennas intended for general
use (laptops, PDA, routers, etc) be evaluated as a "portable"
"modular" transceiver?
Response:
The main issues with the FCC with regards to portable cards and wireless
devices center around the RF Safety/Exposure issues.
First, an integral-antenna
PCMCIA card is a portable device. Modular approval has not been required for
all PCMCIA cards. The FCC is still working on other policies, including
possible host-independent criteria.
The following general points
are critical when discussing these types of devices:
1) A new Certification is required when changing from Mobile Category
to portable. A Class II for mobile to portable is not allowed, mostly
because these have different exposure limits.
2) "Full modular" approval not allowed for portables,
mostly because final product must be known to evaluate compliance for
portable exposure conditions.
3) "Limited modular" approval accounts for EMC in a
"stand-alone" condition, plus possibly RF exposure for some
specific host. Subsequent host or antenna changes need Class II with RF
exposure and radiated EMC.
4) "Modular approval" for licensed-services devices not
allowed, mostly because these operate at powers relatively higher than Part
15 modules, thus it is more important to evaluate exposure conditions of
final host configurations only. In certain cases some licensed-service
devices may qualify for approval for use in a limited class of host devices
for mobile exposure conditions only.
5) From DA-00-1407A1.doc: "The holder of the grant of equipment
authorization (Grantee) of the module is responsible for the compliance of
the module in its final configuration, provided that the OEM, integrator,
and/or end user has complied with all of the instructions provided by the
Grantee which indicate installation and/or operating conditions necessary
for compliance."
6) The FCC is considering working towards possible host-independent
approvals.
Question:
OFDM Testing Outside the Band:
When testing an OFDM 5GHz Unit with a normal frequency range is 5.15~5.35GHz
only. But this system also can tune to 5.725~5.825GHz. When testing
according to part 15.407 (b)(3) The limit is -17dBm/MHz in the 10MHz
frequency range outside the 5.725~5.825GHz. Can the "Average"
function be used to test? And also my RB and VB is both 1MHz. Can we use a
smaller RBW and VBW for testing?
Response:
The out of band spurious emissions for the systems are required to be
recorded in peak and not in average. In fact the out of band spurious
emissions for this measurement calls out an EIRP level in dBm/MHz
Out of band emissions can use
the average limit below 1 GHz. Section 15.407(b)(4) refers to in band peak
power and not out of band emissions.
Section (6) deals with spurious
emissions. Though the reading must be recorded with a peak detector; under
Section15.407 (b)(4) stipulates though a 1 MHz band width is required for
this test, a lower resolution near the band edge may be used if necessary,
provided the measured energy is integrated to show the total power over 1
MHz.
Question:
Methodology for Bandwidth Selection:
What is the recommended test methodology for bandwidth selection when
measuring band edges?
Response:
The recommended test methodology is to use a bandwidth that will include the
center point of the lowest or highest channel that you are measuring and include at least
10 MHz span of the nearest restricted band to that channel.
The plots provided should be
taken using both an average detector and a peak detector.
Plots and data should be provided for each combination of antenna and power
output being certified.
Proper measurements at the band
edge may require the use of a delta type measurement as described in FCC Docket 96-8, which can be downloaded from the FCC web
site at:
www.fcc.gov.
Question:
Wide Band Frequency Hopping Systems: What are the current requirements for
Frequency Hopping systems?
Response:
The FCC has released the final requirements for Wide Band Frequency Hopper
Systems operating under 15.247 on May 16th, 2002. Under the permanent rules
these systems must use at least 15 hop non-overlapping hop channels and are
limited to a maximum power output of 125mW plus 6dBi gain antenna.
The commission has not made the requirement for adaptive hopping mandatory
for these devices since it believes that this can best be addressed by the
standard committees. Frequency hoppers hopping systems using 1 MHz wide
bandwidth are not affected by this power reduction.
FCC Updates
General Spectrum Issues: The FCC recently closed the comment period on
Public Notice 92-135 in which it was seeking comments on Spectrum Issues in
general. The FCC Spectrum Task Force hopes to issue a full report by mid
October on various spectrum issues. Please check www.fcc.gov for this
report.
Higher Frequencies: The FCC has
released NPRM 02-142 addressing licensed and unlicensed operation in 71-76 GHz, 81-86 GHz and 92-95 GHz band. Comment period is 90
days from the publishing in the Federal Register. The FCC is considering
allocating about 1200 MHz of spectrum for unlicensed use in the 92-95 GHz
bands.
Radar Detectors: The FCC has
modified Part 15 rules requiring certification for Radar Detectors Receivers
operating at frequencies greater then 960 MHz. This is a new category of
receivers that now require certification.
Canada Updates
Industry Canada comment period for their spectrum plan ended Sept 2nd of
this year. Information on this proceeding can be obtained from the Industry
Canada web page at http://spectrum.ic.gc.ca
Australian Updates
The comment period for adoption of the new EMR standard was July 31st.
Currently the Australians have postponed adopting new requirements.
Currently under study is the adoption of the international recommendations
and requirements
China Updates
China has rolled back the adoption of their proposed EMR standard until
further information can be gathered. This standard would have been one of
the tightest limits to meet and would have forced manufacturers to reduce
power for mobile and portable transmitters. The MII is postponing adoption until additional studies on EMR limits are complete.
China has also rolled back
it’s power limitation of 10mW for 2.4GHz radios and now will approve
systems with power up to 100mW EIRP. Systems are restricted to indoor use
only.
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