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Ärende: The Weekly ARRL Letter
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The ARRL Letter
December 12, 2019
* FCC Amending Amateur Radio RF Exposure Safety Rules
* ARRL Asks FCC to Dismiss Petition Seeking Declaratory Ruling on
Encoded Message Rule
* A 600 W Broadband HF Amplifier Using Economically Priced LDMOS
Devices
* The Doctor Will See You Now!
* NOAA/NASA Panel Concurs that Solar Cycle 25 will Peak in July 2025
* The K7RA Solar Update
* Just Ahead in Radiosport
* Collegiate QSO Party 2018 and 2019 Plaque Recipients Announced
* Melissa Pore, KM4CZN, is 2020 Carole Perry Educator of the Year
Award Recipient
* In Brief...
* Upcoming ARRL Section, State, and Division Conventions
FCC Amending Amateur Radio RF Exposure Safety Rules
The FCC is amending its Part 97 Amateur Service rules relating to RF
exposure safety. In a lengthy document in ET Docket 19-226 released on
December 4 and addressing a broad range of RF safety issues, the FCC
said current amateur radio RF exposure safety limits will remain
unchanged, but that the amateur-specific exemption from having to
conduct an RF exposure evaluation will be replaced by the FCC's general
exemption criteria. Radio amateurs have always had to comply with RF
exposure limits, but certain stations have been exempt from having to
conduct evaluations based only upon power and frequency. The Commission
indicated that, by and large, if an RF source was "categorically
excluded" from routine evaluation under the old rules, it will most
likely still be exempt under the new rules, which are expected to take
effect in the next couple of months.
"For applicants and licensees in the Amateur Radio Service, we
substitute our general exemption criteria for the specific exemption
from routine evaluation based on power alone in Section 97.13(c)(1) and
specify the use of occupational/controlled limits for amateurs where
appropriate," the FCC said.
"The sky is not falling here," ARRL Lab Manager Ed Hare, W1RFI,
commented. "The major aspects of the rules will not impose major new
burdens on the Amateur Radio Service. As in all regulatory matters,
though, the devil may be in the details, so the ARRL technical staff,
legal staff, and the experts on the ARRL RF Safety Committee are
carefully evaluating this FCC document."
Under the revised Section 97.13(c)(1), "In lieu of evaluation with the
general population/uncontrolled exposure limits, amateur licensees may
evaluate their operation with respect to members of his or her
immediate household using the occupational/controlled exposure limits
in Section 1.1310, provided appropriate training and information has
been accessed by the amateur licensee and members of his/her
household," the amended rule says.
An FCC OET Bulletin 65 illustration
of how to determine exposure
distances.
"RF exposure of other nearby persons who are not members of the amateur
licensee's household must be evaluated with respect to the general
population/uncontrolled exposure limits. Appropriate methodologies and
guidance for evaluating Amateur Radio Service operation is described in
the Office of Engineering and Technology (OET) Bulletin 65, Supplement
B," the revised rule concludes.
The FCC said it was not persuaded by ARRL's argument in its comments
that the routine evaluation exemption for amateur radio stations
operating below a certain power threshold should be maintained.
"Amateur radio licensees operate a variety of installations of
different size, power, and frequency, which can be located in close
proximity to people, giving rise to various RF exposure concerns," the
FCC noted.
In a meeting with FCC OET Chief Julius Knapp and senior staff in early
November, ARRL asked the FCC to make available on the internet a
calculator to facilitate making the correct calculations the rules
require. ARRL said that would be preferable to unofficial third-party
calculators, the results from which might not be accorded the same
degree of deference in local disputes. Several software programs were
suggested as models.
The FCC did not single out amateur radio in drafting its latest RF
exposure rules. The rules affect multiple services, and exemptions for
many other services were also deleted as part of a broader policy
driven by a proliferation of RF devices, some resulting in situations
where gain antennas are sited much closer to people than was expected
in 1996 when the rules were last revised.
ARRL Asks FCC to Dismiss Petition Seeking Declaratory Ruling on Encoded
Message Rule
ARRL has asked the FCC to dismiss a Petition for Declaratory Ruling
filed by New York University (NYU), that in ARRL's view proposes a new
interpretation of the rule -- Section 97.113(a)(4) -- prohibiting
"messages encoded for the purpose of obscuring their meaning." In its
December 2 filing, ARRL said NYU's call to "clarify" the rule's meaning
to prohibit "effectively encrypted or encoded messages, including
messages that cannot be readily decoded over the air for true meaning,"
is not only vague but could weaken the prohibition against encryption.
ARRL pointed out that the FCC rule prohibiting "messages encoded for
the purpose of obscuring their meaning," is essentially the same as
what appears in the International Telecommunication Union (ITU) Radio
Regulations applying to all countries. ARRL made clear that it
continues to support rules prohibiting encrypted messages on the
amateur bands, even for limited emergency communication purposes, and
the ARRL Board reiterated that opposition last July.
In its comments, ARRL said that NYU's request that the FCC adopt its
suggested language would introduce ambiguity and confusion in the
application of a rule that's clearly understood to prohibit encrypted
messages. ARRL noted that Morse code is encoded and would fall within
the prohibition as proposed by NYU. "The very fact that messages sent
in CW are 'encoded' by any definition of the term starkly demonstrates
the problem with this proposal," ARRL said.
ARRL said that adding the word "effectively" would make the definition
even more vague by including all encoded messages plus an additional
set of undefined messages, the extent of which is unknown. Similarly,
ARRL maintained, it is "unclear and undetermined what the petitioner
may mean by 'effectively encrypted.'" Encryption is a binary
proposition, ARRL pointed out, and the meaning either is hidden from
all but the intended recipient(s) or it is not; a message cannot be
considered "encrypted" if the means to enable non-recipients to
understand the message are generally available.
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"The Commission has addressed amateur use of digital signals in
multiple proceedings [and] there has been no showing that the current
regulatory scheme is deficient in prohibiting encrypted messages," ARRL
concluded.
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"ding the modifier 'effectively' to 'encrypted' converts clear
meaning into vague uncertainty," ARRL asserted. FCC rules explicitly
authorize radio amateurs to use new digital techniques on the condition
that the techniques be described adequately and available publicly,
ARRL said, pointing to multiple filings in the FCC record from
individuals who have successfully used the public descriptions to
decode the digital techniques with which NYU has expressed concern.
NYU has not presented any information to demonstrate that the FCC's
current rule is not being complied with by digital innovators, ARRL
said, and adoption of NYU's petition would create more questions for
the FCC than it would be able to answer if called upon to apply the
petition's vague language in specific cases.
"We are unaware of any enforcement case in which the Commission is
experiencing difficulty in understanding and applying the prohibition
against encrypted messages," ARRL maintained.
What the petitioner regards as violations "augurs against its proposal
to interpret in some new fashion the international and domestic
prohibition," ARRL said. "For example," ARRL continued, "the petitioner
asserts, without any basis in fact, that dynamic compression techniques
effectively encrypt or encode communications." Such techniques are
widely recognized ways to increase the efficiency of digital
transmissions," ARRL noted that comments in the record clearly state
that signals using dynamic compression are being decoded by third-party
listeners.
"The Commission has addressed amateur use of digital signals in
multiple proceedings [and] there has been no showing that the current
regulatory scheme is deficient in prohibiting encrypted messages," ARRL
concluded. "To the contrary, adoption of the petitioner's proposals
would add confusion -- rather than clarity -- and diverge from the
international consensus on prohibiting encrypted messages while
fostering vibrant experimentation with digital techniques."
A 600 W Broadband HF Amplifier Using Economically Priced LDMOS Devices
Razvan Fatu, M0HZH/YO9IRF, has designed and built a 600 W broadband HF
amateur radio amplifier that uses a pair of low-cost MRF300 LDMOS
(laterally diffused metal-oxide semiconductor) MOSFET devices. LDMOS
devices are widely used in RF power amplifiers. Fatu's model A600, now
at version 1.2, was designed to demonstrate the capabilities of MRF300s
as linear broadband devices in the 2 - 50 MHz range.
"The announcement of the MRF300 and MRF101 transistors by NXP in 2018
has generated quite a spark of interest in the amateur radio community,
and as soon as I learned about them, I wanted to get some on my
workbench," Fatu said. He has entered his project in the NXP Homebrew
RF Design Challenge 2019.
"To achieve the target of 600 W output while also minimizing the level
of even-number harmonics, a push-pull configuration of two transistors
is used," he explains. "Luckily, the manufacturer made it easy to
design the PCB layout for such a thing by offering two versions -- the
MRF300AN and MRF300BN -- that have mirrored pinouts." The individual
transistors are specified at 330 W output and come in a TO-247 package,
with the source connected to the tab. The recommended supply range is
30 - 50 V dc. "By studying the specifications, it looks like with
correct broadband matching and some operational safety margin, we can
get close to 600 W output at a voltage of around 45 V across a
reasonably large bandwidth; the aim is to cover 1.8 to 54 MHz," Fatu
said. "Main challenges when designing this amplifier are related to
achieving good input and output matching over the entire frequency
range as well as maintaining high and flat gain. Good linearity and a
low level of harmonic products are mandatory. As the TO-247 is not a
package specifically designed for high-power RF, there are some
challenges with thermal design and PCB layout as well."
"This is a homebrew project, so the
test setup is pretty typical of a
hobbyist's test bench," Fatu said.
"Most of the equipment is not of
lab-grade precision, but still
accurate enough for amateur radio."
The circuit uses a 4:1 transformer at the input.
He used surface-mount devices wherever possible, to minimize stray
inductance, and designed the circuit board power traces to be thick
enough to support the high current. Traces also were sized for the
right trace impedance where possible, he explained. Fatu installed an
intermediary 3-millimeter-thick copper plate between the transistors
and the aluminum heatsink. He used a liquid metal product called
Galinstan which, he said, offers exceptional thermal and electrical
conductivity and doesn't require much pressure to achieve best
performance.
During testing, he found that the amplifier will put out about 580 W at
3.7 MHz and works most efficiently in the higher bands. "The highest
output power I've measured was 840 W in the 10-meter band, but the wave
was distorted and the harmonic levels were high," Fatu said.
He has posted a video in addition to an online article.
The Doctor Will See You Now!
"VHF/UHF Propagation" is the topic of the current (December 5) episode
of the ARRL The Doctor is In podcast. Listen...and learn!
Sponsored by DX Engineering, ARRL The Doctor is In is an informative
discussion of all things technical. Listen on your computer, tablet, or
smartphone -- whenever and wherever you like!
ARRL The Doctor is In features your host, QST Editor-in-Chief Steve
Ford, WB8IMY, and the Doctor himself, Joel Hallas, W1ZR, discussing a
broad range of technical topics.
Enjoy ARRL The Doctor is In on Apple iTunes, or by using your iPhone or
iPad podcast app (just search for ARRL The Doctor is In). You can also
listen online at Blubrry, or at Stitcher (free registration required,
or browse the site as a guest) and through the free Stitcher app for
iOS, Kindle, or Android devices. If you've never listened to a podcast
before, download our beginner's guide.
NOAA/NASA Panel Concurs that Solar Cycle 25 will Peak in July 2025
The NOAA/NASA-co-chaired international Solar Cycle Prediction Panel has
released its latest forecast for the coming Solar Cycle 25. The panel's
consensus calls for a peak in July 2025 (ñ8 months), with a smoothed
sunspot number of 115. The panel agreed that Cycle 25 will be of
average intensity and similar to Cycle 24. The panel additionally
concurred that the solar minimum between Cycles 24 and 25 will occur in
April 2020 (ñ6 months). If the solar minimum prediction is correct,
this would make Solar Cycle 24 the seventh longest on [IMG]record at
11.4 years. In its preliminary forecast released last April, the
scientists on the panel forecast that Solar Cycle 25 would likely be
weak, much like the current Cycle 24.
"Solar Cycle 25 may have a slow start, but is anticipated to peak with
solar maximum occurring between 2023 and 2026, and a sunspot range of
95 to 130. This is well below the average number of sunspots," the
panel said last spring, adding with "high confidence" that Cycle 25
"should break the trend of weakening solar activity seen over the past
four cycles." The panel said the expectation that Cycle 25 would be
comparable in size to Cycle 24 suggests that the steady decline in
solar cycle amplitude seen from Cycle 21 through Cycle 24 has ended and
that there is no indication of an approaching "Maunder-type" minimum.
Cycle 24 peaked in April 2014 with an average sunspot number of 82.
The Solar Cycle Prediction Panel forecasts the number of sunspots
expected for solar maximum, along with the timing of the peak and
minimum solar activity levels for the cycle. It is comprised of
scientists representing NOAA, NASA, the International Space Environment
Services, and other US and international scientists.
The K7RA Solar Update
Tad Cook, K7RA, Seattle, reports: Spaceweather.com says that Wednesday,
December 11, was the 28th consecutive day of no sunspots. To date in
2019, 77% of days had no sunspots. Compare this to the previous solar
minimum: In 2008, 73% of days were spotless, and in 2009, 71% of days
had no sunspots.
The average daily solar flux for the December 5 - 11 reporting week was
70.7, up marginally from the previous week's 70.2.
At the bottom of the solar cycle, hardly any geomagnetic activity
occurs, with average daily planetary A index at 3.7 and average middle
latitude A index at 1.9. This is very quiet and is favorable to
propagation on 160 meters.
As was the case in last week's bulletin, the predicted solar flux is 70
on each of the next 45 days -- until January 25.
The predicted planetary A index is 5, 8, and 8 on December 12 - 14; 5
on December 15 - 17; 12 on December 18; 10 on December 19 - 21; 5 on
December 22 - January 4; 8 on January 5; 5 on January 6 - 8; 8 on
January 9 - 10; 5 on January 11 - 13; 12 on January 14; 10 on January
15 - 17, and 5 on January 18 - 25.
Sunspot numbers for December 5 - 11 were 0, 0, 0, 0, 0, 0, and 0, with
a mean of 0. The 10.7-centimeter flux was 70.7, 70.3, 70.2, 71.6, 70.7,
70.6, and 70.7, with a mean of 70.7. Estimated planetary A indices were
3, 4, 2, 3, 4, 4, and 6, with a mean of 3.7. Middle latitude A index
was 1, 2, 1, 2, 2, 2, and 3, with a mean of 1.9.
A comprehensive K7RA Solar Update is posted Fridays on the ARRL
website. For more information concerning radio propagation, visit the
ARRL Technical Information Service, read "What the Numbers Mean...,"
and check out K9LA's Propagation Page.
A propagation bulletin archive is available. Monthly charts offer
propagation projections between the US and a dozen DX locations.
Share your reports and observations.
Just Ahead in Radiosport
* December 14 - 15 -- ARRL 10-Meter Contest (CW, phone)
* December 14 - 15 -- TRC Digi Contest (Digital)
* December 14 - 16 -- PODXS 070 Club Triple Play Low Band Sprint
(Digital)
* December 15 -- CQC Great Colorado Snowshoe Run (CW)
* December 16 -- Run for the Bacon QRP Contest (CW)
* December 18 -- NAQCC CW Sprint
See the ARRL Contest Calendar for more information. For in-depth
reporting on amateur radio contesting, subscribe to The ARRL Contest
Update via your ARRL member profile email preferences.
Collegiate QSO Party 2018 and 2019 Plaque Recipients Announced
The ARRL Collegiate Amateur Radio Initiative has announced plaque
winners from the 2018 and 2019 rounds of the Collegiate QSO Party. They
are:
K4FAU Florida Atlantic University Amateur Radio Club, 2018 First Place,
High Power; W0QQQ Amateur Radio Club at Kansas State University, 2018
Second Place, High Power; W0YQ University of Colorado Boulder Amateur
Radio Club, 2018 First Place, Low Power; W0EEE Missouri S&T Amateur
Radio Club, 2018 Second Place, Low Power; K1EEE, Michael R. Rancourt,
2018 First Place, Employee, High Power; W4ATL, Sherman Banks, 2018
First Place, Alumni, High Power; W2RS, Ray Soifer, 2018 First Place,
Alumni, Low Power; N8FM, Charles S. Romick, 2018 Second Place, Alumni,
Low Power; K4VBM, Robert G. Hensey, Jr., 2018 First Place, Individual,
Low Power; N1SOH, Ethan Handwerker, 2018 Second Place, Individual, Low
Power, and 2019 First Place, Individual (N1SOH, W1FM, ops).
W1RMC Middlebury College Amateur Radio Club, 2019 First Place, High
Power; W8LT Student Radio Club of The Ohio State University, 2019 First
Place, Low Power, and KN4WZX Augusta University Amateur Radio Club,
2019 Second Place, Low Power.
Thanks to organizers Andy Milluzzi, KK4LWR, and Tony Milluzzi, KD8RTT.
The plaques are sponsored by ARRL and the W1YSM Snyder Family
Collegiate Amateur Radio Endowment Fund, established in 2017. The
Collegiate QSO Party will return in September 2020.
Melissa Pore, KM4CZN, is 2020 Carole Perry Educator of the Year Award
Recipient
Melissa Pore, KM4CZN, of Vienna, Virginia, is the 2020 recipient of the
Carole Perry Educator of the Year Award, Orlando HamCation has
announced. The award, which recognizes outstanding contributions in
educating and advancing youth in amateur radio, was first awarded last
year to its namesake, Carole Perry, WB2MGP, in honor of her work
teaching students about ham radio. Pore is an Amateur Radio on the
International Space Station (ARISS) Education Committee member and an
ambassador for the ARISS program.
An educational professional for more than 20 years, Pore is on the
staff at Bishop Denis J. O'Connell High School in Arlington, Virginia,
the site of a November 2018 ARISS contact. In addition to teaching
engineering and computer science, she is involved in the school's
amateur radio and engineering clubs. While she was a teacher at St.
Thomas More Elementary School, Pore was associated with the STMSAT-1
project. The Earth-observation CubeSat, built entirely by students at
the school, was launched in 2015 but failed to transmit any images. It
was the first satellite constructed by elementary schoolers.
Pore was a cofacilitator of a workshop at the 2019 Space Port Area
Conference for Educators. Last year, she and her students presented
during Innovation Day at National Air and Space Museum's Steven F.
Udvar-Hazy Center. She is a member of AMSAT and the NASA Goddard
Amateur Radio Club. As an ambassador for the ARISS Education Team, her
talks and educational outreach have showcased ARISS and the STEM
activities of her students, several of whom are radio amateurs. She
assisted with the Dayton Hamvention 2019 ARISS booth and helped staff
the exhibit at the Space Explorers Education Conference last February
in Houston, where she's set to present a workshop in 2020.
At the 2019 Space Port Area Conference for Educators at Cape Kennedy,
Pore received a plaque from the ISS National Lab Space Station Explorer
Program citing her "service, commitment, and desire to push the
boundaries of STEM Education."
In Brief...
The theme for the 2020 Dayton Hamvention^(R) will be "Amateur Radio,
The Future." Hamvention General Chair Jack Gerbs, WB8SCT, invited
Hamvention attendees to celebrate amateur radio's past, present, and
future. "As amateur radio operators, we enjoy many modes of operating,"
Gerbs said. "We also enjoy challenges such as satellite communications,
moonbounce, meteor scatter, and more. What truly excites me about our
hobby is the diversity of these modes and the fact that, as we move to
the future, we still enjoy the technologies of the past." Gerbs noted
that Hamvention has long been a place to find vintage parts and gear
and to see the latest technology. "The theme acknowledges the role that
amateur radio has always played and will continue to play in future
communication developments," Hamvention said, acknowledging the
contributions of the many hams who actively work on new ideas,
equipment designs, and software to improve electronic communication.
Hamvention 2020 takes place May 15 - 17 at the Greene County
Fairgrounds and Expo Center in Xenia, Ohio.
Massachusetts has settled on a one-hand-on-the-wheel rule for mobiles.
The Bay State's two ARRL Section Managers report they have received
confirmation that the Commonwealth's distracted driving law does not
apply to two-way mobile radio operation. The new law "permits use of a
federally licensed two-way radio, provided that one hand remains on the
steering wheel at all times," except as provided in sections 8M, 12A,
and 13B of the law. -- Thanks to Western Massachusetts SM Ray Lajoie,
KB1LRL, and ARRL Eastern Massachusetts SM Tom Walsh, K1TW
The Boy Scouts say JOTA station participation was up in 2019. The
Scouts report that, although overall Jamboree On the Air (JOTA) 2019
participation was down slightly from 2018, "our calculations show that
each station averaged an additional 13 people in attendance over 2019.
This shows an aggregate increase of 24% attendance per station, even
with our reported stations being down from 266 in 2018 to 201 in 2019."
The Scouts reported that 13,783 individuals took part in JOTA 2019,
down from 14,708 in 2018.
A year-long special event will honor Beethoven. German special event
station DL250BTHVN will be active between December 16, 2019, and
December 17, 2020, to honor the 250th anniversary of the birth of famed
composer Ludwig van Beethoven. The Beethoven anniversary year will take
place under the auspices of Germany's Federal President Frank-Walter
Steinmeier. Beethoven was born in December 1770 in Bonn, Germany, and
lived there for the first 22 years of his life. The anniversary event
is aimed in part at highlighting Beethoven's extensive oeuvre as a
composer and to boost Bonn's reputation as a "Beethoven city." QSL via
direct or by the bureau.
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Upcoming ARRL Section, State, and Division Conventions
* December 13 - 14 -- West Central Florida Section Convention, Plant
City, Florida
* January 4 -- New York City-Long Island Section Convention,
Brookville, New York
* January 17 - 18 -- North Texas Section Convention, Forest Hill,
Texas
* January 19 - 25 -- Quartzfest, Quartzsite, Arizona
* January 24 - 26 -- Puerto Rico State Convention, Hatillo, Puerto
Rico
* January 25 -- ARRL Midwest Conference, Collinsville, Illinois
Find conventions and hamfests in your area.
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* Origin: Outpost BBS * Limestone, TN, USA (1:18/200)
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