RF CURRENT
Welcome to RF Current, a weekly electronic newsletter focusing
on Broadcast technical and F.C.C. related issues. This newsletter
is part of The RF Page @
www.transmitter.com, a web site devoted to TV Broadcast RF
engineering. For more information see the What
is... guide to the R.F. Page site.
This page contains stories from RF Current issues published in October 1997. Links referenced in the articles were current when published but by this time may have changed. If you find a bad link, try connecting to the home page of the publication or company and look for an archive of past articles. If you find a changed link, I'd appreciate it if you'd let me know by dropping me a note indicating the new location at dlung@transmitter.com.
October 27 - Issue 92 Final
Edition
- SATELLITE - Innovative Solution For INTELSAT 605
Anomaly (Oct. 23)
- In the September
15th RF Current we reported on a telemetry anomaly
with INTELSAT 605. In a Press
Release issued today, INTELSAT announced it had come
up with a way to obtain the spacecraft orbital attitude
information it couldn't get from the telemetry. Steve
Stott, INTELSAT Director of Satellite Engineering Support
and Processes, said "INTELSAT has devised a series
of ground-based software monitoring promgrams which can
determine the attitude of the spacecraft by measuring the
RF signal strength. INTELSAT is presently using this
methodology, and this technique will provide the required
information with accuracy levels that result in no impact
on services carried on the spacecraft.
See the Press
Release for more information on this interesting
technique.
- SCIENCE - Spectacular Photos from Hubble Space
Telescope Show Colliding Galaxies (Oct. 21)
- NASA reported its Hubble Space Telescope "has
uncovered over 1,000 bright, young star clusters bursting
to life in a brief, intense, brilliant 'fireworks show'
at the heart of a pair of colliding galaxies." Dr.
Francois Schweizer, Carnegie Institution, said
"These spectacular images are helping use understand
how globular star clusters formed from giant hydrogen
clouds in space."
More details on this discovery are available in the NASA
Press Release. The Space Telescope Science Institute Hubble
Reveals Stellar Fireworks Accompanying Galaxy Collisions
page has links to related images.
- FCC Permits Biomedical Telemetry on TV Channels
(Oct.21)
- Yesterday the FCC released its Report
and Order on ET Docket 95-177 Amendment of Part 15
of the Commission's Rules to Permit Operation of
Biomedical Telemetry Devices on VHF TV channels 7-13 and
on UHF TV channels 14-46. These devices may be used
"solely on the premises of health care
facilities" but not in mobile vehicles, even if they
are associated with a health care facility. The new rules
state "The field strength of the fundamental
emissions shall not exceed 200 mV/m, as measured at a
distance of 3 meters using a quasi-peak detector."
Biomedical devices operating on TV channels must be at
least 10.3 km outside the Grade B contour for VHF
stations, 5.5 km outside a UHF TV station's Grade B
contour, at least 5.1 km outside the Grade A contour of a
VHF low power TV or TV translator station and at least
3.1 km outside the Grade B contour of a UHF LPTV or TV
translator station. Plus, "Whatever distance is
necessary to protect other authorized users within these
bands."
Reading between the lines, it appears the FCC decided to
keep these operations within channels included in both
"core spectrum" DTV channel plans. Also, UHF
LPTV and translator stations received little protection
from interference through the space rules. The FCC rules
clearly state, however, that these biomedical telemetry
devices must not cause harmful interfererence to
broadcast TV stations, LPTV and translator stations (Part
74 Subpart G) and low power auxiliary (wireless
microphones and similar uses under Part 74 Subpart H).
More information is available on the FCC OET Docket ET
95-177 page, which includes links to all relevant FCC
documents available on the 'net. Also see articles in the
December 1995 and March 1996 RF Current.
- OTHER Items of Interest
-
October 20 - Issue 91 Final
Edition
- FCC Sets Rules for Radio Astronomy Coordination Zone
in Puerto Rico (Oct. 17)
- On October 15 the FCC released its Report
and Order in ET Docket 96-2 regarding Amendment of
the Commission's Rules to Establish a Radio Astronomy
Coordination Zone in Puerto Rico. The new rules require
most operators of transmitters to notify the Arecibo
Observatory at least 45 days prior to commencing
operations of a new transmitter. The rules vary slightly
depending on the service. STA (Special Temporary
Authorization) applicants will need to provide technical
information to the Observatory at the same time they file
the STA request with the Commission. Amateur radio
operations are mostly excluded from the Coordination
Zone, but the FCC encourages informal coordination for
new amateur beacon and repeater stations within 10 miles
of the Observatory.
Transmitters above 15 GHz. are excluded, as are
"mobile stations in the land mobile raido services,
temporary base or temporary fixed stations (other than
shor-term broadcast auxiliary operations), the Civil Air
Patrol, new amateur stations (other than amateur beacon
and repeater stations within 10 miles of the
Observatory), mobile earth terminals licensed under Part
25, or stations aboard ships or aircraft."
The FCC did not grant the Observatory the right to insist
on a blank check for interference avoidance. The Report
and Order states "To the extent that the Commission
determines that reasonable efforts have been made by the
applicant to protect the Observatory from interference,
there will be no further obligation for the applicant to
modify its proposed operations or to upgrade the
Observatory's facilities. Consequently, if under those
circumstances the Observatory believes that the
applicant's proposed operations must be modified or its
own facilities upgraded to protect the Observatory from
interference, the Observatory will be required to pay for
any such modification or upgrade."
Broadcasters requesting new permanent installations in
Puerto Rico or modifications to existing authorizations
in Puerto Rico involving changes in frequency, power,
antenna height, directivity or location have to notify
the Interference Office at Arecibo Observatory, in
writing or electronically, of the technical parameters of
the proposal. The FCC will allow Arecibo a period of 20
days for comments or objections to the proposed
operation. Similar rules apply to many TV auxiliary
operations within a 4 mile radius of the Observatory.
More information is available in the Report
and Order.
- FCC Posts Erratum for FCC 97-303 on RF Exposure
Guidelines (Oct. 16)
- Today the FCC posted on the its web site an ERRATUM to
FCC 97-303, the Second Memorandym Opinion and Order in ET
Docket 93-62 on Guidelines for Evaluating the
Environmental Effects of Radiofrequency Radiation. Refer
to the ERRATUM for the text of the change. The correction
applies to Section 1.1307(b)(4) of the final rules and
affects the transition provisions of the rule. The
engineering data did not change.
- SCIENCE Weizmann Institute Finds Evidence of
Radio-Like Mechanism in the Brain (Oct. 14)
- Scientists at the Weizmann Institute of Science in
Rehovot, Israel, have found evidence the brain uses a
mechanism "remarkably similar to that of an FM
radio" when interpreting sensory input. In the
study, researcher Dr. Ehud Ahissar and his colleagues
show that "neural signals generated by touch
modulate the oscillation frequency" of certain cells
in the cortical areas of the brain. The timing of
incoming signals is compared with the regular and
persistent oscillations of the cortex cells.
More information is available in a Press
Release from the Weizmann Institute of Science.
- OTHER Items of Interest
-
October 13 - Issue 90 Final
Edition
- FCC Proposes Allowing Two-way Transmission by MDS and
ITFS Licenses (Oct. 10)
- Friday the FCC said it had issued a Notice of Proposed
Rule Making (NPRM) "seeking comment on proposed
amendments to Parts 21 and 74 of its rules to enable
Multipoint Distribution Service (MDS) and Instructional
Television Fixed Service (ITFS) licensees to engage in
fixed two way transmissions." The NPRM proposes to
allow MDS and ITFS licenses to "utilize all or part
of a 6 MHz. channel for return path transmissions from
subscriber premises, to cellularize their transmission
systems to take advantage of spectrally efficient
frequency reuse techniques, and to emply configurations
involving bandwidths either larger or smaller than 6
MHz., all while providing incumbent MDS and ITFS
licensees interference protection equivalent to what they
currently receive."
Other changes proposed include amending the definition of
a "response station" and proposing response
station hubs, which would service as collection points
for upstream signals from response stations. More
information on proposed changes to this and other
technical rules is available in the News
Report (NRMM7014). The NPRM is now available as an
Adobe Acrobat file - fcc97360.pdf
or a WordPerfect file -
fcc97360.wp..
- FCC Adopts NPRM on New Public Safety Band on Upper TV
channels (Oct. 9)
- In a News
Release (NRWL7043), the FCC's Wireless
Telecommunications Bureau today announced it was issuing
a Notice of Proposed Rule Making (NPRM) on its plans to
allocate 24 MHz. of spectrum between TV channels 60 and
69 for Public Safety use. The NPRM seeks comments on
service rules for the spectrum, including rules to
"advance the goals of developing interoperability
and efficient public safety networks, and to enable
public safety agencies to develop the advanced
capabilities, such as data and video communications, that
will allow them to fulfill their missions more
effectively."
The FCC also proposed technical requirements to protect
incumbent analog broadcast licensees and planned digital
television operations from interference during the DTV
transition period.
Full text of the NPRM had not released on the FCC web
when this was written. It will be added to this story
when it becomes available. Check back later in the week.
- FCC Adopts Policies and Rules for Little LEO Sat
Services (Oct. 9)
- In a News
Release (NRIN7034) issued today the FCC said it had
adopted a Report and Order setting rules and policies for
low earth orbiting, non-geostationary mobile satellite
systems commonly called "Little LEO" satellite
systems. These systems operate below 1 GHz. and provide
various two way data services.
The "Little LEO" systems share spectrum
currently assigned to the Department of the Air Force and
NOAA. The FCC was able to create a spectrum sharing plan
that allows allow second processing round applicants to
be licensed, avoid the need for auctions. The FCC news
release said "The newly licensed systems will
increase competition in the Little LEO service markts,
which will likely result in lower prices and increased
service options for customers."
The full text of the Report and Order is now available in
file ASCII text file fcc97370.txt.
- DIGITAL - WaveTop VBI Decoder Included in Windows 98
(Oct. 8)
- Microsoft Corporation and WavePhore Inc. today announced
an agreement to include the WaveTopTM vertical
blanking interval (VBI) software and service in the
Microsoft® Windows® 98 operating system. WavePhore uses
the PBS National Datacast system to reach more than 99
percent of the TV households in the U.S. WaveTop joins
the
animated Barney dolls, another Microsoft effort,
using the PBS network's VBI.
WavePhore has lined up several content providers for the
new service, including CBS Sportsline, PBS ONLINE,
Quote.com, The Weather Channel, N2K's Music Boulevard,
BarnesandNoble.com, NECX, People, TIME, Entertainment
Weekly, Money, FORTUNE and Sport Illustrated for Kids.
While this announcement focused on the WaveTop product,
it appears stations could take advantage of the
capability built into Windows 98 to add their own web
based content on their signals. The maximum data rate for
VBI signals is equivalent to ISDN. WaveTop, however, will
not have full use of the PBS VBI, due to other data
included in the PBS National Datacast system.
For more information check the web sites for WavePhore, WaveTop and NewsCast. More
details are available in the Microsoft
Press Release.
- INDUSTRY - Kline Iron & Steel Sells Third of the
Company to OmniAmerica Wireless (Oct. 8)
- Jerry Kline, chairman and CEO of Kline Iron and Steel,
a name known to most broadcasters for their tall tower
experience and construction of such landmarks as the
Sutro Tower in San Francisco announced today he was
selling one third of the company to OmniAmerica Wireless,
L.P. OmniAmerica Wireless, based in West Palm Beach
Florida, was recently formed by Carl E. Hirsch and
Anthony S. Ocepek in conjunction with Hicks, Muse, Tate
& Furst, Inc., a Dallas investment firm, to
"construct, aquire and manage broadcast and
telecommunications towers."
The deal is expected to close this month. It includes
Kline Towers, Kline Structural and Kline Coatings. Mr.
Kline will retain controlling interest in the company.
The announcement said the company will continue to
"employ some 300 associates at both its Columbia and
West Columbia facilities:"
Jerry Kline said "This partnership will open new
doors to incredible opportunities for Kline and our
employees, and is key to the success of our long-range
strategic plan for growth." Mr. Hirsch said
"The alliance with Kline fits neatly with
OmniAmerica's strategy to create a vertically-integrated
company that not only designs, fabricates and erects
towers, but also owns two which lease tenant space to
broadcasters and telecommunications companys." He
observed that "Outstanding opportunities exist in
what is currently a fragmented industry with very few
qualified players."
It remains to be seen what the impact of the sale of one
third of Kline to OmniAmerica Wireless will be on other
Kline customers.
- TV - Zenith Earns Emmy Award for Pioneering TV Remote
Control (Oct. 8)
- Most people take the remote control for granted. However,
like so many technologies that are now commonplace, the
TV remote control had an awkward beginning. TV remote
controls began as wired devices, attempted to transition
to wirelesss using visible light (which didn't work), had
success with ultrasonic audio tones and finally evolved
to the advanced infrared transmitters we use today.
Last night the National Academy of Television Arts and
Sciences recognized Zenith Electronics Corporation's role
in inventing the first TV remote control forty years ago
by presenting the company with an Emmy Award for
"Pioneering Development of Wireless Remote Controls
for Consumer Television."
A copy of the Press
Release announcing this award references an
interesting Fact
Sheet on "Four Decades of Channel Surfing:
History of the TV Remote Control." It presents an
interesting view of remote control development by
describing the work of Zenith engineers on the project.
Interesting reading!
- HEALTH - SFSU Study Links Mouse Position to Muscle
Tension (Oct. 7)
- If you use a computer today, you probably use a mouse. A
San Francisco State University found that people who use
a mouse ":suffer more than twice as much muscle
tension in their arms, necks and shoulders as those who
don't use a mouse..." How can you avoid this? One
suggestion is to switch to a centrally located trackball
or trackpad pointer instead of a mouse. Another
suggestion is to place the mouse where you don't have to
extend your arm as much to use it and take quick
"microbreaks" every minute during computer use.
More details are available in the SFSU
Press Release.
- OTHER Items of Interest
-
October 6 - Issue 89 Final
Edition
- DTV - KOMO Seattle Files for Digital Television
Station (Oct. 2)
- The October
2nd FCC Public Notice of Broadcast Applications Accepted
For Filing included an application from Fisher
Broadcasting for a new digital television station KOMO-DT
on channel 38 in Seattle, Washington. The application
requested an average ERP of 810 kW using a Dielectric
TFU-32DSC antenna. The antenna location at 157 Galer
Street is the same as that currently used by the NTSC
KOMO on channel 4. The center of radiation for the DTV
antenna will be 24 meters below the NTSC antenna's center
of radiation, according to the FCC filing.
- TV - FCC Releases NPRM on Video Blocking Technology
(Oct. 1)
- Today the FCC posted its Notice of Proposed Rulemaking
(NPRM) in the Matter of Technical Requirements to Enable
Blocking of Video Programming based on Program Ratings.
It is available in plain
text, Adobe
Acrobat and WordPerfect
file formats. The September
29th RF Current had a summary of this NPRM.
The FCC requested comment on whether date/time/channel
blocking should be required as well as the proposed line
21 based blocking technology. The Commission also sought
comment on "whether ratings are likely to be
distributed via a means other than line 21." The
NPRM said the FCC tentatively concluded that while the
system should be user friendly, it should be secure
enough that children cannot easily override it. Refer to
the NPRM for more detailed information.
- TV - CEMA Announces V-Chip Engineering Standards Now
Available (Oct. 1)
- The Consumer Electronics Manufacturers Association (CEMA)
issued a Press
Release today applauding Vice President Gore's
endorsement of the proposed TV ratings proposal submitted
by the NAB, MPAA and others.
CEMA also said that "On September 23, during an R4.3
engineering meeting in Phoenix of broadcasters, TV set
manufacturers and programmers, industry engineers
approved two V-chip technical proposals." Standard
EIA-744 describes a new extended data packet transmitted
in the vertical blanking interval (VBI). A
"Recommended Practices for the Content Advisory XDS
Packet" stated that channel blocking should include
muting program audio, render video blank or
"otherwise indecipherable" and elimate
captions. The practices also set the default state of the
TV set to a not block the signal until the ratings packet
is received. To avoid confusion, the TV set should
display a message on screen to "indicate to the
viewer that content advisory blocking occurred."
Although this data was sent to the FCC on September 24th,
it did not arrive in time to be incorporated into the
latest Notice of Proposed Rulemaking on the V-chip. (See
article above.)
- DTV - ATSC Conducts First Digital HDTV Broadcasts In
Australia (Oct. 1)
- The Advanced Television Systems Committee (ATSC)
continued its world tour promoting the U.S. ATSC standard
as an international model for HDTV, multiple SDTV and
data delivery services. After demonstrating the ATSC HDTV
standard in China (see the September 1 RF Current for
details), on October 1st the ATSC conducted what is
claimed were the first digital HDTV broadcasts in the
southern hemisphere. The transmission originated from the
TCN Channel 9 tower in Willoughby and was received at the
Observatory Hotel in Sydney, Australia. The Federation of
Australian Commercial Television Stations (FACTS) helped
organized the demonstrations, laboratory tests and field
tests.
Several member ATSC member organizations supported the
tests. The trransmitter was provided by Harris
Corporation. Mitsubishi Electronics American provided the
video decoding equipment. CBS, Snell & Wilcox, Sony,
Dolby Laboratories and Zenith also provided equipment
and/or technical support.
More information is available in the ATSC
Press Release and the Zenith
Electronics Press Release.
- OTHER Items of Interest
-
Other Issues Available:
1998
1997
1995 and 1996
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Last modified October 20, 1997 by Doug Lung dlung@transmitter.com
Copyright © 1997 H. Douglas Lung