[FedCom] 173.500 NJ
ecps92 at earthlink.net
ecps92 at earthlink.net
Wed May 26 07:58:46 EDT 2010
Its NOT Lo/Jack as they are on 173.0750 and the subject line and OP asked about 173.5000
If you can obtain the NAC it will help. I have seen this freq used by both FBI and CBP in the NorthEast.
Try and see if you also hear 166.2000 as that would be the Rptr,if used by CBP
Bill
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-----Original Message-----
From: "bernies at netaxs.com" <bernies at netaxs.com>
Date: Tue, 25 May 2010 21:00:44
To: Discussion of Federal Government Communications<fedcom at mailman.qth.net>
Subject: Re: [FedCom] 173.500 NJ
Quoting radioscan at aol.com:
> Anyone have any idea of who is using 173.500 in New Jersey. No
> clear comms to help identify.
You may be hearing LoJack telemetry on 173.075
This excellent web page on the interesting history of this commercial
allocation in the Federal band has downloadable audio samples of
LoJack signals, so you can determine if that's what you're hearing.
-ed
http://www.freqofnature.com/index.php?m=Common&p=LoJack
Description Frequency Tone
Stolen Vehicle Recovery System (SVRS) 173.0750 CSQ
FCC §90.20(e)(6)
(6) The frequency 173.075 MHz is available for stolen vehicle recovery
systems on a shared basis with the Federal Government. Stolen vehicle
recovery systems are limited to recovering stolen vehicles and are not
authorized for general purpose vehicle tracking or monitoring. Mobile
transmitters operating on this frequency are limited to 2.5 watts
power output and base transmitters are limited to 300 watts ERP. F1D
and F2D emissions may be used within a maximum authorized 20 kHz
bandwidth. Transmissions from mobiles shall be limited to 200
milliseconds every 10 seconds, except that when a vehicle is being
tracked actively transmissions may be 200 milliseconds every second.
Alternatively, transmissions from mobiles shall be limited to 1800
milliseconds every 300 seconds with a maximum of six such messages in
any 30 minute period. Transmissions from base stations shall be
limited to a total time of one second every minute. Applications for
base stations operating on this frequency shall require coordination
with the Federal Government. Applicants shall perform an analysis for
each base station located within 169 km (105 miles) of a TV Channel 7
transmitter of potential interference to TV Channel 7 viewers. Such
stations will be authorized if the applicant has limited the
interference contour to fewer than 100 residences or if the applicant:
(i) Shows that the proposed site is the only suitable location;
(ii) Develops a plan to control any interference caused to TV
reception from the operations; and
(iii) Agrees to make such adjustments in the TV receivers affected as
may be necessary to eliminate interference caused by its operations.
The licensee must eliminate any interference caused by its operation
to TV channel 7 reception within 30 days of the time it is notified in
writing by the Commission. If this interference is not removed within
the 30-day period, operation of the base station must be discontinued.
The licensee is expected to help resolve all complaints of interference.
How LoJack Works
by Harry Marnell
http://www.snowcrest.net/marnells/
The LoJack stolen vehicle recovery system, "SVRS" has two options -
the traditional stolen vehicle tracker, and a new "Early Warning
Detector," which detects and signals either external movement of a
car, or its' being hot-wired. The EWD signal goes to LoJack, and they
attempt to notify the vehicle owner that it's possibly being stolen.
This option is apparently popular with trucking companies and other
fleet operators.
As of 2002, the 2.5 watt mobiles are allowed to transmit a digital
signal for up to 200 ms (1/5 of a second) every 10 seconds - all the
time, it appears. Once they've been reported stolen and are being
"actively tracked," they can transmit a 200ms signal for the police
once every second. Optionally, they can now add a 1800 ms uplink cycle
when activated - (either "early warning" or reported stolen). They can
transmit the 1800ms (1.8 seconds) signal every 5 minutes, with a
maximum of six such messages in any 30-minute period. This 1800ms
signal is long enough to ID the unit and to let the base know that it
has, in fact, received the instruction to transmit its "I'm stolen"
signal to police units. Previously, once a vehicle was reported
stolen, all the LoJack base stations would transmit a 300-watt "turn
yourself on" signal every 15 minutes for the first two hours, and then
once an hour for 30 days, or until the vehicle was recovered,
whichever occurred first. The 1800ms cycle for the mobiles lets the
base stations know "I heard you, I'm turned on, you can shut up now."
Apparently they want to reduce the base stations' transmissions as
much a possible, to avoid interference with adjacent TV Channel 7.
The LoJack Story: Government Frequencies
by Goldberg, Godles, Wiener & Wright
http://www.goldberg.com
The LoJack Corporation of Massachusetts ("LoJack") needed a frequency,
a standard 25 KHz channel, for its newly-developed stolen vehicle
recovery system. The LoJack System consists of a radio
transmitter-receiver unit that is hidden in motor vehicles; a tracking
device mounted in police vehicles; and a computerized network of radio
transmitters by which the law enforcement agencies signal the LoJack
Unit to begin transmitting when a LoJack Unit-equipped vehicle is
reported stolen. Upon receiving this signal, the unit begins
transmitting its unique reply code, and police vehicles with
direction-finding receivers within range of the transmitting LoJack
Unit are able to track and locate the stolen vehicle.
There were a number of practical and technical constraints on LoJack
as to where in the radio spectrum it could find a usable frequency for
its system. Given the fact that the basic function is radio-location
in heavily built-up urban areas, LoJack could not use a frequency too
high in the spectrum because of multipath problems. Also, because
LoJack relies on transmissions over a wide area from a low power
device small enough to be hidden on a vehicle, the ideal frequency
again would have to be fairly low in the radio spectrum -- certainly
under 1000 MHz. The final constraint dictating the lower ranges of the
spectrum was, as a consumer item, the cost of producing the LoJack
unit must be low.
After a, not surprisingly, unsuccessful search for a non-government
frequency below 500 MHz, LoJack approached the Federal Bureau of
Investigation for assistance in finding a frequency. The FBI staff
conducted an informal survey of the federal government's frequencies,
and recommended frequency 173.075 MHz as the best choice for LoJack,
largely because that frequency borders TV Channel 7 (174 to 180 MHz),
which makes traditional federal government land mobile radio uses
difficult to accommodate without the danger of interference to Channel
7. As a result, this frequency was not heavily used by the federal
government.
In 1984, LoJack and the Massachusetts state police began to use
173.075 MHz to demonstrate the LoJack System. Formal approval was
necessary from the federal Interdepartment Radio Advisory Committee
(IRAC), administered by the National Telecommunications and
Information Administration (NTIA), under the Department of Commerce,
which controls all federal government frequencies.
After about a year of technical tests, LoJack had established the
efficacy of the system and wanted to see if there was a consumer
market for the technology. At this point, the federal government
people did not want to be responsible for a market test and suggested
that a market test be administered by the FCC. Therefore, on October
18, 1985, LoJack and the Massachusetts state police filed joint
applications for an experimental authorization, to include a market
test. LoJack's application covered the transmissions from and the
marketing of the in-car mobile LoJack units, and the state's
application covered the base station transmitters. Anticipating
possible broadcaster opposition because of the proximity of the
frequency to Channel 7, included with the initial application was an
extensive engineering test report showing that there was no
significant risk of interference to Channel 7.
Since a government frequency was involved, the FCC's Office of
Engineering and Technology ("OET") forwarded the experimental
application to NTIA for its approval. In a February 21, 1986 letter,
NTIA "agreed in principle" with the proposed use. The NTIA letter went
on to suggest that the Commission explore accommodating permanent use
on a nongovernmental frequency. Because the OET staff did not want to
authorize another market test on delegated authority, the applications
had to go to the full Commission. On March 12, 1986, the Commission
approved the grant.
Three days after the Public Notice of the grant, the Channel 7
licensee in Boston, WNEV-TV, petitioned for reconsideration of the
Commission's order, claiming potential adverse impact from the LoJack
System's operation. The Association of Maximum Service Telecasters
(AMST), a trade association of TV broadcasters, also petitioned for
reconsideration, submitting its own engineering report to support the
claim of potential interference. After further pleadings, including
late comments by the National Association of Broadcasters (NAB) and
various other broadcasters supporting reconsideration, the Commission
denied the petitions in October 1986.
Although LoJack had its market test, the test bed was not entirely a
bed of roses. The FCC and NTIA are understandably wary of market
tests. They expose a new technology or service application to the
public without many of the consumer and regulatory safeguards that
would apply in regular operation. The government wants to be sure that
the public will not be "stuck" with bad products and services and will
not bear the risk if the FCC withdraws or does not renew the
authorization. Therefore, LoJack had an obligation to give stringent
notices, warnings, and caveats to its customers regarding the risks
involved in buying the LoJack product. This obviously was a barrier to
sales and, therefore, skewed the market test results, and LoJack, to
overcome customer resistance, offered a money-back guaranty to all its
customers, if the FCC were to withdraw the authorization. LoJack
donated the base stations and tracking units to the Massachusetts
police, in order to overcome their own resistance to buying products
that were subject to such risks.
Another disadvantage to the market test resulted from the government's
concern that, once the technology was in the marketplace, the horse
was out of the barn and the government's hands would be effectively
tied if it decided to pull LoJack back from the public. As a result,
although LoJack requested market test authority for a larger area than
Massachusetts, the authority that was granted was strictly confined to
Massachusetts.
While the FCC mitigated the worst effects of the geographical
limitation by granting many special temporary authorizations (STA) to
demonstrate the LoJack system for short periods of time outside of
Massachusetts, there was a great reluctance to extend the market test
outside of Massachusetts. This situation eventually led to LoJack's
filing its petition for rulemaking to go operational by obtaining a
regular assignment of 173.075 MHz.
Thus, on March 31, 1988, LoJack petitioned the FCC for a notice of
proposed rulemaking (NPRM) to allocate frequency 173.075 MHz
permanently for stolen vehicle recovery system use across the country,
with state and local law enforcement agencies to be the licensees,
along with continued use by the federal government. Given both the
technical success and consumer acceptance of LoJack, numerous public
safety officials from Massachusetts and other states wrote to support
the petition. However, in May 1988, the FBI advised that it would not
support a permanent authorization of use of 173.075 MHz. Only two
broadcaster groups opposed the petition, basically restating the
possible Channel 7 interference argument.
The FCC again referred the Petition to NTIA and NTIA in turn consulted
IRAC. Despite the FBI's opposition, NTIA advised the FCC that it
supported the sharing of 173.075 MHz with state and local law
enforcement agencies for purposes of stolen vehicle recovery systems.
The FCC issued a proposal for rulemaking on December 12, 1988, and
adopted the proposed rules at the end of September 1989 -- five years
after the first technical tests were started in Massachusetts.
Special thanks to Harry Marnell http://www.snowcrest.net/marnells/ for
contributing information
Copyright © 2008 Freq Of Nature http://www.freqofnature.com
comments at freqofnature.com
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