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ZL3AI > APRDIG 23.05.04 12:18l 228 Lines 9796 Bytes #999 (0) @ WW
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: RE: Conversation with Kenwood at Dayton
From: "Ken Cechura" <kcechura@umr.edu>
Date: Sun, 16 May 2004 15:52:26 -0500
X-Message-Number: 14
I don't weigh in much with this stuff, but with new computers coming out
without USB ports, there's a few things we need to consider...
The "Ham hackers" are going to find a way to make it work. Add a PCI card,
add a PCMCIA card, whatever... USB cards aren't that expensive.
As time goes on, those laptops and computers with serial ports on them are
going to break, and the ones ON the market will end up dying and/or gettign
bought... It took me a while to find a laptop with a true serial port on
it, and, chances are, if I ever upgrade, the next one won't have that....
Thus requiring a USB to serial adaptor.
The newer people getting into the hobby generally AREN'T the hacker group.
I'm just looking at the collegiate crowd here in Rolla (look at the local
group... There's about half a dozen or so who will build their own stuff,
but the rest are appliance operators). Yes, there ARE some who want to
build their own, but there's a LOT of people here who either don't WANT to
roll their own, or just don't know HOW.
Yes, hams like cheap stuff....just put a "free" sign out at a hamfest, and
see what shows up. But they like new stuff, too... Look at the crowd that
new icom monster attracted last year with it's USB, ethernet, keyboard
ports... And all the pretty knobs and flashy lights.
If I COULD do a tracker with a USB interface, I might upgrade.
------------------------
New Icom radio: $11,000.
New Alpha amp: $6,500.
New all band motorized yagi and coax: $2,300.
New tower, rotor, and hardware: $2,000.
Going to a hamfest and seeing all those guys with dirty tee shirts and hard
hats with rubber duck antennas on the top pushing stolen shopping carts full
of junk from the free pile and realizing that's who you just laid out 20 big
to talk to: Priceless
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Subject: GlobalSecurity.org take on GPS vulnerability.
From: "Stephen H. Smith" <WA8LMF2@aol.com>
Date: Mon, 17 May 2004 16:29:15 -0700
X-Message-Number: 15
This web page has a lot of interesting stuff about the past, present and
future of GPS.
http://www.globalsecurity.org/space/systems/gps.htm
Toward the bottom of this page are some interesting takes on the
vulnerability of GPS:
"A peculiar but valid class of vulnerability is the degree of unrealistic
expectations that can be produced in enthusiastic but unwary GPS users."
Like the endless complaints about TIGER map road placement errors in Street
Atlas, Precision Mapping, findu, Mic-E rounded-off position resolution,
etc. ! ! !
"If there is inadequate integrity monitoring, the ready willingness to
accept a GPS-driven electronic display, for example, can magnify the
effectiveness of jamming on the user. Loss of GPS is a threat not only to
civil transportation users, but also to banking, communications, data
processing and internet enterprises that rely increasingly on the GPS
timing signal. "
Further down:
"The enemy can easily use off-the-shelf troposcatter hardware to jam GPS
operations. By shifting digital troposcatter systems like the U.S. AMTD4
down 8 percent in frequency to the GPS range, a user can produce 10 kW with
data rates up to 8.5 Mbps. A small 200-watt drum-sized package could be
assembled from modified ham gear at a cost of $3,000, will allow a large
distributed field deployment. "
1) Are we now going to get a 1.2GHz amplifier ban analogous to the
(totally ineffective) ban on 10-meter coverage in HF amps ? ? ?
2) You don't even need enemy action. I'm already seeing degraded
performance of inexpensive consumer-grade GPS devices near 1.9 GHz PCS
sites (that are practically everywhere now in urban areas) that overload
the amplified active GPS antennas .....
Stephen H. Smith wa8lmf (at) aol.com
Home Page: http://wa8lmf.com
Ham Radio/Mobile SSTV page: http://members.aol.com/wa8lmf/ham
APRS Stuff http://members.aol.com/wa8lmf/aprs
Personal APRS Webserver http://members.aol.com/wa8lmf/webserver
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[commercial content deleted]
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Subject: dumb question about TT3
From: Wes Johnston <wes@johnston.net>
Date: Sun, 16 May 2004 20:41:10 -0400
X-Message-Number: 17
Dumb question about tiny trak 3... when it is NOT using 'power switch'
mode, is the power switch on all the time? I'm thinking of making it
assert +5v to the pin on a tripmate or digitraveler and would like them to
stay on all the time when it is in mode 1, and cycle power between
transmissions when in mode 2. Or should I just set mode1's power switch to
some time greater than the actual TX interval?
What has just occurred to me is that GPS units like the tripmate and
digitraveler can have power on them all the time and by asserting DTR or RX
pins the GPS will power up and down on it's own... no relay needed.
Wes
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Subject: Re: GlobalSecurity.org take on GPS vulnerability.
From: Gerry Creager N5JXS <gerry.creager@tamu.edu>
Date: Sun, 16 May 2004 19:46:23 -0500
X-Message-Number: 18
OK. I've some opinions, and they might not be popular. If you don't
appreciate them, I'm sorry.
Stephen H. Smith wrote:
>This web page has a lot of interesting stuff about the past, present and
>future of GPS.
> http://www.globalsecurity.org/space/systems/gps.htm
When John Pike's commentary started losing credibility via the American
Federation of Scientists, a group that arguably never really let science
get in the way of their opinions, he founded GlobalSecurity.org. The
media, apparently seeking a source for soundbites peripherally related
to security on a global scale, have identified Pike as a "source" and
taken his word with little question.
Of the fellows identified, only Vick and Wood have not suffered either
through the political layoff syndrome, or extended tenure with AFS.
OK. I'm effectively done.
>Toward the bottom of this page are some interesting takes on the
>vulnerability of GPS:
>
>"Apeculiar but valid class of vulnerability is the degree of
>unrealistic expectations that can be produced in enthusiastic but unwary
>GPS users."
>
>Like the endless complaints about TIGER map road placement errors in
>Street Atlas, Precision Mapping, findu, Mic-E rounded-off position
>resolution, etc. ! ! !
Very much. And it's been explained here. Let's also talk about Garmin's
EPE "calculations" and how they can mislead.
>"If there is inadequate integrity monitoring, the ready willingness to
>accept a GPS-driven electronic display, for example, can magnify the
>effectiveness of jamming on the user. Loss of GPS is a threat not only
>to civil transportation users, but also to banking, communications, data
>processing and internet enterprises that rely increasingly on the GPS
>timing signal. "
Few will monitor the Receiver Autonomous Integrity Monitor indicator, if
your receiver has it available. Most do not. RAIM was originally
instituted in the Motorola OnCore and subsequent receivers because they
wanted to make those prime for use in aviation GPS installations; The
FAA's TSO-C129 required RAIM for integrity monitoring for GPS receivers
used under instrument conditions and instrument approach.
>Further down:
>
>"The enemy can easily use off-the-shelf troposcatter hardware to jam
>GPS operations. By shifting digital troposcatter systems like the U.S.
>AMTD4 down 8 percent in frequency to the GPS range, a user can produce
>10 kW with data rates up to 8.5 Mbps. A small 200-watt drum-sized
>package could be assembled from modified ham gear at a cost of $3,000,
>will allow a large distributed field deployment. "
Actually, a Russian entrepreneur started the craze with a pink noise
generator operating at less than a watt, over the range of the L1
spectrum. Subsequent pink noise jammers in the L2 range, and covering
both simultaneously, have appeared. Use of tropo scatter is consistent
with techniques various military organizations have implemented for
denial of service attacks "over the horizon" so that their source will
not readily be identifiable for counter force. And, it doesn't take 10
kw, although having that much power makes it easier.
>1) Are we now going to get a 1.2GHz amplifier ban analogous to the
>(totally ineffective) ban on 10-meter coverage in HF amps ? ? ?
>
>2) You don't even need enemy action. I'm already seeing degraded
>performance of inexpensive consumer-grade GPS devices near 1.9 GHz PCS
>sites (that are practically everywhere now in urban areas) that overload
>the amplified active GPS antennas .....
What you're seeing is GlobalSecurity, AKA Pike Consulting, seeking to
get their name on the news again, and scare some congress-critter. They
won't come anywhere near members of the research and professional
arenas, nor ask knowledgable technical experts in the federal service or
DoD about this, but they'll make some supportable statements (one should
always look at RAIM if available; that only makes sense), but not give
the reporter, or the public, the whole story.
Gerry N5JXS
--
Gerry Creager -- gerry.creager@tamu.edu
Network Engineering -- AATLT, Texas A&M University
Cell: 979.229.5301 Office: 979.458.4020 FAX: 979.847.8578
Page: 979.228.0173
Office: 903A Eller Bldg, TAMU, College Station, TX 77843
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