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	<title>The Treehouse Blog &#187; balleman</title>
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	<link>http://brady.thtech.net</link>
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		<title>Upgrade Fedora 15 to Fedora 16</title>
		<link>http://brady.thtech.net/2011/12/29/upgrade-fedora-15-to-fedora-16/</link>
		<comments>http://brady.thtech.net/2011/12/29/upgrade-fedora-15-to-fedora-16/#comments</comments>
		<pubDate>Fri, 30 Dec 2011 01:29:44 +0000</pubDate>
		<dc:creator>balleman</dc:creator>
				<category><![CDATA[Linux]]></category>

		<guid isPermaLink="false">http://brady.thtech.net/?p=810</guid>
		<description><![CDATA[The desktop upgrade from Fedora 15 to Fedora 16 was about on par with the upgrade from 14 to 15.  Instead of the disaster that is Gnome 3, we&#8217;re instead greeted with GRUB 2 and new systemd quirks. The main portion of the upgrade itself went smoothly.  No unexpected surprises from anaconda until the notice [...]]]></description>
			<content:encoded><![CDATA[<p>The desktop upgrade from Fedora 15 to Fedora 16 was about on par with the upgrade from 14 to 15.  Instead of the disaster that is Gnome 3, we&#8217;re instead greeted with GRUB 2 and new systemd quirks.</p>
<p>The main portion of the upgrade itself went smoothly.  No unexpected surprises from anaconda until the notice that the bootloader didn&#8217;t install right.</p>
<p><strong>GRUB 2</strong></p>
<p>So apparently Fedora 16 incorporates GRUB 2.  While its error messages seem far friendlier than GRUB classic, I really did not delve into all of its supposed benefits.  One downside is that when built with RAID support (which I seem to need since my /boot partition is mirrored), the core.img file ends up &gt;32KiB, and thus does not fit in the post-MBR gap present on my drives.<strong></strong></p>
<p>To address this, I used a gparted live CD and resized and moved the first partition of each drive (which happen to be NTFS drives for my Windows 7 install, one of which was the system volume).  This provided a 2MiB gap between the MBR and first partition.  Booting back into the Fedora 16 rescue mode and using grub2-install on both drives successfully installed GRUB2 and, following a reboot, allowed Fedora 16 to load.</p>
<p>Unfortunately, these partition table and file system hijinks left Windows 7 with a bit of a problem, seeing as it would not boot.  The recommended method of using the Windows 7 installer&#8217;s &#8220;Startup Repair&#8221; feature was unsuccessful.  The &#8220;bootrec /fixboot&#8221; would not fix it, giving an &#8220;unsupported filesystem&#8221; error.  Using diskpart to set the Windows partition to active appears to resolve this, and the fixboot succeeds.  Naturally, I ran fixmbr at some point, which wiped out GRUB again, and thus it had to be reinstalled.  Success with booting both Windows 7 and Fedora 16 was then achieved.</p>
<p><strong>NFS mount</strong></p>
<p>The machine has one NFS share mounted via /etc/fstab.  After the upgrade, this would fail to mount during boot, but would have no difficulty being manually mounted after boot.  After researching a variety of wrong paths with various systemctl changes, the one I found to resolve this was &#8220;systemctl enable NetworkManager-wait-online.service&#8221;.</p>
<p><strong>Update 1/8:</strong></p>
<p>The upgrade of my HTPC wasn&#8217;t too painful.  Mucked with partitions to make room for GRUB2 ahead of time, had to change my lirc init script to not confuse systemd, disable screensaver in gnome 3 (yes, shouldn&#8217;t be using gnome to run mythtv &#8211; need to add that to the list), re-enabling services that weren&#8217;t automatically figured out from existing init scripts, switched mounts from /dev/md* to UUID-based to get the ordering right in the new boot sequence, mythtv ownership changes, etc, etc.</p>
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		<title>Vehicle Work</title>
		<link>http://brady.thtech.net/2011/03/27/vehicle-work/</link>
		<comments>http://brady.thtech.net/2011/03/27/vehicle-work/#comments</comments>
		<pubDate>Sun, 27 Mar 2011 20:14:33 +0000</pubDate>
		<dc:creator>balleman</dc:creator>
				<category><![CDATA[Happenings]]></category>
		<category><![CDATA[ford]]></category>
		<category><![CDATA[fuel pump]]></category>
		<category><![CDATA[inertia switch]]></category>
		<category><![CDATA[ranger]]></category>

		<guid isPermaLink="false">http://brady.thtech.net/?p=735</guid>
		<description><![CDATA[Firstly, I&#8217;m not a mechanic, but with electrical problems I&#8217;m willing to take a stab. A few weeks ago, I was driving my truck (2005 Ford Ranger) back from a hike with a friend when the engine stopped.  I shifted into neutral and tried to restart, and it would crank but that&#8217;s it.  We got [...]]]></description>
			<content:encoded><![CDATA[<p>Firstly, I&#8217;m not a mechanic, but with electrical problems I&#8217;m willing to take a stab.</p>
<p>A few weeks ago, I was driving my truck (2005 Ford Ranger) back from a hike with a friend when the engine stopped.  I shifted into neutral and tried to restart, and it would crank but that&#8217;s it.  We got pushed off the road and checked for fluid leaks, etc.  Eventually I decided to try the fuel pump shutoff inertia switch and the truck started immediately.  I wasn&#8217;t completely convinced this was the problem &#8211; that maybe whatever the problem was had resolved itself around the time I reset the switch.  There was no jolting of the vehicle that should have set off the switch.  Researching the problem online, there was some indication that passenger&#8217;s wandering feet are sometimes the cause of the problem, as the switch is located in the passenger foot-well, and other indications that if it trips once reset it, if it trips twice, replace it.  I was content to reset and forget, as my passenger also indicated he may have been repositioning his feet when it happened.</p>
<p>A week later, the switch tripped again.  The same passenger was present, but this time there was no recollection of any bad feet positioning.  Resetting the switch was the first remedy attempted and was immediately successful.  It was now clear that replacing the switch would be the next step.  Researching Ford&#8217;s parts database found that in addition to a replacement switch, a &#8220;conversion kit&#8221; was available that would move the switch from its foot-well location to behind the trim panel (&#8220;cowl&#8221;) next to the fuse box.  I had initially decided against this (it was 4x as expensive), but the Ford dealer indicated that the kit was the appropriate resolution, so I bought one.</p>
<p>Installation was very straightforward, though it is difficult to position your drill in the necessary orientation to drill the pilot holes for the switch mounting bracket.  After breaking the head off a ground screw while trying to remove it (remedy: different screw), and breaking the pop-off holding the cowl in place (remedy: zip tie), the switch was finally in place.  Upon starting the vehicle, however, the airbag light began flashing a sequence.  Panic.  Must have drilled through airbag wiring or something.  No!</p>
<p>Fortunately, Google translated that code &#8220;27&#8243; was indicating that the passenger airbag off light was burned out.  Interesting coincidental timing.  So, I disassembled the portion of the dash and removed the offending keyswitch/light module for a little repair work.  I de-soldered the light and replaced it with a resistor and LED.  It ended up being a lot dimmer than the factory bulb, but the airbag computer is fine with it.</p>
<p>So far, so good.  Hopefully no relapse is on the horizon.</p>
<p><strong>References</strong></p>
<p>My Haynes Repair Manual does little more than acknowledge the existence of the fuel pump inertia switch and air bag system, so here are some of the resources I found.<strong><br />
</strong></p>
<ul>
<li><a href="http://www.therangerstation.com/tech_library/InertiaSwitch.html">Inertia Switch Teardown</a></li>
<li><a href="http://www.rangerpowersports.com/forum/f10/fuel-pump-inertia-switch-need-help-263318.html">Inertia Switch, notes on a kick shutting it off</a></li>
<li><a href="http://www.fordforums.com/f279/inertia-switch-driving-me-crazy-153792/">Inertia Switch problems</a></li>
<li><a href="http://www.fixya.com/cars/t593306-inertia_switch_2005_ranger">Inertia switch over-sensitivity</a></li>
<li><a href="http://www.automotivehelper.com/topic72315.htm">Airbag Code 27 and Bulb Replacement Instructions</a></li>
<li><a href="http://www.explorerforum.com/forums/showthread.php?t=128047">Airbag Codes</a><strong></strong></li>
</ul>
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		<title>Gunter Valley Dam</title>
		<link>http://brady.thtech.net/2010/09/19/690/</link>
		<comments>http://brady.thtech.net/2010/09/19/690/#comments</comments>
		<pubDate>Mon, 20 Sep 2010 01:06:55 +0000</pubDate>
		<dc:creator>balleman</dc:creator>
				<category><![CDATA[News]]></category>
		<category><![CDATA[Outdoors]]></category>
		<category><![CDATA[gunter valley]]></category>
		<category><![CDATA[gunter valley dam]]></category>

		<guid isPermaLink="false">http://brady.thtech.net/?p=690</guid>
		<description><![CDATA[It looks like deconstruction may be commencing at Gunter Valley Dam. Last summer there was an underwater construction company working at the dam, presumably repairing the gates on the intakes. This summer the reservoir has been consistently at very low levels, and in the past few weeks has been drained to the bottom. Sometime this [...]]]></description>
			<content:encoded><![CDATA[<p>It looks like deconstruction may be commencing at Gunter Valley Dam.  Last summer there was an underwater construction company working at the dam, presumably repairing the gates on the intakes.  This summer the reservoir has been consistently at very low levels, and in the past few weeks has been drained to the bottom.  Sometime this past week, the access road has been improved and earth moving equipment arrived at the dam.  A mound of rocks has been placed encircling the intake tower, and an access road for earth moving equipment has been created from the dam breast on its face to the level area near the spillway, and then down to the floor of the valley around the intake tower.  There were several groups of people touring the site on my visits Friday and today.</p>
<p><strong>UPDATE 2010-10-22: </strong>It looks like whatever the task was is complete for now.  The access way down the face of the dam has been closed up and all of the equipment has been removed.  A hole has been cut in the intake tower above the lowest intake, possibly for repair of the piping contained within (not sure).</p>
<p><img class="alignnone" title="Gunter Valley Dam" src="/pics/gunter.jpg" alt="" width="648" height="486" /></p>
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		<title>GraphViz</title>
		<link>http://brady.thtech.net/2010/08/12/graphviz/</link>
		<comments>http://brady.thtech.net/2010/08/12/graphviz/#comments</comments>
		<pubDate>Fri, 13 Aug 2010 01:31:12 +0000</pubDate>
		<dc:creator>balleman</dc:creator>
				<category><![CDATA[Technology]]></category>
		<category><![CDATA[celerra]]></category>
		<category><![CDATA[ender]]></category>
		<category><![CDATA[graphviz]]></category>
		<category><![CDATA[kerberos]]></category>
		<category><![CDATA[ldap]]></category>
		<category><![CDATA[nfs]]></category>
		<category><![CDATA[svg]]></category>

		<guid isPermaLink="false">http://brady.thtech.net/?p=654</guid>
		<description><![CDATA[A while back I had to diagram interactions between components in a KRB5+LDAP+NFS4 system.  Instead of laying this out by hand, I went with GraphViz.  I think I had known of its existence, but when I forget what the name of it is, I tend to look up this diagram of Ender stories from Wikipedia.  [...]]]></description>
			<content:encoded><![CDATA[<p>A while back I had to diagram interactions between components in a KRB5+LDAP+NFS4 system.  Instead of laying this out by hand, I went with <a href="http://www.graphviz.org/">GraphViz</a>.  I think I had known of its existence, but when I forget what the name of it is, I tend to look up <a href="http://en.wikipedia.org/wiki/File:Ender.svg">this diagram of Ender stories</a> from Wikipedia.  The diagram I made is below, if you happen to have a Celerra laying around.  Recently, I&#8217;ve started playing with GraphViz again to do some stuff for my current job, but have found out that one thing it doesn&#8217;t really do are the directory-tree type layouts one expects to find in most file managers today.  Maybe they&#8217;ll add that as a different layout engine at some point.</p>
<p><object data="/files/multiprotocol.svg" type="image/svg+xml" width="540" height="300"></p>
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		<title>DNSSEC at home</title>
		<link>http://brady.thtech.net/2010/07/17/dnssec-at-home/</link>
		<comments>http://brady.thtech.net/2010/07/17/dnssec-at-home/#comments</comments>
		<pubDate>Sun, 18 Jul 2010 02:26:47 +0000</pubDate>
		<dc:creator>balleman</dc:creator>
				<category><![CDATA[Happenings]]></category>
		<category><![CDATA[Networking]]></category>
		<category><![CDATA[bind]]></category>
		<category><![CDATA[dlv]]></category>
		<category><![CDATA[dns]]></category>
		<category><![CDATA[dnssec]]></category>
		<category><![CDATA[isc]]></category>

		<guid isPermaLink="false">http://brady.thtech.net/?p=632</guid>
		<description><![CDATA[Since the root zone was signed this week, I spent a bit of time today setting up DNSSEC validation on my home recursive server.  It was relatively painless (so far).  I did opt to not enable DLV though &#8211; not fond of it receiving every host name I resolve. Resources: RHEL RPMs from http://people.redhat.com/atkac/bind/5.6-test/ &#8211; [...]]]></description>
			<content:encoded><![CDATA[<p>Since the root zone was signed this week, I spent a bit of time today setting up DNSSEC validation on my home recursive server.  It was relatively painless (so far).  I did opt to not enable DLV though &#8211; not fond of it receiving every host name I resolve.</p>
<p>Resources:</p>
<ul>
<li>RHEL RPMs from <a href="http://people.redhat.com/atkac/bind/5.6-test/">http://people.redhat.com/atkac/bind/5.6-test/</a> &#8211; if someone finds a better source for BIND 9.7+ RHEL RPMs, I&#8217;d like to know.  I had no luck building from the Fedora SRPMs.</li>
<li><a href="http://www.isc.org/community/blog/201007/using-root-dnssec-key-bind-9-resolvers">http://www.isc.org/community/blog/201007/using-root-dnssec-key-bind-9-resolvers</a> &#8211; instructions for setting up BIND to use the root key.</li>
<li><a href="http://fanf.livejournal.com/107310.html">http://fanf.livejournal.com/107310.html</a> &#8211; A more thorough walk-through of setup.</li>
</ul>
<p>One resource I would have liked to find and could not was a deliberately unvalidatable non-root zone/record that could be used to see a validation failure.  If anyone knows of or finds such a thing, please pass it along.  Now we get to wait for .com, .net, etc, to catch up to .bg and .uk in the publishing of DS glue for deeper validation.</p>
<p><strong>UPDATE 7/22/10</strong>:  Just found the following site which makes available bad records for testing purposes: <a href="http://dnssec-tools.org/testzone/index.html">http://dnssec-tools.org/testzone/index.html</a></p>
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		<title>Device Convergence: GPS</title>
		<link>http://brady.thtech.net/2010/06/01/device-convergence-gps/</link>
		<comments>http://brady.thtech.net/2010/06/01/device-convergence-gps/#comments</comments>
		<pubDate>Wed, 02 Jun 2010 01:37:25 +0000</pubDate>
		<dc:creator>balleman</dc:creator>
				<category><![CDATA[Technology]]></category>
		<category><![CDATA[agps]]></category>
		<category><![CDATA[android]]></category>
		<category><![CDATA[g1]]></category>
		<category><![CDATA[garmin]]></category>
		<category><![CDATA[gps]]></category>
		<category><![CDATA[gpsmap76s]]></category>
		<category><![CDATA[gpsOne]]></category>
		<category><![CDATA[my tracks]]></category>
		<category><![CDATA[SiRFstar]]></category>
		<category><![CDATA[waas]]></category>

		<guid isPermaLink="false">http://brady.thtech.net/?p=628</guid>
		<description><![CDATA[Are cell phones yet to the point where they can replace a hand-held hiking GPS?  Up until recently, I&#8217;ve been quick to dismiss this notion.  The announcement of Garmin&#8217;s latest hand-helds that appear to be moving closer to their cell phone brethren has me wondering.  Reports of the new touch-screen interface are about as bad [...]]]></description>
			<content:encoded><![CDATA[<p>Are cell phones yet to the point where they can replace a hand-held hiking GPS?  Up until recently, I&#8217;ve been quick to dismiss this notion.  The announcement of <a href="https://buy.garmin.com/shop/shop.do?cID=145&amp;pID=63350">Garmin&#8217;s latest hand-helds</a> that appear to be moving closer to their cell phone brethren has me wondering.  <a href="http://freegeographytools.com/2010/a-review-of-the-garmin-oregon-450t-gps-for-field-work-part-ii-the-touch-screen-interface">Reports of the new touch-screen interface</a> are about as bad as one would expect.</p>
<p>So, what are the issues?  I tried my G1 running OruxMaps on a 3.5hr / 10 mile hike in the mountains on Monday to get a better perspective.</p>
<p><strong>Battery Life.</strong> It barely survived.  I would probably expect twice the battery life from my Garmin GPSMap 76S with a constantly running display.  Can the battery life issues be solved with an <a href="http://www.gomadic.com/battery-backup-cat.html">external AA-based battery pack</a> to keep the cell phone charged?  I have no experience with these things.  Reviews indicate that ones without regulators aren&#8217;t worth much.  I might have to try one.</p>
<p><strong>GPS Hardware.</strong> Cell phones may have GPS receivers, but it is not their primary function.  Most Android phones I&#8217;ve looked at seem to use the <a href="http://en.wikipedia.org/wiki/GpsOne">Qualcomm gpsOne chipset</a> instead of a dedicated chipset such as the oft-mentioned <a href="http://en.wikipedia.org/wiki/SiRFstar_III">SiRFstar III</a>.  This is a cause for concern, since gpsOne currently seems to lack support for <a href="http://en.wikipedia.org/wiki/Wide_Area_Augmentation_System">WAAS</a> and likely is not as sensitive as the SiRFstar.  The upside of gpsOne is that <a href="http://en.wikipedia.org/wiki/AGPS">AGPS</a> will provide a faster lock when within range of the cell network.</p>
<p><strong>Usability.</strong> Another major hurdle is the availability of high quality GPS software for the phone.  I&#8217;ve tried <a href="http://www.androlib.com/android.application.com-codesector-maverick-lite-qDiC.aspx">Maverick Lite</a>, <a href="http://www.oruxmaps.com/index_en.html">OruxMaps</a>, and <a href="http://mytracks.appspot.com/">My Tracks</a> and found them all to be lacking the necessary features of a hand-held GPS.  My Tracks is the Google-sponsored outdoor activity tracking app that was <a href="http://groups.google.com/group/mytracks/browse_thread/thread/7f2aba2a177b533c">very recently open-sourced</a>.  Maverick and Orux both provide offline map access (another must), but they seem to accomplish this with saved graphic tiles and not vector data as would be desired.  Any new GPS solution I get should have high-resolution topo maps included.</p>
<p><strong>Durability.</strong> Hand-held GPS receivers tend to be waterproof and a bit rugged.  I&#8217;ve dropped my GPSmap 76s a number of times &#8211; and it once fell off my bike at 15+ mph.  There&#8217;s no way any phone I&#8217;ve owned would be happy with that kind of treatment.</p>
<p>Bottom line?  Not sure yet.  I do think the concept of a hand-held GPS is already starting to fade.  I&#8217;m not ready just yet to give mine up in favor of the cell phone.  I hope the newly open-sourced My Tracks starts gaining some useful hand-held features.</p>
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		<title>Tales of X10</title>
		<link>http://brady.thtech.net/2010/05/28/tales-of-x10/</link>
		<comments>http://brady.thtech.net/2010/05/28/tales-of-x10/#comments</comments>
		<pubDate>Sat, 29 May 2010 00:40:06 +0000</pubDate>
		<dc:creator>balleman</dc:creator>
				<category><![CDATA[Happenings]]></category>
		<category><![CDATA[Technology]]></category>
		<category><![CDATA[home automation]]></category>
		<category><![CDATA[lm15a]]></category>
		<category><![CDATA[rr501]]></category>
		<category><![CDATA[ss13a]]></category>
		<category><![CDATA[x10]]></category>
		<category><![CDATA[xpt4w]]></category>

		<guid isPermaLink="false">http://brady.thtech.net/?p=608</guid>
		<description><![CDATA[A few years ago, I decided to improve the light switch situation in my garage.  The garage had lights at either end controlled by pull strings.  It was a frequent hassle to walk from one end to the other, often tripping over a variety of obstacles, to get both of them on or off.  Having [...]]]></description>
			<content:encoded><![CDATA[<p>A few years ago, I decided to improve the light switch situation in my garage.  The garage had lights at either end controlled by pull strings.  It was a frequent hassle to walk from one end to the other, often tripping over a variety of obstacles, to get both of them on or off.  Having already deployed X10 to control a few things around the house, it seemed like a reasonable and economical idea to use X10 here as well.  I used two <a href="http://www.x10.com/automation/lm15a_s.html">LM15A</a>s for load switching, two <a href="http://www.x10.com/automation/ss13a_s.html">SS13A</a>s for control near both doors in the garage, and an <a href="http://kbase.x10.com/wiki/RR501">RR501</a> to tie everything together.  Initially, the project seemed to be a great success.</p>
<p>Then it becomes apparent that the SS13As are not that great.  The adhesive backing would refuse to stick to the garage wall for extended periods of time, necessitating the addition of some screws to provide a slight ledge for them to sit upon.  They are also battery powered, and the stock batteries were nearly useless in cold weather.  Naturally, the colder times of year require the use of lights in the garage more often, and it became incredibly annoying to have to warm the switch with your hand and make multiple attempts to turn on the light&#8230; when the pullstring that otherwise would work is in reach.  My suggestion is to never use SS13As in anything but warm environments, and probably just avoid them altogether.  The one I had used inside would &#8220;forget&#8221; its code assignments and the coldness of the window sill was enough to keep it from working well.</p>
<p>To fix these issues, I revisited the idea of wiring regular three-way switches in the garage.  With the layout of the existing wiring, even the most creative ideas would require two new wires run the length of the garage, with one of them likely needing to be a 3-conductor that I don&#8217;t happen to have laying around.  And copper isn&#8217;t really cheap right now.  So, X10 was again looked at for a solution.</p>
<p>I decided to go with hard-wired X10 controllers, specifically the <a href="http://www.x10.com/pro/automation/xpt4w.htm">XPT4-W</a>.  I installed these near existing wire locations with a minimal of effort &#8211; maybe 3 hours total. So, now I have fully functional control of my garage lights (probably even in cold weather), and didn&#8217;t need to run crazy amounts of cable for three-way switches.</p>
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		<title>Isn&#8217;t AMPS dead yet?</title>
		<link>http://brady.thtech.net/2010/05/10/isnt-amps-dead-yet/</link>
		<comments>http://brady.thtech.net/2010/05/10/isnt-amps-dead-yet/#comments</comments>
		<pubDate>Tue, 11 May 2010 01:21:33 +0000</pubDate>
		<dc:creator>balleman</dc:creator>
				<category><![CDATA[Radio]]></category>
		<category><![CDATA[47 CFR 15.121]]></category>
		<category><![CDATA[abolish]]></category>
		<category><![CDATA[amps]]></category>
		<category><![CDATA[cell]]></category>
		<category><![CDATA[cellular]]></category>
		<category><![CDATA[fcc]]></category>
		<category><![CDATA[fm]]></category>
		<category><![CDATA[freedom]]></category>
		<category><![CDATA[scanner]]></category>

		<guid isPermaLink="false">http://brady.thtech.net/?p=597</guid>
		<description><![CDATA[It was with some great fanfare that AMPS met its death on February 18th, 2008.  But did it really die?  As far as I can tell, all that happened on that date was that the FCC no longer required cellular providers to make AMPS available, and many did eagerly turn it off.  But, unlike the [...]]]></description>
			<content:encoded><![CDATA[<p>It was with some great fanfare that <a href="http://en.wikipedia.org/wiki/Advanced_Mobile_Phone_System">AMPS</a> met its death on February 18th, 2008.  But did it really die?  As far as I can tell, all that happened on that date was that the FCC no longer required cellular providers to make AMPS available, and many did eagerly turn it off.  But, unlike the conversion to digital television, there appears to be no requirement at this point for providers to abandon AMPS if it is still making them money.  That being the case, are there any AMPS providers still out there?  Public filings (<a href="http://wireless.fcc.gov/services/index.htm?job=cellular_reports&amp;id=cellular">available here</a>) concerning AMPS status were made prior to the sunset date and reveal that some companies had a lot of AMPS customers still and had no plans to turn the service off.</p>
<p>Why do I care?  Because I loathe <a href="http://edocket.access.gpo.gov/cfr_2009/octqtr/pdf/47cfr15.121.pdf">47 CFR 15.121</a> and would like to see it abolished.  This is the section of FCC regulations that forbids the manufacture of devices that can receive, or be easily modified to receive, cellular frequencies.  This requirement only covers the <a href="http://wireless.fcc.gov/services/index.htm?job=service_home&amp;id=cellular">Part 22 Cellular Service</a> (824-849, 869-894 MHz) and not the all-digital <a href="http://wireless.fcc.gov/services/index.htm?job=service_home&amp;id=broadband_pcs">PCS</a> and <a href="http://wireless.fcc.gov/services/index.htm?job=service_home&amp;id=aws">AWS</a> bands that cell service has expanded into.  With AMPS, conversations were transmitted using FM, and so could be easily decoded by any FM receiver that could tune to the appropriate frequencies.  With the digital services, more sophisticated handling of the signal (and even decryption) would be required, which apparently made it unnecessary to have the same kind of regulation.  As far as I know, this is the only restriction placed on what frequencies can be tuned by a receiver.  On freedom grounds alone, I have a big problem with that.  If AMPS does finally die &#8211; and I hope it does &#8211; I hope that 47 CFR 15.121 can die with it.</p>
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		<title>Missing L3 Hut Found (demolished)</title>
		<link>http://brady.thtech.net/2010/04/11/missing-l3-hut-found-demolished/</link>
		<comments>http://brady.thtech.net/2010/04/11/missing-l3-hut-found-demolished/#comments</comments>
		<pubDate>Sun, 11 Apr 2010 19:31:11 +0000</pubDate>
		<dc:creator>balleman</dc:creator>
				<category><![CDATA[Technology]]></category>
		<category><![CDATA[Bedford-Harrisburg]]></category>
		<category><![CDATA[coax]]></category>
		<category><![CDATA[L3]]></category>

		<guid isPermaLink="false">http://brady.thtech.net/?p=564</guid>
		<description><![CDATA[While hiking this weekend partly along the suspected area of the long-since-defunct Bedford-Harrisburg L3 cable, I found the apparent demolished remains of one of the repeater huts that had eluded me up to this point.  As they all are, it was not far off the road, near the top of the mountain at Upper Strasburg.  [...]]]></description>
			<content:encoded><![CDATA[<p>While hiking this weekend partly along the suspected area of the long-since-defunct Bedford-Harrisburg L3 cable, I found the apparent demolished remains of one of the repeater huts that had eluded me up to this point.  As they all are, it was not far off the road, near the top of the mountain at Upper Strasburg.  Guard rails have since been erected in front of what would have been it&#8217;s very small level parking area.  Nearby there were also portions of exposed L3 cable that had apparently been covered in rocks instead of buried below grade.  Really awesome, though unintentional, finds!</p>
<p><a href="http://maps.google.com/maps/ms?ie=UTF8&amp;hl=en&amp;msa=0&amp;msid=102028339755959680145.000461bc6c8598a0ffce9&amp;t=h&amp;z=10">The map</a> has been updated.</p>
<div class="wp-caption alignnone" style="width: 410px"><img title="Demolished L3 Repeater Hut" src="/pics/demo-hut.jpg" alt="" width="400" height="300" /><p class="wp-caption-text">Demolished L3 Repeater Hut</p></div>
<div class="wp-caption alignnone" style="width: 410px"><img title="Exposed L3 cable" src="/pics/exposed-l3.jpg" alt="" width="400" height="300" /><p class="wp-caption-text">Exposed L3 cable</p></div>
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		<title>Power vs. Energy</title>
		<link>http://brady.thtech.net/2010/04/08/power-vs-energy/</link>
		<comments>http://brady.thtech.net/2010/04/08/power-vs-energy/#comments</comments>
		<pubDate>Fri, 09 Apr 2010 02:03:32 +0000</pubDate>
		<dc:creator>balleman</dc:creator>
				<category><![CDATA[Science]]></category>
		<category><![CDATA[Technology]]></category>
		<category><![CDATA[caes]]></category>
		<category><![CDATA[energy]]></category>
		<category><![CDATA[gigawatt]]></category>
		<category><![CDATA[gigawatthour]]></category>
		<category><![CDATA[hydro]]></category>
		<category><![CDATA[jigowatt]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[power]]></category>

		<guid isPermaLink="false">http://brady.thtech.net/?p=537</guid>
		<description><![CDATA[I&#8217;m trying to catch up on some reading, and am working through a number of articles concerning energy sources, the power grid, and so forth.  One almost constant source of annoyance I find in these articles is that the difference between power and energy are either ignored, misused, or left hopelessly ambiguous.  The writers are [...]]]></description>
			<content:encoded><![CDATA[<p>I&#8217;m trying to catch up on some reading, and am working through a number of articles concerning energy sources, the power grid, and so forth.  One almost constant source of annoyance I find in these articles is that the difference between power and energy are either ignored, misused, or left hopelessly ambiguous.  The writers are not totally to blame, since our vocabulary for discussing these concepts is weak and it takes a lot of effort to clearly convey the correct meaning.  Consider the following example:</p>
<blockquote><p>The U.S. electric system has 2.5 gigawatts of pumped hydro storage capacity.</p></blockquote>
<p>&#8220;Capacity&#8221; when used to discuss an energy storage apparatus can have two meanings.  It could mean the <em>power</em> capacity of the system, which is the amount of energy that can be released from storage and converted to electricity instantaneously.  For pumped hydro storage, this would be determined to a large degree by the size of the turbines, generators, and penstocks.  This quantity represents, for instance, the number of lights a plant could handle without dimming &#8211; it says nothing about how long it could keep them lit.  A common unit of <em>power</em> capacity is gigawatts.</p>
<p>The other type of &#8220;capacity&#8221; is the <em>energy</em> storage capacity of the system.  For pumped hydro storage, this is the value related to the size of the water reservoir.  This is the quantity that represents <em>how long</em> a plant could keep a given number of lights lit, for instance.  A common unit of <em>energy</em> capacity is gigawatt-hours.</p>
<p>Assuming the author chose the units correctly, this quote tells us that the <em>power</em> capacity of US pumped hydro is 2.5 GW.  Unfortunately, something isn&#8217;t right, because the Energy Information Administration says the number is <a href="http://www.eia.doe.gov/cneaf/electricity/epa/epat1p2.html">actually 20 GW</a>.</p>
<p>Consider another example:</p>
<blockquote><p>The Norton project could store 2.7 gigawatts of power in an abandoned limestone mine.</p>
<div id="TixyyLink"><a href="http://www.wired.com/wiredscience/2010/03/compressed-air-plants/#ixzz0kYydnmJd"></a></div>
</blockquote>
<p>I&#8217;m afraid this one is beyond redemption.  You don&#8217;t store <em>power</em>, you store <em>energy</em>.  But the units given are for power, and from further research in other articles, the <em>power</em> capacity of the plant is expected to be 2.7 gigawatts.  I was not able to find a source that estimated the plant&#8217;s <em>energy</em> storage potential.</p>
<p>Any time you read the words &#8220;power,&#8221; &#8220;energy,&#8221; or &#8220;gigawatt&#8221; in an article, read it very critically.  The commonly cited statistics for power plants are always their <em>power</em> capacity, and even for energy storage plants, storage capacity is seldom stated.  One likely reason is that power capacity is relatively easy to determine &#8211; it is likely written on a nameplate on the generator somewhere.  Calculating the energy capacity of a storage facility would be more challenging, and might not be a number required by regulators &#8211; and hence one that is seldom available.</p>
<p>Both quotes are from this <a href="http://www.wired.com/wiredscience/2010/03/compressed-air-plants/">wired.com article</a>, but many articles discussing energy storage have the same problem.</p>
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