CRV Lift Support Replacement

Replacement of the gas-charged shocks (pneumatic) lift supports on our 1998 Honda CRV.
The original parts are metric, it is most likely that your replacement will US Customary.

Remove old lift support from window side and body side using a 12mm metric wrench or adjustable wrench.

Be careful not to damage the plastic nut assembly which penetrates the glass on the window side.  You will need to re-use them as they are not included with the new part.

The ball joint and washer in my original lift supports cannot be removed from the old part.  New ones are included in the new lift support package.  In the end, I required the use of an additional washer for each glass attachment side of the lift support.

Use a small flat head screwdriver (or precision screwdriver) to loosen the clip band around the lift support head on the new part so that the new ball joint can be inserted.

Push the clip band back into place once the joint is inserted.

New lift support with new ball joint and washer inserted.

Using a 7/16in wrench, attach the body side of the new lift first.

Hand screw the lift support into the glass side.  The rear window will most likely need to be pushed up all the way for the threads to match properly.  This is the most difficult part.  I had to add an additional washer under the included washer so the lift support nut would be flush with the window assembly.

You may have to hold the plastic nut in place while tightening the nut from the lift support.

Once the lift support(s) are tight and in place, operate the window (open and close it a couple of times).  Check the plastic nut assembly on both sides of the glass to ensure that it is flush with the window and appears to make a proper seal.

Any gaps can be closed up by further tightening the lift support nut underneath.  (This is why I needed an extra washer).

My Take on Net Neutrality (from 2006)

Net Neutrality vs. Packet Priority

Recent letters and TV advertisements have presented net neutrality in terms of cost to consumers.  Indeed, most consumers are probably only aware of net neutrality as an abstraction related to the cost of upgrading the internet.  The real story merits everyone’s attention beyond the threat of higher prices.

The existing alliterative title could be renamed “content neutrality.”  It really means that the internet itself is blind (or neutral) to what data (or content) is being transmitted.  When you go to any site of your choice now, the site provides the data and pays for the access speed from their end.  The consumer initiates the transmission of data and pays according to the speed of delivery.  This process is independent of the content being transmitted and all data is treated equally regardless of its source or destination.

Ultimately, ISPs are looking for the chance to bill the content providers not only for the speed of transmission but also for what is being transmitted.  ISPs want web sites to pay extra to prioritize data packets for high speed.  If ISPs get their way, even though you and your favorite web sites pay premium prices for broadband, many of those same sites will be relegated to dial-up speeds because their data is of lower priority than the bigger companies who pay more.  Sort of like if we were all diverted to one congested lane on the highway while the Wal-Mart trucks zoom by in the open lanes.

Ensuring net neutrality means that you get the speed and access that you pay for instead of what your ISP finds financially convenient to provide.  On the other hand, allowing service providers to assign packet priority will stifle web content and provide a potentially sinister means to control information.

Mouse Trap Car

This mouse trap car was built from a SECME kit intended for competition.

Materials that we used which were NOT included in the kit:
One block of 0.75in x 1.75in x 6.5in pine which I had laying around for the body
Two sections of  1.5in x 7/8in dowel rod for axle ends
One 4in piece of 1/8in steel rod
Two 1/8in washers
Two 1/4in fender washers
Two 1 inch pieces of 0.060in or smaller wire
Six small wood screws
Two old CDRs for rear wheels
Wood glue or Elmers

Tools:
Drill with 1/16in, 3/32, 1/8in, 5/64in, 3/8in drill bits
Coping saw or jigsaw
Sandpaper
Hacksaw (for steel rod)
Pliers
Screw driver
Safety glasses
Vise

Start by removing the bait hook and the locking lever.  Only the bail and the spring are necessary to power the car.

Next we secured the trap base to the pine block with four wood screws.  1/8in Pilot holes were drilled into the base to prevent the wood on the trap base from splitting.  Note in the picture below that I have yet to remove the bait hook.

We drilled a 3/8in  hole centered about 1/2in from the rear of the trap base through both the base and the pine block.

This whole was used to create a notch in the back of the trap by which the fishing line connects the bail to the rear axle to propel the car.  *It is recommended that the notch be created at this time before the car is assembled. We waited until the car was assembled (as you will see in the pictures).  Once the fishing line gets used once to propel the car, it becomes very curled from being wrapped around the axle.  It is very hard to feed the fishing line into the axle hole with your fingers with just the 3/8in hole to work with.*

We used the 5/64in bit to drill the holes in the side of the block for the axles to slide through.  Both axle holes were drilled on center through the side at 1/2in from the front and rear of the block

We also cut the bottom front corner off of the pine block to provide plenty of clearance for the front end of the car because of the fact that our car angles downwards at about 30 degrees.

The 6cm 1/8in steel rod front axle which was included in the kit was then installed.  The 3.5cm black plastic wheels included with the kit are secured to the front axle by gently tapping them in place with a hammer until the axle passes about half way through the wheel hub.

The dowel rod sections serve multiple purposes: 1) As a way to attach the CDs to the axle; 2) To build a little extra angular momentum; and 3) As a grip surface with which to prevent the rear axle from spinning once the bail is set.

We drilled a 3/32in hole all the way through the center of each 1.5in length of dowel rod.  The 3/32in hole served as pilot hole for both sides.  The CDs were then attached to the dowel rod with a fender washer and a wood screw being careful to center the CD on the dowel rod as closely as possible when the screw is tightened all the way

We then drilled three 1/16in holes into the 4in rear axle.  The first hole is drilled at the center of the axle length (at 2in).  The other two holes were drilled at 1in and 3in (or 1in on either side of the center hole)
This was perhaps the most difficult part of building our mouse trap car.

The axle was then attached to one CD wheel assembly by placing a dab of glue into 3/32in hole in the dowel rod and gently nailing it about 1/2in into the hole.

One of the small washers was then fed onto the axle and then the axle through rear block axle hole.

The second small washer was fed onto the other end of the axle before securing the other CD wheel assembly to the right side of the axle.

We then secured the right CD wheel assembly using the same process as mentioned above.

Here the two washers have been pressed against the body so that you can see the three axle holes if you look carefully.

The outside two axle holes were used together with the washers and wire to create bushings for the real axle.

The wire is twisted around the axle from both directions creating a makeshift cotter pin.

The fishing line is cut to about a 5in length and tied at one end to the middle of the bail and the other end is fed into the center axle hole. The line must be trimmed to just the right length so that it pulls free of the hole once the bail has fully sprung.  If too much of the line is fed through the hole, it will not come out and instead will rewind itself in the opposite direction around the axle causing the car to brake to a halt as shown in this video:

Carefully pull the bail up while rotating the rear wheels backwards to ravel the fishing line around the axle. It is recommended that you use a block of wood to hold the bail up a little while feeding the line to free up your hands and help minimize the chance of smashing your fingers if you lose your grip on it. Once the bail is fully set, hold the axle by one of the dowel rods to keep the spring from spinning the axle. Set on a smooth, flat floor and release the axle to propel the car.

Our car only went 32 feet, but it was still fun building it and finally getting it to work.  The plastic wheels included in the SECME kit which we used for the front probably add quite a bit of extra friction.

There are several items which were included in the SECME kit which we did not use:

Building an HDTV Antenna db2, db4

We finally cut our cable last summer.  The low-cost, home-built, attic or closet antennas shown below and their appropriate positioning allow us to receive 11 free HDTV VHF/UHF broadcast channels in our area -- Nearly as many (real) channels as we were getting for $30/month from our local basic cable package.

DB4 

DB2

Getting the best signal for all the channels requires some planning prior to building your antenna(s)* so I am going to recommend doing this in the opposite order in which I did.

*antennas is correct plural for radio broadcasting, antennae is correct plural for biology.

STEP 1:  Tower Locations
First, find all the possible stations that you can receive in your area and their distance and direction relative to your home.  Anything outside of  30 miles or so is probably going to need an outdoor antenna. The transmission towers which provide the 11 stations that I receive range in distance from 2-24 miles.

The best resource for locating your stations and towers is http://www.rabbitears.info/search.php


Be sure to enter your actual address with your zip code because this will give you distance and the direction (azimuth) of the station's transmission towers to within a degree of azimuth.  Reading the direction (or azimuth) in degrees of each tower is simple.  Facing due North is 0 degrees, due East is 90 degrees, due South is 180 degrees, and due West is 270 degrees.  360 degrees and 0 degrees are of course the same azimuth.

Don't be surprised when the location of the DTV transmission tower for a particular station is completely different from the location of their local TV studio.


One thing that may confuse you at first is difference between the true broadcast (RF) channel and the PSIP channel.  Among other things, the PSIP channel is the channel that your station carries with its call letters and is the channel that the station tells your TV to display.  Each RF VHF/UHF broadcast channel has a bandwidth of 6MHz which is further subdivided into parts.  Many stations will broadcast two to three PSIP channels or streams from within one allocated RF channel.  For example, my local PBS station channel 5 broadcasts three PSIP channels: 5-1 PBS, 5-2 Create, and 5-3 World.  This is how my TV displays them, but the actual physical channel which the antenna receives is RF channel 36 (602-608MHz) which is subdivided into 36.1, 36.2, and 36.3.

This difference becomes very important if you are designing an antenna to resonate for a particular channel frequency.  From the PBS example above, RF channel 36 has a UHF wavelength of about 50cm (20in).  If you mistakenly thought the PSIP channel 5 was the same as the RF channel, then you would be designing an antenna to receive an RF channel  5 with a VHF wavelength of 3.8m (150in).  With a 1/4 wavelength antenna design, this is a difference in antenna elements of 4in vs nearly 40in.

wavelength = c/frequency (c=speed of light)

or

wavelength = 300/freq in MHz

Fortunately, the antenna design below does a pretty good job of picking up a good spectrum of RF channels including both of these extremes.

Here is a table of the physical radio frequency VHF/UHF channel allocations.  Notice that there is a huge gap in the VHF frequency range between channels 6 and 7 which is carved out for the U.S. FM frequency range of 87.5MHz-108MHz.  This is why you can sometimes hear a television station broadcast at the very low end of the FM Radio dial.

After printing a list of stations with details, I mapped out the azimuth (direction) of each tower on the ceiling right below where one of my antennas is placed.  You are going to need a directional compass (app) or you could use Google maps to get a satellite picture of the top of your house and figure out the axis direction of your house by comparing to the North arrow.  A protractor and straight edge were also for this. The axis of my house is 10 degrees off of due North.

Azimuth (Direction) Map

Of course, estimating will probably get you close enough, but remember, the antennas detailed here are basically directional, despite being sold online as multi-directional antennas.

My transmission tower directions were rather easy to deal with.  I have two different general directions:  Mostly South and Mostly West. I placed two antennas in the same attic location with one pointed at about 180 degrees and the other pointed at about 260 degrees.

STEP 2:  Antenna and TV Locations and Connections
Next you need to figure out where you are going to place your antenna(s) and how you are going to run the coax cable to your TV.  Use the shortest length of digital-grade cable possible.  I used a 25' length to run from the antenna location in the attic to our LCD TV.

The antennas each use an inexpensive balun (300ohm balanced-75ohm unbalanced) transformer which can be purchased at Walmart or RadioShack for about $5.

Balun Attached to Balanced Antenna Array Feed Points

If you are older than thirty then you probably remember screwing a balun into your old CRT television to make your 13 channels of coaxially-delivered 75ohm cable compatible with the 300ohm antenna terminals on the back of the TV.  Now you do the whole thing in reverse.  You may even still have one laying around in a drawer if you are a packrat like me.

The baluns are sometimes sold in a packaged pair with one standard balun and one F-type (pictured below).   Both types of baluns can be used to transmit the balanced VHF/UHF radio signal received by your antenna to the unbalanced, shielded coax cable to your TV.

F-type Balun with Female to Female Jack.

Both Types of Baluns Packaged Together for $5.

Unlike your old cable signal from the cable company, the RF signal which your antenna transmits is very susceptible to interference and degradation before entering the shielded coax cable.  It cannot be reliably split to serve more than one TV without some additional expensive boosting unless the signal is particularly strong.  The coax cable must run the complete distance from the TV to the balun to avoid signal problems and should not be split.



When you are done constructing your antenna (STEP 3), attach the balun directly to the antenna feeds and the coax directly to the balun. Do not attempt to extend the length from the antenna to television with anything other than coax.

While you probably won't be able to split the signal coming from the antenna to your television, you can use your old splitter in reverse as combiner to "join" two different antennas pointed in different directions for maximum reception.  The splitter is a passive device with no active electrical components so it can work in either direction.

Technically speaking when you join two antennas, you are supposed to use a properly filtered antenna device called a combiner or Jointenna to avoid multipath interference.  Antenna engineers will tell you not to use a splitter in reverse as a combiner,  but I found this cheap setup to work quite nicely for both double antenna setups in my house.

At this point it is worth mentioning that our federal government including Congress deserves some credit for making this so inexpensive.  First the 2009 law which forced migration to DTV broadcast and second the law requiring a digital tuner on all HDTVs made after 2007 to be sold in the US.(Citation Needed)


STEP 3: Constructing the Antenna
There are several options for the materials to be used for your antenna.  Both the DB2 and the DB4 designs require three basic elements:
1. Metal wire or rod material (coat hanger, copper wire, steel rod) -- At least 12 feet for the DB4
2. Screws or bolts for connections (wood screws or machine) -- Need 10 for DB4
3. Body material for spine and connections (wood and/or pvc pipe)

I have built several (six in all) of both types of antennas using the materials listed above with varying degrees of success.  My best and most recent antennas have been constructed from 1/8 in steel rod, PVC pipe and fittings, and 10-24 x 2in bolts with nuts and fender washers.

1/8in Plain Steel Rod

One general rule for receiving antennas is that thicker, more straight conductive material works better than thinner--It provides more metal material surface area and therefore more free charge for the radio waves to oscillate back and forth along the antenna and therefore a higher gain for your DTV signal.

10-24 x 2 Machine Bolts w/Nut and 1/4in Fender Washers

I found these to be best all purpose connectors for this purpose.  They are thick enough to provide a very secure connection without the need to solder and thin enough to accept the clips for the balun at the feed points.

Here is the basic plan for the DB4 (Dipole Bowtie 4-bay).  It is made of two electrically isolated vertical arrays (forming a dipole) onto which there are attached bowties in four evenly spaced bays .  The arrays must isolated from each other and cannot touch.  The two crossover points (where blue meets red in diagram) must not be allowed to touch electrically.

This antenna is based on 1/4 wavelength dimensions.  VHF broadcast wavelengths typically range from 1-5m (39-200in) and UHF wavelength range from 10-100cm (4-39in).  This antenna will pick most of those wavelengths if constructed carefully.

Additionally, each connection node from the right should be insulated from the one on the left.  This is why PVC is a good choice for the body of the antenna.

In this case I have used a short 1-inch half section of PVC to insulate the left and right arrays from each other.  The tension created from the 1/8in steel rods is enough to keep it in place.

Each of the connection nodes protrude from the back without connecting to each other.

Each of the bowties is made from one 18 inch length of 1/8 in steel rod which was carefully angled in the middle by hand by pulling each end around the thin edge of some rigid, stationary object. The bowties are fed between the two fender washers at each node.

Each side of the array is connected via one ~22in length of 1/8in steel rod.  These rods are woven underneath the bottom fender washer at each node and also alternate sides from top to bottom which creates  a good tension on each connection node.

Once the antenna is built, gently connect the balun to the feed points and connect your coax to the the balun.  The balun matching transformers are usually pretty sturdy, but you can twist on them too hard and ruin the internal connection.

To connect an F-type balun, simply run two short, evenly spaced wires of equal length from the feed points to F-type terminals.  Then you can connect the coax to the F-type balun with a female-female coupler jack.

As mentioned above, two antennas can be joined together.  The DB2 antenna is good enough for signals that are close and powerful, but the DB4 will be necessary for signals that are farther away.

Be sure to position the antenna vertically with the bowties pointing horizontally such that they are perpendicular to the azimuth direction of the station antenna. Most station antennas have a slight electric beam downtilt of about 1 degree with another 1 degree angle of depression from tower down to ground level.  Of course, the angle of depression becomes more pronounced the closer the tower is.  This means that you will probably get a better signal by angling the antenna slightly upwards if possible.

One thing that I have left out is a reflector.  The DB4 and the DB2 are often fitted with a reflector made of metal mesh, wire caging, or even aluminum foil to increase the gain.  The reflector should be spaced 1/4 wavelength behind the antenna arrays (about 3-5in in most cases).  I have found the addition of various types of reflectors to have little impact on my antenna performance.

Below are a couple of pictures of a professionally designed and manufactured DB2 with a reflector which I stumbled upon recently while visiting a friend.  It is made of aluminum and is (seldom) used in the break room of an office setting in a large metropolitan area.

Extra Notes:
Antenna physics and design is a very complicated topic, but it is probably true that many people who are willing to build their own antenna to save a little cash are also interested how the thing actually works. There are three basic parts:
1.  How the transmitter antenna radiates its signal
2.  How the signal propagates through space
3.  How the receiver antenna "catches" the signal

A very simple (and perhaps simplistic) way to imagine this whole process is to revert to the analogy of water waves.  Imagine a lake in which there is a fish at the bottom.  In this case though we are not trying to catch the fish, but simply trying pass a message to it from the shore.  The fish cannot hear us, but someone else whose fishing line broke has left their bobber at the surface and a fishing line with a weighted hook which drops down to the bottom right in front of the fish.

We can pass a coded message to the fish via the bobber, line, and hook by simply creating water waves with our hand.  If we create a water wave by smacking our hand on the top of the water, then the bobber will transmit the motion of the wave to the hook making the hook move up and down in front of the fish.

Our hand transmits a signal(transmitter)to the water (space) which carries that signal to the bobber line (antenna).  The driving signal at a transmitter antenna (your hand above) causes electrons to flow back and forth along the axis of the transmitter antenna which causes electric and magnetic fields to emanate from the antenna as electromagnetic radiation in the radio spectrum.  The radio waves propagate through space as oscillating electric and magnetic fields (water waves above) eventually enveloping your antenna (bobber above) and causing the electrons in the metal antenna to flow back and forth along the antenna elements thus creating the same signal.

You can carry this analogy a bit further by using it to explain different antenna sizes, wavelengths, and interference.  If you change the size of the bobber, then you can change the size of the waves that will drive it.  A really large bobber will only adequately respond to large waves--Little ripples won't move it enough.
Multi-path interference occurs when the water wave you created reflects off of the shore or some other object interfering with your original water wave.


The real explanation of the operation of a simple dipole antenna whether transmitting or receiving starts with electrons flowing through a wire.  I will be elaborating on this further when get more time.

A visual of of the electric and magnetic fields emanating from a dipole transmitter antenna is helpful, but the propagation of the resulting electromagnetic wave through space requires some background in electrodynamics.

Curvy Shelf

This shelf is made of a 0.90in x 7in x 8ft section cut from a 0.090in x 4 x 8 Non-fiberglass Reinforced Plastic (NRP) sheet intended as wall panelling which I purchased at Lowes.  The shelf supports are cut from a 1in x 8in x 6ft (0.75in x 7.25in x 6ft) piece of pine.

List of Materials:
One sheet of 0.090in x 4ft x 8ft NRP Waterproof Wall Panel
One 1in x 8in x 6ft (0.75in x 7.25in x 6ft) piece of pine
Three corner braces
Wood screws to secure top side of shelf and corner braces into wood supports
Sheet metal screws to secure underside of shelf into wood supports
Sheet metal screws with anchor plugs to mount into drywall
Sandpaper
Drill

I used a jigsaw to cut a 7in x 8ft strip from the 4 x 8 NRP sheet.  This forms the continuous shelf strip which is flexible enough to bend to the shape shown but strong enough for light duty support like those CDs and DVDs you don't use anymore.  To make the shelf able to support more weight, use two strips of the NRP together and/or fender washers on the screws to prevent them from pulling through the NRP sheet.

By the way, if like me you make the mistake of cutting your strip such that you accidentally chose the portion of the panel that the label stuck to, it can easily be removed with WD40 and razor blade or thin putty knife.

I used three different types of shelf supports:

Three 7in x 7.25in rectangular supports.  I added the middle one last after hanging the shelf  because it gave a little more support and served as a bookend.  The 7in side should fit against the NRP so that the support is flush with the shelf and so that the wood grain points out horizontally giving the shelf a better appearance.

Each rectangular support is attached to the wall using a corner brace:

Two 7in x 7.25in cut-away supports:

Two 5in x 7.25in small arch supports:

The cut-away supports and the small arch supports are anchored to the wall using a deep counterbore with a 3/8" to 1/2" drill bit.

You may find that have to play with the spacing of the supports, but I used the spacing shown below.  The diagram displays how the shelf is assembled prior to mounting it on the wall.

The left side of the shelf curves upward and around to form the circular portion which has an approximate diameter of 2 feet from top to bottom.

Of course, part of the point of this shelf is that it is flexible and can be shaped in other ways.  For example the configuration of the shelf could be changed from the horizontal one I have shown to a vertical one in the shape of an S.