Lee Devlin’s Website

The LightSquared Debacle in Layman’s Terms

I’ve been reading about the LightSquared debacle for months. My aviation-related e-newsletters and magazines have been covering the GPS industry’s objection to LightSquared and how it would be disastrous for the GPS receivers, essentially causing a loss of satellite lock or at minimum causing accuracy issues that could lead to disaster. The story received a boost in interest when it was found that there was some political chicanery associated with the White House administration pressuring a reversal in the testimony of an Air Force general. It’s hard to ferret out the underlying reason how this problem got this far, with so much money being invested in a technology that LightSquared should have known would hit a wall during its deployment, namely when it produced interference with a critical service like GPS that is adjacent to its bandwidth allocations. So I decided to do some research and summarize it here.

The problem of radio interference isn’t new. The FCC and similar organizations in other countries were created primarily to help prevent interference problems by licensing radio spectrum and settling disputes among the radio spectrum’s users. All radio transmitters generate some amount of radio frequency (RF) energy on adjacent bands. All receivers are influenced by signals that are in adjacent bands because there is no such thing as a perfect filter to ignore nearby signals. So one must ask the question, is this an interference problem on the part of LightSquared, or a susceptibility problem for the GPS manufacturers? And since there is no such thing as a perfect filtering technique, how much can it help to apply filters to GPS receivers? Can the problem be solved with a 5-cent change to GPS receivers as suggested by LightSquared, a solution promptly dismissed as absurd by the GPS industry? I can tell you one thing that does not work, and that is to expect an industry to accept a problem introduced by some third party AFTER its products have already shipped and are in the hands of its customers. Sure, you can ask for a change to future products, assuming the change actually produces the desired result and isn’t too costly, but if an industry is entrenched, and I think that after 2 decades of shipping millions of products, GPS can be categorized as such, you can’t expect them to accept a problem that wasn’t a problem until your service came along.

Nor can you expect all existing customers to ‘upgrade’ their equipment just to solve some newly introduced interference issue. Yet this is apparently what LightSquared was expecting. And I find that attitude arrogant and ridiculous. Anyone whose money is invested in a technology that expected such a system to work should expect to see his investment lost by those who dismissed or talked around these issues when they were first brought up.

One might tend to lay the blame on LightSquared and its naivete, but I think the FCC is just as culpable. The FCC needed to realize that any service that occupied frequencies adjacent to GPS must necessarily be compatible with it. GPS satellites transmit signals from a distance of about 12,500 miles above the earth. Because of this vast distance, the signals are at a very low level once they arrive on earth, about -130 dBm (which is about 180 x 10^^-18 Watts). The land-based LightSquared 4G transmitters can use as much as 70 dBm (10,000 Watts). So you can see that there is a vast difference of roughly 2 x 10^^20 in signal strength between the two services. The low signal strength is one of the reasons why most Space-to-Earth signals require dishes or other types of high gain antennas pointed at the satellites to amplify only those signals and simultaneously ignore any signals originating from other directions. But GPS receivers cannot do that. First of all, the constellation of 24 satellites is in constant orbiting motion, and secondly, a GPS receiver needs an antenna that can receive from several satellites at once in order for it to do its job so it cannot use a directional antenna. A GPS receiver has none of the amplification and signal isolation benefits provided by a directional antenna. This means that the signals that a GPS receiver has to deal with are extremely weak, and are actually below the noise floor, and must be dug out of this noise floor using sophisticated signal processing techniques.

As shown in the graphic above, (source) the bands adjacent to the GPS spectrum were intended to be used for similar purposes, that is to send signals from space to earth or earth to space, and based on what I’ve been reading about LightSquared, this was how they intended to use the spectrum initially. But most broadband solutions that depend on satellites are not very compelling due to the 44,000 mile round trip the signals they need to make to the geosynchronous satellites. This trip adds about a half second delay which is too high a latency to provide a satisfactory experience compared with terrestrial broadband solutions, especially with modern Internet applications some of which cannot tolerate that kind of latency. People tend to use satellite broadband only when there are no terrestrial broadband offerings in their area.

In 2004, presumably to make its service more financially attractive, LightSquared’s predecessor lobbied for and received authorization by the FCC to deploy thousands of land-based transmitters in the same frequency range as their satellite-to-earth band. I think that this authorization from the FCC is where things went awry. LightSquared, when it was a space-based wireless service that could hypothetically offer 100% coverage over the U.S. had a formidable calling card, namely that it could provide mobile wireless service to previously under-served rural areas. Telling a government bureaucrat that you’re going to provide ‘service to rural and the under-served’ is tantamount to telling them you’re going to cure world hunger or help the blind to see. Everyone knows there is little or no profit in serving the under-served, it just makes for a good story to soften up government bureaucrats so they’ll grant you favors. Indeed, earlier this year, the FCC allowed LightSquared to offer devices with just the terrestrial capability, making them nothing more than just another mobile wireless provider, which might be viewed as a clever bait-and-switch maneuver since those devices would no longer have the large size and expense of a hybrid phone. This would allow them to rake in some real profits by taking business away from the incumbents of lucrative mobile wireless services rather than being just some quirky satellite phone and data service.

So more than any other factor, it was the decision to take its space-based frequency allocation and have the FCC re-authorize it for terrestrial transmitters that made it incompatible with GPS receivers. Even a very low-power transmitter that is in close proximity to a receiver will have signal strength that is many orders of magnitude stronger than one that is located 22,000 miles away. But if you can influence politicians by explaining away the problem, and hoping that the GPS industry looks upon it as an opportunity to force their customers to purchase new receivers that deal with the interference, then it would be a win-win for all parties, except those who have to buy new GPS receivers, namely consumers, who have no lobbyists to protect them. But it appears that all the hand waving about potential technical solutions may not make the GPS interference problem go away. There may be no filtering technique available at any cost that would fix it and still allow a GPS receiver to maintain the accuracy customers rely on. And so, in order for a company and its investors to enrich themselves, they appear to have no qualms about completely destroying another much larger industry that provides an invaluable service to many sectors of the economy. Some might think of this as free market capitalism. I think of it as sociopathic behavior so extreme that it makes me ashamed for the company and the politicians who did the company’s bidding.

I have to wonder whether it’s even possible to provide an economical hybrid mobile wireless device that can be used with geosynchronous satellites and land-based cells. Iridium provides mobile phone service based on satellites, although that service nearly went broke and was only revived when its multi-billion dollar investment in satellites was picked up for pennies on the dollar. But Iridium is a completely different technology since its satellites are in low earth orbit, just 485 miles above the earth, and so the distance is about 2% as far from the earth as a geosynchronous satellite thereby requiring much less power from the mobile device to establish a connection. But these phones and service are very expensive compared with standard mobile phones. The phones tend to be large and bulky and cost upward of $1200. The service is metered at $1.30/min or more in addition to a $50 monthly fee. Compared with standard mobile phones this would not be a competitive offering, so getting the go-ahead from the FCC to have terrestrial transmitters was a key win for LightSquared because a phone that communicated with geostationary satellites would be very large, power hungry, and costly.

The amount of power and antenna you’d need to communicate with a geosynchronous satellite would be difficult to implement in a handheld device that fits in one’s pocket, if it could be done at all, unless they intended for it to go through some form of a roof-mounted gateway. But then it wouldn’t really a true hybrid mobile device as this service had been promoted. And you couldn’t use a satellite handset from inside a car or house without a roof-mounted antenna and transceiver due to blockage of the satellite signals, making the service appear like something that may feel like a throwback to 1980′s technology.

Hughes has offered a satellite/terrestrial mobile phone solution called GMR1-3G for some time. The hardware looks like something you’d need if you were deployed to some remote corner of the earth. In fact, LightSquared initially had planned to use that service before switching to something called EGAL which stands for Earth Geostationary Air Link from Qualcomm. EGAL appears to be some new hypothetical hardware/service that has yet to be deployed. Interestingly, Qualcomm is the company that came up with the estimate of 5 cents for the filter that would fix the GPS issue.

It is usually not a good sign when a company gathering large sums from investors is basing its future success on a yet-to-be proven technology while simultaneously ramrodding its agenda by forcing a government agency to grant approval and thumbing its nose at its spectrum neighbors. These folks need a wake-up call. Maybe the sound of a few billion dollars of their investment swirling around a drain will provide that wake up call for Lightsquared and its investors and anyone foolish enough to embark on a similar venture in the future.

UPDATE (2011-11-11) If you would like to know more about the testing that was done that showed the significant interference on GPS receivers, the Coalition to Save our GPS has a complete list of test reports on their website. The summary is that during these tests, nearly all GPS devices tested couldn’t receive a signal when they were within a few miles from the tower, even though the LightSquared transmitter was operating at 10% of the power they would be permitted to use. In addition, LightSquared claimed that if they simply moved their signals to the first 10Mhz of their allocated bandwidth, then 99% of the GPS receivers would not have been affected, even though there is not a single shred of evidence from this test that would support that claim.

How to remove COM ports that are reported to be ‘in use’

If you’ve got software that uses a pull down menu to assign a COM port in Windows XP, it may require that the device in question be in a low range, like COM1 – COM4, or COM1 – COM8. I’ve noticed that as I have connected various serial devices to my computer (usually devices that use USB-serial drivers), Windows reserves that port for any time I may re-connect that device in the future. After a while, it’s common to notice that new COM port numbers that are automatically assigned start to creep up into the double digits. You can reassign a COM port to a lower number, but to do that, the port has to be available. If you find that all the lower ports are reported to be ‘in use’, then it may not be possible to do that, which may make it impossible to use the software that has a limit on the COM port number range. In general, to move a COM device to a different COM port number, here are the steps:

1. Right-click on the “My Computer” icon on the Desktop and select Properties.

2. In the window that opens, click on the Hardware Tab and then click on the Device Manager button.

3. From the menu at the top of the window, select View – Show Hidden Devices.

4. Expand the node marked Ports (COM & LPT) and examine the current COM port assignments. One should be listed as the device you want to change.

5. Double-click on the port you want to change. This brings up the Properties dialog.

6. Select the Port Settings Tab and then click on the Advanced button. This brings up the Advanced Settings dialog.

7. Set the COM Port Number to the desired setting. If the port that you want to select is marked as “In Use”, you must free that port – as explained here:

How to remove COM ports that are ‘in use’, but not currently connected to anything:

To release COM ports that Windows XP has reserved from previous installations of COM port drivers that are no longer connected follow the steps below. It’s important to follow the steps exactly, i.e., don’t start the device manager using a method like the one mentioned above, you must launch the device manager from a DOS prompt as shown in Step 3 below for this to work properly.

1. Click Start, point to All Programs, point to Accessories, and then click Command Prompt.

2. At a command prompt, type the following command , and then press ENTER:

set devmgr_show_nonpresent_devices=1

3. Type the following command at command prompt to start the Device Manager, and then press ENTER:

start devmgmt.msc

4. Click View > Show hidden devices. This will display devices that are not connected to your computer but Windows XP still reserves space for them.

5. Go to Ports (COM & LPT) and expand that section.

6. Remove all devices in the list of ports that are grayed out but have a specific COM port number assigned to them. (You can do this by right clicking on the grayed out device and choosing Uninstall and then OK in the dialog box that appears).

7. When you are finished troubleshooting, close the Device Manager.

8. Type exit in the Command Prompt

Panasonic Phone Cannot Find Base – solution

We got a set of 4 Panasonic DECT-6 wireless phones (Models KX-TGA931T) a few years ago and they worked beautifully at first. But after a while, the phones began to exhibit an annoying behavior when we attempted to answer a ringing phone where it would display a message that it lost its connection to the base after a single ring, making it impossible to pick up the call. The other phones continued to ring normally. Sometimes repeatedly pressing on the ‘Talk’ key would get it to answer the call, but it became are real annoyance because it always seemed to happen to the phone that was the closest to answer.

Upon searching the Internet, I found many people complaining about the same issue. I read through a number of forums and found that although it was a rather common problem, there was not a consistent sure-fire solution. One solution suggested unplugging the power to the base unit temporarily, but that didn’t fix the issue, at least in my case. Even the Panasonic website was of no help despite having numerous complaints of the problem in its reviews. I had tried replacing the batteries in one of the phones, but even the one with fresh batteries would still misbehave. However, I had used a cheap set of NiMH batteries from Harbor Freight that were a few years old, and so maybe I exchanged one bad set of batteries for another. The amount of talk time available when the phone worked didn’t seem to indicate the batteries were worn out. Sometimes one of the handsets would not charge fully, and it would be warm to the touch when taken out of the cradle. But then later, it appeared to charge to full capacity according to the battery icon.

Eventually, I grew so tired of the problem that I ordered fresh batteries for all 4 phones. I got them from Batteries America, by ordering the high capacity Sanyo AAA NiMH batteries (P/N HR-4U-1000). I’ve had good luck dealing with Batteries America, especially for things like rechargeable batteries for older ham radio and aviation hand held transceivers. They also carry custom rechargeable batteries for equipment that is no longer available even from the original manufacturer of the product.

I am happy to report that by changing all of the batteries, the problem has gone away. Better yet, the new batteries have 50% more capacity than the original Panasonic 650 mah batteries and will last many hours between charges.

These phones have this difficulty when one or both of the batteries wear out, which all rechargeable batteries tend to do after a year or two of use. It’s not unusual for a new rechargeable battery to be weak if it had been on the shelf too long prior to using it so make sure to purchase your batteries from a reliable source only when you need them. The charging circuitry in the phone is not effective at notifying the user of weak batteries. If you experience this issue, I’d recommend getting a new set of high quality NiMH batteries for all of the phones and keeping track of when you replace them, because when they wear out, the phone will not give you any clue about what’s wrong other than this inexplicable problem where its connection to the base becomes flaky along with contradictory evidence that would seem to indicate that the batteries are not the issue.

Commuting Like George Jetson

I knew from watching the cartoon, The Jetsons that when I grew up, commuting would be fun. Surely, by that time all the technology showcased on that cartoon would have arrived. But sadly, much of the Jetsons technology is still missing, especially the flying cars. But lately, I’ve been using George Jetson’s approach to commuting that has made a 108 mile round-trip commute that I do several times a week not just tolerable, but enjoyable.

Here are a few rules I follow to make my commute more enjoyable:

• Ignore roads, travel in a straight line.
• Don’t take a route that has traffic lights, stop signs, or other commuters.
• Travel at twice the maximum speed limit, say, 150 mph or so.
• Stay 2000′ above other commuters.

APRS track of my commute from Greeley to Rocky Mountain Metro Airport

Note speed - 158 MPH

I guess you can tell by the images that I’m talking about commuting using my airplane. This works for me because one of my consulting clients is based at an airport so I don’t need ground transportation after I arrive. One of my colleagues actually lives on an airport, so he has the benefit of commuting door-to-door using his airplane alone. I have to drive 10 miles to the local airport first before I can hop in the plane…. but if I could only figure out how to take off from my back yard….:-)

Fixing a Sony Wega with a 6 or 7 blink code

A few weeks ago I returned home only to find that our Sony Wega TV (Model KV34HS420) was no longer working. It would respond to the remote control and begin to start to turn on, but then it would turn itself off before a picture appeared on the screen. After that, the standby/timer LED would continue blinking 6 or 7 times. This blinking LED is a diagnostic code, but its description of the potential issue provided little value. After reading a few dozen postings on the issue, a pattern began to emerge that made me hopeful that I could repair it myself.

We purchased this TV in 2005 while the jury was still out about which flat panel TV technology would eventually replace the tried-and-true CRT technology. Back then, the LCD and plasma flat panel displays still had viewing angle and reliability issues and cost 2 or 3 times as much as an equivalent-sized CRT model and so we just decided to replace our 15-year-old Sony CRT TV with a more modern HD-capable CRT TV. I was hoping to get 15 years out of this model as well before having to send it to the recycler.

This TV has excellent picture quality along with no restrictions in viewing angle, and other than its size and weight, I found it much better than what was available with newer technologies at the time. It sits in a corner and therefore takes up no more room than an equivalent size flat panel display. So, after only 6 years, I was wondering whether it would need to be replaced or if I could fix it. After a fair amount of forum reading, I found that this 6 or 7 LED blink code was a rather common problem, along with a common solution, namely to replace the MCZ3001DB integrated circuits known as IC8002 and IC6501 on the ‘D’ board. The forums had many people describing their success at making the repair, but pictures of this procedure were non-existent, hence the reason for this blog posting. Also, the level of difficulty and amount of work involved was not clearly described, so I hope to explain and show what I did so the reader can determine whether it is within his or her skill level to attempt this repair.

This TV weighs 200 lbs. I didn’t want to have to move it from its stand. Fortunately, it was possible to remove the entire back shell simply by removing all of its screws and sliding it off. There are a lot of screws, about a dozen around the periphery of the TV along with several more on the back panel, but fortunately, it’s a one-person job although it wouldn’t hurt to have a helper because the shell, although fairly lightweight, is bulky. Removing the shell allows access to the ‘D’ board.

After removing about a 17 screws, the rear shell can be slipped off.

The ‘D’ board is the one shown in the picture below. I should mention that before removing the cover, you must unplug the TV and give it a few hours for the high voltages to dissipate so as to avoid shock hazards. It’s best to unplug it and wait overnight, since if the TV is not working so there’s no need for it to remain connected to power.

The 'D' board shown above is held in with about 8 screws.

It wasn’t clear how to remove the board, or if it would be necessary to undo all of the wiring connections. Some of the connectors were easy to remove, but the 3 high voltage wires that connect to the CRT did not have easy-to-unplug connections. I eventually figured out that I didn’t need to remove those wires at all. There are a number of connectors that need to be flipped upward to disconnect the ‘D’ board from an adjacent board. It wasn’t clear at first how they worked, but if you pull them upward, they unsnap and pivot up 90 degrees. I unplugged all the other cables I could find, removed about 8 screws, and the board came out far enough to let me rotate it into a position where I could access the bottom of the board. It was necessary to use a stubby screw driver to remove one screw that was far forward, hidden between two connectors, and just under the CRT. The board was still tethered by the high voltage connections, but I was able to fix it ‘in place’, by turning it over like shown in the image below.

Bottom of Sony 'D' board shown rotated in repair position. Note, it's not necessary to disconnect the wire with the suction-cup-like insulator on it.

Unsoldering the two ICs is not difficult, if you use a spring loaded solder sucker like the one shown below.

A spring loaded solder sucker like this one works well to remove the solder.

Close up of IC6501 and IC8002 from bottom of board. Note each IC has two unsoldered pins.

Be aware that each chip has two pins are not soldered to the board. This is normal. Take note of the orientation of the chips since there is a notch on one end facing the closest edge of the board. You do NOT want to install the chips backwards. Also, don’t solder the new chips in directly. Use sockets in case you ever need to do this repair again, since having to unsolder these chips is most the work. If they were socketed in the first place, you replace them without having to remove the board at all.

I wasn’t sure of the best way to purchase the ICs, since many forum participants mentioned purchasing them on Ebay, where there are literally dozens of vendors offering MCZ3001DB chips. The vendor I chose was TriState Module out of Evansville, Indiana because of their reasonable price for the ICs ($6.99 each) and fast shipping ($5 for first class mail). The parts made it to Colorado in just 2 days. I also needed a pair of 18-pin dip sockets which I found at the local Radio Shack for $.59 each. They look like this:

After replacing the ICs with sockets, you’ll need to install the replacement ICs. Odds are that only one of the chips is bad, but since you won’t know which one, it’s best to just replace them both. It is necessary to squeeze the pins together to get the legs aligned with the holes in the sockets. This style of IC has its legs spread out by default, and so they won’t automatically align unless you pre-bend them inward just a little to align with the holes in the socket. Carefully examine the chips after you install them to make sure all the legs made it into the socket.

IC8002 and IC6501 installed in their new sockets.

After re-installing the board and attaching all the cables, it would be a good idea to test it to make sure the repair worked before reinstalling the cover. With luck, your TV will be back up and running, avoiding a premature trip to the recycler. I can’t guarantee this fix will work for you, but the consensus on the forums is that it frequently fixes the 6 or 7 blink code problems on the Sony Wega models.

I found the repair to be of intermediate difficulty, certainly not as hard as repairing the transmission in a washing machine, and the result was very gratifying. And if it ever happens again, I could fix it in a few minutes, thanks to the sockets that are installed in there now.

In the event it doesn’t work for you, then maybe getting one of those new and improved flat panel TVs is your best alternative.

Where have I been?

As some of you may have noticed, I have gone missing in action in this blog. Why? Well, it’s because I’ve been busy with several commitments. The commitment that has most distracted me from posting to the blog has been my teaching gig at Aims Community College. Last year I was asked to teach a 4-credit C++ class in the Computer Science department and I agreed to do it. It’s one of the most challenging classes offered by the department, and so I was honored that they thought I’d be able to teach it. Like many people, I was curious to see what it would be like to teach a class at a local college.

If you want to get a sample of the class, you can find the example programs, assignments, and quizzes here. That web page doesn’t describe the entire class, but it does give you a sense of what’s required to pass it. In addition to that class, I also took a 4-credit class in Java. So between the teaching C++ and taking the Java class, it ate up about half of my time but I found that teaching a class was far more work than taking a class. I also have a few engineering consulting clients who took up the rest of my time.

While I was engaged in teaching the class, I felt a bit guilty about posting to this blog because when you teach, you’re never truly caught up with your teaching duties. I think this is particularly true when are teaching a class for the first time. There’s always more work you can do to improve your next lecture, or design the next set of examples or quizzes. There’s also the time you need to get the quizzes and programs graded, as well as helping students debug their programs. Even if you’re caught up on those things, you can still be engaged in improving your understanding of the material you’re teaching. I am also a tutor for two additional classes, one in Javascript and another in PHP/MySQL. I’ve been doing that for the past few years to help people who have trouble understanding the material to get over the challenging spots and that took up some time. The tutoring commitment should end tomorrow.

So you may have noticed that nothing new has appeared here in a few months. But today I delivered my last lecture in the C++ class and I have just one final responsibility for that class, namely to administer the final exam, which will happen on Thursday, May 5th, and after that I promise that I will have a more regular update of this blog.

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Printable Drill Chart Decimal Equivalent

If you have a 115 piece drill set and have lost the chart that translates the diameter of the drills to a decimal equivalent based on the drill number, letter, or fractional size I have scanned mine, stitched it together and have it available as a jpg or pdf file. When I lost mine, I spent an inordinate amount of time with calipers searching for the right drill diameter. Now that I found it again, I keep it near the drill index and if I ever lose it again, I’ll know where to go to make a new copy of it.

The chart is a real time saver. If you click on the image below, you’ll get the full scale jpg image of it. From there you can right click and ‘Save As’ to have your own copy of the jpg file so that you can print it.

I generally print it to fit to a single page, which shrinks it a little. If you prefer, you can print it full size from the pdf file and then cut and tape it together.

UPDATE: After looking at that image for a while, I decided the chart needed a ‘do over’ and so I put it in a spreadsheet and printed it as a PDF which makes it much more readable. Click on the image below for a PDF file suitable for printing on a single page.

Using a Drill Press like a Lathe to make a Center Hole

My friend is building a Stirling engine and when he found out that I owned a small lathe, he asked if I’d machine a piston and cylinder for him. Having some materials on hand like copper tubing for the cylinder and some solid aluminum rod for the piston, I happily agreed to make the parts. Another one of the parts he needed was a 7/16″ bolt with a hole drilled down the center of it. He had tried to make the hole with his drill press, but ran into a problem where the hole he drilled was not centered. This became apparent only after the hole was finished, of course, as it exited the far end of the bolt off center.

I had an idea about a procedure for drilling an accurate center hole in a cylindrical part with a drill press by first aligning a drill vice to hold a drill bit stationary while using the drill chuck to grip and spin the work piece. My drill’s chuck can hold a drill up to 1/2″ in diameter, which would be more than sufficient to grip a 7/16 bolt on its shank. I thought I’d run a quick experiment and document the procedure for anyone else who may want to try using a drill as a lathe for making a center hole in a cylindrical part.

A lathe is most often used to turn a part using a cutter that can either remove material from the diameter or from the part’s face. But it also has a very nice feature when a drill chuck is inserted in the tailstock, and that is to accurately drill a hole precisely down the center of the part. An example of that is shown below.

Normally, you would use something called a center drill to start the hole and then swap it out for the drill of the proper diameter. If the hole is large, you may have to drill with several drill sizes to get it up to the finished diameter. In this case, the hole I wanted to make was just .125″ in diameter so it was possible to do with just a single drill in one step. The procedure I describe below would need to be modified by resetting the alignment for each drill if you need to open the hole up in several steps.

If you didn’t own a lathe but had a drill press and a drill vice, here is a procedure for drilling a center hole in a cylindrical part.

First, you put a drill of the desired diameter in the drill chuck and tighten it. Then gently raise the drill table, clamp the table to set its height, and then and move the drill vise to the bit and clamp the drill vice down on the bit. The drill vice must have a ‘V’ groove one its jaws to align it vertically on the drill bit. This is important for a subsequent step. After everything is aligned, then use a pair of ‘C’ clamps to hold the drill vice to the table so it cannot slide from side-to-side. Then un-clamp the drill bit from the chuck and the drill vice and turn the bit upside down and clamp it in the vice’s V-groove again so that its tip is facing upward. Then clamp the workpiece in the drill chuck. In this case, I’m using a .5″ diameter section of aluminum rod as the workpiece.

Here the drill is clamped in the vice pointing upward and the workpiece is just partly visible and clamped into the drill’s chuck.

Then turn the drill on. Just like on the lathe, the drill bit will be stationary and you can lower the spindle with workpiece and it will drill the hole accurately through the center of the part. Remember to lift up on the spindle periodically to clear out the metal chips. If you got everything aligned correctly, the drill will make the hole directly in the part’s center. In my case, the hole was within .002″ of being concentric with the outside diameter of the part on both ends of the part. That’s about as accurate as you would get with a lathe so the technique works well.

It may not be apparent but the part is spinning, the drill bit is stationary.

Here’s the finished part with the hole perfectly centered.

Fixing a broken latch on the Yaesu YSK-100 Separation Kit

I’ve maintained the Yaesu FT100 FAQ for about 10 years. For those of you not familiar with ham radio, the FT100 is a popular mobile transceiver. I’ve talked to people from all over the world on it. As time went on, the FAQ stabilized and I rarely have to do much updating to it now other than to fix stale links. This FAQ still sees a fair amount of traffic.

My FT100 is mounted in my Durango using a YSK100 separation kit. The separation kit makes this radio easier to mount in a vehicle by separating the user controls, called the ‘head’, from larger body of the radio. The head then can be installed on a faceplate that is connected to the radio’s body with long cables. The body of the radio can be installed wherever you find room in the vehicle. Mine is hidden in the center console.

About a year ago, the latch that holds the head on to the face plate of the YSK-100 separation kit broke while I was removing the head.

I’ve never been happy with the YSK100 faceplate design since the latch requires an excessive amount of force to deflect when installing or removing the head. Without the latch, the radio could still be used, but it would come off easily whenever I brushed against the head. Since the radio has been out of production for a few years, spare parts hare hard to find. So I decided to fix it myself.

The plastic latch had cracked off of my faceplate.

There had been several reports of this problem on the FT100 Yahoo Group, but no one had ever reported figuring out a fix for it. You can’t just glue it back in place, because the part is highly stressed and a glue joint would not hold up to those extreme forces.

As you can see in the above image, a small portion of the latch is still on the wall of the faceplate. I sanded this off with a small belt sander. Next I took some measurements and started bending some .032″ thick aluminum sheet metal to make my own latch. I have a small metal brake/shear, but in this case, I just ended up using a vice to bend the sheet metal since the brake has a limit on how small the bends can be. I drilled some small holes and with attached it with M3 screws and nuts.

Here is a top view of the latch.

It works pretty much like the old latch in that it’s very stiff and holds with a lot of force. I suppose a thinner material, perhaps spring steel, might have worked better, but this one can be bent to get the desired feel. If it ever breaks again, I know how to make a new one.

Here is a side view of the latch.

New metal latch with head installed.

I hope that others are able to take advantage of my description and pictures to help them to fabricate their own latch in the event that they break the plastic one that comes on the faceplate.