Kirt Cathey, NH2GX, JG1FXZ » Electronics

Old Ham Radio Movie – A video documentary gives a glimpse of history in ham radio.

admin — Mon, 15 Feb 2010 15:45:01 +0000

This movie appeared on the MAKE page a couple weeks ago and I finally got around to watching all the way through. It’s a good watch and intriguing to see how tinkering is as old as humankind!!

Check it out some time.

73 JG1FSZ/NH2GX

Posted via email from Kirt Cathey

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Helicopter Project – Eye In The Sky

admin — Mon, 18 Jan 2010 00:54:06 +0000

This posting has nothing to do with security, but everything to do with electronics and building devices. If you’re looking for a fun personal project, read on! Helicopter flying skills required.
A couple weeks ago, a friend called and said he was driving into Akihabara, Tokyo, and asked if I wanted to join for the ride. Akihabara is known as the ‘electric town’ within the Tokyo metropolis. In Aki (as we call it, short for Akihabara) you can find everything from good deals on normal consumer electronics to PIC micro controllers, components, and anything else, including toy guns, dolls, and English maid garbed girls hailing customers. Will try and include some Aki video some time. Smugwimp, my friend, said he wanted to go to an remote control model store to find something to build a camera stabilizer thing-a-majig, but once he said that, I thought about how long I have wanted to get into RC models. Since I was a kid, I’ve wanted to fly RC airplanes and helicopters – especially helicopters. We took a trip to Aki and both of us purchased a tiny indoor helicopter for practice.
Of course, I promptly destroyed my helicopter, smashing it into walls, television, doors, children, myself, so that $90 investment is parked on top of the bread machine awaiting new parts. So I went into Akihabara a few days later and visited Futaba for a look, and picked up another bigger version.
Well, as the story goes, another week later, I found this even bigger RC super store. I visited this store and just had to get the big one. I had to have one of those nice alloy, carbon fiber, tough, fast, shiny 400 or 500 series. helicopters. After about 15 minutes of wandering around and looking for parts for the two other choppers that were crashed, I picked up the box for an Align 450, went to the counter and asked for a beefy battery, speed controller, charger, connectors, and servos. On top of the $450 for the kit, the additional accessories and necessary parts totaled another $200. I thought about it, then proceeded to put everything back, which obviously upset the store clerk. Whatever.

I got on the train, came back home, then noticed this RC forum where they talk about many, many Chinese knock-offs sold out of Hong Kong by an online store called Hobby King. They sell the 500 version of the model I almost purchased above for a mere $67. Of course, there is a price to pay in more building, greater inspection and quality control before flight, and greater attention to detail inspecting bearings. Well on my online journey, I found this forum thread that covers all the shortcomings of the knock-off version and clearly tells you what else to upgrade and purchase while building in order to produce a good stock version of the model.

So far, here is what I’ve put together and should be flying by next weekend….

The next step is to mount a GoPro camera on the front nose.

73s….

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Cool Serial Logging Device – Logomatic v2 Serial SD Datalogger

admin — Fri, 25 Dec 2009 01:55:21 +0000

This cool little electronics device from Sparkfun Electronics allows you to log anything you can connect via a serial connection. A friend of mine handed this to me for Christmas, which is a good surprise that fits quite well with all the logging electronics applications that I have been prototyping lately, including some future ideas that I have for enhanced GPS/APRS/Wx logging, hiker emergency communications, and others. Enjoy! Comment – rants, comments, anything except spam.

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The WanAway… A work In Progress

admin — Sun, 13 Dec 2009 01:34:27 +0000

Over the past year or so, a friend and I have been mulling over a device that can be used in a variety of ways to deter animals from entering certain perimeter areas – such as keeping a dog from doing his business at the front gate of your house. There are other applications as I have learned that apply to keeping wolves off of ranches, or keeping coyotes away from designated areas.

The high level design involves a circuit that produces an ultrasound output at about 20 KHz combined with a circuit that detects motion and size. The motion detection and sizing will come in the next phase of design, since there are a lot of infrared and ultrasound solutions to work with. No matter where I looked in Akihabara or elsewhere for a 20 ~ 24 KHz ultrasound solution, it seemed that none was available, so I turned to Google. This link presents a rather militant solution that will probably make the creator and tester of the circuit deaf by the time the design is complete. Through the Google journey, I also came along this link, which is a forum dialogue that shows how deviant some of these electronics geeks can really get… looks like a neighbor or two have unknowingly lost their hearing as a result of electronics experiments. Then to get into the science, this link helps but don’t read it right before going to bed. Finally, I decided it was time to create a simplified circuit as that displayed in the first link above. That schematic proposes two NE555 timers – one to generate the frequency and one to pulse as the dog barks, which is probably most effective. In other words, if one half second after a dog barked, if a pulse of irritating noise is heard, the dog will stop barking.

The WanAway Proto #1 is the black box in the front...

This design and approach slightly differs from the WanAway objective, which is to deter such animals as they approach a certain point. Therefore, our objective is to increase power as the dog approaches, so the dog does not react to a counter-action, but reacts to an irritating noise that it hears when approaching that gets more irritating the closer it gets. So I adopted the design above and removed the first NE555 timer. The result works quite well on the neighbors poodles, our Jack Russell Terrier, the black lab down the street, and on our black cat Gizmo.

After making the first prototype created above, I wondered why it would only work when I first turned it on, then the dog would go on barking – the answer, as described above, is that the dogs barking is a reaction to the pulse. However, when you hold this device in your hand or place it strategically in the front garden in an area where you do not want the dog to go, it is quite effective too. Yesterday, I hooked this up to the oscilloscope to get 24 KHz coming out of the device, and this seemed to be very effective – you could see Keith’s (our Jack Russell) ears peel to the back of his head immediately. Poor guy….. heh.

Chilling in the basket before launch.

Okay, now this is a tad bit inhumane but my intention hear here is not to be cruel to animals. This is probably the most humane way to deter barking and other animals from entering a perimeter, so please limit comments to the electronics involved or other ‘ideas’.

Our twelve year-old cat that does not go outside.... total house cat that growls from inside at visitors.

Finally, and not least, I feel the need to justify the Japan category on this posting. The word ‘wan wan’ in Japan is the onomatopoeia for the english word bark – i.e., basically “Rrrrrufff!”. However, Japanese use such language as part of a sentence and situational description more than we would use “Ruff” in the typical spoken English language.
Cheers!

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Keyboards – Serial Analysis Using FTD232RL

admin — Fri, 20 Nov 2009 22:36:06 +0000

First, for those friends at work and personal, you cannot just tap into a USB bus connection of any type and analyze like you can a serial connection. If you have to ask why with a condescending voice as if you could make it happen, then keep to yourself and study USB protocol.
Now that is out of the way, let me take a sentence or two to explain. USB is not serial and does not even compare to serial in a couple of areas. Timing on a USB bus is determined by the protocol version, hence 10 Mbs, 100 Mbs and faster all depending on whether you are using 1.0, 2.0 or whatever version. In serial communications, the implementer sets the timing to a baud rate. Next, what is on the bus is on the bus, so the exchange is not one-to-one in USB as it is with serial. The device identification (HID) is established by the host, and the USB host determines which traffic is for which device that is communicating over the bus. In other words, the USB host (computer) controls all communication, not the implementation of the device.
So one would ask why does a USB to PS2 converter just consist of the four pins of a USB connector tied into four pins of a PS2 connector? I too asked this question and performed a bit of analysis, including busting apart a couple of these adapters to see if a tiny ‘conversion’ chip was inside. This is very, very funny now that I understand better. The reason this kind of pin-to-pin connection works is because the computer (USB host) identifies the device as a PS2 device when it is plugged into the computer, and the computer speaks serial to the device. When the USB plug is used to connect the keyboard, the computer recognizes the keyboard as a USB device and the USB device chip in the keyboard talks to the PC accordingly.

What all this means is that if you run a straight wire tap into a USB-to-USB keyboard connection, you are going to get a lot of garbage from other devices running through the same host controller, you are going to have timing problems, and it will be virtually impossible for a PIC, AVR, or any micro controller to keep up with analysis and filtering due to computing limitations. If this has not made things clear, and you want to know more, I suggest a visit to this forum.

Now, onto the next step. How about running a straight wire tap from a USB-to-USB connection into an FTDI USB to serial conversion chip that is powered by the USB bus itself then analyze the serial exchange? Here is a quick mash up thrown together in Eagle late last night. Will spend some time this morning on the breadboard putting this together. The first thing of concern when reviewing this is whether the USB host (computer) will try to enumerate the FTDI chip and load the driver, which is what we don’t want – so may have to install some diodes or something to make sure the communication on goes one way from keyboard to FTDI chip and out the serial port. Another area of concern is whether the FTDI chip will perform the serial conversion without being enumerated by the computer. Stay tuned. Or, comment with some suggestions, because I really do need all the help I can get.

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JG1FXZ…. Ham Fair 2009 In Tokyo

admin — Sun, 23 Aug 2009 21:34:58 +0000

Last Friday, after exactly six weeks had past, I finally received my Japanese call sign. So now in the US I can operate as NH2GX and in Japan, can operate as JG1FXZ. So, of course, I get on the radio first thing Saturday morning and not a soul is broadcasting. Read a couple emails and find that the Japan Ham Fair. It was a great event! Here’s a picture of the Yokohama DX Club booth. A lot of new and used equipment for sale, different clubs with booths. I personally am not much of a ‘club’ kinda guy – Japanese love moving in groups, waiting in lines, and not enjoying privacy and solace. I do things like mountain climbing and experimenting with electronics/radio to break away from people; not to meet more of them. All that said however, going to the Ham Fair was very interesting since it is refreshing to see what other people are up to and exchange ideas when possible.

Here is a picture of yours truly. I picked a small used element holder that I turned into a 50 MHz dipole yesterday, but may find it’s way to a driven element of a bigger yagi antenna over the next couple weeks.

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Weekend Antenna Project

admin — Sun, 12 Apr 2009 21:22:19 +0000

As a prelude to the upcoming amateur radio license exam that i will be sitting for at the first of May, I spent a few hours late last week shopping for some ham radio equipment – a good transceiver, tuner, and antennas to cover most of the interesting stuff out there. Since the next three weeks will be limited to scanning and listening, I decided to focus on the antennas for now and spend some time evaluating my house for possible dipolar wire antenna setups. I must say that when I got home with all the gear, it was much harder than what i had envisioned in my mind while pulling items off the shelf at the local ham shop.
This brings up a good plug opportunity – while reading through CQ Ham on the train last week I noticed a ham shop in Yokohama called ‘Hamers‘. While not having the broadest selection of radios available, they have all the best stuff for just about any category of radio and a lot of antenna gear. The service was very warm and one of the sales persons even spoke fairly fluent English. I picked up the IC-7000 and am still learning how to use it…. as a scanner still for a couple weeks.

This radio is a nice little portable rig. It can be used as a mobile device or for the base station rig – especially if you’re a budding beginner as I am. Plenty enough functionality to keep me learning over the next couple weeks until I pass the license examinations. Also, it sports a built-in SWR meter so that I can prevent a blow-out when I finally do start transmitting in the lower bands. If any body knows of a good mod that will give me the US bands, please send an email or comment with a link. I’ve looked at a couple of the mods available on the internet and it appears that most people only want to mod this thing so that they can watch television through the control panel. This feature is standard in the Japanese version. Of course, not that I would mod this radio while in Japan – only when I am in the US.
I also picked up a Comet 70 cm and 2 meter dual-band antenna. Using the rail mount that I was using for satellite television (we converted to fiber television a few months ago), I managed to mount this from a PVC extension that put the rig well above the surrounding power lines. I must say, a little antenna goes a long way.

When I was sporting my VX-7 with the stock antenna, I thought that as a consequence of where I lived, that I would never be able to pickup any more signals – NOT! I can’t wait to run out and purchase or put together a patch cable so i can plug these antennas into my VX-7 too. Upon powering up my IC-7000 with this Comet antenna, I could hear conversations and repeater broadcasts that were mere scratches or did not even register previously. Interestingly enough, I occasionally receive a strong signal on 430.960 MHz that is a broadcast from Southern California. I know that it is something coming across on a repeater, but would like to figure out if it is closed or not.
The next part of this weekend project is the low bands 2 to 50 MHz. I picked up a G5RV packaged solution produced by MFJ Electronics. When I purchased the rig I ‘imagined’ my house was big enough to mount this thing on! Heh, my property is not even big enough to mount half of this rig on. So I went into Akihabara to Fuji Musen – the worst, cold customer service as expected; but they got a lot of variety so i put up with it, speak loud and make it so they want to help me and send me out the door. At Fuji Musen I picked up another version of the dipolar wire antenna called the BB6W by Diamond.

When I went to mount this thing to the top portion of the second floor patio at my house, that was when i learned that my house is not even 6.3 meters wide! So I put together some laundry poles extended to 4 meters, then extended the wire diagonally down to another mount at a little less than a 45 degree angle. On the low end, this antenna picks up everything from 0.1 through 18 MHz, then either the antenna drops off around 21 MHz or there just were no signals at the time. I am thinking the later since it will pick up what’s available on the 30 MHz band and I was even getting signals on the 6 meter band, although weak. Before going too much further with this part of the project, I want to get another pole installed to bring the lower part of the antenna up a bit more.
A busy weekend getting all this done between studying for the FCC exam, taking the kids to the pool, dying Easter eggs, doing an Easter egg hunt, playing outside with the kids, working out, and running some shopping errands…. really wish the weekends were longer, but like my work too.

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Hamming Lately?

admin — Thu, 19 Mar 2009 23:18:28 +0000

Sitting here on a Friday morning listening to TWiT – the first day of a three-day weekend and a ten-day vacation. Off to Guam with the family on Sunday morning, so I need to get about a weeks worth of geeking in the next three days. After posting this blog entry, will get back to the keyboard logger project, then maybe another blog entry later in the weekend…. maybe.
A really cool friend of mine gave me (or long-term lending, or ….) a brand-new Yaesu VX-7 last weekend. The model that he purchased a while back then hardly used thereafter was a Japanese version, so the bands did not (notice past tense) completely cover the US amateur bands. While I am a strong radio enthusiast, I am not licensed yet so am not able to transmit, but I can receive and scan all I want. I find that as about interesting for the time being, until I sit for the exam in early May. Of course, there is the electronics hobby value of this little rig, then there are all the security experiments that come with such a device, but I am also thinking that the VX-7 would be a lot of fun when used from on top of one of the many mountains that I climb in Japan.
Being the geek that I am, naturally, the first place I went for information about the VX-7 was Google. Then what appeared at the top of the search, were the mods that are available for the device. This page lists most of the mods available for a VX-7R, which is the export version of the VX-7. When picking up one of these devices, the first thing you’ll want to do is get a data cable, so you can software mod the device and program the over 900 available channels with VX-7 Commander.
Soon after getting the data cable and downloading VX-7 Commander, I managed to find this page which lists all the interesting signals available in the Kanto Area of Japan. The cool thing about this is that at the bottom of the page, the author also included a link to a csv file for importing into VX-’ Commander or any other for controlling any other radio. The one difficulty that I had with linking and programming the radio, is that the software does not communicate when the serial cable is connected to a serial-USB conversion cable. I had to pull out the old Compaq laptop that has a serial connection in order to communicate with the device.

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PIC 18F4550 Prototyping Board

admin — Sat, 07 Mar 2009 22:52:21 +0000

In a first step to start creation of the KeyJack , I found this link while Googling for ideas.

This photo was a snapshot from PhotoBooth, so please excuse the reflection, but most of the components are visible. Instead of using the sexy surface mount devices, I used what was available on a rainy day. Of course the micro controller is not mounted yet, but soon enough. All of the empty holes are for mounting headers that can connect other devices or jumper across onto another prototyping board or a breadboard. Here is the circuit side of the PCB:

As you can see, have not sat down to solder the parts yet…. that’s going to start in just a few minutes. When complete and running, will come back for a follow-up post. Stay tuned.

Follow-up… a couple hours later.
Here is the (sloppy) soldered up back side of the board complete with jumpers and connection headers. Had a couple of soldering mishaps along the way, so had to solder a wire into one part of the run. It all tests positive for conductivity. All that is left are two components I don’t have in the parts collection – push buttons for the reset and bootloader.

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