Sorry it has been so long dear readers. Currently, I am putting up about 166 feet of cedar fence at my house and time has not been abundant.

This week, I went over to my friend Les’ (K5RXQ) house to analyze his new antenna. It was a slightly modified Carolina Windom that was supposed to be resonant on 80 meters. I took my trusty MFJ-269 Antenna Analyzer with me. Les has a fantastic MFJ roller inductor tuner, but I wanted to see where exactly he needed for it to be used, and I imagined he did too. Funny thing…after we got done analyzing the antenna, the performance was flat on all bands but 80 meters, 160 meters, and 10 meters. I got a chuckle out of that, but the tuner picked up the slack nicely. I did manage a contact to Italy on my first try.

When i went to grab my tuner, I powered it up. 7 volts. Not enough. Apparently it sat so long that the rechargeable batteries were not charged up enough, and there was no 12 volt wall wart in site. I eventually found an unregulated one, and quickly learned that the circuit powering the analyzer is unregulated as well. Upon turning it on, the meter showed 19 volts. WOAH! (For reference, this was a wall wart for an old 3Com network hub) Good enough for government work, anyway. There HAD to be a better way.

Les and I thought it would be a fantastic idea to have the analyzer feed off of 12 volt input from wherever an Anderson Power Pole equipped station was, since we do work with R.A.C.E.S, and there is usually no reliable 110 volt service where we are deployed. For those of you who didn’t guess at first, the Anderson Power Pole is our standard connector for R.A.C.E.S. equipment.  At first blush, after I started tinkering with it, I took the analyzer completely apart, which was no easy task. The idea was to come off the DC input lugs with a 14AWG pigtail and drill a hole through he chassis where Anderson Powerpoles would be attached. After about an hour and a half, the idea was scrapped. There is simply NO ROOM under the hood of that thing to facilitate the mod.

Instead, I came up with this:

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The above jumper allows me to convert the 12 volt DC modular jack to Anderson Powerpole 12 volt input!

Here is a picture of what it looks like in action (Note: Generally speaking, this is a proof of concept. The actual working model would either be longer, or, have an attachment for a jumper to the distribution block):

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Now I can use my analyzer in the field without worrying about depleting the on board rechargeable batteries. What’dya think, MFJ?

Of course, I could use this adapter for lots of things, but honestly, I don’t own much that I would do a R.A.C.E.S deployment with that doesn’t have Powerpoles already.

Since Ike has me stuck in the house today, it gives me a chance to get to some badly neglected projects. I ripped these two circuit boards out of a couple of dead UPS (Uninteruptable Power Supply) units that my friend Barry gave me to salvage. The batteries are currently being used in a fox hunting transmitter unit. Here’s the before shot before I started doing the recovery:

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You may look at this and think it is total junk. In our modern day ecosystem, the techno-trash our species has produced is causing an overwhelming impact on our landfills, and everything downstream of them. The toxic lead runoff from a circuit board can seep into our water supplies and can have negative consequences on many other things. No, I have not become a hippy, and I’m not encouraging you to go lead a life of poverty just to give back to the environment. What I am saying is, please be careful about what you throw away. If at all possible, recycle it. Be mindful of where that trash is going to go.

That being said, if you are still here, I will continue.

One of my hobbies to keep all of that techno-waste from hitting the landfill is to recover parts that may be of use to future projects of mine. I’ve been stockpiling the circuit boards in boxes, with the intent of taking them to a recycler to reclaim the hazardous materials on them. If anyone knows of such a place in Dallas, let me know. Here is what I reclaimed in about an hour off of the above boards:

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A great bag of loot from this one! About 8 LED’s (light emitting diode), a few LM317 voltage regulators, some N-Channel MOSFET(Metal Oxide Semiconductor Field Effect Transistor) power transistors (60V 10A, AWESOME!), a few 30 amp fuses, transformers, bridge rectifiers, 5 watt resistors, and so on. These parts would probably be about 25 to 30 dollars total if you bought them new. I know your time is worth something, and maybe I came out a little under in that regard. The way I see it though, I am keeping my junk box stocked up for future projects, and keeping a little bit of volume out of the landfill. If it’s your thing to help the environment and have a little fun in the process, this may be something you want to do as well.

This also reminds me of the scrounging I did when I was in school for things. It’s no secret that a lot of students aren’t rich, and a lot of times, this was the only way I could afford the things I needed for projects!

Normally, I don’t write content based on things written in other blogs, but today I couldn’t help myself. Make Magazine featured a post on their blog about some online electronics tutorials from the University of Wisconsin. This is GREAT for all of the hobbyists out there who need something to reference without going to take classes, or getting expensive books. Did I mention they were interactive? That’s right, interactive tutorials on a variety of subjects including everything you ever wanted to know about AC and DC electricity. What a HUGE reference. There are also special sections for sensors, robotics, digital and solid state electronics. Recently, sections on non-electronic subjects were added as well, to include hydraulics and pneumatics; something I know some of my readers are interested in!

If this is something that seems like it is up your alley, or, you just want to validate that I haven’t lost my mind in the quest to bring you quality content, check it out: http://electronics.wisc-online.com/

This past May I had the fortunate experience of riding with Kent Britain, WA5VJB to the Dayton Hamvention in Ohio (he may tell you otherwise). Among other things, Kent is an exceptional antenna designer, with projects on his resume that include antennas that were conceived to reside in the second stomach of a cow (Try to figure out THAT dielectric constant!). You may have read his articles in CQ and CQ VHF magazines. He kind of knows a thing or two. I crap you negative.

Anyway, what I came to tell you about are a unique design approach Kent has for low cost antennas. Before Dayton, a group that I do some hobby work with was looking for a directional WiFi antenna to interface with a Linksys WRT-54G router that was powered by PoE (power over ethernet) and mounted to the side of a piece of antenna mast. The project was created out of necessity to reach a ranger station that was just out of reach for our stock omnidirectional antennas. We ordered some of these from Kent:

What you see are two high gain antennas for 2.4 GHz designed onto printed circuit boards! Here are the datasheets:

Quad Patch antenna datasheet (sadly, this antenna has been discontinued)

Yagi antenna datasheet

We ended up using the Quad Patch for a few reasons. First, we could easily mount it to the side of the weatherproof telecom box we strapped to the tower (the router was mounted inside). The polarization needed by the Yagi to work did not line up with the tower leg we were using. Second, according to the datasheet, ir provides 11 dBi gain, which, in retrospect, was overkill, but who cares.
They work GREAT and do a lot better than a “cantenna”, (Which, if you model it with antenna software, has some serious flaws).

So, if you are on a budget, or just want a great antenna for your project, I highly recommend you check out Kent’s website over at http://www.wa5vjb.com. More on our WiFi project in a later article…..for now, go build your own!

For some reason, when they built a lot of the buildings in the early to mid 90’s, they decided it would be a good idea to wire the entire building with Fiber Optics to every desktop, thinking technology would catch up. Enter Present day: Apparently technology has caught up in every regard except for the cost efficiency of a fiber card in every PC and laptop in the building (Have you ever tried to order a laptop with a fiber optic network interface?). Fiber to Ethernet converter boxes are what a lot of I.T. shops are using to get around that nuance. There is one inherent problem: They don’t last very long. Here is a picture of the circuit boards that came out of a bunch I am in the process of salvaging:

Note the white circles and arrows. Each of these has a 25 MHz crystal oscillator running the clock. Something I have not determined is whether this is an ordinary crystal oscillator or a TCXO (Temperature Controlled Crystal Oscillator). Anyone who is not familiar with the difference between an oscillator and a TCXO need not be afraid. Crystals, by nature, are affected by temperature. The resonant frequency can change (sometimes drastically) with the addition or subtraction of heat. TCXO’s resolve this fundamental problem by providing corrections to the shift in frequency using analog sampling of the output and compensating accordingly.

The challenge with identifying it correctly is that there is virtually no data on the internet for this part, and both types of oscillators can look exactly alike! (For those interested, they are all MMD MB050HA) If anyone knows, please inform me.

Either way, these are all getting reclaimed and thrown in the junk box for a future project! 25 MHz is not ideal for any microcontroller clock, but with a little convincing I could probably turn it into something on one of the HF ham radio bands. Happy circuit bending!