A NYC adventure: 269 Electronics

The month of May was crazy and busy for us--my XYL was in Peru for the first nine days of the month, then a few days after her return we traveled together to New York for our oldest daughter's graduation from graduate school.  We spent about a week in the Big Apple, and before we left, I looked around on the net for anything I could find about surplus electronics parts stores and such in NYC--an article at the Make Magazine site suggested a place called 269 Electronics on Canal Street in Manhattan. 

Years ago, there were many places in NYC where you could find tons of surplus electronics components, but apparently those days are gone.  But I was undaunted, because 269 Electronics looked like it might be a throwback to an earlier time.  So, on a rainy afternoon I rode the subway to Canal Street and began hunting for the store. 

Canal Street is lined with shops where you can buy hats, scarves, t-shirts, watches, consumer electronics, jewelry, purses--almost anything.  Some of these shops apparently sell knock-offs of designer-label apparel and accessories, but if you're looking for those sorts of things, you'll find some great deals (just ask my wife and daughters--they made a second trip to Canal Street later in the week).

I found 269 Electronics just a short (and very wet) walk away from the subway station.  The electronic parts section of the store was at the back, and I have to confess I was underwhelmed.  The stock seemed depleted--there just wasn't much to look at.  I'm not sure what I expected, but I remember my dad's stories of how he could walk from shop to shop on a certain street in NYC (near where the World Trade Center once stood) and collect all the parts he needed for just about anything he wanted to build.  This wasn't that sort of place--not at all.  But even with that said, I did actually make a purchase there--I had seen something on the Web recently about liquid solder flux, and decided I wanted some, and to my surpise, 269 Electronics actually had a bottle of it right there on the counter.

I had heard about another place farther up Canal Street called Argo Electronics, so I bought a $3 umbrella from one of the nearby shops and decided to head up the street--it was a fairly lengthy walk.  Argo actually DID have some surplus electronics, but as near as I could tell, it was mostly just junk, and it was nearly impossible to climb over the piles of boxes, cheap suitcases, and other junk to actually browse through the few boxes of parts they had.  Honestly, as unimpressed as I was with 269 Electronics, Argo Electronics was even less impressive.

But even though the stores themselves were disappointing, I had a great time walking in the rain along Canal Street, and I don't regret having undertaken the NYC adventure. 

73 de aa0ms

I suddenly feel the need to build a homebrew key

Surfing around on WB9JPS' very interesting Web site, I found a link to this incredible gallery of homemade Morse keys.  Now I'm thinking I should go through my junkboxes and search for bits of hardware that I've saved from disassembling broken TVs and other electronic junk--anything that I might be able to cobble together into a working Morse key.  The photo at right is a key from the gallery, made from two paper clips.

73 de aa0ms

Long live the hamfest

This weekend I went to a hamfest, and spent a few dollars--the ticket price and gas to get there cost more than what I spent once I got there, but I am very pleased with what I found.  For the radio hobbyist looking to build up the junkbox and locate parts for building stuff, most hamfests are still potential goldmines.

A case in point:  while digging through a box of junk on one of the swapmeet tables, I found a box that contained a one-pound spool of #30 Belden Polythermaleze magnet wire--the kind with heat-strippable enamel coating--for $5.00.  Just for grins I looked it up on the Mouser Web site and found their price: $83.73.  I checked the price for similar magnet wire from one of the parts and kits places, and they were selling 15 feet of similar stuff for $2.00.  My one-pound spool contains about 3140 feet of wire!

I also found a NOS (new old stock) air-variable capacitor for fifty cents that would probably cost me around $15 if I tried to buy it new from a supplier.

For a quarter I bought a 10-turn turns-counting dial that would have cost $8-10 new. 

For one thin dime I got another nice hank of magnet wire--maybe 50 feet or so.  For $5.00 I got two hanks of multi-strand copper antenna wire and a length of ladder line--enough for a nice end-fed Zepp antenna. 

I found a box of random parts that was marked $1 (for the whole box)--it contained a bunch of integrated circuits, including several ULN2003A Darlington transistor arrays, some quad op-amps, some MC1556G op-amps, some CMOS digital chips, several LM317 voltage regulator chips, a 75-to-300-ohm TV balun, and a bunch of other little odds and ends, including about a dozen short banana plug test leads--a lot the rest of it is useless to me, but the stuff I can use would have cost me a lot more than a dollar. 

I bought one UHF bulkhead connector from a commercial vendor--a whopping $3.85--but everything else I bought was from the swapmeet tables.  Plus I had a great time connecting with some hams that I knew from the local club, and it was a lot of fun to see a bunch of old radios and test gear and antennas and other junk.

If you like to build stuff, and if you are lucky enough to have a hamfest happening nearby, don't think twice about it--take the time to go and see what you can find.  You may not be able to find everything you need for that next project, but chances are you'll be able to save some money and collect parts for a future project, and you might even learn something in the process!

73 de aa0ms

I love building receivers

There is something very, very cool about building receivers.  You start with a handful of parts, and in a few hours (or a few evenings), you flick on the power switch and (if all has gone well) you hear signals.  Of course, quite often I have to spend a few more hours troubleshooting things before I can get my receivers to work, but that can provide very helpful experience.

I've been wanting to build another regenerative receiver, just for grins and giggles, and hearing Bill, N2CQR, speak on the Soldersmoke podcast about how he suspects regens are possessed and possibly evil made me want to try another one of these guys again.  I have built a couple of different regen rigs--one was a regenerative W1AW code-practice receiver built around a 3.579 MHz color-burst crystal, and the other was a Ten-Tec multi-band regenerative shortwave receiver kit.

I had found an old article by Charles Kitchin, N1TEV, titled "A Simple Regen Radio for Beginners," from the September 2000 issue of QST, that didn't require any tough-to-find parts (except for the air-variable capacitor), and after about 15 minutes of going through my parts bins and drawers, I had gathered up just about everything I needed.

I started by building an enclosure--well, it's really not an enclosure, because the back, top and sides are open to the air.  I suppose it's more of a chassis, of sorts--really just a base and a front panel, made of double-side copper-clad PC board.  I used a 150 pF variable capacitor for the main tuning control, and I wound the coil on a plastic pill bottle.  The article called for 22-gauge solid insulated wire for the coil, but I didn't have any around, so I used some enameled wire I harvested a few years ago from a TV degaussing coil.

I drilled holes in the front panel and mounted the pots and the tuning capacitor, then began breadboarding the circuit with the schematic at my side.  My aim was to finish the receiver in one evening, so I worked quickly (more quickly than I should have), and my layout admittedly leaves a lot to be desired.  And, of course, it didn't work the first time I turned it on.

N1TEV kindly included a few voltages at various test points in his schematic, so I checked those, and found that proper voltage was not getting to the transistor, though it was not apparent why.  I suspected a bad diode, so I replaced it, but to no avail.  I gave it up for the evening.

So the next evening I decided I was going to make this radio work one way or another, and I started poking around and found that the voltages that were incorrect the day before were magically correct.  (How does that happen?  Probably a bad solder connection or a short somewhere that was remedied by my poking around.) I turned the power on and started tuning through the entire range, to see if it would be possible to hear it oscillating on my store-bought shortwave receiver on the bench.  The good news is that I did hear it--the bad news is that there was still nothing in the headphones, so I turned my attention to the audio part of the circuit.

I had used an old LM386 amplifier chip that I had salvaged from another project--it occurred to me that it might actually be dead, so I replaced it with a new one, and when I powered back up I began hearing things in the headphones.  I connected three or four feet of hook-up wire for an antenna and just draped it across the bench, and was able to hear dozens of signals.  WWV came in loud and clear, along with a number of shortwave broadcast stations in a variety of languages.  Sweet, sweet success!

Tuning a regenerative receiver is definitely an acquired skill and it takes some getting used to, but eventually you get the hang of two-handed tuning (one hand on the main tune control, the other on the regen control).  My radio is really sensitive to hand capacitance, meaning that once I tune a station in, I have to keep my hands on the controls, because moving them away changes the tuning.  If I had gone to the extra trouble of using insulated shaft couplers, I might have avoided this problem.  (As you can tell from the photograph, I could also have built this thing with a lot more care given to lead length and layout, and that might have helped a bit.)

But hey--it was a fun project, and it worked, and there was great satisfaction in being able to troubleshoot it successfully.  I think my next receiver project will be some sort of direct-conversion rig, and after that, I'll turn my attention to a superhet design--I have a whole bunch of surplus crystals that I might be able to use.

I hope you're melting solder in some useful (and fun) way!

73 de aa0ms

Scrounging for parts

I used to do this all the time--any time any electronic thing I owned finally broke down and ceased to function, I attacked it mercilessly, soldering iron and pliers in hand, and stripped it of every potentially useful component.  I did it partly because I am cheap and I like getting parts pretty much for free, and partly for the sheer joy of taking things apart to see what they are made of.

So today I went to my local thrift store to scrounge about for old electronics to cannibalize for parts.  I spent $4 on a small portable TV.  I was actually looking for a TV--an older TV--I didn't want one that was made of surface-mount parts.  I was looking for a TV because in some of the radio circuits I've seen on the 'net, the designers include transformers built with TV balun cores, and I figured I would start tearing up old TVs and harvesting their cores (and other parts).

I walked out with a small, old portable B/W TV--there were other, full-size TVs there, but they were more expensive, and they appeared to be newer, and for my purposes, I just felt an older unit was what I wanted.  And it only set me back about four bucks.

I know different people use different methods to scrounge parts from circuit boards--I've heard of the blow-torch approach, where you basically heat up the back (soldered) side of the board with a propane torch (after bending all of the leads straight up), then allow the parts to fall into a bin.  There's a similar technique that involves a heat gun, rather than a blowtorch, but it's basically the same thing.  I opted for neither of those approaches, but rather decided to unsolder the parts I wanted one at a time--remember, I was not as interested in efficiency as in the joy of the activity itself.

But here are some things I've learned when scavenging for parts in this way:

1. Sometimes certain parts are glued down.  Electrolytic capacitors are often secured to the circuit board with a blob of some kind of adhesive, and it can stick very, very tightly.  I've peeled some of the plastic sleeve from more than one electrolytic cap because of that stuff.  It helps to try to unstick the part before you try to unsolder the part.
2. Some parts are practically impossible to remove (using my method) without destroying them--those little IF transformers have not only multiple pins, but usually the shielding cans themselves are soldered to the board--the blowtorch method would probably be a more reasonable approach.  I've pulled many a pin from a transformer while trying to remove it.
3. You've got to be careful with semiconductors, because too much heat can destroy them, and desoldering can require a lot more time than soldering.
4. Don't get your hopes up about all the electrolytic caps in whatever you're taking apart.  If it's old, there's a good chance that at least some of the electrolytic caps are bad.  That usually doesn't deter me or keep me from trying to use them anyway, but it's just something to keep in mind.
5. I don't often salvage resistors, unless they are installed in such a way that there is sufficient lead length so they can be re-used (which isn't often the case).
6. Board-mounted pots are really hard to uninstall using my method.  I usually don't even bother if they are soldered directly to the circuit board.
7. If you take a TV apart, be careful.  The CRT can hold a pretty significant charge.  Years ago I took a TV apart and I carefully discharged the tube; but while I carried it to the dumpster, it  developed enough of a charge from touching my clothing that I still got a nasty shock.
8. If there are big electrolytic caps in the thing you're taking apart, make sure you discharge them before you play with them.

So after a couple of hours of messing around (and even using my old solder-sucker, which never really has worked all that well), here's what I harvested from this little old TV:

1 - 4.7-ohm power resistor (10 watts)
5 - plastic knobs for pots
1 - pot with a pulley on the shaft (for connection to dial-cord)
Various little rollers that go with the pot above (for use with the dial cord)
1 - pot with a switch
3 - power transistors
5 - small signal transistors
1 - varactor diode (I think that's what it is)
5 - miscellaneous fixed inductors
1 - ferrite balun core (whoopee!)
6 - rectifier diodes
3 - signal or switching diodes (appear to be germaniums, but I haven't tested them yet)
3 - thermistors (?)
about 20 capacitors (mylars, ceramics)
about 15 electrolytic capacitors
1 -fuse
1 - chunk of thick aluminum, used as a heat sink
a few resistors
a bunch of hook-up wire, including some coax and two-conductor wire
a little pile of screws of various types
3 of those little plastic-coated metal tabs with a mounting screw hole; they are used as wire tie points--you gather the wires together and bend the tabs around them (I like these little guys)

In my book, that's a lot of parts for $4.00.  Just the transistors, capacitors or inductors alone could have cost that much.  As spring settles in, the local garage sales should net me a bunch of old TVs, radios, broken VCRs and who knows what other kinds of electronic gear to either fix up or cannibalize.  If you hit a garage sale toward the end of the day, people might very well give you their old electronics, just to be rid of them.

Have fun!

73 de aa0ms

Empirical evidence for black holes discovered

Yes, it's true--there is, in fact, a black hole under my workbench.  Seems like every time I work on a project, the smallest parts are somehow sucked off of my bench and disappear forever under there.  I'm guessing that somewhere in the space-time continuum there are enough parts floating around to build several QRP transceivers.

That's my story and I'm sticking to it.  Happy April Fool's Day, everyone!

73 de aa0ms

Goal-setting

Prior to receiving my ham radio license in 1991, I was already an electronics experimenter.  I had built a lot of audio-frequency gear, such as guitar effects devices and preamps and mixers and such.  But I didn't really keep good notes on the stuff I made.  Shortly after I was licensed (originally as N0NZQ), I decided to begin a radio electronics experiments notebook.  In it I keep schematics of circuits I've built, results of experiments I've tried, calculations of component values for VFOs, and stuff like that.  I also periodically have written down my amateur radio goals for the year.

I've drifted in and out of the hobby over the years (mostly because work or other interests have supplanted radio at times), so I'm still using the same notebook I started with (although it is nearly full now).  (For what it's worth, the notebook I chose was one of those composition notebooks with the black speckled cover, like they sell at college bookstores, except mine was filled with graph paper, to make it easier to draw neat schematics and diagrams.)

Anyway--today I sat down and reviewed that notebook, which now covers about 18 years of messing around with radio electronics.  And I read with particular interest my recurring lists of goals, noting that some of the same goals keep coming up, time after time.  For example, it seems like I'm always hoping to get a better antenna system up, and another recurring theme is the goal to build small QRP rigs for every HF band.

One of the things I've learned over the years about setting goals (not just in ham radio, but in any area of life) is that it is a good idea to review them periodically, keep track of your progress, and if necessary, change or update them.  This spring I think I'm finally going to get that antenna project done--my new son-in-law is a strapping young man who is game for climbing a tall tree in my back yard, so I'm optimistic that I'll at least have some wire up soon, higher than I've ever had it before.  I also have noted that I have completed small QRP rigs for 40 and 20 meters--granted, they were kits and not purely homebrew designs, but I'll count them.  One goal was to try one of the digital modes--PSK31, and while I haven't transmitted in PSK31 yet, I've got some software and have been able to receive, so that goal seems attainable soon, too.

My goals in the past have often included acquiring or building various bits of test gear, and I've been fortunate in that regard, as well.  I now have a pretty nice (albeit basic) 30 MHz oscilloscope to replace an old 5MHz 'scope that I borrowed from my dad years ago.  I've managed to find a nice frequency counter at a hamfest, and a signal generator, too (although it only goes to about 2MHz).  I've recently built a crystal test oscillator that works from around 2MHz to around 25MHz, which has been quite useful, and I also built a small dual-range QRP wattmeter--it's not calibrated, but it has two ranges (50 mW and 4W), and it's enough to tell me if I'm stirring the ether at all.  One of my goals for this year to is figure out a way to calibrate the thing and replace the meter's scale with one that is more useful to me.

So here are some of my latest goals:

1. I want to build something with tubes.  I have a bunch of old tubes and high-voltage parts (resistors and capacitors), plus some broken tube-type gear that I can cannibalize for parts.  Maybe I'll start with a simple one-tube regenerative receiver or something.
2. I want to restore an old Atwater-Kent radio that a friend gave me a few years ago.
3. I want to restore a couple of old tube testers that another friend gave me a long time ago.
4. I want to build a CW rig for 6 meters.
5. I want to try my hand at QRSS or WSPR.
6. I want to experiment with frequency multiplier circuits.
7. I want to build a variable DC power supply.
8. I want to build a very small trail-friendly 40-meter CW transceiver to take on hikes and bike trips (with a portable antenna and transmatch).
9. I have a large supply of 2N2222 transistors, so I'd like to try one of the 2N2-xx rig designs.

That's probably enough to keep me busy for the year, don't you think?

So (in case there is anyone reading this out there), what are YOUR goals for this year?

73 de aa0ms