Archive for the ‘radio’ category

Resume of a Master Dumpster Diver: the Early Years

February 21st, 2009
Dumpster

Dumpster

With transition imminent in our lives, I have begun packing up some of my things that I don’t use much right now. It’ll save some time and headaches when we finally figure out where we’re going and begin the moving process. Coincidentally, my good friend Matt recently moved cross-country and elected to dispatch the majority of his tinkering resources via Craigslist. You see, Matt and I share a common vice: we are master dumpster divers.

I was reminded of this reality as I have been trying to center myself with respect to what’s important in life last week week. I have a lot of stuff, frankly, an embarassing amount of stuff. And, although I use a surprising amount of it, I really don’t need it. But, this post is about collecting the stuff, not getting rid of it. I’ll save that for a later post.

As I began sifting through some of the goodies tonight, a confluence of thoughts began to swirl in my head. I’ve had resumes and vitae on my mind for quite a few months now since I’ve been looking for employment (if you hire engineers or scientists, particularly for RF/signal processing/remote sensing/upper atmospheric/space research and development, I’m your man). And, I was poking through the rubble of my home “office,” which is actually my office, hamshack, and workshop, plus Sarah’s desk and books and the place that Sarah and I cram stuff into when company comes. Suddenly, it hit me: my entire resume can be read through my collection of odds and ends.

Dumpster diving, to borrow the analogy from Nelson Muntz, is like “kicking butt” in the sense that it might not involve any kicking at all. Likewise, you have to get to the stuff before it gets to the dumpster. This is the first rule of dumpster diving: Know who to ask, how to ask, and when to ask. The second rule is don’t get greedy. I learned both of these rules at a tender young age.

You see, the house I lived in between the ages of three and nine was next to the Village of Millersburg’s street department garage. Of course, this was a great boon for a child of my age to see all of the equipment and workers coming and going. Mom and Dad may remember this story differently; but, this is my recollection.

Although I was fascinated by all aspects of construction work, the one thing that I obsessed over more than anything else was signage. Some kids are experts on dinosaurs, I was fascinated by road signs. I coveted the road sign poster on the wall at the BMV. Mom had inquired about obtaining one for me to no avail. The other thing I coveted was a road sign or two of my own. A friend had a stop sign in his room; but, I was looking for something more exotic, maybe a yield sign. My poor mother worked some connection she had at the Street Department to get a discarded sign. She told me that we could go down to the sign depot and pick one out in the morning, which was probably a mistake.

I rose particularly early the next morning and, after locating the sign depot, collected a few signs for myself. When you’re a kid, street signs don’t look big and heavy on their posts. But, when you get up close, they rival your personal geometry. So, I left a trail of signs I couldn’t carry back up to the house. I don’t remember the details of what happened next, other than that we had to return all of the signs and get “approved” ones. I hope somebody thought it was funny; goodness knows I learned a lesson that day about the difference between dumpster diving and theft of city property.

A few years later, Mom had an antique dealer come through the barn behind the house and the signs caught his eye. She let him have them for a song. I was incensed at the time, although in retrospect, it was probably better to not profit too much on them.

The basement of the Inventor’s Hall of Fame once hosted an area where kids could dismantle old hardware. We were fortunate to visit when some racks of AT&T Long Lines hardware had been recently donated. I think I carried a half-dozen plastic sacks of relays, waveguide, transistors, meters, and other assemblies out of there that day. Although I have sifted through most of that by now, the juiciest pieces still remain in my inventory, ready for use. I still don’t think that the docents knew what hit them when the budding master dumpster diver rolled in.

Although I dabbled off and on in the barter of used electronics and such in high school, the dumpster diving began in earnest again in college, where I met guys who weren’t afraid to actually climb into real dumpsters to fish things out. Those were good times. Most of the stuff we pulled out of the dumpsters was building materials, which we used to spruce up our living spaces. Blocks from a demolished (the Young Building of Philosophy and Relgion, a grievous sin against architecture and HVAC) academic building allowed us to put an “upper deck” couch behind the regular couch in our apartment for stadium seating. This was great for watching movies, or at least watching my roommates play Mario Kart 64 with their pharmacy notes on their laps…right.

One of the other great successes was DuddiNet and the Tower of Power. I dragged an 8-foot relay rack (rescued from the scrap heap at a summer job) into my dorm room and filled it full of computers and networking equipment. I asked the university IT people if they had any leftover rolls of CAT5 cable and they gave me as much as I wanted. We pulled our own network in the dorm. At that time, the dorms were 10baseT with hubs. So, it was a real bottleneck if you wanted to move some data (use your imagination here) around. We put in a private switched 100baseT network that connected four rooms on two floors.

In more recent years, I’ve scored some terrific stuff just by paying attention when spaces are being cleaned-up. For instance, that’s how I got my HP vector voltmeter and my oscilloscope. And, indirectly, through Dad, it’s how I got some more Greenlee punches and a set of metal-marking stamps. Anyhow, in order to protect “sources and methods,” I’ll decline from disclosing too many details about my more recent activities…I haven’t swiped anything from a forbidden dumpster, though. Promise.

» Read more: Resume of a Master Dumpster Diver: the Early Years

Contest Blues

January 18th, 2009

I got on for the CW version of the North American QSO Party last weekend for about 45 minutes.  I did all S&P, although some of it was the fatiguing two-radio S&P.  For some reason, it wasn’t the same for me as it was last year.  Maybe it’s because I didn’t prepare much in advance.  Or perhaps it’s the fact that my favorite 930 is dead.  Shoot, it could be that I’ve patched my antennas so many times that they’ve changed SWR minima from the CW end to the phone end of the bands!  Whatever it was, I didn’t feel the rush of the contest this time.

During SS CW, I suspected that this moment might be coming.  Am I getting old?  Tired?  Lazy?  Or just disinterested.  I don’t know.  Maybe some sunspots would help?  Maybe I should liquidate all of my aging hardware to buy a K3 or an MP and tickets to the Caribbean in February and November?

Perhaps it’s a more personal thing.  Why spend so much money on something that takes me away from my family (wife right now)?  Certainly, it is a social event among friends to get on the air and make some noise.  But, I can do that with one radio and a wire in the trees.  Do I need to keep the KT-34XA’s I plan to stack?  The T2X to turn one of them?  The 402BA-S?  Will I ever be able to spend what it takes to put up a tower that can hold that stuff with a clear conscience?  I used to look forward to having a dominating signal and pushing the state of the art in receiving.  I’m not sure any of that is too important to me today.

I think I’ll wait to see where we land next year before I make any decisions.  But, I may be cutting back.

» Read more: Contest Blues

HP 8405A Vector Voltmeter

December 8th, 2008
HP 8405A

HP 8405A

A recent find.

» Read more: HP 8405A Vector Voltmeter

Cold, Football, and SS Phone

November 16th, 2008
OSU at Illinois

OSU at Illinois

I picked up a cold last week.  It’s been with me since about Tuesday.  I thought I pretty well was getting it kicked.  And, then Sarah’s family came to watch the OSU-Illinois game.  I’m not a big football fan.  But, I did enjoy watching the game despite the icy wind.  Watching Beanie Wells jump an Illinois defender was definitely worth the price of admission (I was not fast enough with my camera and I don’t have a telephoto lens).  But, the cold came back—with a vengeance.  That put a damper on the 200 QSOs I hoped to contribute to the SMC total for SS Phone.  I made about 60 this morning, mostly on 40 meters, and mostly thanks to nice blistering run on 7187 kHz.  I was really weak on 20 meters.  I’ll probably make some more contacts this evening before the contest ends.

» Read more: Cold, Football, and SS Phone

Miscellaneous

October 27th, 2008

Just some miscellaneous news from happenings over the past month…first, the good news…

I passed the oral exam on Tuesday.  So, I’m officially ABD now.  There is a light at the end of the tunnel.

Nikon released the 50mm f/1.4G AF-S SWM prime lens at the end of September.  I guess I wasn’t paying close enough attention.  This is good news for D40 owners such as myself.  But, the price is almost as steep as the Sigma f/1.4 30mm and 50mm HSM lenses.  The 30mm lens would be a better all-around choice.  Perhaps Nikon will come out with something a little shorter by the time I’m ready to buy.  Until then, I’ll keep using the 50mm f/1.4 AF-D that I have on indefinite loan from work.

I managed to destroy the drivers in my recently-repaired TS-930S.  I considered swapping the drivers from my second radio into this one.  But, when I took that radio apart, I found that the capacitors had swollen.  So, I have parts on order to fix that.  UPS says they’ll be here today.  I requested a quote for the NTE236 replacement for the MRF-485 drivers.  They want almost as much for the NTE236 as RF Parts does for the MRF-485.  I think I’ll get the MRF-485s.

We had high winds yesterday (Sunday).  I lost the 80-, 40-, and 20-meter dipoles.  Sarah said, “Do you expect that (80-meter) antenna to last the winter?  It just broke in September.”  She’s right.  I’m not sure I’ll repair it if it breaks again.   It’s less than a week to the CW Sweepstakes and I only have one working radio (FT-840) and antennas for 10 and 15 meters.  The forecast calls for 65 and sunny on Thursday.  So, I’ll probably take the day to work on antennas.

» Read more: Miscellaneous

TS-930 update

October 9th, 2008
TS-930S AVR board

TS-930S AVR board

Thanks to KA5IPF and WE0H, who answered my query on the TS-930S reflector!  The oscillation was due to dried-out electrolytic capacitors on the AVR board and unhappy pass transistors on the heatsink in the back.  I bought 105 C capacitors instead of the 85 C ones that Kenwood used, plus bumped the voltage rating up to 63 V instead of 50 and 35.  Fortunately, I still had some leftover 2N5886’s, but I need to buy a replacement set of capacitors and pass transistors to have on hand in case the other radio fails.  I haven’t tested it in contest conditions, but all signs are good that we should be ok.  Maybe the NS tonight?

Have a Synton ARC (sorry about the ancient web site…we are going to fix it…sometime) meeting at 2:00 today.  Everybody else in the Club is building SoftRocks.  I’m bringing my IK4AUY preamp parts to start building.  Need to order some PL-259’s, probably today.  Yeah, and I need to finish writing my prelim exam document and presentation.  So much to do.  So little time.

» Read more: TS-930 update

TS-930S power supply

September 28th, 2008
Benched TS-930S

Benched TS-930S

Remember how I said that I thought the W9RE switchbox had terrible isolation?  Well, although I didn’t measure it with a VNA, I was doing some testing the other day and noticed that it only seemed only bad when the left radio was transmitting.  For example, I put the left radio on 40 meters and the right radio on 20 meters.  There was terrible broadband hash whenever I closed the PTT line on the left radio.  So, I put the right radio on 40 and the left radio on 20 and transmitted again on 40.  No hash, just some faint trash that followed the keying.

I had noticed during the Sprint that the vacuum fluorescent display on the left radio was flickering following the keying.  But, I didn’t give it much thought until now.  I flicked the meter selection switch to Vc and sure enough, it was too high (>28 volts) on transmit.  Plus, it would spike and pin the meter whenever I released the key.

Today, I built a band decoder cable (fortunately, I had stocked-up on the mini-DIN plugs and the PIEXX board uses Yaesu BCD format) for the Yaesu FT-840 and put it into the left radio position. It’s clean, too.
The left ‘930 is now on my workbench, which is barely large enough for it.  It turns out that there is a substantial (4 volts peak-to-peak) ripple on the power supply when I close the PTT.  I sent a note to the TS-930S reflector; but, unless KA5IPF answers it, I’m probably on my own.  I suspect it’s just going to be a matter of disconnecting subsystems until I find the offender.

Until then, I’ll be using the FT-840 and the old TS-930 for SO2R.  But, at least I’ll be able to hear!  I’m also relieved that I probably won’t need to rewire W9RE’s switchbox.  I just need to build some short jumpers and W3NQN filters for all bands.

» Read more: TS-930S power supply

K8GU/9 – Urbana, IL

September 24th, 2008
K8GU/9 shack

K8GU/9 shack

80 meters and the Moon

80 meters and the Moon

This is my humble station in Urbana, IL. Inside, I have:

  • Kenwood TS-930S/AT with PIEXX digital upgrade (5-million S/N)
    • Inrad #103 and #104 400-Hz CW filters cascaded
    • Inrad #94 and #96 2.1-kHz SSB filters cascaded
    • Inrad roofing filter
  • Kenwood TS-930S/AT with PIEXX digital upgrade (2-million S/N)
    • Kenwood YG-455C-1 and YK-88C-1 500-Hz CW filters cascaded
  • Softrock v6.2 40-/80- and 160-meter SDR front ends
  • Yaesu FT-840 with Inrad 500-Hz CW filter (not shown)
  • Astron SS-30 and RS-7A (not shown)
  • W9RE-style 6×2 switch (not shown)
  • KK1L band decoder and relay driver box (not shown)
  • Heil HM-10 headphone mixer for SO2R
  • Homebrew W3NQN 200-watt transmitting bandpass filters for 160-20 meters
  • IBM Pentium 166 MHz 80 Mb RAM w/ Windows 95B
    • TR-Log
  • Dual Pentium III 500 MHz 512 Mb RAM w/ Windows XP and Xubuntu
    • N1MM
    • VE3NEA Rocky

Outside:

  • 10/15-meter fan dipole at 25 ft
  • 20-meter dipole at 35 ft
  • 40-meter dipole at 40 ft
  • 80-meter dipole at 40 ft (open-wire feed can be fed against radials on 160 via shack-operated relay)

The 10-40 dipoles favor the E/W direction, although on 40 most of it goes straight up. The 80-meter dipole would favor N/S if it mattered. If I install any new antennas this Fall or Winter, they will be receiving antennas for 40-160. We hope to leave Urbana in the Summer of 2009. Destination TBD.

Stored hardware:

  • Two KLM KT-34XA 32-foot boom tribanders
  • Hy-Gain 402BA-S 2-element 40-meter yagi
  • Mosley TA-33jr tribander (no boom)
  • Lots of wire and coax
  • 100+ ft of 7/8″ hardline
  • Hy-Gain T2X Tailtwister
  • 50 ft of Rohn 25G and accessories

» Read more: K8GU/9 – Urbana, IL

Station work

September 20th, 2008

A couple of shots with the ole Wrist Rocket and some creativity with the DK9SQ mast got a new line into the tree.  I’ll be back on 80 again soon!  I’m still trying to figure out what to do with the 6×2 switching system.  I found two relays in my junk box.  But, I need four more, plus a clue about how to wire it all up.  I want to rebuild it as a system like Top Ten Devices suggests.

I also picked up a dead, but cosmetically pleasing, 19-inch Dell flat panel from the scrap pile at work on Friday.  This afternoon, I tore it apart and put it back together.  It works now.  For my good conscience, I’ll be taking it back to work on Monday.  Rats.  I was hoping I’d at least have to solder something…

» Read more: Station work

If it stayed up…it wasn't big enough: A visit from Ike

September 14th, 2008
Drooping feedline

Drooping feedline

There’s a saying in the ham radio world about antennas:  If it stayed up last winter, it wasn’t big enough.  Well, my 80-meter dipole / 160-meter vertical lasted from February to September.  I guess it was big enough.  The remnants of Hurricane Ike passed through Illinois today, dropping four inches of rain in about five hours.  It was the wind, not the rain, that did the antenna in.  Sarah and I were laying on the floor in our living room looking up into the big tree in front of the house, watching the branches swirl.  For good measure, I craned my neck to see where the dipole crossed into the spruce in the other corner of the yard.  Indeed, it was still there.

Not five minutes later, I heard a thump on the roof.  I craned my neck again and the antenna was gone.  It was hard work getting that antenna up!  Actually, I think the hard part through the oak in the back yard is still intact.  The easy part was getting a line over the spruce.  The weather is supposed to be decent later in the week.  The antenna was made of #14 solid THHN, which was probably most of the problem.  I haven’t done a full forensic analysis of the failure, but I’d guess it was near the center insulator.  I used continuous pieces of wire to form the dipole legs and the open-wire feeder, like W7FG does.  But, the solid wire was probably undoing…

» Read more: If it stayed up…it wasn't big enough: A visit from Ike