Shopping in Brussels: Composants Electroniques et Jeux de Société

Overexposed picture showing conjunction of venus and jupiter above the grande place
Conjunction of Venus and Jupiter above the Grande Place

I had a couple hours on Friday to do a little shopping before meeting up with friends for dinner in Brussels. We had planned to eat near St. Catherine’s, so I took the metro there a bit early. My first goal was Elak’s electronics, which is one of the best hobby electronics stores on the planet, as far as I’m concerned. Part of the store is given over to computer components, but the rest of the store is discrete components: walls of switches, transformers, project boxes, batteries, etc. There is a center counter area where they maintain an impressive assortment of ICs as well. They carry the entire velleman kit line, plus related accessories.

The only drawback to the store is that it is in a corner of Brussels where the streets do not conform to any sort of rectilinear plan. I always get lost trying to find the store, and having a Google map in hand only makes things worse. It is like that part of Brussels does not obey the normal rules of time and space. Sometimes I try to get to it from the De Brokère metro, sometimes from Ste. Cathérine’s, but no matter what, I end up getting spun around and asking directions. When I get there and think about the path I took it all makes sense, but as soon as I leave, the store randomly pops up in some other universe.

External view of Elak ElectronicsAt least I can recognize the outside of the store when I do find it: the wall next to it has a mural with an elephant and a gorilla. The other place that has a reasonable selection of more common components is MB Tronics. When I last visited them, they had a storefront on Chausée de Louvain not far from the Meiser traffic circle, but I believe they’ve moved the store in the last year a couple blocks to the east. MB’s store hours are not quite as fixed as Elak’s, and the store does shut down during part of the summer for vacation, so Elak’s is always a safer bet.

I ended up buying a set of machine screws and a package of assorted ceramic disc capacitors. I’ve bought this screw set before, and had used them up making various projects. The screws are just the right size for most small projects, particularly the kind that you build in an altoids tin. The capacitor assortment is much better than you can find at Radio Shack. The Radio Shack bag-o-capacitors is full of unhelpfully small value components, whereas the Velleman-brand assortment has a full range (in searching the web, I note that they are also sold by Fry’s Electronics stateside). I am sure that these caps are not top-of-the-line low variance components, but they are great for prototyping.

External shot of Wonderland windowOn the way back to the restaurant, I stopped by a game shop, Wonderland, that is only a few minute walk from Elak’s. This store sells primarily  French language versions of “Euro” table top games: Settlers of Catan, Dominion, Carcassonne, etc.  I don’t think that I saw any Z-man or Rio Grande games, but that’s not a criticism as the store wouldn’t have had room for them. The games were predominantly board rather than card, and I wish I had had more time to look through their inventory. Next time I visit the store, I’ll make sure I have more time, and I will also be sure to have more room in my suitcase. They get extra credit for having zombie dice on the counter. While I’m certainly loyal to my local supplier (Area 42 Games), Wonderland may carry some games that haven’t made it over the Atlantic yet.

Winterfest 2012

SA-2040 tuner: two big capacitor knobs, one central roller inductor knob, a turn counter and a knob to select output

At the end of February, the Vienna Wireless Society held its annual hamfest, Winterfest, and this partially accounts for my absence of blog entries in recent months, as I was coordinator for the event. We had more than 100 vendors in our indoor area, another 40 in our tailgating space, and about 700 people were attracted to the event. I could go on at length about the event, and maybe I will at some point, but for now I’d like to post about the items that I picked up at the event. I’ve mentioned my acquisitions to a couple friends and want to show some pictures.

As soon as the event opened, my eyes landed on a Heathkit SA-2040 Tuner. I have an LDG AT100Pro automatic tuner and it does a great job, but for the Collins gear, I wanted a fully manual tuner. The automatic tuner makes excursions in and out of good match, and I just don’t want to subject the finals of the S-line equipment to variable and out-of-range vSWRs. I’d rather map out the setting for the band segments that I use and then manually adjust.

I had, in fact, been looking for a few months at several models of manual antenna tuner on ebay, eham, and the other usual places. The SA-2040 was high on my list. Typically they run over $100, plus shipping. When I found one at Winterfest, I was happy to see that it was less than $100, in good shape, and already had the modifications that I was considering — a knob with a thumb wheel on the roller inductor, a switch to select multiple coax outputs, and a switch that takes the input to ground. I had a lot of administrative work to do at Winterfest, so I bought it as soon as the event opened and stuck it in my car for the day.

An overhead shot of the internal workings of the SA-2040

When I got home, I took a look inside it. Truthfully, when I got home, I crashed on the couch for the day and didn’t get around to looking inside the tuner for a few days, but either way, I did look inside, and saw that it’s in fine shape. The roller inductor and capacitors are heavy duty and in pristine condition, with no evidence of arcing. The modifications look solid, and I couldn’t spot anything troubling. I screwed it back together and then started trying to figure out how I could possibly fit it on my bench.

The SA-2040 does not have an SWR meter, so I needed one. Luckily, I had ordered one several months ago from Ten-Tec as a kit: the 1225 SWR/Wattmeter. I had a good experience putting together the model 1320 QRP transceiver from Ten-Tec, and it has held up well as I’ve lugged it all over the world making contacts. The SWR kit was also a first-class affair — packed well, parts grouped meaningfully in several bags, all parts present with appropriate excess on wire, and a great manual. The wattmeter consists of a metal cabinet, a large cross-needle display, a range switch, and the option of average or peak-reading for both forward and reverse power.

Front view of the TenTec 1225 wattmeter, with meter illuminated in blue

The organization of the manual was excellent, with the usual check it and then check it again double column for checking off completed steps. There was no ambiguity in the instructions, all the landmarks were obvious, and I didn’t need to do any sort of clever interpretation or fall back on the internet to find exceptions, modifications, etc.

Calibration requires no equipment beyond a digital VOM. One trimmer pot controls internal reference voltage, and other pots are used to set the forward/reverse fudge factors for each power range. Having built the WM-2 QRP watt meter, I’d say that this one was slightly easier to calibrate. This SWR meter was a more complex build with more parts and more mechanical connections, but that is commensurate with its additional features (and I’m certainly keeping the WM-2 as well).

So, the 1225 Wattmeter was assembled over the last week and is now inserted inline between whatever rig I’m using (the first coax switch) and whatever antenna is selected (second coax switch). One fun feature of the 1225 is the RGB backlight, which can be adjusted to any color with trimmer pots. I’ve set mine to a dark blue.

TRS-80 model 100 and manualThe other item I bought was not radio equipment. Near the end of the hamfest, I walked by a table and saw a TRS80-Model 100 “laptop” computer. I’ve always thought this computer was way ahead of its time, and that it represented an important milestone in engineering, so when I saw one marked down to $50, I bought it.

This computer is powered either by wall wart or four AA batteries, has a full keyboard, boots instantly, and has a number of I/O ports including an RS-232 and the venerable S100 bus. I verified that this one is fully operational. I’m not sure exactly what I’ll do with it, but I think it was a good purchase.

 

Contests 2011

It’s still barely the first week in January, so I’m going to do a little retrospective on contests entered in 2011. Some contests I just hear on the air and jump into (particularly QSO parties), others I obsessively prepare for over several months (like the Indiana QSO Party, Operation Sizzling Pork). Usually, though, I don’t think much about them when they are over.

Not included in my retrospective are some of the contests that I participated in as a member of VWS, e.g., Field Day, and the NAQP SSB and CW.

Except for some of the QRP sprints, most contests take at least a few months to turn around results, which is somewhat puzzling considering that log submission is almost universally electronic. So, here’s the run down, based  on a quick scan of outgoing emails with logs attached. Unless otherwise stated, I entered as single operator, low power, CW only:

MN QSOP 1st VA station in category
BC QSOP Hey — I was one of only 20 outside BC in the contest
CQ WW WPX RTTY No way I was going to do well in this contest, but I made some contacts at least
2011 ARRL International DX CW I gave up trying to find the results on the ARRL website
VA QSOP I worked part of this contest with the VWS club, but them went home in the evening. I ended up getting a certificate as 1st place station in Fairfax, County, Virginia. Not bad for a half day’s work.
FL QSOP I recall this one — I was on the back porch with a QRP rig and only worked a couple, but had fun.
IN QSOP Well, I’ve certainly written enough about Operation Sizzling Pork on this blog, but it was the highlight of the year for me. I had fun preparing, during the contest, and even afterwards in compiling the scores. We placed second in the category of multioperator, multistation. Our station ran low power and worked both CW and SSB.
CQ WW WPX CW I think I was camping an entered this one QRP. A bit frustrating because only one out ten heard me, but after a few hours, I had a decent number of international contacts on 5W with an improvised antenna
REF The French amateur radio league contest. I placed 20th among US operators – pas mal.
HA DX I always enjoy the Hungarian contest. I came in at #278, but I still like the way they run this contest, communicate with log submitters, post the results, etc.
RAC Canada Day The RAC contest is also a favorite, although the results are not broken down geographically.
IARU HF The International Amateur Radio Union contest was fun in that I made contact with a number of headquarters stations and added a few new countries to my list. The results have not been posted yet.
The MARAC US Country QSO Party I had just installed the rig in my car and I made exactly one SSB QSO in this contest, but one is better than none. I’d like to try this again next year, but working CW.
Maryland/DC QSOP I worked this one with the NIH Amateur Radio Club, so it wasn’t an individual effort. We ranked second as club station in Maryland.
TN QSO Party I always seem to have great propagation in TN, so I worked this one QRP. I came in as the #3 out of state QRP operator, so I was very happy.
Arkansas QSO Party Luckily, they break the scores down by state, and as not many others from Virginia entered, I was the top VA station. It’s always worth sending in a score.
WAE SSB Again, I don’t have a chance in this sort of contest, but I did finally figure out how the whole QTC thing works.
OSPOTA I heard a random call for the Ohio State Parks on the Air Contest and dialed around to catch a few more. I came in #10 for stations outside Ohio.
Arizona QSO Party I had one QRP CW contact while I was in Montreal for a conference. Results aren’t up, but looking at logs received, I can guarantee that I was the only VE2 entrant!
NY QSO Party I usually have good connections to New York during the QRP sprints, so I also worked this contest QRP. I think I did pretty well, because I recall crossing a bunch of counties off my list, but results are not yet posted.
IL QSO Party I came in 49th in this short contest
ARCI Hoot Owl I worked this contest in the dark with a 20m rockmite, a longwire antenna and some mosquito spray. I had a great time and my score was roughly in the middle of the range, largely thanks to the bonus for working portable. I’d like to do more ARCI events this year.
NAQCC Sprint Hands down my favorite sprint. I have slowly worked my way up, both in terms of operating skill and antennas. I look forward to this every month, but schedules don’t always work out.
Spartan Sprint I also enjoy the SS, and have been working on trimming the station down from a chubby to a skinny. I can now operate pretty skinny, but only on one band at a time.

AKA Interface Considerations

A couple months ago, Ben, NN9S, suggested developing a morse code keyer that would run on android devices (see his write up and video). Since then, we’ve been designing hardware and software to get the job done. The software lives in a repository on the Google Code site, and is moderately functional, but far short of ready for general release. On the hardware side, we’re still batting around ideas. Here is a brief history of the ground we’ve covered with regard to hardware design, and some idea of what’s coming next.

Phone, AKA, paddles and a transmitter - the most common configuration.

We considered all sorts of options such as having the device’s left and right channels run into a standard keyer, using the USB port directly, and some other more exotic alternatives (bluetooth anyone?), but we eventually settled on the idea of having the android device output a sound, which could be used directly to modulate a signal, or could drive a switch of some sort.  The simplest configuration would be the device plugged into the androidomatic keying adapter (AKA), and the AKA plugged into the radio’s key  jack. Presumably, most people would want to be able to also key their rig using a straight key, paddle, or bug, so we assumed that the AKA and some other sending device would connect to the key jack via a Y adapter of some sort.

Android devices encompass a gamut of hardware platforms including phones, pads, netbooks, and dishwashers. Well, soon. At home, my only android devices were a Nexus S phone and an Optimus T phone, so that’s where I started in terms of characterizing the platform. Two essential tools were the android app “FuncGen” and the multiplatform audio editor “Audacity“. FuncGen runs on the android device and can generate various waveforms with all sorts of parameters, whereas Audacity test files (e.g., *.wav files) can be generated on a desktop computer and transferred to the android device for playback using apps like media player or winamp. The phone’s output can also be recorded via Audacity to analyze fine timing events (for those of us without fancier equipment).

Using FuncGen at full media volume to generate a 1000hz sine wave, the Nexus S put out about 1.85V peak-to-peak (654 mVrms) into a 20-100k load, and the Optimus T put out 1.9V peak-to-peak (671 mVrms). The output impedance of the Nexus S was about 14 ohms, and the Optimus T was near 17 ohms. I calculated the maximum power transfer at around 7.9mW per channel for the Nexus S, and 6.4 mW for the Optimus T.

Output voltage at maximum volume into a fixed (20k) load was flat for the Nexus S from 20Hz to 3000 Hz, with only slight attenuation (down less than half a decibel) at 10kHz, and down almost 2 dB at 20kHz. The Optimus was more sensitive to frequency and was ideally flat from 300-3000 kHz, with more marked attenuation at 10kHz (less than 1 dB) and 20 kHz (down almost 5 dB). Both phones demonstrated a log-linear relationship between the number of clicks on the media volume scrollbar and the rms voltage output (e.g., for the Nexus, if full volume was 707 mV, one detent down was 477 mV, the next was 317 mV, 224, 150, 100, 70, etc.) — meaning that the voltage drops off fairly quickly to relatively low levels.

The first hardware design considered was literally a VOX keyer circuit. A quick websearch turned up a nice design by N1HFX. This straightforward circuit is based on a 1458 op amp, which is essentially two 741C op op amps in one package. The circuit was meant to work from very low voltages generated by a microphone, so the first op amp acts as an inverting amplifier, and the second as a comparator. The 741C op amp is a dual voltage op amp, so to run this from a battery, the positive input of the first amplifier is raised to half Vcc by a voltage divider; likewise, the set point for the negative input is a bit above half Vcc. The output from the second amplifier will be a square wave at the same frequency as the input wave, and ranging from about 1V to (Vcc-1V). Since this drive would only be half-duty cycle, some smoothing is necessary before driving a transistor. A simple RC circuit sets the degree of smoothing, and a diode prevents back-discharge of the capacitor into the amplifier. Since the circuit was designed for voice, the RC values were chosen for a relatively long time constant; however for purposes of keying a rig for fast CW or even Hellscreiber transmission, a low time constant is preferable.

Based on the N1HFX design, we prototyped a similar circuit, with the following exceptions – for cost/availability, we used an RC 4558 op amp, which is a workalike to the 1458. Because the phone’s volume is adjustable, and the output is relatively high, we used a fixed resistance ratio for the comparator set point. The smaller RC values used were just large enough to smoothen output wave. We added some bells and whistles including a power indicator LED, and another LED to indicate when the keying circuit was closed. It was probably overkill, but to further protect the phone, we stuck an optoisolator between the rig and the rest of the circuitry. In retrospect, all of these LEDs are nice looking, but consume many orders of magnitude more power than the keying circuit itself, and they might as well be omitted — in our final designs, we just key the rig from the switching transistor.

Another design that we considered was based on a circuit described by Robots Everywhere in their implementation of an earphone jack-based serial port on android devices. Their write up made us wonder if android phones could put out digital levels through the ear phone port — boy, that would certainly make our job easy. As it turns out, some can and some cannot.  The Nexus S can sustain a very flat positive or negative voltage without breaking a sweat: at 20Hz, the output waveform is very square, at 1000Hz, there is some ringing. The Optimus T, however, looks like it’s output is capacitively coupled. At low frequencies, it’s not very square at all — the output capacitor bleeds voltage until the next half cycle. The take home is that around 1000Hz and above, both phones can generate some semblance of a square wave.

The Robots Everywhere design centered on an LM324 single voltage source quad op amp, but used only two of the four op amp subunits. Our next design was aimed at getting away from timing issues related to signal rectification and need for a “filler” capacitor prior to the switching transistor.

Since the phone can generate a stereo output, our next circuit used the left and right channel to generate square waves180 degrees out of phase — effectively get a halfwave rectifier for free by doing it in the software. These waveforms were fed into op amps like in the first design, with amplification occurring in the first stage and inversion in the second stage for each channel. When the positive portions of two channels are then brought together through diodes, the result is just about a flat positive voltage, about about 1V under Vcc (due to the diode drop). This voltage is applied to the gate of a 2N7000 enhancement mode N-channel FET, which has a threshold voltage of just under 3V. The gate capacitance itself further smooths the small defect at the edges of the two square waves. The 2N7000 could be directly connected to the rig, but we again used an optoisolator, since the design required the use of a battery anyhow.

Both the dual and quad op amp designs resulted in some prolongation of tone sent out the phone’s earphone port. The best we got with the dual was about 4-5ms, and the quad op amp design yielded around 3ms extra duration. We could compensate in software, ending the signal earlier, but it would be preferable to avoid that complication. For morse code, this extra delay would probably be unremarkable, as a single code element at 30 wpm is 40 milliseconds, so +/- 10% is probably tolerable. At fast code, it becomes significant, though — at 60 wpm, a single element is 20 milliseconds. Since we had plans to implement Hellscreiber keying as well, with a minimal on-time of 8.163 milliseconds, this delay was not acceptable.

In addition to the timing issue, we realized that it would be preferable to not require a power source for the adapter. Luckily, one solution address both problems — using a transformer to step up the voltage enough to directly bias a switching transistor. This approach was inspired by the interesting work done by the “HiJack” team exploring power harvesting from the iPhone’s earphone port. They designed a miniature power supply using the AC from the iPhone’s audio output as driving voltage. A similar approach was taken by Wolphi, in connecting the iPhone to microphone input for his excellent PSK31 appplication for android. His circuit was, in turn, based on a circuit proposed by KH6TY.  Similar solutions have also occurred to hams in the past developing interfaces for sound-based keying of Hellscreiber, including a design by K9JRI that includes a voltage doubler.

In considering transformers for stepping up voltage, we did try the nearly microscopic one employed by the HiJack team. Unfortunately, it was too far off in terms of impedance matching to function well. We ended up going for the most accessible transformer, a 8:1000 ohm audio transformer from Radio Shack. This transformer gives about an 11-fold voltage step-up, so some losses in rectification are tolerable. In principle, germanium diodes or even synchronous rectification could reduce these losses, but there is enough head room to not worry about it. The currents involves are minuscule, so there is no problem is using tiny (read: cheap and available) signal diodes like a 1n914. A 0.01 uF capacitor does not entirely smooth the wave, but it ensures that the voltage is never below about five volts, and the 2n2222a transistor remains saturated when the transformer is energized. The additional duration introduced by this circuit is around 300 microseconds. I tried adding a voltage doubler per the K9JRI circuit mentioned above; the voltage was marginally increased and the duration increased slightly as well to around 1 millisecond. Since the extra complexity did not add much, I’ve opted to stick to the simpler design, which can be built from easily obtained parts for less than ten dollars (much less, if you mail order and/or buy in bulk).

The transformer-based designs have the benefit of providing galvanic isolation between the android device and the the keying circuit and rig. One downside to transformer-based designs is that they need relatively high volume output from the phone. The design above required that media volume be set within three clicks of maximum on the Nexus S. The dual op amp design worked down to 9 clicks below max, and the quad op amp design worked down to 12 clicks below max.  Both devices tested put out about the same voltage and power, and hopefully most android devices are in the same ballpark, but if there were a particularly underpowered device, or if this circuit was used in some other context where lower output were available, a design with active components might be necessary. The other drawback to

We are now trying to figure out ways to miniaturize the design, and of course, the most limiting factor is the transformer. If anyone spots a suitable transformer let me know. I guess the idea one would be 16 ohm on the primary, and 2000 on the secondary (or 4000 on the secondary, with a center tap — allowing us to get rid of two diodes).

[Update 17 May 2016]

The androidomatic keyer has not had a lot of love lately; Ben and I have been busy with other projects and developing for android requires more sustained attention than we can afford for now. However, I’d still like to see this work preserved. When the GoogleCode repository blinked out of existence, I moved the software archive over to github, where it now resides: https://github.com/dhakajack/androidomatic-keyer

Warming the shack

The power supply, receiver, transmitter and station monitor/phone patch, plus microphone and key
Collins S-Line Station

For several years, I have been putting together a Collins S-line station, and earlier this week, I fired it up for the first time.  This station was the top of the line, when it was produced in the 1960s, and although there have been plenty of technical innovations along the lines of improved frequency stability, image rejection and DSP, these units still sound great.  Now that winter is approaching and the basement is growing chilly, I was more motivated than ever to get this tube equipment on the air.

I have had these radios packed up for quite a few years, not really wanting to ship them all over the world as we moved. Last year, I started putting them back into order. I started by looking through the archive at the Collins Collectors Association and joining their email list. Between the archive and routine access to people who know these rigs inside and out, I came up to speed in no time.  I didn’t see anything too amiss on my inspection of the rigs, aside from some carbon residue near the rectifier tube in the power supply. This is a common defect in these supplies — some arcing occurs from the rectifier tube to the metal cabinet, so I wasn’t too worried about that, but realized that the rectifier socket would need to be replaced by a ceramic one down the road.

photo of the underside of the 32S-3 transmitter
I took a lot of photos during the survey phase to provide some insurance that I'd be able to reassemble the radio after working on it. The underside of the 32S-3 transmitter showing extensive point-to-point wiring. The "black beauty" capacitors are prominent. They and the surrounding silver-colored electrolytic capacitors were replaced.

The most likely items to fail in rigs of this age are the electrolytic capacitors, so I went through each unit and replaced all electrolytic capacitors, plus any paper capacitors and some of the less reliable “black beauty” oil-filled caps. There is some debate about whether it is better to replace preemptively or only when there is evidence of failure, but I leaned towards the preemptive side. While I want to preserve the original engineering, I also want these units to perform well and get some actual on-the-air use.  The other obvious thing that can fail are the tubes. Of course, I can’t just run down to the corner store anymore and use their tube tester. To put that statement in context, these radios are just slightly older than I am.

There are a lot of patch cords that run between the station components, some audio, some RF. These and the power plugs and control connectors had degraded to the point that I wanted to replace them. I rebuilt the connecting cords and power cords using the original plugs and sockets, but for everything else, I visited Joel at RF Connection in Gaithersburg, Maryland. Conveniently, his store is about five miles from where I work, and it is packed with every connector, cable and adapter known to man. He also stocks a lot of the materials used in restoring Collins equipment, including replacement feet. Yes, I replaced the little rubber feet, because they also had degraded over time.

photo of a capacitor deep within a metal slot
This was my favorite capacitor to replace -- deep down in a metal pocket that I couldn't disassemble. It was like soldering a ship in a bottle.

After inspecting the units, I took each out of its cabinet and to greater or lesser extent stripped them down. All the tubes came out and everything got a thorough cleaning. All the pots got a shot of deoxit, and other bits of mechanical tune up were performed. I replaced the burnt out panel lights with long life replacements from D.A. Buska Engineers, LLC.  These LED lamps should last just about forever, which is good because it is something of a hassle to replace bulbs. It involves my wrist bending in ways that seem unnatural. However, I would think twice about using the LED lights again if I did another restoration. Their light is harsher than the original incandescent lamps, and there is some barely perceptible flicker.

After putting everything together came the smoke test. Since these rigs had been off for more than two decades, I approached this cautiously. I tested each unit separately, bringing power up slowly using a variac (auto-transformer). The power supply came up to voltage and all the supply outputs tested nominal. The receiver also powered up, and when I hooked it up to an antenna, it seemed reasonably sensitive. The band calibrator seemed to work, and put the dial right on WWV. I flipped through the different bands, and could hear signals on all of them.

Photo of the upper deck of the transmitter, with the final amplifier cage in the foreground
The top side of the transmitter. The front of the radio and the main tuning dial are in the rear, the final amplifier cage is in the foreground. A bunch of the tubes have already been removed at this stage.

The transmitter was more complicated. When I got to about 80V on the variac, a thin wisp of grey smoke wafted upwards from the power amplifier section of the transmitter. I couldn’t find where the smoke was coming from, but the take home message was clear — I needed some professional help.

Even if I had not hit this snag, I would have sent the radios in for some professional servicing at this point. After such a long period on the shelf, they were in need of a laboratory realignment, which is beyond what I can do with my current equipment. I also wanted someone who really knew Collins equipment to look them over.

I contacted Peter Wittenburg at Collins Rebuilders. He is located near Annapolis, Maryland, which is close enough that I could carefully pack the rigs in my car and drive them up. It was definitely the right call — the radios got the love and attention that they deserved from an expert. Peter swapped out the rectifier in the power supply, fixed a fairly major problem in the receiver’s permeability-tuned oscillator (not for the faint of heart), replaced a few tubes that had seen their day as well as a few other discrete components that were not up to spec.  He ran the rig through its paces and gave me a nice report, that shows by and large, the rigs were seaworthy.

An Astatic microphone
An Astatic D-104 microphone.

While he was performing his analysis and repairs, I picked up an Asiatic “lollipop” microphone with the proper Collins connector at a hamfest. I had previously borrowed a variac for testing, but decided to purchase one for fulltime use in the station. The Collins equipment was made for a time when the line voltage was lower than the present, and higher voltages will shorten component life. The whole station is now plugged into an isobar strip that itself is plugged into the variac, which maintains voltage at 117V RMS. The station is turned on/off with the isobar rather than each unit’s power knob, as those knobs are all but irreplaceable and are prone to mechanical wearing.

Over last weekend, I made sure that my attic antennas were tuned up, presenting less than a 2:1 vSWR across their useful ranges, as the tube equipment is not tolerant of (read: smokes when confronted with) less well-behaved loads. The ionosphere was revved up as high as it has been in the last decade or so, which boded well. I made my first contact on 40m with WB8PPH (“wb8-pumpkin-pie-headquarters”), who was running a special event station for the Circleville Ohio Pumpkin Festival. I had a few more contacts with PA, IA, and IL and then Sweden, England, Croatia and the Czech Republic on 20m, and Cuba, Honduras, Mexico and finally South Africa on 10m. The received sound quality was golden, and I received favorable reports concerning my audio quality as well.

schema of s-line wiring between different modules
Interconnections for transceiver operation.

The rigs can be run in transceiver mode, where the transmitter is slaved to the receiver’s VFO, or they can be run independently, with the both the receiver and transmitter VFOs in action; this is what you would have to do to operate split, for instance, as there is no other RIT/XIT function. Separate operation is also the way to go for CW operation. In transceiver mode, you would hear nothing when zero-beat to the incoming signal (naturally), and the offset in CW mode is 1.3 khz, which is impractically large. To operate CW, I picked a clear frequency and used the “cw-spot” function on the transmitter to send a low-level signal to the receiver, allowing me to adjust them to the same frequency. I did one round of calling (straight key, natch) and had an immediate reply from Northern Ireland and Bulgaria. I had a little difficulty getting the vox-balance right to accomodate semi-breakin operation (some hangtime after transmit so the relays aren’t constantly clicking, but not so much that I miss the reply). According to the overseas stations, there was no problem with key clicks or chirps, so I guess we’re okay on that front as well.

I’ve never been a big fan of sideband, but I got a big kick out of working stations with this rig, and I think I might be spending more time behind the mike this winter.

QRV à Montréal

Graffitied picnic table with Tentec 1320, Winkeyer, Palm Paddles, and wiresI’m up in Montreal for a conference on rare diseases and the agenda is pretty tight. However, after meetings ended this afternoon, I scampered northwards from the hotel, up past McGill University, heading for the high ground of Mont Royal Park. The downtown is a canyon of metal buildings, but ground slopes up as you head north, away from the river.  I actually didn’t climb to the top of Mont Royal — I stopped when I found a picnic table about half way up. The top of the hill sports a bunch of antennas, and I thought it best to keep some distance from other radiators (and the giant metal crucifix at the top of the hill. I’m not sure if it radiates, but I didn’t want to go near it either).

My picnic table was already decorated by the local artisans with their initials and names, so I knew it was something of which they were proud. Conveniently, but not too surprisingly, there was a tall maple tree nearby, and the antenna went up in one throw (because no one was looking). I set up the TenTec 1320, the Hendricks SLT+ tuner, and my Swedish lead-acid battery. I should mention that this time, TSA had no problem with lead acid batteries. I guess that was last week’s policy.

I was operating as “AI4SV/VE2”, which is a quite a mouth [fist] full. The first station I worked was Ivan, IZ4DLR, who gave me a 569. He was running 200W into a 3 element beam. I informed him that his beam was performing very well both coming and going. My next contact was with Stan, N7OC, who was also running 5W in Custer, Washington. I was pretty happy with the distances — Italy and Washington within a few minute of each other. I had a few more contacts, working Virginia, South Carolina, and even one station in the Arizona QSO Party. I hope I was a multiplier for him. I’ll have to think about what station category I’d be in that contest — Single op, single transmitter, single band, cw only, qrp, portable, Candian.

A basket of friesOn the way back, I stopped by a restaurant advertising itself as a transplanted Belgian fritérie. It was nice to see a place that served different sauces with their fries, but the fries themselves were a bit overcooked, and the sauce andalouse could have been a bit spicier. Nonetheless, their beer was good, and they had hockey on a big TV, so it was still worth the trip.

Visiting with Swedish Hams

Continuing the visit to Sweden from the previous post

Saturday morning, Kjell pulled his car up to the hotel, and we took off towards the village of Dalarö. Along the way, he showed me his mobile set-up, which included a Kenwood mobile rig set up for ARPS and an associated GPS unit.  As we drove, he gave me a brief run down of the history of the area and what was going on in terms of ham radio activity.

A scan of a business card from the restaurant SaltskutanAfter about fifteen minutes, we arrived at quiet village on the water (I realize “on the water” may not be very informative when it comes to an archipelago). Kjell mentioned that this particular village is popular among the well-off who maintain summer cottages there. One of the stops on our tour of this town was the tiny sea cabin that belonged to Anders Franzen, the archeologist who discovered the 17th Century wooden ship Vasa, preserved in the brackish waters of the Baltic.  For lunch, he took me to a restaurant in the building that at one time has served as the customs house (tullhuset) for ships bring in goods. The meal was very tasty and involved a meat similar to bacon, but thicker, served over what I think was a potato pancake.

A photographic qsl card for club station sk0qoAfter eating, we continued the trip towards the club station, SK0QO. The station is located on the Gålö peninsula, which until fairly recent times was an island. The station has been there for about a year, and the club owns the building, which is on the edge of some farm land. Driving up to the station, I noticed that they had a number of dipole antennas strung up, a vertical, and I think even a discone.

A number of hams were present at the station, some on the air, and others preparing for their annual hamfest, which will occur next week. I learned that the club is among the largest in Sweden, and that they frequently take part in contests.

The club house has a main room with a central table and a corner fireplace. One rig was set up on the table for QRP voice. I could hear some morse code sounds coming from behind the door to a side room. I peeked in a found a few operators on an IC-7000. It turns out that one of the operators was Jonas, with whom I had a CW QSO the previous day. He filled out a QSL card on the spot, and handed it to me, which is about the fastest turn around time I think I will ever have for a “dx” QSL. Afterwards, Kjell snapped a photo of some of us out in front of the station.

Photo with some Swedish hams in front of the SK0QO club stationJonas explained that on the previous day, by the time our qso took place, he had been operating for a few hours, mostly in English, and was relieved to hear a Swedish call — which turned out to be me.  I was relieved to learn that he had, in fact, sent to me in Swedish and that there wasn’t something wrong with my listening skills.

Also in the photo are Olaf, who oversees the station itself, and Carin, who is working on her sea captain’s license, and was also sending morse code that day.

After a nice time chatting with the hams at the stations (all of whom spoke excellent English), Kjell took me to visit his friend Sven, an extraordinary homebrew experimenter who definitely has “the knack”.

Sven is interested in monitoring the planet’s Schuman resonance, an extremely low frequency (i.e., 7 Hz fundamental) signal, and he has gone to extreme lengths to build his own equipment to do so. It is well worth reading Kjell’s excellent article on Sven’s efforts. What is amazing is that Sven has built equipment sensitive enough to isolate these tenuous signals, and that he does it in a populated area, where radiation from power lines, heating systems, and every other domestic electrical device complicates the situation.

This was no small task, and Sven is willing to put in an extreme effort. He has, for example, entirely cut AC power to the second floor of his house, where he has built a magnetic loop antenna the size of an upright piano. The coil itself is suspended by elastic supports and the ceiling and walls are covered in anechoic material to avoid acoustic vibration of the coil. He has gone so far as to “tune” the room itself, by positioning baffles to null out the room’s intrinsic acoustic resonances. No half measures there.

a map showing the route driven earlier in the day as reported by ARPSAfter all of this, I thanked Kjell for being an amazing host and for extending such a warm welcome to a visiting ham. We agreed to set up a sked at some point, and I hope we’re able to meet on the air in the future. Later that evening, Kjell sent me a link to our APRS tracked route from earlier in the day.

I was able to get on the air again that evening from the hotel room using a longwire thrown out my 8th floor window. Even with this very suboptimal antenna arrangement, I worked two stations on 20m, one in Wales, and one in the Czech Republic. For kicks, I did try the rockmite on 40m. I didn’t get any replies, but I did at least show up on a Netherlands reverse beacon monitoring station at 8dB above noise.

On Sunday, I again hiked into the woods behind the hotel, spent about two hours on the air, and worked eight stations (in Russia, Germany, Italy, Slovenia and England). I turns out that I was lucky, as not too long afterwards, a series of solar events disturbed the ionosphere for a few days. In all, I worked 14 stations and 9 DXCC entities with my 5w 20m transceiver.

 

 

SM0/AI4SV versus the TSA

Last week, I attended the European Cancer Organisation (ECCO) conference in Stockholm. Most of the time, I was either at the conference, or at side meetings that took place between meeting sessions. My schedule was pretty tight, but I packed my QRP bag in case I had some free time.

My plans almost ended at Dulles Airport. The United Airlines baggage clerk gleefully told me that my suitcase was about 500 grams over the limit, and that it would cost an extra $200 to ship it to Europe. I reached in, took out my QRP bag, and brought the suitcase weight back under the limit.  I had hoped to pack the QRP equipment in the checked luggage rather than to carry it through security, but having travelled many times with the same equipement, I wasn’t really worried about it. That was something of a mistake.

A TSA agent adjusts his light blue vinyl examination glovesWhen my QRP bag went through TSA screening, as expected, they wanted to hand-inspect it. They pulled the sealed lead battery out and said that it couldn’t go on the plane — they were unable to get a good image on their x-ray machine. I replied that this made some sense, it was, after all, a lead battery. I suggested they rescan it, rotating it 90 degrees in one axis or the other, so that the lead plates would be parallel to the beam. I got a puzzled expression. I explained that the exact same battery had gone through security many times, including at that same airport on other international flights, and had not been a problem. I wasn’t getting anywhere, though, so finally I let the issue drop, handed the battery to the TSA agent, and said he could keep it. I suppose they must have a nice collection of confiscated electronic gear by now, so they are probably in need of some batteries as well.

On the flight over, I wracked my brains trying to think where I might find a suitable power source, with limited times between meetings. I recalled that batteries were expensive in Belgium, and assumed that the cost would be similar across the EU, related primarily to ecological concerns about battery waste — in fact, I had guessed batteries would be even more costly considering exchange rates and Sweden’s reputation as a green country. One option I considered was visiting the hotel’s business center and borrowing the battery out of a UPS for a day or two, but I’m glad to say it didn’t come to that.

Right before jet lag caught up with me on the first day, Thursday, it occurred to me that no one would know better about where to find a battery than a local ham. A quick Google search led me to the blog of SM0FOB, Kjell Bergqvist. I strongly recommend reading through his blog entries — they’re interesting, even if you’re not headed for Sweden. Anyhow, I noticed that he lived very close to the town in which I was staying, so I shot off an email and turned in for the night.

Kjell's FB QSL card printed on glossy photo paperKjell wrote back the next day and identified two stores within a five minute walk from my hotel, both of which sold a variety of lead acid batteries and chargers. Kjell also suggested that I could just borrow an already charged battery from him, but since I had donated my last battery to the TSA, I thought it better to buy a replacement, plus a smaller charger. The cost was comparable to what I would have paid in the US, so I guess the cost of batteries in Belgium may have been driven more by local taxes or that lead acid batteries are considered more ecologically sound since they are rechargeable and in the end, somewhat recyclable.

Beyond giving me helpful advice about where to buy batteries, Kjell suggested that we go out for lunch on Saturday and visit a couple local hams and their club station. The timing couldn’t have been better, since my first meeting on Saturday was late in the afternoon, so we set a time to meet.

Friday morning, I visited the conference, caught up on email, and picked up a battery. The battery was fully charged when I received it, and since I had some time before an afternoon teleconference, I took my QRP bag and went for a hike.  The hotel is just east of the Handen commuter rail (pendeltåg) station, and just across the railway tracks is a park and a lake. I took a footbridge over the tracks and then followed some trails in the park. I assume that in the winter, these trails are for cross-country skiing. I followed the trail that looked like it led to the greatest elevation, and walked more or less parallel to the lake front. Eventually, I found a nice rocky area to one side of the path, and threw an antenna into a tree.

radio, tuner, earphones on a moss-covered rockThe location was perfect: a rock to sit on and a few other rocks at just the right distance to serve as a desk. The rocks were coated with moss, and the whole area was so undisturbed that I was a bit worried that perhaps people weren’t allowed off the trails. I tried not to bruise the moss and brushed pine needles over my footprints on the way out.

Once set up, I realized that I had not packed an RCA phono cable to go from the keyer to the rig. Luckily, I had some wire leads with alligator clips in the bag. I opened up  both the keyer and the rig and made the connection directly (that’s why the keyer is open in the photo). The rig was the usual — my TenTec 1320 and a longwire antenna tuned with a Hendricks SLT+.

I spent about an hour there and worked four stations: two in Russia, and one each in Bosnia-Herzegovina and Sweden. I didn’t realize that the final station, SK0QO, was Swedish at first. I thought the SK prefix was in Eastern Europe. After a while, I realized that the station was sending to me in Swedish, though, assuming from my “SM0” prefix that I was a Swedish operator. I copied the name of the operator, Jonas, wished him a vy 73, and figured I would look it up when I got back to the hotel room.

When I got back, I did search it on qrz.com, and realized that SK0QO is the same station that Kjell had mentioned in his blog, and that we would be visiting the following day. While I was at the computer, I checked the reverse beacon network, which showed that my 5w signal had made it as far as Canada.

More on that and the rest of the Swedish QRP adventure in the next entry

Attic Antennas Are Go

Last week, I stuck a RCS-8V remote switch in the attic, and ran some RG-213 and a CAT5 control cable down to the shack in the basement. The switch has five ports (plus the common feed port), so there is lots of room for experimentation. Just in time for the Vienna Wireless Society 10m net on Thursday of last week, I got a 10m dipole in place, peaking near the center of the roof, with the arms following the sloping contours of the roof, running South to North, roughly in the center of the attic. The next day, I put up the Alpha Delta DX-EE multiband dipole, although the ends had to bend a little to fit. In principle, the dipole should tune 10/15/20 and 40m. The DX-EE runs flat from East to West.

I haven’t run an antenna analyzer over the whole set up yet, but I did try everything out in a trial by fire this weekend with the some contests. Before the contests, I did a quick comparisons between antennas.

For most purposes, the 10m inverted dipole and the 10m element in the DX-EE behave the same. The main difference in them is that I cut the inverted V to resonate near the voice segment and our local net, versus the DX-EE favoring the lower portion of the band and CW. Since most of the local net antennas are vertically polarized, I figured that having some vertical component in the local net signal would not be a bad idea. I’ve heard South America on both of them, and they seem comparable.

Comparing the DX-EE to the ground-mounted vertical out back, the dipole shines on the higher frequency bands. For the comparison, the DX-EE is tuned (if needed) via the radio’s internal tuner, and the vertical is tuned through the LDG AT100proII in the shack.  10m (and 12m) are barely tunable on the vertical. They *do* tune, but very little power is radiated. As for 15m, I tried calling CQ and watched the reverse beacon network.  The signal detected by K3MM was 18dB and 36dB above background for the vertical and dipole, respectively. For N7TR, the difference was less marked at 19 vs 22 dB. For 20m, I got similar results for WA7LNW 9 vs 17dB and for W0MU 7 versus 18dB. A number of stations received only the dipole signal.

On 40m, the vertical definitely wins. I am not sure if I can trim the dipole adequately to make it work on 40m, as the ends approach the sides of the attic, one of which is covered in aluminum siding, and the other of which is the concrete wall (rebar?) between our townhouse and the next one. The ends of the antenna take a jog right around the 40m traps, and the right angle turn may be too sharp. When it comes to lower frequency bands, the vertical is my only choice right now. I think this means that some sort of loop antenna is in the cards.

I took park in a few of the weekend contests. The WAE SSB contest ran all weekend, but was made difficult by two periods of unsettled solar conditions. Nonetheless, I made contacts with a bunch of countries including Austria, Belgium, Bulgaria, Croatia, Denmark, Estonia, France, Germany, Hungary, Italy, Luxembourg, Netherlands, Northern Ireland, Poland, Romania, Serbia, the Slovak Republic, Slovenia, Spain, the Ukraine, and Wales.  Not too bad for voice. Most of the contacts were on 20m, but some were on 40m, so both the attic and external antennas got a work out. I’m not sure if it  was the propagation, my antenna or just the nature of the contest, but I didn’t work stations on 15m.

While WAE was running in N1MM, I used my regular logging program to keep track of the other contests and events  going on over the weekend. I worked a fair number of stations in the Arkansas QSO party by voice and CW, and even a few parks on the air in Ohio and Indiana.

I had some firsts as well: I ran across a station calling CQ from Guyana, so that’s now in the log book. I also randomly dialed over to 60m and found that my tuner can match the vertical. I’ve never heard a QSO on 60m, so I tried calling and got a response from Chuck, KD8NLL. So, I guess that band does work after all.


	

MDC QSO P 2011

the logo for the Maryland-DC QSO Party "The Fun Contest"Last weekend, National Institutes of Health amateur radio station W3NIH went on the air to participate in the Maryland/DC QSO Party. The event ran on both Saturday and Sunday, plus a break in the middle. It’s been quite a while (as in, years) since the club has participated in a contest, and I had suggested that we try out this local, low pressure contest to gauge interest in this and other on-air activities.

While the club has a couple contesters, most of the members are more casual operators, and not all have experience in operating on HF. Nonetheless, a couple members made their first HF contacts during the event, and perhaps we enticed our one unlicensed guest to get her ticket.

We ended up working from about noon to 6 pm both days, with more phone than cw contacts. I don’t have the log in front of me, but I think we ended up with an estimated score above 20,000 or so. We were somewhat limited in cw because of the WAE contest the same weekend. 20m cw was bristling with European station. When we did go to cw, we tried not to pick bands accessible to EU, but even so, contesters there sniffed us out (yes Germany, Bulgaria, Slovenia, Russia, and Northern Island, I am looking at you). They were no doubt confused to get an exchange of “CLB MON” instead of “599 001”, but at least a couple knew about the QSOP and sent “STD DX”.

The NIH has a reasonably well-equipped station with an excellent antenna farm, mounted on the roof of one of the buildings on the main campus in Bethesda — a spiderbeam, a couple dipoles with broad coverage, a semi-functional GAP challenger vertical, but the radio room is not used frequently. As a contest station, it would take some work to optimize the room for efficient and comfortable operation. We’ll have to see after this event if any appetites have been whetted, and whether W3NIH will ride again in some other contest.

Listing of DX Cluster spots from 3 stations, one in Spain
We were spotted!