For the past couple weeks, we’ve been experiencing load-shedding that starts about an hour after sunset. The capital region of Madagascar does not have enough electrical power production capacity at present to run everything at once, so there is a rotating blackout. Now that I’ve added some UPSes, this has minimal impact on my family because we have a back-up generator that comes online in under a minute — usually. Last week, the generator didn’t start rumbling and we sat in the dark [presumably] looking at each other.
I was in Vienna on a business trip, but I had some time on Sunday to put the portable station on the air using my Austrian guest license, OE1ZJW.
At the Vienna radio club meeting, OE1VFW gave me two invaluable pieces of advice. The first was where to shop for electronics: Conrads. Their megastores in Vienna carry consumer electronics, hardware and tools, and hobby electronics like arduinos, raspberry pis, various kits, parts, project boxes, etc. I was able to restock a few items that I needed back in Madagascar. The other bit of wisdom: where to operate.
If I had lived in Vienna for a few years, I probably would have eventually come to the same conclusion: Cobenzl. It is elevated and far from any noise sources. I have rarely heard background so low. I could hear signals that would not even budget the S meter.
Just outside the city on the North side there is a wine-producing area known as Grinzing. From the Heiligenstadt Bahnhof, the 38A bus runs through this region and up to a park. Near the bus stop, there are restaurants and public bathrooms, so this is civilized sort of “field” trip. Behind these facilities, however, is a large public field.
Three years ago, I paid a visit to Lamb’s Knoll Summit in Maryland (as detailed on this very blog). At that time, I went up the Appalachian Trail to the summit with a handheld to test my VX8GR handheld and a 70cm hand-held yagi. I verified that I could hit the VWS 2 meter and 70 cm repeaters in Virginia even with the Comet SRH320A antenna, a short whip. I also checked out possible operating positions and access paths with the intent of returning at some point for a SOTA activation. I also verified that from the summit I had good cellular connectivity and could hit a bunch of APRS digipeaters. Today I returned with my FT817 and activated the peak, W3/WE-007.
I’m back in the US for about a month, part vacation, part work. Stop one was field day with the Vienna Wireless Society at Burke Lake Park in Virginia. After that, I joined the family first in New Jersey and now in Montauk, New York. I’ll be in Montauk through around July 12th and then back and forth a bit to Washington, DC. I have a week of work, from July 20 to July 27 in Bethesda, and then the last few days in Indianapolis to attend GenCon.
Field Day was as always enjoyable, but this year particularly wet. I arrived less than 48 hours before the event, so I was still on Madagascar time, which helped with the late night operating. On the Thursday before field day, I was driving all over the place to catch up on shopping, including a visit to Ham Radio Outlet in Woodbridge, VA. On the way back, I passed the field day site and noted that a huge tree had been chopped down. This tree is right in the middle of the field day site and was traditionally used for antennas in the past. It had a number of dead branches last year (I’m not blaming RF) and the park authorities decided that it represented a hazard. Consequently, the antenna plan needed some rearrangement.
On the Friday of field day weekend, I showed up around noon to Lee’s (KD4RE) house to see if I could help with antennas. He was in charge of both food and antennas, but had simulated some designs in the previous week, so I followed his drawings and put together wire and PVC spreaders for a 20 meter and 40 meter vertically polarized delta loop. In the past, we’ve had some issues with interstation interference, so the idea was to cross polarize the various antennas where possible. The 40m was used by the 40m SSB station and the 20m by the GOTA.
Antenna deployment was slowed by heavy rains on Friday. In areas near the park, roads flooded, rivers overflowed, and our simulated deployment came nearer and nearer to being an actual deployment. We got most of the antennas in place including a huge 40m moxon, but left the hex beam and spider beams just above ground level because we were worried about wind. Additionally, we were liberal in the use of plastic sheeting to supplement the weatherproofing of our tents, particularly the network operations tent, which already had equipment in it on Friday.
The next morning was sunnier, but the fields (and our shoes) were saturated with water. The antennas went up, with extra care to secure ground guys to either very large stakes or other fixed objects that would hold in the muddy soil. By the start of the event, 14.00h, the four HF stations were ready to go. In addition, we had the GOTA, a VHF/UHF and a satellite station in the field. GOTA attendance was somewhat down due to weather, which cut down on foot traffic through the park. We did not succeed in the satellite contact; we heard the ISS APRS beacon, but no one was operating from the station. Otherwise, the timing of the couple of operational FM birds was not favorable. Almost all of the contacts made were HF, although we did get in a little 6m activity at the end.
Field Day was successful in a number of ways: as always, a large club turn out despite the weather. There were many new (to me) faces at this year’s event, so that bodes well for the general health of the club. At least one CW and one SSB station stayed on the air around the clock. Finally, the club maintained its tradition of gourmet food — amazing steak, pulled pork, chicken, beans, potato salad, hamburgers, hot dogs, eggs, sausages. No one went hungry and the calorie/QSO ratio remained strongly positive.
After FD, I drove up to Montauk, threw a rope in the trees and set up shop on an elevated porch with my FT817. I tested the set up in the Canada Day event on July 1st. In an about three hour period, I logged 51 QSOs, mostly CW, but seven were SSB. For provinces, I got ON, QC, MB, BC, SK, NL, NB, and NS. Since everyone can work everyone in the event, I also picked up a few stations from even further over the pole: Belarus, Ukraine, Czech Republic and Slovenia. A 5Ah battery lasted the whole operating period, as I was mostly S&P, although I did get a handful of replies to CQs.
Since then, I’ve operated sporadically, both CW and voice. I had forgotten how useful 40m is, since that band is next to useless at my QTH in Madagascar due both to noise and lack of close-in stations. In the last few nights, though, I’ve had very clear contacts to the west coast on 40m.
I’m putting small updates on qrz.com and when I get a bunch, I’ll transfer them to the blog and add some pictures. I’ve set up the QRP station on the back porch, an FT-817 plus a memory keyer that is saving me a lot of work. I am running off SLA batteries, a workhorse 9Ah and two 2Ah batteries for when I’m recharging the 9Ah or when I’m more portable. The matching box end of the LNR 40/20/10 end-fed antenna is in a palm tree about 20 feet up, just next the the porch, and the other end is about 40 feet up, suspended from a tree branch with a water bottle counterweight.
This weekend, I attended the GI Cancer Symposium in San Francisco. I had back-to-back meetings from Thursday through Saturday morning, and didn’t see the light of day for half a week. Due to the trip, I missed operating the NAQP SSB with the folks at VWS, but I did get in some VHF operating on Saturday afternoon.
When I was planning the trip, I had more or less written off operating, but then I noticed that this weekend was not only NAQP SSB, but the January ARRL VHF contest. I have only participated in one VHF contest in the past (the June VHF contest), so I wasn’t sure about the level of participation in this contest or how well I would do working portable and QRP, but given great weather and ideal local topology for VHF, I decided the night before I left to pack the FT-817 and some antennas.
On previous trips, I had worked HF from Buena Vista Park, and I knew that there is a bench with a good view of the arc from the Golden Gate Bridge to Oakland. However, the bench is a little off the path, there are trees here and there in the line of sight, and couldn’t think of a good way to mount the antenna. I wanted to travel light, so I wasn’t really keen to pack a tripod. After fiddling with Google Maps for a while, I decided that the observation point at Twin Peaks would be better. Twin Peaks are the second highest point in SF. The highest is point is not far away, Mount Davidson, which supports the Sutro Tower. I didn’t opt for Mount Davidson because I wasn’t sure how accessible it would be and also didn’t think it would be a great idea to operate VHF/UHF right under a giant television tower. From StreetView, I had scoped out the observation point (“Christmas Tree Point”) on Twin Peaks and saw a spot with a low metal railing next to a stone wall. It looked possible to fix the antenna to the fence on a stand-off and put the radio on the stone wall.
I packed a 1×2 piece of wood, a couple screws and a bit of PVC that I had previously used to wind coils. The PVC fit over the wood and became my azimuth rotor. The cut-out in the PVC was about the right size for the central axis of my arrow antenna. When I got to the site, I found that the StreetView was accurate and I dumped the gear at the junction of the wall and fence while it was clear of tourists. Every few minutes, a tour bus would arrive, mostly with foreign tourists, who watched with curiosity as I set up. I stopped a few times to pose for photos with them. I taped the wood to the fence with Gorilla tape, making spacers as needed from cardboard. I screwed some wood screws into the wood a couple inches below the top to prevent the PVC from sliding down. After assembling the arrow antenna, I put it into PVC slot and taped it into position. The radio, battery, mike and log book rested comfortably on the stone wall to the side of the fence, and I started operation on 2m.
I was able to pan the antenna more than 180 degrees, starting with the Pacific Ocean to the West of the Golden Gate Bridge, swinging North and then East, panning through downtown San Francisco, Berkeley, Oakland, and then South. I did not hit the Southwest because the top of Twin Peaks was behind me, as well as an antenna installation, mostly microwave. If I were to do this again, I might bring a tripod and climb to the top of Twin Peaks to have 360 degree coverage.
I was surprised that when I tuned around in the weak signal portion of the band (144.050-144.100 CW, 144.2-144.275 USB), that I did not hear stations working a frequency. Even odder, I heard no CW at all. All my contacts on 2m were made right on the SSB calling frequency, 144.2 Mhz. In the June contest, back in Virginia, I had heard a number of station calling on various frequencies, both CW and SSB. I thought it a reasonable chance that some one in San Francisco might be operating FM, so I rotate the antenna for vertical polarization. Again, sweeping from horizon to horizon, listening and calling on standard simplex frequencies (other than the national calling frequency, which is verboten), I didn’t hear any activity.
I tried the same thing on 70cm and contacted about the same number of stations as on two meters. Again, my only contacts were SSB at the calling frequency, 432.1 Mhz. I had to check the contest rules to reassure myself that CW was permitted, and it was — just no one doing it. I am not sure why I had so few contacts on 2m and 70cm despite having what I thought was an excellent location. I can’t say from experience if the January contest is less popular than the June one, or if perhaps there are regional differences in the popularity of the contest, with East-coasters that much more active on these bands.
In the June contest, I had parked my car on a tall parking garage and my antennas were my trunk-mounted 2m/70cm vertical and my mini-Tarheel tuned for 6m. Although these antennas were suboptimal given their limited efficiency and vertical polarization, I had some power behind them: 100W on 2m and 6m, and I believe 50W on 70cm. I had much less power this past week, running 5W, but I assumed that the two mountain-top yagis, would put out comparable EIRP to the mobile rig, albeit in a directional pattern. I assumed that the beam antennas would also be great for scanning the horizon for both strong and weaker signals.
I noticed that all of the SSB stations SSB sounded strong. This would make more sense if I had been operating FM, but I expected to hear a range of SSB signal strengths from scratchy to booming. I realize that my QRP signal might not have sounded similarly strong to them, but I can’t account for not hearing some stations that were softer, unless my background noise level was higher than I appreciated. I suppose that being on a hill surrounded by other antennas might have had some negative effect on reception, but I don’t think this is the case. I would really doubt that this could affect CW so much that I wouldn’t have heard even one signal. I noted that many of the stations that I did work indicated that they had what I’d consider to be elaborate VHF set ups: large permanent, rotatable antennas, high power, and so on, so I am wondering if these stations are just used to working only strong signal stations.
After a while, I disassembled the arrow antenna and wandered a bit further up the hill towards a pine tree. The night before leaving for SFO, I had made a 6m dipole using the usual formula. I didn’t have time to test it, but just coiled it up and chucked it in my luggage. I threw a couple ropes about 15 feet up in to the tree (about the length of my coax) and suspended the antenna horizontally, roughly east-west so it could be broadside to downtown San Francisco. The computer bag that had contained everything became my seat. Again, I hit a number of stations on 50.125, the CW calling frequency, but only heard a couple more up around 50.135 and 50.140. I was determined to bag at least one CW contact, which I did, KJ6M. I’m not sure if he was in the contest or just scanning by the CW portion of the band, but I’m glad he was listening.
I got excited at one point that I had broken out of local area when one station on 6m indicated a QTH of Nevada. I thought maybe 6 meters was opening up and tried to figure out, with my limited recall of Western US geography, what sort of propagation would land a 6m signal in Nevada. The more I thought about it, the less it made sense, particularly since the station had a W6 call. When I got back to the hotel that evening, it made more sense: Novato, California. Not as far as I had hoped. Nonetheless, I had two contacts at a range typical range: a 6m contact at 143 miles and, more surprisingly, a 2m contact of 137 miles.
Since I got out of my conference around noon and had to go back to the hotel to change, grab a quick bite and collect the radio equipment, I splurged for a cab ride up the mountain because I was concerned about the amount of daylight I’d have for operating. It felt like I was cheating, but this wasn’t a SOTA activation, my time table, and the fact that I have limited familiarity with getting around in San Francisco. As the cab dropped me near the summit, he asked how I’d get down, and I indicated that I’d figure something out. I was sorely tempted to just blend in with a tour bus crown and head back down the mountain, but after plugging away for a few hours, I still had enough light to walk down the mountain (much easier in that direction) and take a bus to Castro, where I was able to hop on one of the Market Street trams, which I rode just about to the front door of my hotel. The $2.00 return trip made me feel better about taking a cab on the outbound leg.
Without the 6m opening, I made a lot fewer contacts in this contest than I had in June. So, plans for future VHF contests? Yes, probably, depending how busy I am in June. Working the contest from Skyline drive and combining a gain antenna with the higher power output from the car’s transceiver sounds like a winning combination.
I was in Chile this week for a conference on clinical trials in Latin America. I delivered about five talks in three days, but also managed to carve out a few hours to meet with the Radio Club of Chile — more about that in a subsequent post. Today, I had a few hours free before the flight out and decided to explore the city a little before the taxi to the airport would arrive at the hotel.
I had charged the QRP gear during the conference, and I even had an external 2Ah lead acid battery. This time, TSA had decided that it was permitted to take it on the plane. Maybe it helped to label everything I was carrying as “sealed, unspillable, non-spillable, absorbed glass mat, lead-acid battery” and “not lithium”. I even went so far as to write “this is a wheelchair” on my bag, since I know that lead-acid batteries are explicitly permitted in the cabin when the are “part of a wheelchair.”
I headed for the metro system and took the red line from Los Leones to Banqueda, which is just south of the furnicular that runs up the side of Santiago Hill to Santiago Municipal Park. The furnicular has a plaque that advertises that it is the same train that Pope John Paul II took to the top during his trip here. Well, if it’s good enough for the pope…
The furnicular ran smoothly, and we passed the zoological park on the way up. The top of the line is a plaza, which was full of bicyclers, who were taking advantage of the great Spring weather. I exercised some restraint and did not follow the signs pointing “this way to the virgin”, but continued along the trail, towards the antennas that run along the ridge. The biking trail run along the side of the mountain, and followed it for a bit, then turned towards higher ground on dirt trails. I walked to the very top and checked out the antennas, but decided I really didn’t want to pitch my wire antenna anywhere near them.
I continued on a bit more to the East and found a nice place to plunk down on the side of a hill.
I decided to go with a 15m antenna plus my SLT+ tuner. I pitched the wire into a tree and threw the counterpoise down the hill on the pine needles. I got everything else set up, turned on the radio, and didn’t hear much. The background was just not right. I tried tuning the antenna starting with the suggested inductor setting, but the little red light didn’t change at all. I gave the SLT+ a couple knocks to see if anything was loose, and heard an occasional burst of static.
Of course, I didn’t have tools with me. I almost threw some into the bag, but recalling previous run-ins with TSA, I decided against it. I was, however, able to rip the pocket clip off my pen and use that as a screw driver to open the SLT+. I had suspected that the toroids might have come loose, but when I opened it, I saw that I had already addressed that after the last incident — all were firmly anchored with hot glue. What had happened was that the red antenna banana terminal’s solder lug had rotated and was grounded. I twisted it around, and the noise level went up. As I tuned around, I started hearing signals.
But, my troubles with the SLT+ weren’t over. When I tried to run the antenna this time, the capacitor knob spun freely. If I recall, it had been attached to the underlying polyvaricon shaft with either glue or nail polish. I tried to turn the capacitor from the side using the jaws of an alligator clip, but found it very difficult to do so. I had little choice but to settle for the best match I could get using the inductors, although the loudest settings didn’t correspond well to the suggested settings. I decided to go by the SWR reading on the radio itself. My “feedline” was a piece of BNC-terminated coax only about a half meter long, so as long as the radio could tolerate the impedance mismatch, I figured I’d be okay. I did push the radio when it read “high vSWR”, but was willing to transmit with a few bars on the swr meter. Being less picky let me transmit on both 10m and 15m; it seemed to work on both. The moral of this story: always throw a leatherman into the checked baggage. It may get stolen, but most of the time it won’t.
I was extremely relieved when I heard PY1XM, Tom, come back to me on 10m. Up to that point, I thought that I might be skunked on this outing, with nothing to show for hauling my equipment half a world away and up a mountain. Tom was operating from Rio, which is about 3000 km from Santiago. Right after working him, I talked with Paulo, PR2W operating from Brasilia. Paulo gave me a 579, so I was glad that my signal was not entirely in the mud, although I’m sure his antenna did the heavy lifting.
While listening down the band, I heard an Italian station calling — he was pretty faint, so I though I would have no chance, but I could hear another station calling nearby. The more I spun the dial, the louder it became. It was slow but sure, and I had to hear it a few times because I was not familiar with the structure of the call sign: CD6792. After one exchange, I found out that it was Álvaro, a member of the Radio Club of Chile that I had met the previous day. ¡Fine business, Álvaro!
I had two more contacts: LU8WX in Argentina was rapid-firing DX contacts, and he got didn’t miss a beat in replying to my unusually long call. I also found that I could also get a reasonable match on 15m, so my final contact was with Rei, PY2VJ in Brazil.
So, five contacts isn’t anything to gloat about, but considering that Murphy accompanied me up the mountain, I was happy to have had even one. It seemed that conditions were getting better as the day went along, so propagation may also have played some role. I’ll note that the previous day, the K index had gone up to 4, and when I was operating it, it was declining, but still about 2.
This is how I looked this evening at 8 pm, at the conclusion of the CQ WW SSB contest. I didn’t work the whole contest in “iron butt” mode, but I my throat was sore and my ears were ringing at the end of the event anyhow — I think I’m out of practice (particularly on voice), as I’ve been more focused on projects than operating lately.
I started early on Saturday morning, rather than the night before and took a few breaks during the day. In the evening, I hung up the earphones around 7 pm and went out for dinner and to see the movie “Gravity”. I didn’t get back on the radio until Sunday morning around 11 am, but then worked more or less straight through to the end of the contest at 8 pm.
The notable feature of this year’s CQ WW SSB was the highly energized state of the ionosphere, with solar flux above 160 for the entire contest, and no solar events to spoil the fun. Ten meters was an endless ocean of signals, with stations dotting the landscape up to around 29.6 Mhz. The flip side of this was that atmospheric absorption and noise were elevated on the lower bands, but the trade off seemed very reasonable to me.
By category, I was a single operator, low power (95W), all band station. My ulterior motive during the contest was to find some new ones, so I was “assisted” in that I kept an eye occasionally on the DX cluster and checked my signal on the reverse beacon network. Most of the time, I cruised the bands, just listening for callers, though. As a “little gun”, I didn’t go a lot of calling myself.
The rig was the K3 and my antennas consisted of my attic antennas: a DX-CC covering 10, 15, 20, and 40m (shortened) and a fan dipole for the lower portion of 10m and 17m (the 17m portion wasn’t used). In addition, I had a chance to use the 80m vertical that I had recently modified. Unfortunately, both 40m and 80m were very noisy, both due to atmospheric noise and local QRM. I had anticipated that 80m would be my secret weapon for working the Caribbean an perhaps Europe, but not so much. The conditions were poor on 80m, and those stations were already doing good business on the upper bands.
The contest was enjoyable for the variety of stations worked, as well as the number: 254. I did log one entirely new DXCC entity: Trinidad and Tobago, and worked a number of countries for the first time on phone, including three consecutive voice contacts with Japan. My final score was 123,467 according to N1MM, which I suppose is good, since I didn’t really have a goal. After caressing the data, here is the list of countries worked: Aland Island, Alaska, Antigua & Barbuda, Argentina, Aruba, Austria, Barbados, Belgium, Bonaire, Brazil, Canada, Canary Islands, Cape Verde, Chile, Colombia, Costa Rica, Croatia, Curacao, Czech Republic, Denmark, Dominican Republic, Ecuador, England, Estonia, European Russia, France, French Guiana, Germany, Hawaii, Honduras, Hungary, Iceland, Ireland, Italy, Jamaica, Japan, Jersey, Latvia, Lithuania, Madeira Island, Martinique, Mexico, Morocco, Netherlands, Nicaragua, Norway, Poland, Portugal, Puerto Rico, Scotland, Serbia, Slovak Republic, Slovenia, Spain, St. Maarten, Saba, St. Eustatius, Sweden, Trinidad & Tobago, Tunisia, Turks & Caicos Islands, Ukraine, Uruguay, USA, Venezuela, Virgin Islands, Wales.
As usual, after the contest, I uploaded logs to Lord-Of-The-Web server, and of course, even one else did the same. I checked back and hour later, and my log had not been processed — it must take a lot of computing power to crunch and correlate that many records. Being the patient type, I checked back another 20 minutes later, and sure enough, I saw a familiar post-contest sight:
In addition to the CQ WW SSB, I shambled-on-out for the 2013 Zombie Shuffle on Friday night. I joined in late because of a Vienna Wireless meeting on Friday night, so I only caught about two hours, from ten to midnight. Twenty meters was dead by the time I got there, and 40 and 80 meters were really noisy. I had six tortured QSOs in all, but I’m glad I had a chance to take part in the QRP event.
I had two projects this weekend, one involving microwave and the other involving HF. The microwave project is now firmly attached to the kitchen cabinet and works fine at reheating pizzas. The HF project took more doing. My goal was to set up my Softrock Lite II as a 30m reporting station for the reverse beacon network. I’ve found the RBN useful, and wanted a chance to participate in it from the server rather than the client end.
Last year, I put together a Softrock Lite II, a less than $20 kit that could be built for a single band. I built mine for the 30 meter band. I tried it out with a laptop and could resolve cw signals, but I realized that with a mono input, I would not be able to get any image rejection. The whole value of resolving the signal into quadrature components was lost. I tried using a Mac, which I knew had stereo input, but it was too much to expect this time-critical application to work well in emulation. In these attempts, I noted that there was a lot of noise around the local oscillator frequency, but I didn’t make much of it because there were so many competing issues. I did note that the noise was much better when the unit was run on battery, though.
In the interest of running more advanced sound modes on my aging laptops, I thought it would be helpful to buy an external sound card that would not load down the CPU. In searching for the sound card, I had in mind both the Soft Rock Lite II project and the future construction of a SoftRock Ensemble Transceiver that I had purchased as a kit last year.
I purchased an EMU 0204, an external USB “sound card” ADC/DAC that can take a left and right input and sample at up to 192 kHz. The card has been around for a while and is known to work well under WinXP with system requirements commensurate with the state of the art about five years ago. The laptop I had in mind was the nc6000 that I had salvaged a few months back. The machine has a Pentium M CPU clocked at 1.8 Ghz, 1.5 gigabytes of memory, and is running XP SP3. The machine came with USB 2.0 ports, which are required by the EMU 0204.
I plugged in the EMU 0204, loaded up the drivers, and downloaded updates from Creative Labs. The rear of the EMU 0204 has two inputs: the left input is a hybrid XLR microphone and quarter-inch TRS jack, the other is a quarter-inch TRS jack. The asymmetry of the ports looks odd, but the primary market is musicians, who are more likely to want to plug in a microphone and an instrument rather than the I and Q channel of an SDR radio.
There is a standard 1/4″ jack on the front for headphones, two line out jacks on the back for left and right out, and a 3.5mm stereo jack on the back for external speakers. I plugged some old powered computer speakers into that jack.
The Softrock was built with a stereo 3.5mm jack as output, so I put together a Y-cable that took the tip and ring and distributed it to the tip of a left channel and right channel quarter-inch plug. I had 3-terminal jacks and plugs on hand, so that is what I used. I expected everything to work right off, and of course, it didn’t.
I fired up the SDR program “Rocky” and set the input to the EMU 0204, with sample rate 48 kHz. What I saw was a huge bump in the middle of the spectrum, at the local oscillator frequency. Clicking on it produced horrible feedback. I did see some cw signals buried, but everything was mirrored around the center frequency, meaning I had no image reject, just as if I had only one signal going in. I recalled that running on battery had made things better the first time, and that did clear up some of the noise, but the image reject problem remained.
There is an LED for each channel on front of the EMU 0204, and it is green when the sound source is in a good range for sampling, red when there is too much overdrive and the signal is going into clip. Even with the EMU-0204 dialed up all the way, the signal was never strong enough to turn on the green lights. I thought this was strange, but maybe the Softrock just didn’t have a lot of output, or perhaps the band was legitimately quiet, and there wasn’t any signal in the first place.
I closed Rocky and fired up audacity, which showed some signal on the left channel, but low level on the right channel. Plugging into another source (like my ipad playing music) showed that the cabling was intact. I wondered if perhaps one of the channels was out on the softrock board. I was able to confirm that the local oscillator was working and that the divider was supplying clock pulses with the correct phasing to the mixer. All the voltages on ICs checked out, so I became suspicious of the transformer that takes an input signal at the antenna and picks up signal to feed to the I and Q channels. I pulled the transformer, rewound it, and stuck it back in. No change. I traced the signal as best I could, made sure all the surface mount capacitors were passing signal, and came to the conclusion that the softrock seemed to be fine.
Then it occurred to me that the EMU0204 is meant for professional sound work and that it was expected balanced inputs by default. But surely, a typical electric guitar isn’t a balanced input. Then I realized that the EMU must detect an unbalanced line by seeing continuity between sleeve and ring. I revised my Y-cable, and now everything worked fine: solid audio levels on both I and Q inputs, barely detectable signal artifact at the LO frequency on the spectral dislplay, and strong image rejection. I made sure that I got the right/left side matched up with I/Q by sending a test signal with the K3 on a dummy load, and saw the signal detected at approximately the right frequency. I saw only a hint of the signal on the other side of the LO, which was reasonable considering how strong the signal was.
Connecting the softrock to a power supply created hash, particularly near the center frequency. Not unexpectedly, it was worse on the SS30 switched power supply than the Astron RS-30 linear supply, but I was surprised it was an issue at all on the Astron. I wondered if the problem could related to a ground-loop (the softrock’s antenna is isolated, but audio out ground has continuity with power), but playing with the EMU ground pull-ups did not fix it. I may play around a bit more with the power input and see if some line filtering fixes it. I’m not sure what effect adding isolation transformers on the audio out would have in terms of increased impedance at higher frequencies needed for SDR decoding. Meanwhile, since the softrock pulls less than 30mA, I can run it off one of the rechargeable batteries in the shack just about until the heat death of the universe (rounding up).
Even with this set-up, I was not able to run with Rocky set to 96 kHz sampling. Trying to do so resulted in some stuttering. I also managed to crash rocky by going beyond the band edges in the waterfall display. I had a much better experience using CW skimmer, by the same author. Presumably, it is a later iteration built on the same code base, but it works much smoother. Without changing anything else in the set up, its waterfall was much cleaner, even without cutting in the noise blanker and key click suppressor.
For both Rocky and CW skimmer, one of the set up parameters is the local oscillator frequency. I had chosen 30m because I thought I might only be able to sample at 48 kHz with my original setup, and the band is only 50 kHz wide. Softrock uses a 13. 5 Mhz oscillator, which is divided down by four, and then the third harmonic, 10.125 Mhz becomes the center frequency, so I figured that 10.125+/-24 kHz would get me all but the edges of the band. While building the softrock, I sampled the crystal output as 13.497 Mhz using a lab grade HP counter, albeit one that hadn’t been calibrated in years. Similarly, I measured the divided frequency as the expected 3374 kHz. Both readings were confirmed by my freqmite. Consequently, I calculated the center frequency as 10.122 Mhz, and I entered this into the CW skimmer.
I let the skimmer go for a while, identifying stations in order to compare its frequency read out with others on the reverse beacon network. Noting that I was a few kHz off, I aligned my center frequency to 10,123,150 Hz to bring readings into line with other stations, who I assumed were more calibrated.
CW Skimmer has an integrated telnet server, with a default port of 7300. I set up the skimmer to send its readings to that port. I then sent over to the laptop that I use for contesting and launched N1MM. N1MM can import spots from packet or telnet and add them to the bandmap. I created a new telnet shortcut to the laptop running the skimmer, opened the telnet session, and was pleased to see that N1MM began correctly importing stations identified by the skimmer.
Going back to the skimmer computer, I downloaded the Reverse Beacon Network aggregator. To run it, I also had to download the Microsoft .NET 4.0 framework, which required a reboot. I unpacked the aggregator into the cw skimmer directory, as instructed and launched the skimmer. Next, I launched the aggregator. Setting up the aggregator was mostly intuitive, putting in my name, call sign, etc., but getting the skimmer to submit hits to the RBN required going back into the skimmer and checking the “Allow SKIMMER commands” box.
The aggregator talks to the cw skimmer on the localhosts’s port 7300, but makes data available to port 7550. I was able to re-establish a telnet session from the contest computer to the aggregator using that port, and the bandmap populated correctly.
At this point, I was able to see AI4SV listed as a skimmer station on the reverse beacon network search page. After letting the skimmer run for a while, I searched for stations reported by AI4SV (i.e., I set the “DE” to AI4SV) and got a list. I noticed that there was an annotation in the aggregator that my frequency spots had been adjusted by 0.1 Khz to correct for slight skew versus the majority of reporting stations.
Here’s what it looks like to be on the *other* side of the reverse beacon network:
A few weeks after the Flight of the Bumblebees, and I was ready for the Second Annual Skeeter Hunt coordinated by Larry, W2LJ. I had registered as operating from Virginia, but the evening before the event I looked over the list of participants and realized that there were already plenty of stations operating from VA. Likewise, West Virginia and Maryland had some coverage, but Delaware had no skeeters. I remember that in getting my WAS-50 on LOTW, I had a hard time with Delaware. It’s a small state, there are a limited number of hams, and it seemed that not many used LOTW. So, I figured I’d give Delaware some coverage. Like the FOBB, I opted for a coastal location, this time Fenwick Island State Park.
The other motivation to drive to Delaware was that I had to cross through a lot of Maryland, allowing me to participate in the Maryland-DC QSO Party using the car radio. I didn’t have the log computer along, so I jotted my log on a pad as I went along and only operated voice. I had some nice strings where I worked the same stations from multiple Maryland counties.
I had scoped out Fenwick Island State Park on Google Earth, so I had some idea where I was going. After paying the somewhat punitive-feeling out of state price to park (eight bucks! Oh well, I’m here now…), I followed the beach goers seaward, hauling a radio bag and a wrist-rocket tennis ball launcher. After reconnoitering the beach, I found that the “stand of trees” that I had seen on Google satellite view was a bunch of bushes about three feet tall. I hiked back to the car, got a telescoping mast, and tied it to a log that had been piled into the sand in front of a dune. As in the FOBB, I set up a 20m “untangleable dipole” and got to work.
I immediately worked a bunch of stations S&P, but had less success calling. As the afternoon went along, I heard more and more WAE stations in the QRP area. While I have a sharp audio filter on the 817, the front end is wide open. I had held off on working the WAE stations, but was pleased to hear F5NBU responding not with a WAE exchange, but “599 5W”. I realize now that my strategy should have been to work more of the WAE stations (and that I should get an RF filter for the 817). Also, although I like the dipole, I might have been better served by lofting the 40m EFHW with tuner. In any event, I had a great time and as a side benefit, had the opportunity to explain ham radio to a bunch of curious beach goers. One guy asked me,
“Did you need to get special permission to put that [the antenna] up?”. I replied, “No. It’s just like a very tall beach umbrella, without the umbrella part.”
Aside from the usual radio operating skills, two others came into play: 1) working the radio while explaining what I was doing to curious beachgoers; and 2) managing not to get sand in everything.
The bottom line: I worked 18 other skeeters, plus 3 non-skeeters in thirteen states plus Ontario. My two DX contacts were France and Poland. While I had a number of homebrew components in the station (the antenna, the audio filter, etc.), the main rig was commercial, so I took the “3x” multiplier for field operation.