Solar CDX

Internet backup power

About the time I am wrapping up in the office, the sun has risen and people are getting into work on the East Coast of the United States. I leave early enough to get home so I can make teleconferences that start at 9 Eastern. I’d have quite a phone bill if I dialed direct, but fortunately, I can make most of these calls over the internet. Although Madagascar is a developing country, we have fiber to the house. The upstream connection isn’t entirely stable, but it is up most of the time, and throughput is surprisingly high. However, I still run into problems when the power blinks off.

The ISP has adequate backup power to maintain the connection, at least for some time, so this is my problem in the house. The house too has a backup generator, but there’s a couple seconds to shift over from mains to generator and vice versa. In that time, the houses’s router goes down and takes a minute or so to reboot every time power switches over. What’s needed is a UPS, but the smallest computer UPS here runs around $150. Also, it seems like a UPS is massive overkill when the problem is just to keep a router happy for about a minute.

I have a good stash of small lead acid batteries for portable ham radio use, and it occurred to me that I could probably use a couple in backup power supply projects. At this point, I’ve come up with two designs built of materials squirreled away in my garage. Schematics are below the cut for anyone interested. Continue reading Internet backup power

Concours IF 2015: Sourire

15391458183_f602481b75_o“Sourire” s’agit d’une courte histoire racontée du point de vue d’une marionnette. Vingt-quatre commandes — 19 de spécifique et 5 juste pour passer le temps — suffissent pour atteindre la solution. Néanmoins, j’ai bloqué quelques fois et de temps en temps j’ai eu besoin de jeter un coup d’oeil au walkthrough.

C’est un imposant défi d’écrire une IF dans laquelle le jouer est littéralement pendu des fils et presque immobilisé. Le joueur apprend immédiatement que ce n’est pas possible de se déplacer dans les directions cardinaux. D’ailleurs, il n’y a beaucoup de voir est les objets vus sont hors de portés du joueur. Qu’est-ce qu’on doit faire? C’est un bon commencement, pourvu que le joueur ne devient pas frustré après quelques tentatives de faire avancer la scène.

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Visit to Zambia

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Flooding in Madagacar after the most recent cyclone.

This year’s cyclone season has been unusually severe – folks in Madagascar are telling me that it is the worst one since around 1959, particularly from the perspective of the central highlands. However, most of the precipitation has been on the coasts, where towns are literally underwater. Storm systems tend to form over Mozambique, intensify in crossing the channel, land forcefully on the west coast of the island, cut across it, and continue into the Indian ocean, either eastwards towards Réunion or shifting towards the south. Along the way, the storms dumped enough rain to entirely saturate the soil in the first month or two. Now, there is nowhere for the water to go, and it is overflowing dikes, bursting dams, and causing mudslides. Before the rainy season, the government was struggling to keep the wobbly national infrastructure working, but at this point, it is struggling to maintain basic services such as electricity and road maintenance. Continue reading Visit to Zambia

2015 ARRL CW DX

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If North America were a toroid, one could pass the windings through the Dakotas.

Having recently put up the G5RV, I gave the ARRL DX CW contest a shot this past weekend. The antenna is up only about 10m and is not resonant on 15m, but it has performed well on 10 and 20m in the past. On the first night, 10m was very quiet, but activity on 20m was brisk, particularly in the early morning hours when I was working two calls per minute.

In principle, 10m should have been open starting the in mid-afternoon on Sunday, but it was slow until around dinner time. Again, 20m was my main band, despite having mostly mined it out the previous day. I managed to get a few contacts on 15m, and even fewer on 40m, where local noise was a problem.

I didn’t stay in the chair the full time, even when I had favorable North American windows. I had to disconnect the antenna for some time due to thunderstorms on Saturday afternoon and on Sunday evening I had a guest in town and went out for dinner. Still, I am happy with the number of contacts I made given my conditions.

I worked a few states that I hadn’t such as Vermont, Rhode Island, Delaware, West Virginia, Nevada and Wyoming — hopefully, those stations will QSL via LOTW. I heard a North Dakota station, but barely, and he was drowning in a pile up. Maybe I’ll take another shot when Sweepstakes or some other convenient contest rolls around and I have the hexbeam up.

My final tally:

Band QSOs Mults
40m 7 4
20m 418 52
15m 18 13
10m 56 26

3A/AI4SV Reverse Dxpedition

Sunset in Nice.

Sunset in Nice.

Living in Madagascar, I have enjoyed operating from a sought after DXCC entity; little did I suspect the same would be true on my recent trip to Europe. I packed along the FT817 on a trip to Nice, France, where I attended a business meeting. I had picked a hotel with an open 8th floor deck and hoped to string up the end-fed to operate in the evening. On the way out the door, my wife asked me, “so I don’t suppose you’ll have any time to visit Monaco, while you’re there?”  I have to admit that I hadn’t really thought about it, but as soon as she mentioned it, the gears began turning. I had meetings in Nice and Lyon, but some free time on Saturday before flying out. On the way to the airport, I double checked that Monaco was a signatory to the CEPT convention.

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How my antenna switch became a loudspeaker

ad4I envision having a few antennas: the hexbeam, the G5RV, lindenblads for 70cm and 2 satellite work, perhaps a vertical of some sort if I can figure out where to place it, and maybe some kind of beam antenna for six meters. To make all that work, I’ll need some sort of way to bring the lines in the shack and to switch among them. I brought four alpha-delta four position switches, which should be enough to both perform this function and switch the lines to the available rigs. With that intention, I laid the switches on the bench and drew out the wiring diagram.

However, I never got there; not yet, at least. After piling up some connectors and coax and wood, I realized that what I really needed in the garage in order to do this sort of work was some kind of background noise to keep me entertained. So, I pushed the very useful antenna switching project to the side and turned back to the computer that I had fried a few weeks ago by plugging it into the 230V while its power supply was set to 110V.

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The G5RV is up

G5RVF4The antenna situation has improved. There is progress on the hex beam, but in the meantime I’ve put up a G5RV. It is almost exactly the size of the largest run possible on my property. I had some difficulty getting enough angle on the trees to shoot the line and I am frankly surprised it all worked. The line is tied down to the tree trunk on one end, and the other loops over a tree, then through a metal loop screwed into the property wall, and that end suspends a brick, which maintains tension on the line but has enough give to allow tree motion. The center twin lead is centered over my house and I was not able to get the two arms of the antenna high enough to allow the feed line to hang down straight; this is not ideal as it will change the plane of radiation since the feed line is active in this design. I was also concerned about the feed line coming down too close to the metal roof, so I have arranged another support for the feed line, which pulls it close to horizontal. It also keeps it away from the high power security lights that rim the roof and which put out some RF.

I swept the antenna with an MFJ analyzer in the shack and the SWR is less than 3:1 on 80, 40, 20, 17 and 10m. I have had some good runs on 10, 17, and 20 meters, and a few contacts on 40m. Even on bands where it it not resonant, I’ve had reasonable success using a tuner; being able to run 100W gives me some margin for inefficiency. I worked one EU station after another one afternoon on 30m, and finally had a contact with Alain, 5R8AL, also in Madagascar on 12m. The additional power has allowed me to run a frequency on voice.  I’ve now set up the TS450 for digital communications and have had a few PSK31 contacts as well. I’ve getting some RF back, which is affecting the external USB sound card, so a near term project will be fixing station grounding.

wood mill workers milling the tree into a postAs for the hex beam, I finally have all materials. I visited a local lumber yard and had a 4m x 15cm x 15cm post milled. It arrived at my house on a cart and is now sitting across two chairs on my porch. I’ve given the post a coat of wood treatment (permethrin + cobalt salts) and will paint it for more protection. Meanwhile, an almost 2m deep hole has been dug in the backyard, and I’ve purchased about 200 kg of cement, which with some aggregate will become the base for the wooden support beam.

The plan is to get the base in place and set up a shelf using angle iron to support the G450 rotor. Further up the post, I will install a universal thrust bearing to handle the lateral load. A 10m spiderbeam telescoping mast will support the hex beam, and will itself be guyed at two levels. Finishing this project will await some good weather and enough time to see it through.

Concours IF 2015: Comédie

730px-New_Theatre_-_stage_-_The_Architect_1909Voici ma première critique d’une IF française en français (ou, j’espère en une langue qui se ressemble un peu au français)…

Comédie par “Edgar Havre” est composée des scènes liées par les courtes conversations. Grace au module “Simple Chat” par Mark Tilford, les conversations se déroule comme une série de choix. Pour commencer une conversation il faut “parler à qqn”. Les conversations se modifie un peu en fonction des événements observés. En cette manière, les conversations sont limitées, mais elles servent pour introduire les puzzles.

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Fried Power Supply

The original fuse (white tube) after cutting away black heats hrink tubing.

The original fuse (white tube, bottom left) after cutting away black heatshrink tubing.

As a public service message, I feel obliged to share the following nugget of wisdom: before plugging a tower computer into a 220V outlet, reach around to the back of the computer and make sure the input voltage select is 220. Sounds simple, right? This isn’t something you have to think about for most laptops, which have dual voltage power supplies. They are happy plugged into either voltage and the power supply brick just works.

I’m not [arguably, perhaps] an idiot – I was aware of the switch. I just thought that the power outlet was off, but also I didn’t expect to encounter an issue until the computer itself was turned on. Wrong — ATX switching power supplies are always on. When I plugged the computer in 220V, there was a popping sound followed by smoke from the back of the unit. Never a good sign.

I pulled the power supply out, opened it up, and looked around. Nothing was obviously charred. My nose has lousy spatial resolution — it confirmed that something wasn’t right, but couldn’t help me localize the problem. I followed the wiring from the outlet inward. For a cheap supply, I was glad to see some decent capacitors on both live and return wires to ground, and across them. Also, some inductors to quell EMI. Next in line: the fuse. It had blended in because as a safety precaution, it was wrapped in heat-shrink. I cut away the heat shrink to reveal a white tube. I couldn’t see into the fuse, but my continuity tester showed it had blown. There was no fuse holder; the fuse was just soldered in by its leads, so I dutifully unsoldered it.

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First Big Storm

Friday afternoon, a “moderate tropical cyclone” swept west-to-east across the Island. It was a big enough storm to get a name, Chezda, and I’d been watching it on satellite pictures for a couple days. In the last afternoon, it hit the west coast, bringing rain and wind. This is what it looked like. It’s the swirly cotton thing on the left. The more ominous looking storm on the right is another one, Bansi, that wasn’t a problem for Madagascar, but did affect Ile Rodriques. It is headed southeast, so not so much of a concern.

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Since the picture was taken, the center of Chezda has moved off the east coast of Madagascar, but not before dumping a lot of water yesterday and blowing fiercely overnight. Many low-lying areas were flooded. We’re a couple weeks into the rice harvesting season, and in this area, it looked like only about half the rice had been harvested, so I would guess some crops might have been lost to inundation.

There were a lot of power fluctuations yesterday, but as far as I can tell, no major damage in the local area. The wind died down the the sun came out around ten this morning. I’m pleased to report that aside from a bit of water around the garage door, no water entered the garage. The improvements to drainage happened just in time.

The storm is predicted to continue to move south-east and should miss the populated islands in our region.

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