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Archive for January, 2011

CQ 160 CW

January 31st, 2011

We got a dose of Mid-Atlantic winter weather last week—that once or twice a year event that is too much for the utilities and drivers to handle. Snow, sleet, freezing rain, and rain arrived on Wednesday. Power was out from 2030 LT to 0200 LT on Wednesday night/Thursday morning and then again from 1600 LT on Thursday to around 1100 LT on Friday. So, I didn’t get to operate NS this week on account of no power! I did think of going out to the car, but I was too wiped out and cold from the furnace blower being off. I just wanted to crawl under a big pile of blankets and sleep until the electricity came back on. As I have mentioned before, I grew up in an area with many Amish. A coworker many years ago was teasing me about finding an Amish girlfriend. I responded by asking him how an electrical engineer would fare in a society dedicated to not using electricity. He had to agree, although the Amish have rather ingenious mechanisms for harnessing electricity to do their work. But, as usual, I digress—we’re slightly dependent on electricity in ways we probably should not be!

I like contesting on 160 meters (1.8 MHz). When you call CQ, you are usually rewarded with blistering rate from loud stateside stations. When you’re tuning up and down the band, weak DX stations pop out from between said loud stateside stations. Now that I have something resembling a 160-meter antenna, I gave the CQ 160 CW contest a shot after some friends left on Saturday night. Another nice thing was that the station is working well enough (with the exception of the K9AY relays and possibly directivity) that I could just walk into the shack and operate.

So, that’s what I did… Only worked a handful of Europeans, but that’s not too surprising. They were loud here, even with 10 dB of attenuation in line to reduce IMD from really loud local stations. There were numerous other European stations that I could hear (on the TX antenna) but was unable to raise. But, in about four hours (three in the CQ 160 and one in the NAQP) of operating on Topband, I have only the hard states left for WAS from this QTH: ID, SD, ND, WY, AK, HI. I’m waiting for the LoTW confirmations to start showing up!

                    CQ 160-Meter Contest, CW

Call: K8GU
Operator(s): K8GU
Station: K8GU

Class: Single Op LP
QTH: MD
Operating Time (hrs): 3

Summary:
Total:  QSOs = 182  State/Prov = 48  Countries = 8  Total Score = 25,984

Club: Potomac Valley Radio Club

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Posted in life, radio

ARRL January VHF Sweepstakes

January 31st, 2011

Last weekend (two weekends ago now), Sarah was out of town with friends from college, so I was free to meander in and out of the shack at will. Between making QSOs on 2 meters, I got a “modern” computer set up for SDR. More on this in the future. Was pleased to make some QSOs into New England with the “$200 VHF station” that consists of the TS-700S, Mirage B3016G amplifier, and homebrew FO12 antenna. Nevermind that the Pro-Set, Bencher, and Keyer cost at least that much again.

Still working on getting the other bands going. 50 MHz is very close, although with the recent sale of some extra gear, a K3 is almost within striking distance if I sold one the of the TS-930s. One of the locals has offered to lend me his FT-736R to get on 222 and 432 for now. So, I think I’ll try to finish up the 50-MHz transverter and pick up the ‘736 while working on the antenna situation for those bands. I’m going to have to change the rotor/mast situation to do that. Not sure how that will go…I may just duplicate a “rover mast” and accept whatever sacrifice is introduced by stacking the beams too close together.

                    ARRL January VHF Sweepstakes

Call: K8GU
Operator(s): K8GU
Station: K8GU

Class: Single Op LP
QTH: FM19la
Operating Time (hrs): 

Summary:
 Band  QSOs  Mults
-------------------
    6:
    2:  44     15
  222:
  432:
  903:
  1.2:
  2.3:
  3.4:
  5.7:
  10G:
  24G:
-------------------
Total:  44     15  Total Score = 660

Club: Potomac Valley Radio Club

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Posted in radio

Ice Snake

January 27th, 2011

More ice formation on the car—this time on the helical windings of my 40-meter mobile antenna. That ought to tell us something about the structure of ice.

2 comments »

Posted in nature, noticed, radio

Ice on the hood

January 21st, 2011

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Posted in engineering, nature, noticed

W7IUV preamplifier

January 20th, 2011

An evening project: W7IUV low-band receive preamplifier. Total cost: < $10. Total time: 1 hour.

It worked pretty well on 80 and 160 with the crossed K9AYs. The 48-volt relays in the box at the antennas are sticking (thanks to using a 40-volt PSU). I need to rebuild this with lower-voltage relays or a higher-voltage power supply.

W7IUV claims that he just leaves his connected to his RX port all the time. But, he probably has more spacing between his TX and RX antennas than I do. It will be interesting to see if I get enough RF coupled from my TX antennas to destroy the transistor.

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Posted in engineering, radio

SoftRocks

January 15th, 2011

Finally got all of the SoftRock downconverters here enclosed and repaired. Turns out I managed to cross two of the wires on the input transformer of my 20-meter v6.2 Lite (“upgraded” variant). Once I found that, it sprung to life. The other project was getting the 144-MHz Ensemble II VHF into an enclosure. This has been a long-standing struggle since the nearest size diecast box is just a hair too small. So, I put it into an extruded aluminum enclosure I found at Dayton a few years ago. Unfortunately, I had to make my own front and rear panels. But, I had an old minibox that was perfect for the donor material.

I should have polished the edges of the front and rear panels, but it’s not too bad. KK7B opined in a QST article many years ago that after homebrewing “about 50 enclosures, they start to look respectable.”

Holes were punched with a hand punch from Harbor Freight. Given the cost of the Roper-Whitney equivalent and for as much as I will use it, this is perfectly acceptable. There’s nothing like having the right tool for the job! However, mine came with two 5/16-inch punches (no 1/4-inch), but one each 1/4-inch and 5/16-inch die. Ooops. VFBBYQC. So, I had to drill the 1/4-inch LED hole. A nibbling tool made quick work of the USB cut-out. I cut the panels with hand shears. So, I guess it should be clear what’s next on my sheetmetal shopping list…

Now, I need to actually play with some “real” SDR instead of just diddling around with Rocky (which is very capable). I’m running it under Windows XP on a 1.3 GHz Pentium IV with 1 GB of RAM. The sound card is a Creative Labs Audigy 2 ZS. There is a little latency when running a large waterfall and resizing windows, but it’s adequate for tinkering. Eventually, I’d like to try some of the GNU/Linux SDR engines. But, I’m just going to wait until a new (to me) computer falls into my lap before that happens.

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Posted in radio

Tags: cheap VHF SDR

Recent tinkerings (9 Jan 2011 edition)

January 9th, 2011

Several people have commented over the years that I should “write more” on the blog. I usually respond that I could spend my free time tinkering/hamming or blogging, but not both. Here are a month’s worth of blog posts as freestyle poetry:

A section on my workshop has been added to k8gu.com under Engineering.
Discovered that although the SoftRock VHF Ensemble II won’t fit (barely) into the Bud CU-473 diecast box I bought for it, it will fit into an extruded enclosure that housed an ancient X-band radar detector I picked up at Dayton in 2002 in hopes of stripping the Gunn diode assembly and getting on 10 GHz. Bonus points for thriftiness. Photos will follow once I finish the project.
Did not observe Quadrantid meteor pings with the SoftRock VHF Ensemble II, but did notice something interesting about the W3APL beacon. Need to investigate.
Have more CE/K8GU QSL cards again, finally. Tonight, I might finish the bureau (and, ashamedly one direct) cards languishing. Some K8GU (and AA8UP, no kidding) bureau cards are sitting here staring at me, too. Not a big project, though.
Operated the NAQP CW on Saturday (8 January 2011) for four hours and twenty minutes and made 318 QSOs x 128 multipliers for 40,740 points before log-checking discounts. This total is pleasing to me especially considering that it was almost all leap-frogging SO2R search-and-pounce, which can be very fatiguing. It’s fun to see the rate meter stay over 100 when you’re S&Ping. Good Sprint practice.
Still the best 30 minutes on the radio every week: I operated the NS Ladder on Thursday (6 January) night and made my customary 30 QSOs x 24 multipliers for 720 points. Hopefully, adding 160 will give me some momentum to increase this score back over 1000.
We had a spell of 50F (10C) weather on New Years’ Eve. So, I put the 2-meter beam back up on the chimney. It was formerly mounted on a steel mast that was ratchet-strapped to the chimney. A strong wind (>50 mph gusts) before Christmas bent the mast (actually a fence top-rail) and I had removed it. I cut the bent lower portion of the mast off and attached the remaining top portion with rotator to a “girder” constructed from two pieces of treated 2″ x 4″ x 10′ lumber joined with a half-dozen lag screws. Again, I ratchet-strapped the entire assembly to the chimney. The present configuration is much stronger and less prone to damage. The 3-element 50-MHz Yagi is still on the ground until I actually get the transverter finished, which should be soon (as it has been for 12 months now).
Repaired a SoftRock v6.2 downconverter for WF1L and learned that you can solder leads back onto SOIC packages if you’re careful.
Have had delightful exchanges with KN6X and ZL1CDP about repairing the TS-930S. Some of these discussions (and their fruits) may make it onto the site at some point.
Back in December, I started integrating the W1GHZ transverters using UT-141 semirigid jumpers with pre-installed SMA connectors obtained on attractive terms from Max-Gain Systems. Mitsubishi RA18H1213G (1296 MHz) and RA30H0608M (50 MHz) modules arrived from RF Parts. May have a lead on something less expensive with more gain for 903 MHz via HA1AG. The big remaining tasks in all three transverter projects are the sequencer and IF interfacing.
Also in December, I had dinner with NS Ladder father Bill, N6ZFO, in San Francisco at the Hyde Street Seafood House & Raw Bar, which is a favorite of NA Sprint father, Rusty, W6OAT. Yes, I did feel that I was in the presence of greatness. (I had their excellent pork chops since I’m not into seafood, especially raw seafood.) Like most contesters, Bill’s a super, fascinating guy apart from his radio contesting interests.

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Posted in engineering, hobbies, life, radio, site, travel

Tags: 50MHz cheap VHF contests repair ts930 W1GHZ

A short vertical for 160 meters

January 9th, 2011

160 meters, Topband, …the names conjure all sorts of visions of grandeur, enigmatic propagation modes, and big antennas in the minds of hams everywhere. Since I have lived on suburban lots for the past five and a half years and in an apartment for two years before that, it has been the better part of a decade since I’ve had my own permanent 160-meter antenna system at my “home” station. (Despite this, I did manage to get 160-meter WAS from NO9Z’s station and if my Rhode Island and Delaware contacts ever upload to LoTW, I’ll request the certificate from ARRL.)

So, the story at hand. Just before the November Sweepstakes contest, I put up a secondary 80-meter antenna—the open-wire fed dipole I used at K8GU/9. Its performance was underwhelming and the vertical seemed to play just fine. But, I got busy and just left it up in the trees. Somewhere in the annals of the Blog, I may or may not have described this antenna, which was designed to also operate on 160 by shorting the feeder and feeding the whole mess against ground. I never used this functionality because I had to lay radials on top of the patio and that was a pain to take them up and put them down.

The North American QSO Party was this weekend and I’ve been participating in the NCCC Sprint Ladder, both of which include 160 meters. Around about last Thursday, after the NS Ladder, I decided it might be fun to have 160 for the NSL and NAQP. So, I ducked out of the office early on Friday afternoon and set about stripping the old tuning network from the K8GU/9 incarnation of the antenna.

We have a lot of AM broadcast stations in the DC area. And, because of that, antenna analyzers are not always too useful on the low bands. So, knowing already that the antenna was near self-resonance after my K8GU/9 efforts, the first thing I did was just hook the antenna up to a TS-930 and give it a 5-10 watts fed against my nearby 80-meter vertical’s radial field. Sure enough, the VSWR was about 3 at 1.999 MHz and off-scale at 1.801 MHz. So, I inserted the loading coil from the old matching box. The coil is just #14 THHN solid wire in approximately the optimum-Q configuration of diameter to length and wound on a cardboard shipping tube. (As is clear from the photograph, it’s not really pretty nor the lowest-loss possible. But, it was great for what I had on-hand.)

The coil has four taps on it. I clipped the fourth tap, shorting the bottom half of the inductor and did the VSWR sweep, finding a dip at 1.950 MHz or so. Each successive tap brought the minimum lower and lower. With no taps clipped, it was tuned to the bottom of the band. I got lucky (erm, did a lot of tweaking at the previous QTH).

The best news of all of this is that there is enough RF actually being radiated (not just as heat, either!) to make some contacts! Further good news is that even though the antenna is between three and five feet from my 80-meter vertical, with the W3NQN filters, I can operate SO2R on both bands simultaneously. Of course, the RX noise level may just be hiding the trash. I haven’t tried the K9AY because I had that portion of the station torn-up during the conversion of all my DC accessories to PowerPoles and the preamp popped a fuse in my RigRunner when I plugged it back in.

The bottom line is that it’s not a full-sized 4-square, but it gets me on 160 from my lot in a way that’s compatible with my operating style.

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Posted in engineering, radio

Tags: 160m re-purpose

Locality Bias

January 3rd, 2011

Slate Labs has an “interactive tool” to look at food deserts in the U.S. by county—places where a healthy variety of food is unavailable. They define a metric of desertification by counting the number of people who do not have access (not sure how this is defined) to a car AND live farther than one mile from a supermarket (not sure how this is defined, either). So, I went looking at some places I’ve lived.

My home county is Holmes County, Ohio. If you look at the map, it’s the one that’s an island of dark brown in the middle of Ohio. 27.91 percent of Holmes County is a food desert by this metric! Blame it on the Amish. Because the county is rural, there are few grocery stores. And, because the Amish do not have access to their own cars, they count a large portion of this population. Other counties with large Amish populations (relative to the non-Amish population) also stand out clearly.

It also appears that the map is distorted by population density, with sparsely populated areas being more prone to classification as food deserts. Is this fair? Is there anything that can be reasonably done about these areas even if they are food deserts? I don’t at all disagree that this is an important, significant problem, but it seems that there might have been a better metric. Perhaps it’s the most accessible metric with the available data?

Although this map may be revealing in many ways, it also distorts the reality a bit. For me, it’s a reminder to not consume “news infographics” too casually. I haven’t read all of the comments on the Slate piece and probably won’t. So, forgive me if someone has already noted some of the above. As a final note, most of the people who write for Slate are relatively ignorant of what happens in the part of the country between the Coast Ranges and the Appalachians. So, as one commenter wrote, it’s a “typical urbanite view” of food.

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Posted in communication, education, food, life, noticed

Tags: science

“Electricity is NOT a toy”

January 2nd, 2011

The ARRL 10-meter (28-MHz) contest was a couple of weeks ago. Given that I had bothered to install a 10-meter antenna at this QTH and that conditions seem to be improving, I thought it would be fun to play.

I fired up CQing on Saturday and after a few minutes, Sarah appeared at the shack doorway. This usually means that something is broken or I’m causing RFI to something she wants to be using. Since I’m not KT0R, who used to tell his neighbors that he was “busy and please come back on Monday,” I obliged her. It was the CO detector again. I unplugged it (it’s battery-backed, so it just means that contesting burns through 9-volt batteries) and returned to the game. Peace reigned again in the Miller household.

Sneaking in a little bit of contesting before church on Sunday morning is a long-standing habit of mine, although it seems that the Sunday openings are usually better than the Saturday openings. Today was no exception. I was working hard to extract a few QSOs out of what appeared to be a mostly dead band and Sarah again showed up at the shack doorway—this time with wet hair and quite agitated.

“The outlet is popping when I plug the hair-dryer into it!”

I assured her that I would take care of it, adding that it was “probably just the radio getting into the GFI. Let me send a few dits and see if it starts clicking.”

“No, you stay there, I’ll send the dits. How do you do it?”

“Just press the left paddle.”

And so, Sarah made her first ham radio transmission on 10-meter CW this morning (after which I did identify, for the record). I confirmed that the outlet made a little click. She was not completely convinced, but I told her I would shut down while she dried her hair so I could monitor the situation.

The hairdryer (a prior unit), Sarah, and I have had run-ins before. Several years ago, when we were poor graduate students, a loose screw was causing a nasty vibration in the old hairdryer. So, I tightened it up and gave it back to her, not knowing that there was another screw floating around inside the case. One morning, that screw found its way into the motor and sparked. When Sarah called me on the phone, I thought she’d burnt the house down. As much as it pains me, I no longer attempt to fix any appliances that cost less than $50 as a result of this episode.

Still worked up, Sarah took the opportunity to grill me about the compatibility of contesting with family life…”When have children, how will you hear them if they’re in trouble and you have your headphones on? (In jest, I later proposed wiring a baby monitor into the SOnR audio chain.) Can’t you listen with the speaker? How will we keep them from eating your little parts, bits of wire, and globs of solder? Electricity is not a toy!”

We laughed at the last one. And she added, “I hope they’re all girls who want everything hot pink—so much hot pink that we want to barf.”

I suppose if someone makes a hot-pink Hello Kitty AK-47 (the photo actually looks like a painting of an AR-15) and the Sarah-cuda bow, we can find hot-pink solder irons, paddle finger pieces, headphones, and even radios (I seem to recall that there was a BabyPhat mod’ed hot-pink Motorola HT floating around the web a few years ago).

Anyhow, this post is for Sarah because she puts up with a lot of tinkering, RFI, and headphone time and gets very little blog recognition in return for it.

(The photo above is of Ft Rock, Oregon, taken by me when I was on assignment there.)