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Signal and Noise

August 4th, 2014 by k8gu No comments »

“One man’s signal is another man’s noise,” began Dr. Kudeki as he derived incoherent scatter radar theory from Nyquist’s noise theorem in ECE458. I think of that statement often, whether it be QRM on the ham bands or sifting through the pocket litter of web users looking for their consumption preferences.

This morning, I admired just such an example of signal and noise while watching the NOAA Doppler weather radar. Undesired targets of a radar that return echoes are termed “clutter” in the radar parlance and one simplistic way of eliminating clutter, especially when you expect the desired scatterers (“targets”) to move, is to assume that all of the stationary returns are clutter. In the weather radar, we get clutter from all sorts of stationary things like trees, hills, and buildings. Of course, what causes the clutter to move?

You see, it was one of those humid August mornings when a ham’s mind wanders to…tropospheric ducting. Yes, indeed the clutter returns were moving, intensifying before and after sunrise. I was fixated on this and watched the loop over and over again before noticing an even more interesting bit of clutter!

Beginning at 0958 UT on 4 August 2014, there is a small ring forming out over the Elk River area. The ring, which is indicated by the downward-pointing vertical arrows, expanded over the next >40 minutes. I was puzzled and watched the loop over and over. I considered and discarded a number of theories before resorting to Google. Apparently, it’s very likely a flock of birds. Sure enough, the epicenter of the ring is Elk Neck State Park. Fascinating.

The slanted arrows in the figure above indicates the ground clutter that I was originally noticing as a signature of tropo ducting, obviously now of secondary interest in this sequence of images!

Epilogue: I sent these frames to my father, who is an avid observer of the natural world. He passed them along to two friends back home who are birders. At press time, one reported that he had learned of these “bird circles” from Greg Miller, another birder from the area who got famous as one of the subjects of the book (and movie of the same title) The Big Year. I haven’t read/seen it, but I guess they went to Adak, which has a special place in my heart. Anyhow, it’s a funny small and interesting world in which we live.

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Posted in nature, noticed, radio

Tags: freq'n magic re-purpose science tropo

Notes and Ramblings

August 3rd, 2014 by k8gu No comments »

Three perhaps noteworthy amateur radio activities occurred recently around K8GU: 1. During the course of some HVAC upgrades, I was able to get two holes core drilled through the foundation to bring coax and control cables into the house; 2. I operated in the NAQP August CW contest; 3. My oldest and I went to the Berryville, VA, hamfest.

These two ports exit the basement into a crawl space where I will ground the cables before they enter the house. I still need to get some hydraulic cement or other quick-setting patch mortar to clean up the drill crater on the outside. Total cost: $5 in materials and a large pizza for the crew.

Screenshot above shows TRLinux after the end of the contest (obviously it was today, not last night). TRLinux performed flawlessly again with the YCCC SO2R+ box driving the KK1L band-decoder and 6×2 switch. I operated for about five hours (probably a little more, and definitely more if I used the NAQP 30-minute time-off rule to calculate it). I got up after my first operating sitting at the beginning of the contest and left the shack. As I exited the door, I was hit with the smell of hot electronics. You know the smell: like when you just let the smoke out of a transistor. I walked over to the antenna switch matrix where I was using a triplexer to split the hexagonal beam to both radios. It was warm to the touch. It seems to have continued to function, but I’ll have to disassemble it at some point to see if any irreversible damage was done.

The August NAQPs are always fun for us out East because there is the ever-present opportunity for sporadic-E throughout the contest, giving us a chance to work nearby states, which can really drive up the multiplier (and QSO, depending on the direction of the opening) total. Of course, this is the real boon of having a second radio: you can call CQ on your most productive band while looking for openings on the others. I came down after supper with the family to “work 40 meters before it goes long” and ended up with blistering 10- and 15-meter runs into the Midwest and South. Since my son and I were planning to go to the hamfest and I don’t yet have a 160-meter antenna at the “new” QTH, I pulled the plug at midnight local time (0400). Not sure 40 meters was even getting long at that point. At any rate, it was wonderful to say “hi” to so many old friends from MRRC, MWA, SMC, PVRC, and beyond!

A final comment: You can really tell how much better one radio is than another when you have them both side-by-side on your desk. This was quite apparent when I had the K3 and the TS-930S and it is also apparent with the K3 and the K2. The K2 is a wonderful radio and fun to operate, especially in the field, but it’s not the K3 as far as fit and finish, among other things. No, I’m not buying another K3 anytime soon. The K2 is quite enough for the second radio.

I’ve always heard that the Berryville, VA, hamfest had a good boneyard/fleamarket/swapmeet but I’ve never managed to attend. I resolved to attend this year and was pleasantly surprised. My oldest came along for the ham-and-egg breakfast, which was good but he rejected the ham after only consuming about 1/3 of it, and a trip to the playground at the school across the road. This is still a “real” hamfest like the ones I remember going to in the early 1990s before eBay and online trading really took the wind out of swapmeets. There were plenty of rigs spanning the spectrum of boatanchor to relatively modern, HF and VHF/UHF. There were lots of amplifiers, as well, (and a small quantity of CB junk; Texas Star, anyone?) There were also lots of antennas, and even some Rohn 25. The computer and cell phone accessory dealers were mercifully few and there were lots of tables of parts, bits and pieces. This is a ham’s hamfest and I’ll be returning. I picked up a bunch of Cinch-Jones plugs and sockets for my new cable ingress, plus some SMA connectors and flexible coax jumpers. Plus, I ran into a few friends, although not the ones I expected to see!

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Posted in radio

Tags: joy of homebrew K2 K3 unobtanium

IARU HF 2014

July 14th, 2014 by k8gu No comments »

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

Class: SO CW LP
QTH: FM19li
Operating Time (hrs): 5
Radios: SO2R

Summary:
 Band  CW Qs  Ph Qs  Zones  HQ Mults
-------------------------------------
  160:    0     0       0       0
   80:   50     0       3       4
   40:   87     0      11      12
   20:   47     0       7      15
   15:   16     0       7       9
   10:    0     0       0       0
-------------------------------------
Total:  200     0      28      40  Total Score = 25,092

Club: Potomac Valley Radio Club

Since the birth of our second child, I’ve had to become a little more creative in my approach to operating contests. There are rare days when both children are in phase with their eating and sleeping needs and we can accomplish some things, and then there are the other days. With the coincidence of the quadrennial World Radiosport Team Championship (WRTC) and IARU HF World Championship contests this year, I thought I would make a game of trying to contact all 59 of the competitors rather than maximizing contest score. The motivation for this is that WRTC was in New England this year, which is a stone’s throw away from me and middle-of-the-night operation would yield QSOs with the WRTC stations on 40 and 80.

I did end up working all 59 of the WRTC stations with their distinctive 1×1 callsigns by furiously searching and pouncing on both radios on 40 and 80. In fact, I worked most of them twice before I finally found K1T. I’m going to do an analysis of the standings of the teams versus when I worked them to test if any of the teams were better at “marketing” than others. Should be fun! Anyhow, all of these operators were really outstanding but a special congratulations to N6MJ and KL9A who seem to have run away with the whole thing operating as K1A.

In the lead up to the contest, I finally managed to get the station fully SO2R (single operator, two radio—essentially the ability to operate interference-free duplex on any pair of HF bands) again. And, in the process, I have automatic band switching again, so I don’t have to run across the basement to switch antennas. Thank goodness for small conveniences.

Here’s the mess for low-power (100 watts and less): KK1L 6×2 switch to connect two radios to any of six antennas, W3NQN single-band 200-watt transmitting filters for each band (10-80 meters shown here since I still don’t have a 160 antenna yet), and the K6KV-K8GU triplexer that allows me to share the feedline to the G3TXQ broadband hexagonal beam with both radios. All this stuff was homebrewed by me but it is all available in commercial form as well.

I’ve described the W3NQN filters considerably in the past, but the triplexer is new (built in March 2014) and since I’ve had some e-mail traffic from a couple of people who know I built one, I’ll probably write something up on it in the next few weeks. I mention it here because WRTC is actually one of the events that popularized the use of triplexers, which are downright freaky when you think about plugging two 100-watt class radios into a box that separates/combines the signals. Electrical engineering for the win on this one. Anyhow, I based my triplexer off the K6KV QST article from June 2010, finding some beautiful Johnson capacitors in a flea market for $5 each and using leftover toroids from the W3NQN filter project instead of the solenoid coils used by K6KV. The whole thing set me back about $30 total and it works great with the W3NQN filters, to say the least.

This was the second contest with TRLinux contest software by N6TR and W9CF. It has some idiosyncrasies, such as the effect of CAPS LOCK on the shortcut keys. For example, did you know that ALT-r is not the same as ALT-R? The great thing about it is that TRLinux talks natively with the YCCC SO2R+ box that I use to handle keying and audio switching for both radios. And, the band data is handled by the YCCC SO2R+ with TRLinux, so I didn’t have to buy a band decoder for the K2. That whole process of setting up the band decoding was another midnight oil project Friday night before the contest started. Fun and games. But, it worked flawlessly.

And my three-year-old son, future SO2R CW operator, rocking the Bencher and Palm paddles…”I’m doin’ lots of Morse code!”

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Posted in radio

Tags: contests

Remoting K8GU…kinda

June 19th, 2014 by k8gu No comments »

I recently had to spend some time away from home without a radio wished I could remote control my station…

Having been party to the discussion surrounding remoting a local contest station (K4VV), I had seen enough traffic about different VOIP options to start with Mumble for the audio stream. I set up a Mumble server on my Linux server at the house, and then setup the Mumble client on my hamshack computer. I ran a 1/8-inch TRS cable from the rear-apron line-out port of the K3 into the line input of one of my sound cards on the computer. I put a free Mumble client on my iPhone and viola! It worked out of the box.

I have been using Pignology’s HamLog on my phone for quick logging of one-off QSOs and goofing off with its vast array of tools. HamLog also has the ability to remote control a rig using Pignology’s hardware. Since, I’m really not in a good position to drop $300 on a box I’ll use a couple of times per year, I reasoned that there might be an alternative. Enter the socat utility:

root@tula:~# socat /dev/ttyUSB1,raw,echo=0 tcp-listen:7373,fork

Freakin magic. I used HamLog to connect to a “Remote PigTail” and it mostly works. The frequency display does not seem to work and HamLog loses the connection if the phone falls asleep. But, it is functional. Another interesting wrinkle is that when my shack PC screensaver comes on, it mutes the audio stream piped into Mumble. But, those are all minor irritations at this point considering the trivial amount of effort that went into getting a remote control going…

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Posted in computing, radio

Tags: gnu/linux K3 mumble remote

Svalbard

June 1st, 2014 by k8gu No comments »

An annually-recurring professional meeting has started to put me in interesting DX locales. This year was no different: the meeting was held at UNIS (University Centre in Svalbard) in Longyearbyen, Svalbard. My friend and colleague, Nathaniel, W2NAF, did a semester of his graduate studies at UNIS and was excited to return for the meeting. He suggested that the JW5E clubstation “hut” (depicted below) might be both an attractive lodging option for cost, location, and of course, radio. The hut is a bit rustic with no running water but we did manage to maintain a nearly professional level of appearance and personal hygene due to Nathaniel’s insider knowledge.

As is typical for the kind of travel I do, there was no straightforward way to get from A to B. Nathaniel and my flight schedules put us into Longyearbyen (via London, Oslo, and Tromso, in my case) on Friday and Saturday, respectively, giving us a shot at the CQ WPX CW contest. We elected to operate this under our own callsigns, which proved to be a bit of a limitation since for much of the contest 20 meters was the only band that produced rates. So, we had to share 20m. Nathaniel operated high power using the JW5E FT-1000MP mkV and Icom IC-2KL amplifier connected to the JW5E antenna system. I operated low power with my K2/100 and the JW5E antennas. He came out a little bit ahead on QSOs and pretty far ahead on points, mostly due to the day of head start and effectively exploiting 20m. I also worked a lot of empty-calorie EU stations while he focused on 3-pt DX stations. Despite our initial optimism, neither of us were particularly dedicated to a full effort in the contest. We both had a bit of trouble adapting to polar day and slept through prime openings on Sunday.

40 meters and lower frequency bands were useless, as were 10 and 12 meters. Nathaniel and I did work each other on 160 with the power turned all the way down. And, of course we worked each other in the contest for an easy prefix multiplier. The 12m situation was a little disappointing since I know a lot of people needed JW there. Had we been there in March, it probably would have been open. I worked two CTs and that’s it.

During the week of the meetings, I only managed 1-2 of hours operating each day, and Nathaniel maybe a little more. We developed a protocol of uploading to LoTW first thing in the morning when we got to the meeting (where we had free network access, versus roaming 3G on my phone at JW5E). Since I don’t use ClubLog, this is a good way for DXers to see if they’re in the log and get a quick confirmation. As I told a DXer who thanked me profusely for doing it, my employment covers the largest costs of my DX travel and my operating is secondary to my work. Therefore, I feel no need to extract or solicit donations from DXers. I am ordering cards today and they will be ready to mail in a week or two.

On the last night, I put in a solid 6 hours of operating, making about 600 QSOs in one sitting. 30m was always a struggle with most signals right near the noise level. The other bands (15/17/20) produced big signals and were pretty easy to work. I’m always a bit slow to operate split because I don’t want to use more bandwidth than necessary. With an amp, I could probably have operated simplex most of the time. Usually once people stop coming back to my 599s or they start duping me mercilessly, I know it’s time to split the pile.

The pileups were generally very responsive to my instructions with only one station really raising my blood pressure to the point that I QRT’ed to cool off. Based on his QRZ.com profile and how loud he was compared to all the stations he was obliterating, he was running as much as 4 kW on 30m. Good show.

I heard that someone on a DX club e-mail list suggested that I go next to Jan Mayen (JX). Please negotiate that with my wife and we can work something out. Don’t forget to include that Jan Mayen has one flight per month. My Norwegian colleagues were amused by this and asked also about Bouvet (3Y). Only scientists and hams know about Bouvet and Jan Mayen. Seriously, if I didn’t have a young family, I would consider doing that sort of thing, but I miss them too much when I travel. The next DX trip will be someplace warmer with regular commercial air service.

I’m still sort of converging on the best equipment for portable DX operating. While I like the K3 a lot, the K2 is a bit smaller. In its flight case, it fits under all airliner seats and not just some of them like the K3. Although it is a stupendous performer, the K2 has some idiosyncrasies occasionally cause me to notice that it’s not as well integrated as the K3 and modern JA radios. The diminutive size and negligible RF emissions from the MRF-4125 switching power supply are big pros, but I noticed the fan making a particularly awful noise on this trip. Need to look into that. The K1EL WKUSB continues to be a star performer for computer and hand keying. While I love the action of the Palm Mini paddle, the lack of a solid base can be frustrating. I brought the recently-mounted Schurr Einbau and it sang. Although, it produces the best reactions from security screeners: “What is it? Is it an antique?” And, my favorite from a screener in Longyearbyen: “Is that the new iPhone?”

The real stars of this operation were the Etymotic Research MC5 in-ear monitor earphones. Wow. I’ve been using them for a couple of months now at the recommendation of someone on the Elecraft reflector and they are my new favorite headphones for travel. They do excellent with noise isolation on long-haul flights and in noisy QTHs; they reproduce music flawlessly; you don’t have to turn the volume up to 11 to hear with them; and they fit in a tiny little pouch that’s smaller than a deck of playing cards. And the best part? They only cost 60 USD.

The GU Special came along on this trip but was not needed since I had access to an OptiBeam for 20/17/15 meters, dipoles for 30/40/80, and a Cushcraft R7 vertical for 40-10 meters. I was tempted to take my gear on the 8-hr boat trip we took up another fjord. However, I decided against it for a variety of reasons including the desire to do some birdwatching and look for polar bears—we saw some seals and an artic fox but no bears. The seals and the fox amounted to no more than a couple of pixels in the photos I tried to shoot of them, even with a modest 200mm telephoto lens. OK, that’s a short lens by wildlife photo standards. Please accept this puffin photo in place of a bear photo.

And the Tempelfjorden glacier and sea ice shot from my phone…

This photo is looking back up Adventfjorden toward Longyearbyen and shows the JW5E tower right near the water in the center. (The heftier one on the right.) Also in the background are the dishes for the EISCAT Svalbard incoherent scatter radar.

And a photo from our visit to EISCAT in tracked vehicles. It was practically June and there was a lot of snow on the ground.

Finally, here are two YouTube videos related to our operation. The first was shot by W2NAF and has a tour of the JW5E station. The second was shot by KB9UWU during the WPX contest and shows pretty much what 15m was like for me: the band was obviously open but I didn’t have many callers.

Thanks to everybody who stopped by to say hi. I worked lots of friends on the air from all over the world and received SWL reports from a few more.

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Posted in radio

Tags: DX operating K2 portable science

Getting off Windows XP

May 18th, 2014 by k8gu No comments »

With the impending end-of-life of Windows XP a few weeks ago, I found myself with a bit of a predicament: My shack PC is a dual-core 64-bit system (3.0-GHz Pentium-D) so it’s not really a slouch performer. But, it had only 1 GB of RAM, which was fine for XP. I could upgrade my RAM and upgrade Windows, or I could upgrade the RAM and dispense with Windows altogether.

I opted to drop Windows.

My almost-3-year-old son helped me install 4 GB of RAM last weekend. (Actually, he spent more time asking about the capacitors on the motherboard. Kids these days.)

I’m a long-time GNU/Linux user (just over 15 years, actually) and fan. However, as I wrote once in the past, I’m also fan of getting things done. So, I kept using Windows 95 / MS-DOS for many years on my hamshack computer, with a brief several-year foray into using Windows XP when I moved to TR4W logging software. Linux finally became ready for prime time in my hamshack when Kevin, W9CF, ported TR-Log over a couple of years ago. After ensuring it wasn’t a fad, I was ready to jump. Over the past week or so, I’ve been tailoring the setup of everything to bring back the functionality I had previously.

So, what broke?

I have an nVidia graphics card for my second monitor. Failure. Not sure how much I care. Maybe I’ll look for an old ATI card or something else with drivers? Anybody have a plain PCI video card with VGA or HDMI kicking around?
Windows-specific software that I’ll probably just quit using: AVR Studio and SH5. Didn’t really use these much anyway.
Now, for the truly bizarre: My Elecraft K2/100 throws an ERR 080 on power-up if I disrupt communication between it and TR-Linux (does not matter if the K2 goes off first or TRLinux quits first). I have to disconnect the RS-232 cable at the back of the K2 for a while and then it comes back OK.
ARRL’s Trusted QSL software version 2.0.1 didn’t compile immediately without dependency problems. Further study indicated.

And, what works?

TRLinux talks to both the K3/100 and the K2/100, as well as the YCCC SO2R+ controller.
Made some QSOs and uploaded the signed log to LoTW.
Pretty much everything else…

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Posted in computing, radio

Tags: gnu/linux kids say the darndest things re-use repair

More paddle work

May 16th, 2014 by k8gu No comments »

Over the past couple of weeks, I’ve managed to steal away to the machine shop and continue to work on mounting the Schurr Einbau mechanism. I found a piece of polycarbonate in my scrap bin to make the interface between the Einbau and the base. It turned out that the mounting holes are tapped M3-0.5 so I had to make trip to Ace. While I was there, I picked up some brass screws also. Total cost of the project is 52.99 USD. I bored the holes in the base today with the milling machine and tapped them when I got home. Couldn’t resist putting it all together even though I haven’t finished polishing the base or the polycarbonate plate…

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Posted in radio

Tags: joy of homebrew portable

Paddle project

May 1st, 2014 by k8gu No comments »

Over the years, I’ve fancifully imagined that I would build a set of keyer paddles. I even went so far as designing a couple concepts and collecting materials…but, inevitably I moved on from the institution with the machine shop and sucker machinist who was showing me the ropes. About a week ago, Mike, W3MC, posted a bunch of goodies for sale, including a Schurr Einbau key mechanism. Since I love my Profi 2, I snapped it up, recalling also that I had a nice hunk of brass for a base. Today, I cut and milled a little base for it. Lots of finishing and some acrylic work remain, but for now, there’s something special about a freshly-milled hunk of metal.

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Posted in radio

Tags: joy of homebrew re-use unobtanium

MiQP from Ohio

April 22nd, 2014 by k8gu No comments »

Sarah, Evan, and I had the opportunity to go to her parents’ place for the Easter holiday weekend. Since the trip coincided with the Michigan QSO Party, I decided this might be a good test of the portability of the K2. Unfortunately, I was unable to operate much longer than a half hour but I had some fun on 40 meters and tried out N3WG’s (Pignology) HamLog for logging. Neat stuff.