Archive for the ‘computing’ category

Thoughts on Digital

May 19th, 2012

I have opined in the past (although perhaps not on the blog directly) that CW is the reason I am still an active ham after almost 19 years…actually, I think a week from today marks the 19-year anniversary of passing elements 2 and 3A in the basement of the Stark County Sheriff’s office.  CW permitted me to make interesting, intriguing, compelling QSOs that I simply could not complete on SSB with my meager station as a beginner.

Over the years, I have used this as the argument for retaining the Morse code testing requirement:  Morse code proficiency gave newcomers the opportunity to make exciting DX contacts under all solar conditions (except disturbed, of course) and hook them on the hobby.

PSK31 was the first mode that challenged CW in that arena.  I made a couple of PSK contacts almost 10 years ago now and decided it was harder than CW.  So, I did not pursue it.  Aside from making a half-hearted effort to get ARRL’s Triple Play Worked All States using only unassisted (no cluster, no RBN, no skeds) contest contacts, I haven’t really operated digital modes much and didn’t really understand why anyone would want to because CW is so much easier.  I’ve seen dozens of JT65 posts by fellow AmateurRadio.com bloggers.  And, about a year ago, I met Paul, N8HM, who lives in an apartment in DC.  He’s very active on HF digital modes with a shoestring setup…and he’s very passionate about it.  That’s when it clicked.

Digital modes are the new CW:  the DX mode for the average ham.  I must be slow!

I still think CW is way easier than digital QSOs, especially in contests and pileups:  there is a certain amount of critical humanity (varying timing, sending speed, spacing, or calling frequency) that you can’t apply to cracking a digital pileup…or maybe I just haven’t figured it out yet.  I guess I have years of Morse practice and shouldn’t expect digital to be easy just because the computer is doing the sending and decoding.  But, I think I understand digital operators a little better after this revelation.

You guys are alright.

The Spam Report

January 8th, 2012

First of all, Happy New Year, loyal readers.  I have been exhorted by several enthusiasts of the blog to write more.  The months of November and December are busy around the Miller household with the CQ WWs, ARRL Sweepstakes, Thanksgiving, Christmas, and an annual professional conference on the West Coast between Thanksgiving and Christmas.  So, this is a drought time of year for writing.  A number of projects around the station have been started or completed and those will be written up as time allows.  Travel and potential DX operation is on the horizon, etc, etc.  However, today’s topic is WordPress comment spam.

I hadn’t checked the moderation queue on the blog comments for about six weeks until recently.  There were some 1500 comments pending.  Exactly two of them were from real commenters.  (Thanks, by the way!)  I could subscribe to a service (like Akismet) to stem the flow of spam, but I’m a cheapskate and skimming the spam is a bit like reading the police blotter in your local newspaper—a guilty pleasure.

The Internet democratizes the sale of nearly everything, legal or not, by providing a low-cost storefront for a business that can be based anywhere in the world, plus  (semi-)anonymous payment.  This is great for obtaining otherwise unobtanium surplus electronics and parts.  But, it’s also great for anyone selling anything else that is high-risk (for vendor or purchaser) or low-volume in a standard retail setting.  The difficulty for everyone is getting your business noticed.  Enter search-engine optimization (SEO):  techniques that game search engine algorithms to increase your visibility in a search.  Google’s PageRank, for example considers the number of links to a site as a measure of its popularity.  So, blasting every blog’s comment boxes with links to your site is a brute-force way to game that system (except the smart engineers at Google have weighted PageRank with the “quality” of the linking page and a whole host of other trade-secrets).  Some SEO schemes appear also to develop trees of “link farms” to improve “quality.”  But, this is just an arm-chair assessment.

Anyhow, the upshot is that there are a lot of keywords and links embedded in SEO spam.  The keywords generally reflect what’s offered for sale and they seem to reflect typical black and gray market goods—counterfeit designer clothing (Ugg boots are the informal favorite in my spam tin, with sports jerseys a distant second), pornography, and dubious medical products and home remedies (“tattoo removal creams” was a recent example).   Today, the bit bucket found a dozen or so messages such as these:

All point to the same site and contain keywords about amateur radio topics (except the SEO one at top).  So, I can infer that one of several things happened:  1. The site owner’s site got hacked and the SEO scumbags wove their material into it to make the SEO look somehow more “legitimate.”   2. The site owner acted (paid…*shudder*) on one of those spam e-mails every domain owner receives that offer to “increase traffic to your site.”  3.  The site owner is an SEO scumbag himself.

I’m leaning toward explanation #2, since the site itself makes him sound like the Homer Simpson line, “Oh, they have the Internet on computers now?!”  Whatever the case, this is inappropriate behavior and I refuse to mention the site owner by name, callsign, or link, lest the action be successful.  It’s the equivalent of splattering up and down the band on SSB when running high power to a good antenna.  You’re a lid.

Ok, I feel better now.

Eliminating CRTs

October 9th, 2011

Ever since I replaced my primary station computer (a decision that may be reversed soon—details in a later post), I desired to replace the remaining 19-inch Dell Trinitron CRT monitor with something lighter and smaller.  Mom and Dad were in town a few weeks ago on a much-needed vacation and we went to the National Air and Space Museum’s Udvar-Hazy facility near Dulles Airport.  This is only a few miles from one of the best used computer shops in the DC area—CedarPC.

CedarPC is nice because they’ll sell you “damaged” stuff at a discount if you don’t care about the damage.  I inquired about a 24-inch flat panel I had seen on the web site, but they could not find it.  They did find me a nice 20-inch flat panel that was just missing the stand and the price was right.  The missing stand was no big deal because I wanted to mount the monitor on an arm so I could bring it closer to the HF end of the station desk, tuck it in at the VHF end, or even swivel it out over the couch to watch a DVD.  Sold.

Monitor arms are generally expensive…at least 2-3 times what I paid for the monitor itself, often more.  So, I went to trusty eBay and found something designed for mounting televisions for $15 including shipping.  This did require some modification of the monitor housing and liberal application of wide washers to reinforce the plastic in the housing.  But, it was done with all junkbox screws and washers.

Marrying the TI-85 and the DJ-580T

April 13th, 2011

The May issue of QST arrived in the mail today and an article about building a “fox” for hidden-transmitter hunting was included.  That brought back memories of a teenage project of mine that I had once thought of writing up for QST, but now just makes a good story for the blog.

The first (and only) handheld radio I’ve owned is an Alinco DJ-580T.  Like most HTs of a certain age, it has provision for an external (“speaker”) microphone.  The microphone input is a sub-miniature (3/32-inch, “2.5 mm”) stereo phone plug.  As a high school student, one of my passions was tinkering with a graphing calculator—the venerable Texas Instruments TI-85—do kids these days even use this stuff or have they gone the way of slide rules and nomograms?  The TI-85 offered the provision to link to a computer or another calculator through a similar sub-miniature stereo phone plug.

Well, one afternoon in probably 1997, I was sitting with the DJ-580T in one hand and the TI-85 in the other…and it hit me…I wonder if I can use the the TI-85 to drive the DJ-580T microphone input?

A few preliminaries are now in order.  Thanks to a helpful (and still operational, albeit now with a CMS and the attendant spam) web site called ticalc.org, a few friends and I had learned to load our TI-85s with third-party binary machine code programs with considerably faster execution times than the built-in scripting language.  This allowed us to play relatively powerful video games surreptitiously on a school-sanctioned platform…a tactic that worked well until the English teacher wisened up to the fact that the five students with their calculators out were not typing essays on them.  Not satisfied to just play games—although I did set a very high score in Tetris during Spanish class—I sought to harness the power of the Z80 microprocessor in the TI-85 for myself.  Recall that this was before widely-available and inexpensive microcontroller development systems like the PIC, Arduino, and AVR.

I gathered the tools and eventually managed to write some fairly sophisticated (given my utter lack of formal training in computing) software in Z80 assembly language, including a crude clone of Space Invaders and a crude adventure game I called “Kashmir.”  Maybe some screenshots or stories about them will come later.

But, for the story at hand, I learned how to manipulate the link port.  Fortunately, the sleeve was ground on both the TI-85 and the DJ-580T.  So, it was just a matter of tip and ring—one was audio and the other was PTT on the radio, and both were settable on the TI-85 for some kind of two-wire communication link.  So, I reasoned that I could write up a bit of assembly code that would key the PTT by pulling it low, then toggle the audio line back and forth at 500 Hz or so to generate a rough audio tone.  It worked!

This was an expensive, although trivially so since I had the hardware, way to build a hidden transmitter.  So, I modified the software to send my callsign in Morse code (using a look-up table) and stuffed the whole thing in a cigar box.  It was good fun for a few of us teenage boys.

And, for the interested, I found the original source code, which is sadly not well commented or dated.  But, it does have my old callsign (AA8UP) listed by the lookup table.

Great Idea: Light Painting WiFi

March 21st, 2011

Saw this in my Google Reader at work and had to post.  Apply to work, ham radio, …?  It’s clearly an artist’s take and not an engineer’s.

LoTW tools

November 30th, 2010

I have assembled some of my tools for massaging logs for upload to the ARRL’s Logbook of the World (LoTW).  They’re written in perl and should run with just about any modern perl distribution, including that found on Macs and GNU/Linux distributions.

lotwtools-1.0.tar.gz

The principal features are:  conversion from TRLog log.dat and mangled Cabrillo files to ADIF and fixing hour offsets.

More on Platform Agnostic

June 4th, 2010

Glad to see that someone else aggrees with me, at least from a security standpoint.

This reminds me of a liberal arts professor I got to know as an undergraduate.  I was a bit more idealistic at the time and told him that if he upgraded his Power Mac to OS X, he would be less vulnerable to viruses since it was based on (BSD) UNIX.  “That makes sense, ” he said, “eunichs don’t get viruses.”  Good guy, but weird sometimes.

Odds and Ends

May 25th, 2010

Yesterday, I revisited this post listing on-going projects from December 2009.  Some things have changed, some remain the same.

The computer stuff has all been crossed-off the list, except that the home server is off-line with a dead power supply (or motherboard).  I’m somewhat loathe to spend any money on it, but I should be able to pick something up.

While it would probably have been cheaper to buy one of the HF/VHF/UHF combo radios, I’ve set off stupidly down the trail of building (and interfacing) transverters.  I am just three amplifier stages away from having 3-5 watts on 50 MHz!  …plus the interfacing.  I’ve decided that interfacing transverters to radios is more difficult than actually designing and building the transverters themselves.  I built the 903-MHz W1GHZ transverter during the Winter, but haven’t tried it on the air just yet.  W8ISS announced recently that he had some leftovers from the group buy of W1GHZ transverter parts, including boards for 2304 and 3456 as well as some G6Y relay kits.  I bought the lot.  I have enough MMICs and chip caps in the shop to build these and since I’ll need to order a couple of mixers for the other transverters, I can hit the Mini-Circuits minimum order.  Sometime.  Microwaves may all get pushed off to Fall and Winter.

Through a strange coincidence, my wife and I independently decided that it would be a good idea to move my ham shack.  The new location is closer to the center of activity in the house, which means I’ll operate more radio and be more accessible to her while I’m doing it.  But, the feedline and rotator cable no longer reach my 144-MHz Yagi.  Fortunately, I’ll be able to raid the K8GU coax stash shortly.  In the mean time, I’ve been missing what appear from the Hepburn maps to be epic tropo conditions.  Stuff happens.

QSLing, notably my favorite QSL topic—bureau cards.  All bureau requests for KP4/K8GU have been processed.  I ran out of CE/K8GU cards with 10 to go.  I will run some more of these from a photo printer in the next couple of days.  Piles of PJ2/K8GU, K8GU, and (go figure) AA8UP cards remain.  I will get the PJ2 cards done this weekend since I have a box of cards on-hand.  K8GU and AA8UP cards are awaiting a redesign.

Although it sounds like a lot, relatively little is getting done on any of these things thanks to an outdoor project at home.  More on this in the future.

Platform Agnostic

May 6th, 2010

Are you?  Objectivity trumps hype.

Computer Projects

April 24th, 2010

Worked on a couple of computer projects this afternoon:  1. Finally requested a username/password from Verizon so I could do authenticated SMTP through their server and thus end my relationship with gmail.  I did not think this was working earlier, but now it is after fixing a couple of lines in the Postfix main.cf file.  2. Thinking about IPsec VPN for home to use the iPod Touch from the road.  Ideas solicited.  3.  Still fighting with the mod_rewrite error in Omeka.  Would like to get this working.  More later…