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  • VA2SFX 9:54 pm on April 13, 2017 Permalink | Reply
    Tags: Building, , Construction, , Home Improvement   


    I became a carpenter by way of theatre. It’s a weird style of carpentry relative to what you end up using in residential situations, but it served as a good foundation. I worked briefly doing “real” carpentry for a contractor, and did lots of small jobs and projects around these subjects, but re-doing the basement stairs of our 100-year old house was a challenge.

    Sadly, I didn’t take a ‘before’ photo of the old stairs, but they were a mess. I did measure them though, with the idea that emulating their basic form would make sense since they were originally custom-built for this space.

    I’ll be the first to admit — especially after this escapade — that I don’t know what the “right” way to build stairs in a steep angle/narrow opening like a basement entrance is. I never got that far in my training with Yoda.

    I looked around a lot at stores initially while I was scoping out the project for stair stringers. The only pre-made things I found at box stores around here were short wood zig-zaggy things for decks, and eventually some steel box tubing things. I actually bought at first a set of steel stringers and steps, because it seemed to fit the overall stringer length I thought I needed. But when I got them home it was like…. uh, no.

    There are a lot of angles at play here, and getting them sorted out without a specific logical framework to peg them into didn’t quite come together. I tried just copying the 8″ rise, 8″ run of the old stairs, but with my stringers being these flat 2″x10″s instead of the cut-out zig-zag stringers.

    But that didn’t work out. I made some tests, and ended up with these divergent lines where my stairs wanted to be in 3D space, versus where the stringers actually were in real life.

    Maybe this will help if you visualize it:

    “Two roads diverged in a yellow wood…”

    Real life, of course, has to ultimately win out in carpentry. It’s why carpenters end up hard-headed. It is not a theoretical exploration of possibilities. You have to actually build something — or bring the materials back to the store, which I did on the first go round.

    Anyway, my all-wood system eventually worked out with help from a friend. Honestly, I couldn’t tell you the calculation we did to figure it out. Basically I started with what I knew was right: the dit of my diagonal stringers into the space.

    So you start with a known good value. You have your ideal, of course, always in mind. But from your known good value, you build up, you attach onto, applying (hopefully) values abstracted out of your ideal.

    I looked at a number of carpentry staircase planning calculator sites where you could input your desired dimensions and it would spit out drawings with measurements for you. It was helpful in some ways in conceptualizing, but the execution in actual space was still a different story, even knowing what some website said I should do

    Eventually, as you can see it all worked out. The run is shorter than I wanted, but it actually fits about as well for the space as I think is practicable. I need to add a handrail and smooth out the noses on the stairs, and probably stain them, but they are solid and have a really good feel. Way less scary than what used to be there, which was all cracked, crooked, and broken in sections.

    I also took this rebuild opportunity to widen the mouth of the stairs going down from the kitchen. I cut off with a sawzall about 6 inches of wood on the left side. It was tough for me to squeeze my shoulders through the opening before but now it’s breathable and you can more easily pass downstairs carrying stuff into (or out of) storage.

    Total project cost:

    • Pretty cheap, since it’s just wood and screws. I spent about a hundred dollars Canadian, though that included a bunch of cuts I had them do at the store for convenience (which i had to re-do later).

    Total time:

    • With demolition, two weekend days, one of them a half day. I’ll probably need to put another half-day in tomorrow to clean up and finish the area off suitably.

    Project difficulty:

    • High intermediate to advanced, depending on the space restrictions you’re dealing with. This is way beyond a novice carpenter and was a challenge for me to get right with about 6 years experience. Replacing something in an already-built structure and space is always much more difficult than new construction in an open area.
  • VA2SFX 1:41 am on April 6, 2017 Permalink | Reply
    Tags: , , , , Writing Prompts   

    Nature is what we do. 

    An Invironment writing prompt

    For the editors and readers of Invironment, ‘Nature’ isn’t a place you go on weekends

    Photo by Somin Khanna

    Nature is what we do.

    Nature is all around us. It’s like the Force. It exists inside us, flows out through us. Waves crashing on waves — onto rocks. We cannot escape it. 
    It’s in our nature.

    So how do you Nature?

    DIY Nature writing wanted.

    Theme: How do you Nature?

    • Are you an eater, a watcher, a listener, a toucher, a smeller, a taster?
    • Do you have practical, hands-on experience, expertise and interest as an avant-gardener, a forward-thinking forager, an adventurous culinary artist, enterprising farmer, or concerned climate scientist?
    • Do you watch the Weather Channel religiously? Do you talk to animals? Do you check moon phases? Do you try to identify birds from your back porch with binoculars? Do you take up close pictures of flowers? Do you just like mowing your lawn?

    If you answered yes to any of the above and can condense your Nature know-how into engaging first-person essays with a tutorial slant and 1 or 2 original photos, we would love to share your DIY Nature with our community of nearly 11K readers.*

    Email us: pitches and links to published posts for consideration at the email address below. Thanks!

    *Stories selected to be published in Invironment remain the copyright of their respective authors, are not edited by us (though we may offer occasional suggestions) and are unpaid.

  • VA2SFX 1:13 pm on April 4, 2017 Permalink | Reply
    Tags: , , , , Outdoors   

    What to do with wood 

    Managing windfalls of materials in the garden

    We bought a house at the beginning of February with piles and piles of old semi-rotten wood out front:

    I would estimate there is probably about 10x this quantity of wood piled in various spots around the property, thanks to some big old dying trees that were cut down last year.

    Part of the vista from Google Street View:

    There are some other stashes in other places as well, not shown above.

    Since we were living just next door when those trees were cut last year, I was happily able to capture a big quantity of mulchy goodness, which I incorporated onto my garden soil.

    View story at

    Option #1: Firewood

    Clearly the most obvious option for using a bunch of pre-cut logs is turn it into firewood.

    Now, I’m no expert here — and we do have a woodstove (plus electric heat)— but people with more experience in the matter say that this wood won’t produce quality heat as it’s old and in some cases rotten. It will burn too fast, and maybe dirty. Sounds probable.

    Plus splitting and storing all of it sounds… boring!

    Option #2: Mushrooms

    I’ve played around pretty extensively with inoculating logs with various types of edible mushrooms, like shiitake, oysters and even reishi.

    View story at

    This season will tell me whether or not I’ve finally found the pathway to success on that front. But I know from experience, again, you don’t want to inoculate old bad wood with mushrooms, as there will be too much competition: wild strains, etc will have taken hold by now. Best practice seems to be cut fresh wood, let it age a few weeks and inoculate once it’s only somewhat dried out.

    Option #3: Hugelkultur

    There’s a permaculture thing, hugelkultur, where you bury a bunch of wood in mounds, it decomposes slowly and holds moisture and builds soil over time.

    View story at

    It sort of works/sort of doesn’t/maybe I haven’t found the right technique yet. From my experiments, it seems that on a relatively small scale, it’s a challenge to get these things to perform.

    I suspect, based on the Sepp Holzer examples you always see of this, that you have to pile these things really high with tons of material in order to achieve the critical mass necessary to accelerate the biological processes at play. It’s *probably* like a hot compost pile — it won’t get hot if it’s not big enough and the chemical reactions at play are restricted.

    That said, I finally think I have a large enough quantity of wood to actually try out a freakin’ big mound of buried wood, plant over it and see what happens. For the soil moving though, I will enlist the aid of someone with a tractor. Because I don’t want to spend the next 4 months spading soil out and getting nowhere.

    Option #4: Beds

    There are any number of variations on the old “wood in soil” trick in gardening.

    • Use logs for garden bed borders.
    • Dig a trench and stick logs in it. Plant over top.

    Or some combination of the above.

    Given the sheer quantity of material with which I have to experiment, you can rest assured that I will exhaust every possible configuration of the above and post my results. Oh the wheelbarrowing that is going to take place!

    Option #5: Walls

    Lastly, we’ve noticed a benefit of having the wood in stacks as they presently are, since it forms a basically free barrier between us and the street. It’s a bit haphazard though, since it was “built” by a tree-cutting crew. A more formalized wall or walls, perhaps even including masonry of some sort — a more true cordwood wall — is in my future.

    Anything is possible, but everything requires work. I’m fine with wheelbarrowing, and a certain amount of digging, but I’m not into “getting my hands dirty” just for the sake of it. I have a limited amount of energy and tons of things to do in the house, garden and at work — and the name of the game with land management seems to be the least effort for the maximum payoff. So we’ll see what develops!

  • VA2SFX 6:38 pm on March 31, 2017 Permalink | Reply
    Tags: , , Help Center, ,   

    Write quality help center content 

    Getting started guide

    I wrote my first Help Center (or “Knowledge Base,” depending who you ask) without any on-the-ground experience working in Support. It probably showed.

    It was written through the lens of a power user wanting to document every aspect of the product thoroughly. A noble intent, to be sure. This meant not only tons of screenshots and walk-throughs of all states of UI flow, but also big walls of text with elaborate explanations, and an enormously high number of pages (well over 400).

    It made sense at the time to pick apart the product this way, but over the following year and a half interacting with both users and the product team, I came to gradually realize how backwards I was approaching it originally.

    Less is more.

    People don’t go searching for help articles because they have an hour they want to pleasurably spend parsing through a technical treatise to solve a fiddly problem they should not have in the first place.

    Users are simply looking for the shortest path to satisfy an intent.

    • Give it to them ASAP, and get the hell out of the way.

    Satisfy user intents.

    At its best, software enables you to do things. To achieve some over-arching objective, by actualizing smaller intents along the way into achievable steps with the tools at hand. The user might stumble in that process for a variety of reasons:

    1. Users don’t understand how the product works.
    2. Required steps to satisfy a given intent are non-obvious (e.g., hidden or poorly-designed).
    3. The intent is outside the scope of the product. (e.g., you_can’t_do_that).

    → This is where Support lives: in that grey-world of either misunderstanding leading to frustration and insanity — or the smooth routing of questions to answers (like in an old-timey switchboard) invisibly serving the actualization of human intents via a product in harmony with its user community.

    What can I say, I’m still a Support Utopian at heart!

    View story at

    With that vision in mind, here are a few other guidelines I’ve been operating under in my second go-round at writing a help center.

    Title using active verbs and fewest words possible.

    Every microsecond someone has to take parsing your help content is multiplied against the sum of their existing frustrations. Use fewer words to reduce their Time To Solution to almost zero so they can get on with their life…

    As someone on the computer all day, text also can become very fatiguing. Reducing word counts and even character counts wherever possible can make a help center a place of visual as well as psychological relief.

    How-to articles begin with ‘To…’

    Call me old-fashioned, but I think a good rule of thumb is: how-to articles begin with ‘To…’

    So, let’s say your short page title is “This thing.” Not Shakespeare, but it will do. With rare exception, then, the first words on the page should be:

    To do this thing…
    • It’s basic.
    • It gets to the point.
    • Immediately useful.
    • You know why you’re there.
    • It can be linked out to from product for really specific usages.

    More broadly: the article acts a link in a tool chain to achieve an intent for the user in your product. Not as a further blocker or source of confusion for users who never wanted to go sifting through your help center for a solution in the first place. Help them get done, and leave.

    Minimize surface area to reduce maintenance.

    The first time I wrote a help center, I thought documenting every little thing visually would be a great aid to customers. Maybe for some it was, but then I learned what “continuous innovation” means in the SaaS industry. It means your product is literally always changing. From week to week, or even day to day.

    In a practical sense, then, the more material you include in your help center content, the more you will have to constantly monitor and update as the moving target of your product changes.

    Not just that, but the more images you have, the more images you potentially have broken. The more links, the more dead links. And so on.

    It sounds counter-intuitive to the old me, but now seems better to:

    1. Minimize images.
    2. Minimize cross-linking to other pages.
    3. Minimize repeatetion content on multiple pages or sections.

    And anyway, if your product is good, nearly every operation performed in it should be easily describable in words. You shouldn’t need umpteen-million screenshots.

    View story at

    So, only include a screenshot with arrows in an article if it’s a complex operation and words alone aren’t sufficient to convey the user action required.

    Write for Google Rich Snippets.

    When people search “how to” information on Google, Google tries to automatically excerpt relevant information from websites. I made a big collection of these as reference here:

    View story at

    Google refers to them as “Rich Snippets.” They look like this:

    Google finds a well-ranked page in its index whose title matches the user intent, and tries to yank out relevant step-by-step information, with a single small picture if available.

    I did some tests with character count on these snippets from a variety of how-to searches on Google and came up with an approximate count of ~360 characters.

    Given the direction automated information extraction is going, write expressly with the goal of having your how-to information accurately picked up and re-transmitted by Google to the user.

    It used to be that you wanted people to visit your help center. And that may still be all well and good for certain things… But if a user can now get the answer to satisfy their intent right in the search results page, there’s literally no reason for them to ever go to your help center.

    And in fact, that’s better for everyone. Their frustration and TTS (Time to Solution) drops to almost nothing. They can close the tab and bounce back to the task at hand. They don’t even have to *think* about navigating around looking for answers, getting more frustrated, and finally opening a help request.

    So how do you write for Google Rich Snippets? Allow me to demonstrate:

    To write help center articles for Google rich snippets:

    1. Choose a short relevant title for your page, focusing on the user intent served.
    2. Begin how-to articles with “To do ____” and answer that question as concisely as possible.
    3. Use numbered lists.
    4. Break everything into short singular, but substantial steps.
    5. Aim to deliver your information payload in under 400 characters.

    If your information can be conveyed in one or two sentences, answer it immediately first and explain it or support it with details after.

    An alternative or supplement to numbered lists, especially for very short answers with few steps is to use a right-bracket ( > ) between linked steps. Like:

    Click on the bubble > click the field > start typing

    It’s clear. The clauses are short. It’s easy to parse that they are sequential steps. I personally find it preferable to a more “correct” English sentence which might read like:

    First click the bubble, then click the field, and then start typing. 

    Both have their advantages, appropriate audiences and contexts, but I’m a big > guy. Seems more “Support-y” to me. Makes me feel like I’m a robot.

    Speaking of robots… 🤖

    Automation is radically changing Support.

    Google Rich Snippets is the tip of the iceberg of the tidal changes that are underway beneath the surface of Support.

    If we think of Support as routing questions to answers with the aim of satisfying user intents, human agents may soon be both augmented and eclipsed by bots, natural language processing and integrated automations.

    Yes, Support should be about empathy, and your agents shouldn’t rely solely on macros and shortcuts. But if they don’t use automation tools at all, they’ll be reproducing work for no reason — work that can be easily handled by bots as they improve.

    Basically, I’m thinking of Support nowadays as a process and mechanism of wiring together some combination of the following:

    • A source of questions
    • A bank of answers
    • Identifying user intents
    • Product feature map
    • What capacities Support agents have

    Most problems users face aren’t unique. Most problems express themselves as repeating patterns with one or two preferred solutions.

    I look at it almost like the I Ching: there are (figuratively speaking) approximately 64 possible outcomes, configurations, or arrangements users can get into relative to your product which cause problems. And for each there is a fix, a workaround, a linked work-flow or a big fat “No,” which is required as a response.

    Some are big and common issues. Some are bugs that get solved rapidly. Some are #knownissuenotfixed. Some are things that come up only rarely for a few users in special circumstances. Whatever they are, they form patterns.

    And where there are patterns, there is the possibility of detection and of automation of subsequent workflows.

    View story at

    While chat-bots running natural language processing aren’t yet fully-featured enough to be able to independently run a help desk ticketing solution without human intervention, that day is definitely coming. The race is on.

    What will remain in demand as that Support Singularity approaches will, of course, always be clear, concise, brief, consistently micro-formatted documentation which can be cut up and manually or automatically reassembled based on circumstance, product state, and user need. So in effect, the game will change, but the rules will stay the same.

    Other miscellaneous rules, because I’m running out of time.

    1. Write in an active voice. Be direct and declarative. Don’t mince words, muddle around, or waste people’s time.
    2. Help centers are for factual statements about how things work now. Marketing and future product promises should go somewhere else.
    3. When ordering lists of pages, start with the positive actions users can take at the top (e.g. “Make something”), followed with the negative stuff they can do (e.g., “Delete your account”) and ending with the things they just can’t do with your product (e.g., basically any FAQ which starts with “How can I ___?” and whose answer is “You can’t.”)
    4. Don’t lock things up into long paragraphs. Break to a new line as soon as a new idea arrives, or throw in a bullet point to split things up for scan-ability, and eventual automation.

    Okay, that will have to do for now. Good luck!

  • VA2SFX 10:44 pm on March 30, 2017 Permalink | Reply
    Tags: , Nooelec, , ,   

    Things I can’t figure out in SDR 

    Software-defined radio is awesome, cheap and confusing af

    I’m using gqrx with a Nooelec NESDR Smart from amd am trying to keep track of my progress with learning this and RF technology in general.

    • How do I figure out what the frequency range of my dongle is? What are the upper and lower limits I should test?
    • Why is an “up-converter” required for HF, when those bands are actually lower?
    • How to get gqrx ghost-box to work.
    • How to get dump1090 to work.
    • Why everything requires the command line.
    • If there’s even anybody doing a good podcast about this to listen to for pointers and ideas.
    • Which one of these three antennas is for what.
  • VA2SFX 3:27 pm on March 27, 2017 Permalink | Reply
    Tags: Arabian Sea, , , ,   

    Algae bloom size of Mexico in Arabian Sea 

    Via Science Alert:

    “An algae bloom the size of Mexico has appeared in the Arabian Sea, thanks to a growing ‘dead zone’ in the Gulf of Oman. […]

    But what’s really concerning is the fact that these dinoflagellate blooms weren’t regularly seen until the past decade or so, and now are becoming increasingly common around the planet — particularly in the Arabian Sea. […]

    A 2008 study in Science found that, globally, dead zones have doubled in size each decade and now cover more than 153,000 square km (95,000 square miles) of the planet’s oceans.”

    Image via NASA.

  • VA2SFX 3:05 pm on March 27, 2017 Permalink | Reply
    Tags: , , , ,   

    Beginning with Software Defined Radio 

    Observation and exploration with gqrx for Mac

    I bought a Nooelec NESDR Smart, which is a USB dongle that allow you to connect an antenna to your computer so you can listen to RF (radio frequency) signals over the air.

    It’s really cool but also daunting for new users without much experience or understanding of RF technology. I’m on Mac, so I finally settled on gqrx as my app to interface with the SDR dongle. The main app view looks like this:

    The above screenshot appears to depict a broadcast FM station at 96.185 mHz.

    Tuning into broadcast FM stations is the easy part of tinkering with SDR, whatever app you’re using. It’s all the stuff outside of that where it gets complicated.

    Check, for example, this 2014 Radio Spectrum Allocations chart for Canada:

    Depending on what band you’re looking at, the whole thing gets pretty complicated — and fast.

    I’ve used a little bit as a guide the RadioReference site, Canada section, to help me figure out some broad strokes of what areas to go hunting for what kinds of signals (ie, what frequencies in mHz to try monitoring). Things like local police, for example, though I haven’t had huge success with that. But as a result of my experiments, I’ve come up with a sort of generalized “listening protocol” as I work my way blindly through the mass of RF frequencies out there.


    Since I only rarely know what a signal is, I’ve started simply taking notes on what I observe, and in some cases recording samples of signals I hear.

    Generally, what I will do is choose a specific frequency band that I’ve heard works on SDR (you can’t get all bands on an unmodified SDR unit), like I read that 400–500 mHz is supposed to contain walkie-talkie traffic. Now, it’s tough when you read something like that online, as the same band might be allocated differently depending on the country you live in. I don’t even know if that’s valid for Canada, but I gave it a shot and starting at 400 mHz incremented 1 mHz at a time upwards and simply wrote down what I observed in the app.

    For example, at 406.536, exactly at the stroke of 5pm, I heard a man’s voice in French say “dix-sept heure” (five o’clock).

    At 406.588 400 mhz (NFM — narrow-band FM), I recorded the following signal:

    Now, I don’t actually know what this signal is, nor “what it means” in the grand scheme of things. I simply noted it, described it, and recorded it. On a piano, I also tested until I found the two initial notes or tones (e.g., frequencies), which begin the segment, F → C (F3 → C3, I think). [Tone generator, to test and determine freq.]

    Again, I have almost no idea of what the above frequency is. Sounds like “data” of some kind, but I’m not advanced enough to know what exactly. Or even to begin looking. However, I believe there is great utility in using this kind of observational method and careful listening to uncover patterns in just about *any* domain of knowledge, but especially in RF. I figure, with enough practice and research, I’ll be able to hear a signal, check the band its on, and eventually with a certain degree of accuracy figure out what’s going on.

    It may seem like a kind of “why bother” activity, but I’ve set myself to learn all about RF technology, and so far it’s really fun for me. It’s a way to participate in a sort of “secret internet” of signals that surround us every day without having to go through my wifi router, my internet service provider, etc. Without being exposed to ads and trolls and fake news and bad news. To just experience the raw signals and hopefully, eventually, to understand them.

  • VA2SFX 1:26 pm on March 23, 2017 Permalink | Reply
    Tags: Britain, , , ,   

    India gives legal rights to rivers— Brits dump shit in it. 

    I just find the timing of these two stories in my news feed amusing —


    “New Delhi (CNN) — A decades-long fight against river pollution in India has been given a much needed boost.

    On Monday, a court in the Himalayan state of Uttarakhand declared the Yamuna and Ganges rivers “living entities.”

    The ruling said the rivers, both of which are considered sacred to Hindus and personified as goddesses, were crucial in providing “physical and spiritual sustenance” to locals.”


    “Thames Water has been fined a record £20m after pumping nearly 1.5 billion litres of untreated sewage into the River Thames.

    The company admitted water pollution and other offences at sewage facilities in Buckinghamshire and Oxfordshire.

    Fish and birds died following the spills in 2013 and 2014.

    The £20.3m fine is the largest penalty handed down to a water utility for an environmental disaster.”

    If you haven’t been following, there was a recent ruling in New Zealand, of which India’s is an echo, that a river has been granted legal personhood in recognition of the role it plays in both the ecosystem and traditional life. It’s a bit similar to the notion of giving legal personhood to corporations…

    This is part of the larger Rights of Nature movement, and comes out of essentially Deep Ecology of the 1970’s.

    See also: 1982’s more or less ignored World Charter for Nature.

    Critics tend to call the Rights of Nature movement, in usually a shrill voice, communist/marxist or similar — in that it threatens the supreme right of man to make profits by actively destroying the ecosystems in which he is embedded and on which his continued existence is entirely dependent. I guess from that statement, you can probably tell where my sympathies lay.

  • VA2SFX 4:17 pm on March 21, 2017 Permalink | Reply
    Tags: , , , Home, Woodworking   

    Hanging Doors 

    DIY Home Improvements

    We recently bought a 100+ year old house, so I’ve gotten into doing a lot of small-to-medium size fix-its.

    I’m looking at housing as like a continuum that connects you to your environment and the ecosystem. It’s your linking system to Nature, but you build in “cyber” controls over which insects you’ll let in, how fast your food decays, and little things like how much water on the floor is acceptable…

    DIY Nature

    This door ^ I bought as a blank, which means it had no hinges or doorknob. No hole for the doorknob.

    Work done:

    1. Cut with circular saw bottom 3 inches to make it fit in threshold.
    2. Cut with chisels indentations into door edge for hinges. Freshen up existing threshold indents.
    3. Hang door — easier said than done.
    4. Cut with hole saw space for handle.
    5. Attach handle. Also easier said than done, but now I know more too.
    6. Freshen up and expand indent for strike plate and attach.

    Time to completion:

    Probably about three mornings. (3–4 hrs total?) That’s how I tend to measure these things — in mornings, rather than hours. Work a little around the house before going to my “day” job: where I work at home also, but on a computer.

    Total cost:

    Probably around $100 CAD or just a little more with the door (on sale for $50, the hinges, doorknob and taxes).


    Interior of door, with wood paneling that I installed after demolishing an existing closet in this room. (You can see a little bit of fancy footwork I did to plug an area of the floor — in lighter-colored pine — that was under the closet)

    French doors

    Hot on the heels of this door-hanging success, I decided I was ready to try and flip our French doors to fit on the other side of a threshold in our cuisine d’ete (summer kitchen? I don’t know what the English-language equivalent is).

    I knew this was a risky maneuver, but it would mean that the doors would open out into the room instead of out into the entryway, where there was less room for them (previous occupant had removed doors altogether — which is a shame because they’re beautiful).

    Depicted above are the doors after being flipped inward. You can see the old hinge-indentations left on the threshold.

    This operation went remarkably well for the first door, but hit a bit of a hurdle on second door, when I discovered that both sides of the threshold did not have equivalent openings.

    You can see in this shot, where the hinges are on this door that I had to cut a not insignificant slot into the existing threshold upright member, in order to have enough space for both doors to close.

    For this cut, I used a combination of the “multi-tool” I bought recently from Canadian Tire.

    I bought it on sale for $40 CAD, versus it’s semi-ridiculous normal price-tag of $140.

    After performing this cut though, it’s pretty much worth it at either price though, because I don’t know how I would do this cut otherwise.

    Maybe with just chisels and a lot of cursing — and probably a much worse finish. I’m not thrilled with some of the finish quality in the above, but it was a learning process for how to remove that wood in sections without ripping up too much what remained.

    It’s one of those things, if I had it to do over, I would know how to do a better job. But it’s such a custom operation that I will never have to do it over — at least not exactly in this configuration. But then you take from it skills and approaches which you find ways to apply elsewhere.

    Happily, without more than 4 hours work, I was able to flip these doors so they close snugly and pretty accurately — if not quite as perfect as I’d like.

    Headless hockey chicken belongs to my dog, Bob

    Some work you have to save for other days though. I still need to put in some wood strips at top and bottom somehow to act as stoppers for when you close the door. They are sort of free-floating right now.

    The floor one will be harder due to the fairly extreme height distance you can see as the floor slopes downward under bottom door edge toward right of photo. Like I said, an old house.

    I would like maybe also to add one of those bolts that communicates to the floor from the left door, which holds the strike plate. Then the one door could be locked into place for convenience as necessary.

    Total cost:

    $0 for flipping the French doors, as all materials were already in house.

    Total time:

    4 hours

    Life-saving tool:

    Multi-tool from Canadian Tire for deepening the threshold to accept doors on interior side:

  • VA2SFX 1:35 pm on March 20, 2017 Permalink | Reply
    Tags: , , , , Spectrogram   

    Waterfall view in gqrx 

    Visualizing RF and audio signals

    This is a visual display of the RF energy emitted when I click the keys for my Toyota Matrix (more details at link):

    The part below in green/yellow is referred to as the “waterfall.” It’s a way of visualizing RF signal intensity over time at specific frequencies. You can see in the graph above, this is mid-signal on the third click of the keys. The intensity is spiking during the click event.

    This is a rough approximation of how Morse code actually works: CW, or continuous wave. The wave is continuous until interrupted. The interruption patterns are codified into letter equivalents — dits and dahs — and you have your electrical signal converted into a human readable message.

    So you could basically do the same thing with any RF emission source at any frequency. Send out spikes and interruptions of signals.

    Now, I’m not too sharp on all the technical stuff here. But from what I understand, you can do visualizations — spectrograms — of all different kinds of signals. From RF to audio of bird song, like the below:

    The waterfall scrolls to the right, instead of down like my example image at top of the cay key clicks. But it’s the same idea. Here’s another one of multiple birds, each doing their unique song/signal:

    I think all this information about radio signals, etc didn’t really start to gel for me until I made the leap over to just analyzing audio spectrum, with a free Mac utility called iSpectrum:

    That’s a visualization in iSpectrum based on a tone generator I found online.

    The tone is 440 Hz and in this case the waterfall scrolls upward, so you can see a record of when this frequency is spiking.

    So the audio frequency above, converted to mHz is significantly lower than what I can hear with an RF tuner (lowest my SDR dongle goes is ~24 mHz):

    You can see in the image below human-audible frequencies graphed relative to RF to get a better idea:

    Human audio frequency range is said to be between about 20 to 20,000 Hz. To see this in action, check out some videos on Youtube of an audio signal climbing up in frequency and see where the lower and upper thresholds of your hearing are (I’m about 30 to 14,ooo Hz):

    And you can see this type of audio tone sweep at play in a modified form in the old XDR tone bursts which accompanied some old cassette formats back in the day:

    It doesn’t really show up in the waterfall here (guess I have to dial in the settings better) but it’s pretty evident when the frequency sweeps from left to right here in iSpectrum:

    Anyway, speaking of audio frequencies in the human range, this is also fun to experiment with (as is the oscilloscope view in iSpectrume). It’s a tuner for flutes:

    But you can just whistle into it to dial in notes. And you can see both your actual frequency as well as the musical note assigned to it. More on those assignments here:

    Go forth and emit frequencies!

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