The 2m/440 Super J-Pole

This antenna is also known as the “copper cactus” (because it kind of looks like one of course!). It is an outstanding performer, especially when you get it up in the air. A friend of mine (KC0UYK) convinced me I should build this antenna and I’m certainly glad he talked me into it.

I built mine from 3/4″ copper pipe. This provides you with a greater bandwidth than 1/2″ pipe and the SWR stays low throughout the 2m Amateur band. I’ve built two of them to date, and they both work wonderfully with very little tinkering. Even if you’ve never used a soldering torch to weld copper before it’s a good project to learn on. (I had never done any copper pipe work before my first cactus antenna).

If I was going to do it again, I’d use a stronger type of copper pipe simply because it tends to flex in the wind just a bit. I chose the cheaper of the materials and in hind site I regret it a bit.

I’m not going to go over all the details of how to build one since there are links below to help you with that. I’m only going to discuss the lessons I learned while constructing and using it.

Building It

The instructions I followed were from this site:

• http://www.n7qvc.com/copper.html

Here is a nice calculator as well showing the proper lengths for a given frequency. I strongly recommend using this to do the design:

• Super J-Pole Calculator

The only modifications I needed to make were to increase the space between the two vertical components by 1/4″ to account for the increase in the size of the pipe (those directions are for 1/2 inch pipe).

Finally, if you’re one of those modern “I’d rather watch an instructional video” kind of folk, here’s a youtube video of someone building a smaller J-pole (non-super) for just the 70cm band.

Feeding It

It’s recommended you use a short coil of 4 turns of coax as close to the input of the antenna as you can. The super-J’s tend to be affected by near-by metal structures and this is supposed to help alleviate that. I’ve done this in the past and I think it did help, but the way I have my current one mounted I don’t have a coil at the moment and it still works wonderfully, but there isn’t a huge amount of metal near it either.

Getting It In The Air

I had mine in the attic for a while, and it did just fine. But when I finally got it up on the roof connected with high quality co-ax boy does it reach out better.

I mounted mine to the chimney of my roof using a chimney mount I picked up from Radio Shack. The mount is somewhat of a pain to put up and I don’t think it’s a high quality ratchet system on the mount, but it seems solid and doesn’t move. I added extra metal braces to the corners of the chimney to keep the metal from eating into the stucko (I don’t have a brick chimney which would be better). The metal corner brackets are actually just held there by the mount strips itself.

Tuning It

To tune it with a SWR meter, take a reading and if it’s off move the two clamps (ie, the feed-point) simultaneously up or down the copper piping until you hit near a 1:1 SWR. Now, if you’ve already put it on the roof you’ll either have to run up and down a lot or take a radio (with power) up to the roof with you.

Results

With this mounted on my roof I’ve had conversations at 5 watts quite far away. For those familiar with the Davis area, I’ve talked to people mobile from my house in Davis simplex at 50 watts out to nearly Hazel on the far side of Sacramento. My wife (KI6UTP) and I held a conversation between each other from Davis to beyond Sunrise without straining too much to hear each other except when I dropped down into a dip on the highway. That’s a total flat-land distance of 25 miles. We also talked as I was roaming around the mountains up near the Echo Summit (7500 feet or so), which was a distance of 90 miles. But the elevation helps a bit there. WB6ISO (I think) in Pine Crest (elevation 2000 feet or so) said I was 40 over S9 at 5 Watts.

One interesting aspect is that a friend of mine, who lives about a mile from me, said my lower antenna in the attic actually gave him better performance. I suspect that the downward angle of the antenna propagation isn’t as good as it is closer to the horizontal plane. This makes some sense since it performs really well out to the horizon. Since he could hear me anyway, only a mile away, I’m hardly worried about it since I think it’s more important to have the main propagation closer to the horizontal to get a better reach.

[Update Jan 2011: Check out the results of measuring the antenna along with adding a balun and a lightning ground strap.]

Still To Do

Simulate it. I generally like to run antennas through simulators before building them, but I haven’t done so with this one. It just works 🙂

Anyone who’s talked with me about computers and communication know that I have wanted to rewrite the email architecture and have a lot of good ideas about what is needed to make it happen. Well, yesterday the folks at google trumped me. And boy did they.

Now I’m not one to generally proclaim ahead of time that something is going to be the next big something. In fact the first time I opened a web page back in the 90s long before most people had heard of “http” I merely thought “yeah, that’s nice but nothing amazingly new”. Even http was a minor improvement on other things. The famous web 2.0, that brought us many cool webpages like google maps, facebook, etc, were really just minor steps forward in technology that I again thought were cool, but nothing outstanding.

For the first time, I’m here to say: Google Wave will indeed change the world. Or the way we work with it. It’s the first technology that has ever caught me completely off guard.

Learn About It

The best way to learn about it is to watch the demo video. You probably want to watch at least from about 0:05 to 0:15 on it to get a feel for how cool it is. The trick, I think, will be to stop watching it as it keeps rolling out new things as you watch it (the interesting non-geeky content is a full hour long, out of the hour and a half). Though the video is targeted for developers (and as a developer it targets me perfectly), but it’s not so geeky that everyone else will be annoyed.

I May Actually Quit Using My Current Mail Reader

I’ve tried, over the years, to move away from the mail reader I use today (something 99% of the population have never heard of: Gnus). The reason I have never succeeded in finding anything else that would fit my bill is that gnus helps me manage email like nothing else can. Yesterday, on May 28th 2009, I received 4661 pieces of email. Now, certainly a large portion of that is spam. But a lot of it was stuff I needed to at least consider and the power of gnus lets me sort it appropriately so I can actually handle the load. But that’s a whole other subject for another time (many people wonder how I do it; I should write it up sometime too).

Google Wave, on the other hand, may finally offer enough of a new enough complete change in the way communication happens that I’ll actually be able to keep up with the level of communication that I need.

Features

It provides real-time updates, shared tagging, proper thread control, reduced bandwidth, retroactive publishing a conversation to a new person. All these features are likely enough to actually pull me over. There are issues as well, and I’ll probably document those later, but on the whole they’re a fantastic change in thinking and are a lot along the lines of how I’ve wanted to revamp things but I think they’ve succeeded in taking to a level further than I was thinking.

It’s really like mixing email, web, chat, and usenet news all together in a single form. Or it looks like it at least. Kudos on taking the best of all those highly useful worlds and actually getting them to fit together.

And they already have it working on android and the iphone!

The Right Developmental Path

One of the reasons that I don’t use gmail much, or many other web-based solutions is that I don’t necessarily think that http and javascript are always the right tool for every job. Yes, javascript turns websites into wonderfully interactive sites, but in the end I still prefer writing text/editing into speedy local applications (I’m saying this while typing into a web page, oddly enough).

With waves, however, they’re extending both the web API and the protocol definition itself to the world. The protocol is based on XMPP, which is the standardized version of Jabber, and this is huge. This means that people will be able to write import/export components for waves and thus you can actually continue to edit in something else and publish it as a wave later.

Kudos to their forward thinking about the realm of standardization and allowing data access to other types of applications and programming languages. This is what will make it huge.

There is always a but…

I do wonder about some of the negative communication aspects that could happen. Centralized data storage about a conversation thread is a great thing when the data is generally public in the first place.

However, we still need to be careful when transmitting important information. Wave provides the ability to grant someone retroactive access to a wave. Imagine having a wave discussion and then suddenly excluding person X from a branch of it and then later intentionally or accidentally granting person X access again. Imagine how they’d feel when they realize they’ve been excluded. This happens all the time in email, but when in email when person X sees part of the conversation again he likely didn’t see the message that said “I’ve excluded person X because …”. This is really just a new management issue, but by far the benefit outweighs the negative.

(and there are more odd use cases, but certainly the benefits will outweigh the oddities of them as well)

I Can’t Wait…

And I’m not sure I’ve ever said that before about an upcoming technology.

A while back I discussed some parenting plans that came back to bite me in the end. This time, I’m writing up the results about the time I planned nothing. Just to see what would happen if I planned absolutely nothing.

Background

Both of our kids went to the
Davis Parent Nursery School (DPNS), which is an amazing preschool here in Davis. One of the responsibilities of being a parent of a child attending DPNS is that you have attend a certain number of “educational seminars” (which are usually worth the time even though you dread going).

One such seminar professed the benefits of letting your children control the schedule sometimes. I.E., rather than swimming at 3:30, 4:15 for soccer, followed by a 5:38 dinner you should provide them with a block of time where they got to pick any activity they want. And yes, the parents have to participate too and follow the direction of the child (while still providing the obvious acceptability boundaries).

Background Part 2: Daddy Days

The other regular event in my life at the time was something my kid’s had entitled “Daddy Days“. My wife was having regular meetings in our home and rather than try and keep my kids from politely, but continually, offering the guests pretend sandwiches and hamburgers from their diner of delectable plastic foods, I opted instead to take them somewhere fun. We’d go to the zoo, or to a science museum, or go geocaching or to the Nimbus Fish Hatchery or whatever I felt like concocting for the day…

On to Doing Nothing

So of course I had to test out the theory that planning nothing was beneficial. I mean, it was a statement by the lecturer with no data or references to back it up. The scientist in me couldn’t let it go at that, so I selected a big green area on the map in Sacramento and we headed out. When we got there it turned out to be a big grass field with no playground infrastructure: just soccer fields and a big pond (complete with geese).

So, I turned them loose. “What do you want to do?” I asked realizing
there wasn’t much there to choose from. They, undeterred by the lack of brightly colored plastic, picked things like “walk around the pond” and “watch soccer” and “walk over there”, … Four hours later after we had walked everywhere, looked at everything, climbed on random objects, spent 30 mind numbing minutes dropping grass down a storm drain and another 30 shouting down one storm drain while someone listened to another I finally uttered words I’d been waiting to say for 3 hours and 52 minutes: “well guys, it’s time to go”.

My daughter reached out and grabbed my hand, looked up at me and enthusiastically said “this has been the best day EVER“. Mixed emotions of surprise, parental happiness and the serious need of some coffee mixed together and left me with nothing but a huge smile and a wonderful hand-in-hand walk back to the car. To this day (4 years later?), that was the only time I’ve ever heard that particular phrase.

Lessons Learned

(no science paper would be complete without them)

People constantly think you need to supply kids with lessons to learn. This isn’t actually true: you need to supply them with lessons only when you want them to learn the lessons YOU think are important. They can happily study social interaction (soccer), communication (yelling) and physics (the terminal velocity of falling grass blades) without your direction. The trick is keeping your eyelids open while their experiments run their course.

Parents get to pick the agendas for most of a child’s life. But how can children become world leaders if they don’t practice leading themselves once in a while.

Looking back, it was an experiment that I’d highly recommend to anyone when interacting with kids. I learned a lot from my kids that day as I still think frequently of the day I set out to do nothing.

Remember the days when you were stumped doing your research and in order to get help you had to write some other famous person a long and detailed letter about the problem and then have it delivered by a messenger on horseback. No? Ok, well me neither. But I do remember a time where getting help on a problem was a bit more difficult than it is now.

In the Good Old Days (TM)

Back in the day, when scientists were scientists and intellects were intellects, we solved our own problems, darn it. If we were stuck on a science problem and we needed to write Isaac Newton to get help on a new gravitational theory, we made darn sure we were truly stuck. The reason was simple: it would take a month (at least) to complete the round trip. And that’s assuming he wrote back right away. We would never give up immediately. We’d always explore every last option before firing off that letter. Probably because writing with a quill can’t be easy (I wouldn’t know; I haven’t actually tried. I get mad enough when the ink in my mechanical pencil runs out.)

But today…

But you don’t live in that era, do you? (unless you succeeded in some back-to-the-future mojo) No, today, when you’re stuck on a difficult problem you probably just fire off an email to someone saying “help me”. Obi-wan, you’re really my only hope in figuring out how that silly web page actually picked the card I was thinking about.

We’ve Grown Impatient

I participate in (free) software support mailing lists where savy internet users will write in with a question on Friday afternoon and respond to themselves on Saturday saying “does anyone have an answer for my problem? No one has written me back yet.” What’s worse is that 90% of the time, the question was probably could have been solved by RTFM (“reading the fine manual”; or at least that’s what the polite form of the acronym is).

The Result

The result of modern, quick communication forums is that we don’t solve problems for ourselves any longer. We immediately ask for help or simply give up on sometimes the most trivial of problems. We’ve lost the ability to analyze the situation for ourselves and ensure every possible path has been checked to the best of our own ability. What’s worse, is we expect people on the other end of the communication chain to take time out of their day to solve the problem for us.

Fight back, I say. When you run into a snag: learn something about what you’re working on. Take the time to get truly, truly stumped. Even if you don’t succeed in solving your problem you’ll have learned something in the end. I promise.

It’s been long debated how much time computers actually save in our lives. Multiple productivity studies have shown that after spending quite a bit of cash to bring an office into the modern age the increase in productivity is actually very low (if I recall, most studies said around 8%). But I’d argue they’re still worth the cost outlay but not because they provide an increase in productivity.

Pencil, Paper and Typewriters

Our tools were simple before computers. If you needed to do a bit of math, you simply did it. Those were the days! The problem came when you needed to do a whole lot of math. Repeatedly. Over and over. Sure it could still be done but it was mind-numbingling boring. Calculators improved things by removing the tediousness of the math calculations and allowed significant improvements in the data crunching per hour metric. Calculators actually provided significant increases in productivity, for the few that actually needed them for their job. Certainly McDonalds couldn’t possibly serve so many customers if the cashiers actually had to calculate the correct change for every transaction.

Enter the Modern Era

And then came computers (big ones at first that only did small things followed by small ones that do big things). Computers, like calculators, save time for certain tasks (but be careful what tasks you pick, which is likely going to be a future topic in its own right). Now when you’re plugging away on your budget and trying to figure out how to assign more money to the important mini-golf green-fees row you can twiddle all the other rows as needed until everything balances out ok (who needs healthy organic food when there is balls to hit into a castle). And remember when you wrote that paper in college (about the average hair density on a baby bunny vs a adult bunny or something like that)? That backspace key sure saved you compared to the time it would have taken you to use a typewriter. (for those that never had to use a typewriter, you’ll have to trust me on this one; for those that couldn’t use computers to write college papers, you’ll have to trust me too.)

But did you really save time?

Or did you simply redirect your time?

Virtual Housecleaning

Congratulations, you now inhabit two residences. You’re physical residence is probably getting slowly covered in dust and dirty dishes. It requires regular cleaning and maintenance to stay on top of it all. Well, I hate to tell ya but you probably spend a measurable amount of time cleaning up you desktop, organizing your bookmarks, deleting old files, installing and upgrading software, training yourself how to create power-point slides full of animated circles and arrows. (If you’re not doing these things, your disk is probably a mess. But hey, maybe your house is a mess too.)

When was the last time you moved? Some of you are hopefully quickly wondering “did he mean move physically or virtually?” Well, both. They both take a lot of effort. When you get a spiffy new machine, you have to move your old data (boxes of unused junk) from your old residence to your new one. You need to replace older software (cat-scratched furniture) with better versions with fancy-dancy graphics (untorn fabric with polka-dots).

But who cares?

Ok, now that I’ve convinced you that you haven’t saved any time by owning a computer (I have convinced you, right) you should disregard your sudden depression about this and exchange it for relief that you’re no longer bored. Everyone at some point has a chore so monotonous that you’ve nearly fallen asleep doing it. (Or maybe actually fell asleep!) Computers relieve much of the boredom and monotony and replace it with mind-expanding tasks like learning where your menu item moved to when you upgraded. Your boredom may have changed to anger when that animated paperclip poped up yet again. So the next time you’re dragging text around as you reorganize a well composed email just think back to the days when you retyped an entire paper because you forgot the transitioning sentence between the 3rd and 4th paragraphs. Put on a smile the next time you defragment your hard disk to speed up your aging equipment since it may someday save you from the monotonous chore of manually recalculating your household budget. And most importantly: where there is less monotony in life there is more learning and more brain activity. This will keep your brain healthier into your old age (assuming you at those organic veggies). Now go check you email and clean out your inbox. It’s been a while. Poking someone on facebook can wait while you do your virtual chores.

Travel Happens

Unfortunately, we’re rarely in control when we travel long
distances. Be it by plane, train bus, metro, etc. This is in stark
contrast to the rest of our lives when we are in firm control of at
least our time and location. Sure, sometimes we need to wait in long
lines or twiddle our thumbs during long hold-times on the phone. But
in that case, we’re still in control. We continue wait or hold
instead of walking away or hanging up but we’ve measured the cost
against the goal and have made the decision to continue waiting. We
consciously continue to sit there because the goal is worth it.

But travel is different. You can’t just get out of the plane, or
off the train, or off the bus or out of traffic. You’re stuck. The
“out” is never better (unless you happen to have a parachute) and that
feeling of out-of-options is not a comfortable one.

My Experiences

I’ve travelled a fair amount by various modes of transport for both
work and pleasure. I’ve been through a number of, um, interesting
events:

• I put my kids to sleep for the night under benches at an
  airport because they finally announced at around midnight that our
  flight had been cancelled until early the next morning.
• In a flight from Florida to Utah I watched 3 full length
  movies. 2 of them were sitting on the tarmac waiting to take off.
  Without air-conditioning. I, of course, missed my connection and
  got stuck overnight in Salt Lake.
• After missing a connection in Florida we ended up renting a
  car to drive to our final destination (arriving at 3AM) because
  the airline refused to even put us up for the night.
• I had packages left on a train because men with (big) guns
  were telling us that dogs weren’t allowed on the train, even
  though we specifically had a dog-ticket for said dog.
• I was trapped in an airport’s terminal-to-terminal train
  system that failed about 50 feet from my destination
  platform (causing me to miss my flight).
• I’ve travelled across the country for a meeting that ended up
  being cancelled.
• I got stuck in Seattle because of grid-lock on the highways
  preventing me from reaching the airport in time. But it was a
  day-trip, which means I only had a backpack and no
  luggage/clothes/etc.

Now, I’ve had a lot of uneventful trips too of course. But somehow
the story that “I flew from Sacramento to Denver and arrived 30
minutes early” just doesn’t have the same interesting story behind it.
And I’ve had a lot of other delays, missed flights and other negative
events that also aren’t worth mentioning.

What I’ve Learned

Out of all those mishaps, the ones that I look back at with the
least negative feelings were the ones that I refused to let myself be
stressed by the events of the day (or night). Fighting it, in the
end, never had any significant effect because, as I’ve mentioned
previously, you’re the visiting team in a game where the home
team has a huge advantage. In the end I was always still stuck
somewhere other than home. I was just angrier. If you must fight the
fight, fight it at home. Pick another carrier for your
next trip.

One eastern philosophy worth studying teaches that we should be
more like water than a rock. When obstacles get in the way of water,
water just flows around it and is, in the end, unaffected. It’s the
rock that is continually broken down by oncoming obstacles until it’s
own health is seriously jeopardized.

The next time you’re stuck in the river of travel, try being the
water instead of the rock. The trick, of course, is letting go of
your desire to be somewhere else immediately. Instead, buy a book and
relax. You’ll get there eventually so you might as well be as rested
as possible and in a good mood when you arrive.

The Plan

A while back I considered ways to get my son to try a few new foods. So I came up with this plan: take ingredients he liked and put them in a matrix that he could put stickers on. Some fun ingredients and some wacky ones. IE, something like this:

And then we’d try new combinations and put stickers in the squares we liked, and Xs in the squares we didn’t.

The execution

“This’ll do it” I thought to myself. Well, stop laughing all you seasoned parents. The result was my adventurous daughter was eager to fill every square. My reserved son (the one I was trying to impress with this whole setup) refused to try any combination he hadn’t tried before.

Don’t get me wrong: kid’s are different. I was wrong in thinking I could influence them. They each have their own personalities. I love the fact that my daughter points at a ridge and says “lets hike there”. I love the fact that my son has shot goals past me in soccer because he’s had me laughing so hard there was no way to defend myself. They each have their own special talents and attributes. I’m the one who has learned to adapt to them, not the other way around.

The recent results

Meanwhile, years later, my Daughter has been begging me to do another “try it” meal. So I gave in again (we’re up to a count of about 4 at this point) and we gave another whack at it tonight. My son, who started complaining immediately, got oatmeal and other random things for dinner since I the rules say you don’t force a kid when it comes to food. My daughter and I embarked on a episode of trials and tribulations. So here are the two winners(?) for the night:

• Best Combination: Graham Crackers and Yogurt. Holy cow batman. This one surprised me. I mean, I knew it would be good. But this is like dessert-quality good, not just “good”. My daughter and I both agree.
• Worst Combination: Pears and Ketchup. Holy cow batman. I knew it’d be bad, but this is really really really really bad. Insert a few infinity-signs before the “bad” in that statement. Oh man. I mean bad. I mean don’t try this at home bad.

Tips for Parents

Try fun but simple adventures some times. You’ll be amazed how profound of an effect you’ll have on your kids, regardless of whether it was the effect you intended or not. Either way, they’ll gain something from the experience.

This is by far one of my best computer-based inventions, and yet is the most simple think I’ve ever come up with and installed. The origin is simple: I hate cleaning up old files on my system. When I started thinking about it, most of my files were things that I really only expected to have a short life-expectancy. You know, like those silly pictures people send you. Or Word documents you need to open and read once. Or … you get the point. I decided that most of these fell into four basic timing categories:

1. Files that were truly intended to be short-lived.  On the order of hours.
2. Files that I needed only for today.
3. Files that I needed for a bit longer, but not a really long time.  Like a week.
4. Files that I needed for something on the order of a month.

So I created 4 directories (folders to some of you) and made them be auto-cleaned on a regular basis.  The cleaner would remove things that hadn’t been looked at within the time period I selected for the folder.  It’s as simple as that.  The 4 directories I created were called h, d, w and m.  You can probably guess what each one means.  I put them as subdirectiories of ~/tmp but you could put them anywhere.

This example implementation assumes unix-like OS which is pretty much everything but windows. But I know there are cron systems out there for windows too. The important aspect of cron is that it lets you run commands on a regular and scheduled basis.

Here’s the crontab entries for my auto-cleaning system.  I used tmpwatch on my system but you just as easily use the find utility as well.

11 2,7,11,15,19 * * * /usr/sbin/tmpwatch 1 /users/hardaker/tmp/h
21 2,7,11,15,19 * * * /usr/sbin/tmpwatch 24 /users/hardaker/tmp/d
31 2,7,11,15,19 * * * /usr/sbin/tmpwatch 168 /users/hardaker/tmp/w
41 2,7,11,15,19 * * * /usr/sbin/tmpwatch 744 /users/hardaker/tmp/m

That’s it!  Drop things in the various folders based on how fast you want them auto-removed and you’re done.

The month based folder is the most interesting.  Basically stuff I put there is stuff that I expected to look at but if I forget to ever look at it within a month, it’s likely I never will.

For those needing first help with cron, run crontab -e and cut and past that into your editor when it pops up. Done!