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Thursday, July 22, 2010

My Current Podcast Listening List

My Android phone travels with me constantly. One of my favourite applications for it is a podcast manager/client called 'listen'. When 'listen' is working (a story in itself) it transparently manages downloading my favourite podcasts onto my SD card so that I can listen to them whereever I am with or without network access.

I've accumulated a list of podcasts that are pretty much my staples now and I thought I'd share them with a comment as to why I like them. They are unashamedly dominated by science casts as I find this medium about the only way that I get to regularly consume science now.


All in the Mind

I'm fascinated by brains and nervous systems and intelligence and thought and the things that can go wrong with them. Natasha Mitchell has an engineering background and does a fantastic job of hosting this program each week. Ironically thought provoking.

60 Second Psych

This program is prepared by Scientific American magazine and pithily describes an interesting and topical story of psychology in 60 seconds.

60-Second Science

This program is prepared by Scientific American magazine and pithily describes an interesting and topical story of science in 60 seconds.


The presenter of this program sounds far too chirpy and up-beat to sound credibly like a scientist himself, but balanced against the scientists he interviews it kinds works. If you're interested in keeping up to date with some of what the C.S.I.R.O. are doing this podcast is great.

Discovery Now

I presume this podcast is a spin-off of the Discovery channel. It presents succint coverage of a topical U.S-based science story.

Groks Science Radio Show

These guys are the real deal. Dr. Charles Lee and Dr. Frank Ling have been hosting this quirky show for a number of years now and I love it. Originally based in University of California Berkeley the show is primarily now centred around a well conducted interview with a featured guest each week. It's got a nice balance of science and quirky humour that I enjoy.

NASACast Audio

What's not to love about NASA? This is a weekly news show with good depth.

Ockham's Razor

While not strictly confined to science this show features special guests talking on a range of relevant and topical subjects of their choosing, thematically centred around William of Ockham's famous principle: "entia non sunt multiplicanda praeter necessitatem". Great speakers, interesting topics.

Quirks and Quarks

Science news from Canada. We don't hear much about what the Canadians are doing (outside of their television productions anyway). This show is Canada's Science Show and Bob McDonald is a great speaker and interviewer.

Science @ NASA

Another NASA podcast, but this one comes with a quirkiness and an earthiness that I think makes it more compelling and credible than some of its more heavily produced peers. One interesting and short story per episode.


There is only one way to say "Star Stuff" and that is Stuart Gary's way. It's quirky and Stuart has an annoying habit of interrupting and talking over his interview guests sometimes but if you're into Astronomy and Cosmology there is nothing better than comes from this country.

The Science Show

This show has been around forever, a testament to its quality. The show is sometimes irritatingly biased toward U.K-based research and sometimes feels a little slow and heavy-going but in every other respect is a must-listen.

This Week in Science

Kirsten ("Dr Kiki") and Justin host this refreshing science program each week. It's another organic program primarily driven by the personalities of the hosts, but I enjoy it. Sometimes they ramble, sometimes they forget what they're talking about but most of the time it's fun. I love the theme song and the over-all theme of enthusiasm for science is infectious.


Health Report

I love this program and admire its host, Dr Norman Swan. It's interesting, factual and compellingly no-bullshit coverage of medicine with a focus on relevance to Australia.


This is a new podcast to me, but it's already one of my favourites. Produced by the U.S. National Institute of Health it is remarkably palatable and covers stories of topical interest in medical research and practice.


Philosopher's Zone

I love Allan Saunders' voice. It's deep and rich and resonant and I listen to every word he says. I'm not going to pretend for a minute that I understand anything much about philosophy but I find this program fascinating and Saunders almost has me convinced I should learn more, either way I'm continuing to listen.

Old Time Radio

Horror Stories

I'm a big fan of short fiction and short fiction dramatised for radio works even better for me. This feed is of "old-time" radio horror stories. Some of my favourite authors are represented.

Old Time Radio Scifi

Old Time Science Fiction Radio? Do I really need to say any more?


Friday Night Comedy from BBC Radio 4

The BBC publish an enormous amount of online material. This feed currently provides the "Now Show" which is a funny take on the past week of UK politics. Hilarious during the past election, not the least for the parallels to our own comedic troupe.

Scotland's Funny Bits

This is a bit of an unusual choice. It's essentially a mash-up of out-takes from Scottish BBC radio. I like it for the funny accents and the strange things they say, it all seems pretty relaxed and human.

Shut Up Weirdo

This is one of my favourites. You take a witty, good-natured male Baby-boomer and pair him up with a sassy, rapier-witted female Gen-Y and then sit them in New Jersey amongst a collection of bizarre and quirky Jerseyites and New-Yorkers dialling in to tell their stories relating to whatever the topic of the week is. Andy and Frangry run this show like it's Lord of the Flies on Sesame Street. I love Frangry's voice, it's like the mewing of kittens, the cooing of Doves and the shick of a tempered blade being whetted on a stone.

You Can't Make This Stuff Up

I have something from CNN on my list, go figure. This show is a collection of weird news stories from around the world. I sometimes find the stories from Australia the funniest, as much more how they're told as what they are. It's fast-paced and makes me laugh.

Other podcasts have moved in and moved out, but these I listen to every episode of. What am I missing?

Tuesday, April 13, 2010

An impromptu field test of my FT817 and Squid pole.

I recently acquired a second-hand FT817. It's got warts but it is never-the-less a capable little rig that I purchased specifically for HFpack purposes.

Only yesterday I'd purchased three heavy duty 7m squid poles and spikes from Haverford Pty Ltd, a local supplier in Sydney. I don't mind plugging these guys as their product seems very good quality and was a great price. As soon as I walked in the door and asked for squid poles the response was: "For radio use?". I guess I don't look like the fishing type :^)

Today, while on leave from work with the kids who are on school holidays we took them bike riding at a large nearby park. It occurred to me that this would be a good opportunity to give the radio a try.

Anyway .. I quickly grabbed a back-pack, the FT817, a squid pole, a spike, a pair of diagonal-cutters, a length of wire, my old antenna tuning unit and a patch cable and stuffed, or strapped stuff onto the bike before I went. It literally took me about 20 minutes to collect and pack the relevant bits and pieces.

After arriving at the park I found a shaded spot and stuck the spike into the ground helped by a handy bit of wood as the soil was firm. I threaded a length of wire inside the pole and used the rubber cap at the top to hold it in place. A strap around the spike secured the pole into the spike. Another length of wire run along the ground served as a counter-poise. Connected both to the tuner and the tuner to the radio.

After working out that I had the radio misconfigured to use a filter that wasn't installed, everything was up and running. Again, it took about 20 minutes to assemble.

I didn't bother trying to make contact with anyone this time, I didn't have time to charge the batteries. So instead I tuned the antenna for all HF bands in turn and listened about to what was to be heard. I've been out of touch with HF for quite a few years. I was surprised. This setup seemed to work really well for something thrown together with little thought or planning. I spent a short time listening to some Shortwave thinking about what I'd do differently next time and then packed up again to join the kids.

I'm pretty enthused. I've got my eye on the Elecraft T1 tuner; it looks perfect for my intended use. Now to plan the hiking trip :^)

Wednesday, March 24, 2010

Found on a footpath ..

I often find things as I walk.

Sometimes they're just pieces of foil, wrapping paper or plastic that have reflected a glint of sunlight into my eyes and caught my attention, other times they're something altogether more interesting .. such as this one ..

It's a 680 ohm resistor, never been used, with some of the reel packaging attached. The nearest electronics store was kilometres away. I've never found components before, not ones that weren't inside some piece of smashed or discarded electronic equipment anyway.

I hope whoever lost it had enough spares to finish their project.

Friday, March 5, 2010

My PICkit arrived today.

My PICkit 2 Starter Kit arrived today. I'm surprised at how reasonable a cost it was, even compared to many of the built-it-yourself offerings out there. The integration with the Microchip MPLAB IDE sealed the deal for me.

It's a real pity Microchip don't produce a Linux version of MPLAB. Hopefully their acquisition of Hitech will encourage them to increase support for the Linux platform.

Saturday, February 20, 2010

For my birthday I got ..

  • an SMD soldering/rework station
  • a 1 litre bottle of good quality Bourbon whiskey
  • an ice-cream cake with a chocolate/ganache penguin
  • a ton of best wishes.

Fourty-four isn't so bad after all :)

Half the cake is left, all of the bourbon and everything is looking like it needs a bit of soldering, desoldering or rework ... now to get to work!

Hand Casting using Alginate

As part of a larger project I decided that I needed a plaster cast of a hand.

I'd read a number of articles about body-part casting using a magic substance called Alginate. This stuff comes as a non-toxic dry powder which when mixed with water turns into a fast setting gel. When mixed it smells vaguely citrus-like. It's the stuff that dentists use for doing moulds of your teeth if you've had any of that sort of dental work done.

I hunted around and found two good sources of the stuff in Australia. The first was just up the street from where I live in NSW at Barnes and the second was in Victoria from Dalchem. Both seem to have reasonable prices and both deliver. Due to my deciding to do this over the christmas/new year period when shops were closed and a mixup with the courier I ended up ordering it from both. Not to worry, I have plenty now.

The basic ingredients for the hand casting are:

  • A large-enough container to use to hold the moulding compound
  • Alginate
  • Plaster
  • A stirring implement or two
  • A body-part
  • Vaseline
  • Water
  • Mixing bowls
  • Paper towel to clean up with afterwards

You can see that I used a 2 litre juice bottle with the top removed to contain the goop. Unless you build a fancy container that you can take apart you'll probably want to use something disposable, as getting the gel out once it has set is much easier if you destroy the container first.

The next step involves preparing the body-part. The advice that I'd read on the net suggested that using petroleum jelly to coat the body-part helps when trying to get the part out of the gel later. This seems to be true, so we'll do that next time too. We used just enough to coat the skin, but not so much that there was any significant residue.

Mary lent a hand here.

Now is a good time for your body-part model to practice the desired posture for the mould. The Alginate mixes into an opaque gel so your model won't be able to see their body-part once immersed, so a bit of practice in adopting the right posture and then putting it into the mould container helps get it right at show time.

Next you mix the Alginate gel. There was a trick here that wasn't obvious until it came time to actually do it. The trick is determing how much of the Alginate powder and water you need. The stuff is reasonably expensive so you want to minimise waste. At the same time the stuff sets pretty quickly so you don't really get time for a second chance. The trick is to work out how much you need and to mix that amount.

The Alginate I used recommended a ratio of about 4.25 parts water to 1 part Alginate by weight. The trick here is what you're looking for is a target volume and I couldn't find any guidance on how you did that.

I started by looking at the container and figuring out what my target volume would be. A simple experiment involving filling the container to the brim with water and putting Mary's hand into it to see how much water was displaced determined the volume of her hand. Armed with that knowledge I figured that I needed about 1.5 litres of Alginate goop to do the casting. I then started with 1.5 litres of water and working out what amount of Alginate I'd need for that.

The result was an enormous-looking amount (by volume) of powder. Looking at the two it seemed clear that there was no way those two were going to mix into an amount that wouldn't be more than what I wanted, even after taking into account how much the powder would pack down. So I scaled the amount down and ended up with about 1 litre of water and about 250 grams of Alginate. It still seemed like a lot, but I trusted my instinct.

Here I learnt something; my instinct was wrong. The alginate virtually disappears into the water. Next time I'll just do the calculations assuming the volume of water pretty closely approximates the desired volume of the gel. As I mentioned earlier there isn't really time for second chances so I ploughed on ahead anyway.

It's important that you find somewhere comfortable for the owner of your body-part to sit. The Alginate comes in a range of setting times. I chose a medium rate gel that sets in about five minutes. That can be a long time to wait while holding a limb immobile in goop. You can see here the result of my miscalculation in volume. I'd intended to cast the wrist as well, but I didn't end up with quite enough to make it.

Now the fun bit. The body-part model slowly eases their body-part into the goop. It'll be cold and slimy initially. A bit of a wiggle of the body-part helps to ensure that the Alginate gel has made contact all over. They now must keep the part pretty much immobile while the gel sets. I insisted on waiting the full five minutes before testing if the gel had set. They'll know when setting occurs, if they very gently try tiny wiggles they'll feel the gel has solidified around their part. This stuff ends up with a texture/consistency somewhat like Silicon sealant. It's firm and rubbery.

I'd read a fair bit of advice about how to actually remove the body-part from the gel after it has set. The problem to overcome is atmospheric pressure and vacuum. The trick is to get air into and around the skin so that the vacuum doesn't hold it in. I've seen people suggesting blowing air in and this might be a good idea. We opted for a gentle pulling motion combined with gentle wiggles.

When the body-part is removed you have your mould. The Alginate capture quite a bit of detail and I found myself somewhat fascinated by it. Apparently it's a kelp extract. You can at this stage rinse the mould out with water if you wish. I didn't bother, it looked pretty clean to me.

Now comes time for the cast itself.

This bit is pretty straight-forward but in some respects is the most difficult to get right. Mix the plaster as per the instructions that came with it. The plaster is quite cheap so I wasn't anywhere near as concerned about wastage as I was for the Alginate. Additionally, it sets slowly so you've got time to adjust your volume anyway. I knew the volume of Mary's hand from my previous measurement so I knew roughly how much I needed.

I factored in some extra to use as over-pour because I wanted the hand to have a solid base, why will become obvious later.

I learned a few valuable lessons here. Firstly, don't rush this bit. I was excited and wanted to see how this would turn out so I didn't stir the plaster properly. I stirred it by hand, next time I think I'll use a paint stirrer and an electric drill. Secondly don't make it too thick. The plaster needs to be fluid enough to reach the extremities of the mould while at the same time allowing air bubbles to escape. Pour the plaster slowly to prevent the air bubbles being there in the first place. I read somewhere that it's a good idea to pour some in and then rotate the mould around in all angles to coat the interior surface of the mould with plaster before pouring any more in. This was good advice and I wish I'd taken it; next time. After you've poured the plaster you can gently agitate/tap the mould to encourage the air bubbles to rise to the surface. I did this and you can see that it works quite well. Keep in mind the shape of the object you're casting though, air bubbles can get trapped in high points inside the cast, the idea is to get them outside.

Now comes the waiting. Put the whole thing aside and leave it alone until you're sure the plaster has set.

Don't touch it. Wait.

Keep waiting.

Are you sure the plaster should have set already?

When the plaster has set you can remove the Alginate gel from your creation. First you need to get the whole lot out of the container without damaging the cast. You can see that I just cut/tore the plastic container away and dropped it into the recycling bin. I damaged the Alginate gel slightly getting it out, but that doesn't matter I need to remove that too.

The Alginate is thick and rubbery, but can be cut easily. I used a pair of kitchen shears to trim away large chunks of it and then a utility knife to carefully trim it away from the plaster. I found that in some detailed sections such as in skin-folds the Alginate tended to stick but was easily enough removed with a sharp implement.

Argh! A finger is broken! How did that happen? It was a clean but not perfect break so it presumably occurred late in the setting of the plaster. I really don't know how it happened but I'm pretty sure it didn't happen while I was removing the Alginate. I do recall moving the mould at some point during setting because I'd put it in a silly place and maybe it broke then. Next time I'll follow the advice about not moving it.

No matter. Plaster glues readily and because it was a clean break I managed to repair it satisfactorily. You can see the air bubbles in the plaster. If you can imagine the image inverted you can see that they are all on the upward surface of the mould. If I'd made the plaster a little more runny, if I'd poured it more slowly, if I'd followed the advice about running it around the inside surface, and perhaps if I'd used a funnel to pour the plaster into each finger first this wouldn't have happened. On the upside you can see some of the detail of the hand in the plaster. All things considered I was pretty happy with it as a first attempt. I could have filled the holes if I'd been bothered but not this time, next time I'll take more care and do a better job.

Now to finish it off.

I used some acrylic paint to paint the hand. I'm no artist and frankly the acrylic paint was annoyingly thick so the paint job isn't fantastic, but I think the end-result is honest.

I've got a few ideas for things I'd like to use various casts for.

Next time I'll get the kids involved too, they'll love it.