Archive for month: July, 2011

On the Ham Nation podcast, or the perils of perpetual promotion.

July 29, 2011 | Amateur Radio | By: Mark VandeWettering

Ham Nation is a relatively new weekly podcast that is brought to us through the power of the TWIT network, Leo Laporte’s mighty podcast empire. Fellow blogger KE9V had some comments on it, some of which I agree with, and some of which I do not. Of Dits and Bits | KE9V’s Ham Radio Blog. […]

On RC Filters…

July 29, 2011 | Amateur Radio, electronics | By: Mark VandeWettering

Over on the #savagecircuits IRC channel on, Atdiy was trying to decipher the mysteries of a mainstay of analog circuit design: the RC filter such as the one pictured on the right (diagram cribbed from Wikipedia) It dawned on me that (newbie as I am) I didn’t really have a clear understanding of them […]

PDP-10/X on an FPGA

July 29, 2011 | Link of the Day | By: Mark VandeWettering

I think I saw this a couple of years ago, but Doug Conroy seems to have made some progress on his implementation of a PDP-10 on an FPGA. It now can apparently boot ITS. I’m more interested in the prospect of running TOPS-10 so I can relive my early days, but booting ITS is pretty […]

Hackaday Comment Policy: We’re cleaning up

July 27, 2011 | Blogging, Rants and Raves | By: Mark VandeWettering

I am a long time reader of Hack A Day. It’s a great website, and often details projects that I find interesting well before they are picked up on other sites. It also tends to drive significant amounts of traffic to sites mentioned, so it’s good publicity for many interesting objects. But lately, their comment […]

How to mistake correlation and causality, from Scientific American

July 27, 2011 | Rants and Raves | By: Mark VandeWettering

My tweets this morning included a link to a story by Scientific American editor Anna Kuchment, entitled “How to raise a science fair champ”. How to raise a science fair champ | Scientific American Blog Network On the one hand, it’s a mildly interesting look at some talented kids who have risen to the top […]

Unboxing the Digikey Monday Mash Prizes!

July 26, 2011 | Video | By: Mark VandeWettering

Digikey runs a Monday Mash puzzle every week on Monday. Last week, I entered and won! Huzzah! Here’s the video of me unboxing my prizes. Thanks to Roy Eltham from the #savagecircuits IRC channel for urging me to enter, and condolences for him not winning.

Dave Richards, AA7EE constructs The WBR by N1BYT

July 26, 2011 | Amateur Radio | By: Mark VandeWettering

Thanks to Bill at the SolderSmoke blog for posting a link to Dave Richards’ construction project. He made a slick version of the Wheatstone Bridge Receiver, a regenerative variant created by N1BYT and published in More QRP Power. I’ve looked at this receiver before, and found the design to be pretty interesting, but Dave goes […]

The Kansas City Standard

July 22, 2011 | Amateur Radio, diy, electronics | By: Mark VandeWettering

I was pondering my laser transmitter the other day, and began to think of how I might transmit digital information from the Arduino to the remote receiver. Since I am old, I remember the old days where programs used to be stored on an obsolete audio storage medium called cassette tape. Indeed, the first storage […]

Nine years of blogging…

July 21, 2011 | Blogging | By: Mark VandeWettering

Glancing to the side bar, it appears that today in 2002 was the first post on my blog. This should be post number 3,690. I’ve had 2,286 comments. I’ve used 110 category tags. Over the 12 months, Akismet has removed 193,915 spam comments, and there have been 798 pieces of “ham”. The peak month for […]

Hallway Test of the Arduino PWM Laser Transmitter

July 21, 2011 | Arduino, electronics, My Projects | By: Mark VandeWettering

The other day, I showed how the Arduino could be used to generate PWM audio and send it over a very short distance using an LED. In my ever increasing pile of parts, I had some small 5mw red laser diode modules. These modules are supposed to be driven by direct connection to three 1.5 […]

AE6TY on Software Defined Radio

July 21, 2011 | Amateur Radio | By: Mark VandeWettering

This morning I realized that somehow I had failed to listen to the latest SolderSmoke episode (#135), so during my somewhat longer than usual commute (traffic) I set it going and had a listen. And wow, some really great stuff, especially the report by Bob Crane, W8SX on the Four Days in May (FDIM) QRP […]

Parents can trump mentors…

July 18, 2011 | My Diary, Rants and Raves | By: Mark VandeWettering

Back on July 8th, I wrote a brief post about mentoring. Hopefully, some of you read it. In case you didn’t, I made the completely unsupported claim that mentors don’t normally create interest, they merely nurture the interests that are already there. They also serve to help remove the obstacles that frustrate the enthusiasm of […]

Using the Arduino to send audio via pulse width modulation

July 17, 2011 | electronics | By: Mark VandeWettering

I’m still interested in doing light based communication, but I haven’t made a lot of progress. I did build an LTSpice model of the circuit I used yesterday, but other than verifying that it probably would work as built (which it did) I didn’t feel like I had enough brain cells working to optimize the […]

Laser audio transmitter…

July 16, 2011 | electronics | By: Mark VandeWettering

Okay, so last night, after just testing one of the laser modules I had, I decided to try to make a transmitter to send audio over laser light to my “solar cell + Radio Shack amplified speaker” receiver that I was experimenting with earlier. I suppose I could have used my linear current LED modulator, […]

Just playing with laser diodes…

July 15, 2011 | electronics | By: Mark VandeWettering

A while ago, I got some laser diodes from from They were dirt cheap, but I haven’t had any chance to hook them up. I didn’t have a datasheet for them either, so wasn’t sure exactly what I should do to current limit them. So, I hooked it in series with a 150 ohm […]