Electronics and computer material

Here is just a geneal collection of semi-useful or interesting material, in no real order. A sort of collection of things I have found, or written, or tips, or .. just basicially anything that might be useuful to others, but which does not fit nicely into any other web pages I have. You will also find bits which are humerous to me personally.

Syncronising a pendulum clock to a quartz crystal

Many years ago my wife and I bought an old pendulum clock. It looks nice, but never kept very good time. After looking for a way to improve it, I was made aware of an article: A venerable clock is made highly accurate by equipping it with a quartz-crystal works in the 'Amateur Scientist' part of Scientific America, where the author syncronised a pendulum clock to a quartz crystal. I was hoping to implement this, but somehow I doubt I ever will.

Time interval counters

Online is a scanned copy of the HP 5370B manual, as well as application notes related to this.

RMS Power

There was an argument on the amps mailing list (not a rare occurance it must be said) about RMS power. Here is a Mathematica calculation performed to compute RMS power. The data is presented in several forms. In order of preference they are:

Mathematica notebook. That will give you the best view of it, but you must download Mathematica Player to read Mathematica files. If you fancy playing with the equations and graphs, then you can download a demo version of Mathematica. The demo will allow you to do anything for 15 days, but you will be unable to save the files to disk.
HTML Should display in any browser - how well I don't know
XML version. You will only be able to look at it, and it might need new fonts installed to see it properly.

BTW, if you have Mathematica, you might like to take a look at WITM which is an acronym for Web interface to Mathematica. WITM allows you to access a Mathematica server via a web browser. There are some screen shots at http://witm.sourceforge.net/screenshots.php. WITM is particulary useful on an iPAQ or other PDA to allow you to use the power of Mathematica on such a device.

HP A3589A 5.5 kW UPS

The HP A3589A 5.5 kW UPS is quite a nice unit, but HP in their infinite wisdom do not make the manaul avaialble, although after a lot of pestering, they did send me a copy. Here is the 257 page manual but there are some other related documents too, which cover some similar Compaq models, software, and network cards. You will have to download the lot and sort it out yourself.

How to cool a Sun SPARCstation 20

Here's my ideas on how to cool a Sun SPARCstation 20. The machines are rather an old now (in 2004), but still okay for a web server, or other low end task. This web site is run on a SPARCstation 20.

Installing ipfilter to secure a Sun

With all the internet hackers around, it is worth setting up a firewall.

Documents on older UNIX Workstations

Here's a list of documents of use to owners (like me) of the :

Aromatherapy and Audiophools

Aromatherapy and Audiophools is an amusing article that appeared in Electronics World and Wireless World, October 1999, page 795. It basically takes the **** out of the idiots who spend fortunes on Hi-Fi rubbish. You just need to read it to appreciate it.

Best eBay Auctions

Some eBay auctions are quite funny. This is one of them I found so, and will add others as time goes on.

Most Hideous homebrew amp ever built SCARY

Kraus Antenna book (1950)

Apparently the copyright on the first edition of the 568 page book "Antennas" by John D. Kraus (1950) has expired. A copy was scanned and made available at http://www.pmillett.com/Books/Kraus_antennas.pdf (there are other scanned books there - see http://www.pmillett.com/technical_books_online.htm) However, that scanned copy has very few bookmarks. I own a copy of the 3rd edition of the book, but find that first edition useful to have on my laptop. I added some bookmarks to enhance this. You can download my enhanced version if you wish, but please do not attempt to sell it.