This article pulls back the curtain on CISPR 25 conducted-emissions testing, demonstrating how a fully functional voltage-method setup can be built and operated on a standard lab bench. This approach shows how conducted emissions can be characterized with precision using accessible tools and a carefully structured setup, while walking through all critical elements needed to … [Read more…]
WebP is a modern image format which shines through its fairly small filesize. Google recommends through their PageSpeed Insights that all PNG- and JPEG-files should be served as WebP images instead. There are of course plugins to facilitate the automatic generation of WebP versions of existing images but a few lines of PHP code and a .htaccess rewrite rule is really all that is needed to automatically serve all existing PNG- and JPEG- images as WebP versions to browsers that support it.
Updating and installing new firewall rules on remote servers always comes with the risk of locking yourself out completely. Many server administrators have inadvertently lost access to their servers, including SSH access, at some point due to a moment of inattention. This article shows how to install a backdoor on your own server that can be used to regain access to a misconfigured server. The bash script showed can also be used to update firewall rules dynamically based on the A record of a domain, which is handy for someone with DDNS and a dynamic IP address.
Proxy servers are a great tool. Be it for security, filtering, load balancing through multiple origin servers or origin shielding. Unfortunately, reverse proxy requests make it a bit more difficult to recover the original visitor IPs. This article shows how to securely restore visitor IPs through the use of the Apache module mod_remoteip.
Electret microphones are cheap and extremely useful for DIY audio projects. One of their drawbacks, as with many microphones, is their very low voltage output level. The easy solution is to build a simple microphone preamplifer that boosts the signal to a much higher level.
This article plunges you into the mesmerrizing world of early radio technology through the assembly and analysis of a DIY spark gap transmitter. This project offers a practical insight into the fascinating dynamics of damped harmonic oscillators and explains charasteristics such the logarithmic decrement, decay rate, damping factor, q factor, and beyond. Prepare to spark your curiosity in a technology that once revolutionized global communication.
High voltage power supplies can open interesting doors to research topics such as laser, x-ray, spark gap transmitters. And many other specialized niches. Unfortunately, laboratory grade high voltage power supplies are rather costly. Luckily, there is a much less expensive way to put high voltage experiments into the hobbyists reach. This article shows how to build an inexpensive and adjustable 5 kV to 30 kV high voltage supply from a commercial laser supply.
This article shows how to build a simple Triplexer (Diplexer plus integrated DC Bias-T) for use with commercial TV LNBs for QO-100 or X-band microwave experiments.