Welcome to KF7LZE! I’m an amateur radio enthusiast and freelance electronics technician. I write this site with a goal to make it easy and enjoyable to put together electronics projects and perform your own repairs to save money, have fun, keep electronics out of landfills, and maybe learn a thing or two along the way. I write up many of the projects I complete on this blog, take in many kinds of equipment for diagnostics and repair, and run a joint venture to sell the kits and parts to complete the same projects and repairs yourself at home with another hobbyist.
- Easy-Kits.com for fun projects and parts kits featured in articles on my blog.
- Rain City Audio (web site coming soon!) for your Antique Electronic and Modern Stereo Needs in the Seattle Area.
- Round-Up of RTLSDR Upconverters: A nearly comprehensive listing, with pointers for where to buy, for the most common and most desired HF converters designed to allow the reception of HF or 6m and higher radio signals using any RTL2383U-based DVT-B dongle.
- Bose 901 Active Equalizer Repair and Bose Projects List: I bring the classic Bose 901 Series 1 speakers back to their best performance by rebuilding the equalizer with modern precision components to replace the originals which have almost universally failed and introduced distortion or outright failure into the system. Lots of photos, and parts kits are available as well.
- 1st Generation Mazda Miata MX-5 Airbag Computer Repair: Bad capacitors can strike anywhere; in this case it results in a permanent Code 10 for the car’s SRS system. It’s a short and sweet process to replace them, and the thermal fuse which triggers the Code 10 error. Many readers have found this article helpful, although not everyone is up for attempting this particular repair.
- Samsung 225BW Monitor Capacitor Replacement: This model, and similar aged Samsung monitors, are known from the Internet for failing power supply capacitors starting a few years ago. It’s easy and cheap to restore full functionality, and is definitely worth doing for a nice quality LCD monitor like this one.
- 1934 Simplex Model P “Dual Band” Antique Radio Restoration: Featured on Hack-a-Day, a dead old radio with quite a few problems and very challenging wiring sings again, with many photos of the entire process along the way.
Feel free to leave a comment or question, and thanks for stopping in!
I came across Partsim, a free and easy to use circuit simulator that runs in the web browser, and would definitely encourage you to check it out if you’re looking for a tool to design and simulate circuits.
It supports a wide variety of components, and even supports Digi-Key integration to make it easy to buy your project once you’ve seen its results. That’s a great feature! Anything to take some of the pain out of generating a Bill of Materials is welcome in my book.
Check it out! Partsim
I just discovered the fascinating Wide-band WebSDR operated by the amateur radio club ETGD at the University of Twente in the Netherlands.
PA3FWM built a fascinating wideband SDR using a Xilinx FPGA, high-speed ADC and gigabit Ethernet interface to receive most of the entire shortwave and amateur radio bands at once and allow tuning and processing in software via an HTML5 or Java web browser.
I’m listening to a station on 9760 kHz right now, which is broadcasting what sounds like classical choral hymns and dialog in Italian and Latin, so it could be a Vatican shortwave broadcast station. The interface is easy to use, and right now 142 users are tuning in from around the world.
It’s definitely worth checking out. I like shortwave listening but even with a great converter and my RTLSDR, my location just isn’t optimal for receiving the kind of signals I’m interested in – this web option is a lot of fun to go exploring.
I’m moving towards hosting the majority of my content on an on-premises server, versus the mix of hosted services I’m using currently. I’ve been running into some issues, though, that maybe one of you who is reading could help with…
The issue appears to be: some users, for no particular reason I’m able to identify, are unable to access any of my web sites.
My web domains are pointed at my server’s public, static IP address. The DNS records are valid, and DNS resolution works as expected always returning the correct address. The server responds to ping, and can complete a trace route. But, for users who this problem effects, it’s as if the server doesn’t respond. From my mobile device, for instance, I receive an Error 504 Gateway Timeout, the cell phone network’s caching proxy can’t receive data from my server. Port scanning reveals the ports are open and accepting connections on the server, but bonnection requests time out with no received data from a system on a Time Warner connection, as well.
This is all occurring while other users are logged in and actively using some services, so it seems unlikely to be an issue with the server itself failing. Even more vexingly, it’s intermittent. My mobile web site was working yesterday. It is not working today, from my cell phone.
If anyone has troubleshooting suggestions, I’d love to hear them.
Beautiful weather has finally arrived in the Pacific Northwest and I’ve been taking advantage of it as often as I have time. One thing about living where it’s grey and rainy for so much of the year, it really almost forces me to go outside and be active when it’s nice out. I’ve been riding my bike around, and wanted an easy way to keep track of my stats like speed, distance, which trails I was riding and altitude. Turns out there’s a free and easy way that integrates well with Android: Google My Tracks
My Tracks uses your phone’s GPS to record your position and plots it on a map, where you can upload it to Google Maps or export your track as an industry-standard KML file for analysis in another application.
You get a print out of your statistics at the end, and can optionally insert markers with interval statistics on a custom schedule. The app has been around for a few years but has become much easier to use lately. My last ride was 12.9 miles long at an average moving speed of 7.5 miles per hour:
Total distance: 20.78 km (12.9 mi)
Total time: 2:56:35
Moving time: 1:43:56
Average speed: 7.06 km/h (4.4 mi/h)
Average moving speed: 11.99 km/h (7.5 mi/h)
Max speed: 34.62 km/h (21.5 mi/h)
Average pace: 8.50 min/km (13.7 min/mi)
Average moving pace: 5.00 min/km (8.1 min/mi)
Min pace: 1.73 min/km (2.8 min/mi)
Max elevation: 179 m (589 ft)
Min elevation: 93 m (304 ft)
Elevation gain: 984 m (3228 ft)
Max grade: 12 %
Min grade: -17 %
Recorded: 5/26/2012 12:21 PM
The application also integrates with a Polar brand heart rate monitor over Bluetooth to record heart rate statistics along with the other information. I don’t have that option yet, but plan to add it fairly soon. This is a great free app that everyone should know about. It’s not just useful for mapping a trail, either – you could use it to mark where you left your car, see where you’ve been in an amusement park, or record the location of interesting landmarks you see while wandering around the city. Check it out!