Ka7oei blog. On the left is a zippered section with...
Ka7oei blog. On the left is a zippered section with the balun, strap, feedpoint and On August 31, 2012 I posted about problems that I'd been experiencing with three "12 Volt" LiFePO4 batteries that I'd bought in 2010 - see: Note: For information about the H-field loop used for this testing - and using an inexpensive spectrum analyzer such as the "Tiny SA" or, better yet, the "Tiny SA Ultra", see a previous blog entry "RFI Important: If you are at this page you probably have a Polaris with a bad speedometer which means that you can't put it in 4 wheel drive a Random musings - usually on a technical (nerdy) subject - perhaps related to amateur radio and things found at ka7oei. As with most projects, On January 4, 2010 at about 9:40pm Robb, N0KGM and I worked each other, across the valley - a distance of approximately 13. I have published a post on my blog (a link to the blog just below) that has consolidated several other articles related to Solar and noisy devices like power supplies and inverters. RSPDuo, RSPdx and the discontinued RSP1, RSP2 and In several previous posts (See: " A Limited Attenuation High Pass Filter " and " Revisiting the Limited Attenuation High Pass Filter " I d Comment: This article - while it centers about the investigation of a SolarEdge PV (PhotoVoltaic) system - the discussions of techniques an. 17km) in what is believed to have been the first 2-way While the above blog entry showed a modest (200 watt) system, the above can be scaled up for higher-power systems: Larger wire will handle more current and larger toroids will The NanoVNA has become a ubiquitous device for the RF toolbox: For less than US$200 you can get a device that is reasonably capable, accurate and covers a usefully-wide frequency Repeater coverage analysis using the FT-817 and GPS - This page describes using the FT-817 to accurately measure signal strength, interfacing the '817 with a computer, and using GPS to The JPC-12 antenna (possibly designed by BD7JPC) is relatively inexpensive a portable vertical antenna - made in China, of course - that Updates: The RaspberrySDR schematic and a fork of the source code is now available - see the addendum near the end of this article for comm Figure 1: The front panel and original green monochrome screen of the 4031. g. 5mm audio connectors and the red/green RX/TX LED - which have been Random musings - usually on a technical (nerdy) subject - perhaps related to amateur radio and things found at ka7oei. com and modulatedlight. Noting degraded transmission toward the north, a customized signal mapping system using a Yaesu FT-817, GPS, and software was developed to log real After my first version of this article was posted and syndicated through AmateurRadio. 78 miles (22. org KA7OEI - 10 gig transverter page As we did with previous 10 GHz work, we used a beacon as a frequency reference and once we found each other's signals (while he was on the horn) we managed The Transimpedance Amplifier: This left me with the photodiode (article here) and the most commonly-seen circuit using this device is the "TIA" - TransImpedance Note: This is a follow-up to a Part 1 blog post on this topic where we discuss in general how "rotating" (or switched) antennas may be used to determine the While I was originally unsure if this would work, it was actually quite easy to put the bend in the leads - before soldering them to prevent tearing the etched copper ring from the board - using a pair of stout, This study analyzes the antenna pattern of the Utah Amateur Radio Club's 146. 760 MHz repeater following antenna relocation in 1997. org Figure 1: The JPC-7 and its original set of components in the case. com, Clint KA7OEI posted a comment there in which he questioned some of the Q For more information about the "Silver-plated versus Stainless Steel" topic, see the blog entry "Rewinding the Stainless Steel coils with Silver-Plated copper wire on the JPC-7 and JPC-12 Back in 2003 I bought a used HP Z3801A GPS receiver (often called a "Z-Box") with the intent of using it as a time/frequency reference. Noting degraded For the purposes of this discussion, there is no difference between the RSP1a and some of the other receivers in the product lineup (e. A close look shows the "blistering" on the screen protectors One of these is used at each transmitter site, which are held at 4 Hz apart to eliminated "standing nulls" - and they have stayed put in frequency for over a One of the (many) banes of the amateur radio operator's existence is often found at the end of an Ethernet cable - specifically a device th Figure 1: Front panel of the SDR TX/RX antenna switch showing the the 3.