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Exploring the "1-930MHz 2W RF Broadband Power Amplifier Module for FM Radio...
Figure 1: The amplifier - with heat sinkOn EvilBay, you can find a number of sellers of a device described as: "1-930MHz 2W RF Broadband Power Amplifier Module for FM Radio HF VHF Transmission". This...
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Characterizing spurious (Harmonic) responses of the SDRPlay RSP1a (and other...
The SDRPlay RSP2pro (left) and RSP1a receivers (right)The SDRPlay RSP1a is a popular Software Defined Radio (SDR). This device, connected to and powered by the computer via a USB cable covers from VLF...
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It *is* possible to have an RF-quiet home PV (solar) electric system!
Figure 1: Half of the array on my garage - the other half is on the west-facing aspect.There's a bit of shade in the morning around the end of June,but it detracts little during the peak solar...
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Modifying an "O2-Cool" battery fan to (also) run from 12 volts
A blog posting about a fan? Really?Why not!Figure 1: The modified fan on my cluttered workbench, runningfrom 13 volts.The external DC input plug is visible on the lower left.Click on the image for a...
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A solid state replacement for an old radio's "vibrator" (Wards Airline 62-345)
Figure 1:The front of the Wards Airline 62-345 with its ratherdistinctive "telephone dial" tuning dial.It's powered up and running from 12 volts!Click on the image for a larger version.Quite some time...
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Improving the thermal management of the RX-888 (Mk2)
Figure 1:The RX888 showing the "top" and RF connectors. Whilethe heat sinks attached to the sides are visible, the large oneon the "bottom" plate are not.Click on the image for a larger version.The...
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Measuring signal dynamics of the RX-888 (Mk2)
As a sort of follow-up to the previous posting about the RX-888 (Mk2) I decided to make some measurements to help characterize the gain and attenuation settings.The RX-888 (Mk2) has two mechanisms for...
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Resurrecting my FE-5680A Rubidium frequency reference
Fig 1:The Hammond 1590 aluminum casehousing the FE-5860A rubidium osc-oscillator and other circuitry - themarkings faded by time and heat.Click on the image for a larger version.Recently I was getting...
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Remote (POTA) operation from Canyonlands National Park (K-0010)
As I am wont to do, I recently spent a week camping in the "Needles" district of Canyonlands National Park. To be sure, this was a bit closer to "glamping" in the sense that we had a tent, a...
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Multi-band transmitter and monitoring system for Eclipse monitoring (Part 1)
It should not have escaped your attention - at least if you live in North America - there there are/have been two significant solar eclipses occurring in recent/near times: One that occurred on...
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Observations, analysis and field use of the JPC-7 portable "dipole" antenna
Figure 1:The JPC-7 and its original set of components in the case. Onthe left is a zippered section with the balun, strap, feedpointand mounting hardware for the elements. On the rightcan be seen the...
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A simple VHF notch cavity from scraps of (large) Heliax
In a previous post I discussed how a band-pass"cavity" could be constructed from a chunk of 1-5/8" Heliax (tm) cable (a link to that article is here). This is the follow-up to that article.Figure 1:...
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"TDOA" direction finder systems - Part 2 - Determining signal bearing from...
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 apparent bearing of a transmitter. It is...
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Remote (POTA) operation from the Conger Mountain BLM Wilderness Area (K-6085)
It is likely that - almost no matter where you were - you were aware that a solar eclipse occurred in the Western U.S. in the middle of October, 2023. Wanting to go somewhere away from the crowds -...
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Reducing RFI (Radio Frequency Interference) for a POE (Power Over Ethernet)...
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 that is being powered via "Ethernet": It is often the case that...
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Repairing a dead Kenwood TS-850S
Recently, a Kenwood TS-850S - a radio from the mid-early 1990s - crossed my workbench. While I'm not in the "repair business", I do fix my own radios, those of close friends, and occasionally those of...
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Using an external clock with the RX-888 (Mk2)
The RX-888 (Mk2) and external clockingFigure 1:The RX-888 with external clock input (right)The enable/disable switch is barelyvisible behind the USB connector.Click on the image for a larger...
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Analysis of interference from a SolarEdge PV (solar) electric system.
Comment:This article - while it centers about the investigation of a SolarEdge PV (PhotoVoltaic) system - the discussions of techniques and strategies should be generally useful when investigating...
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Repairing a dead RX-888 (no A/D converter clocking)
On this blog I have posted three previous entries related to the RX-888 (Mk2) which may be of interest to the reader:Figure 1 - The (stock) RX-888Using an external clock with the RX-888 (Mk2) - link -...
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Observations, analysis and modifications of the JPC-12 vertical antenna
The JPC-12antenna (possibly made by BD7JPC) is relatively inexpensive a portable vertical antenna - made in China, of course - that may be found for sale at quite a few places under a few different...
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Reducing QRM (interference) from a Renogy 200 watt portable solar panel system
Figure 1: Renogy 200 watt folding panel, in the sunClick on the image for a larger version.A year or so ago I got a 200 watt foldable solar panel system. This unit - made by Renogy - consists of two...
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Rewinding the stainless steel for silver-plated copper coils on the JPC-7 and...
Portable antennas (verticals, loaded dipoles) typically use coils on the lower HF bands to make them electrically "larger" - but what about losses in those coils?While it's "traditional" to use copper...
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Neon bar-graph VSWR/Power meter using the ИН-13 (a.k.a "IN-13") "Nixie" - Part 1
Figure 1: Power/VSWR meter using ИН-13 (a.k.a. "IN-13") neon bar-graph indicators.Click on the image for a larger version.Several years ago I bought some Soviet-era neon bar-graph displays - mainly...
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DRAFT - Neon bar-graph VSWR/Power meter using the ИН-13 (a.k.a "IN-13")...
Figure 1: Power/VSWR meter using ИН-13 neon bar-graphindicators.Click on the image for a larger versionIn Part 1 I laid out the requirements of the ИН-13-based neon bar-graph VSWR/power meter....
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Hiking and POTA (Parks On the Air) operation from Arches National Park (US-0004)
Figure 1:Double-O ArchClick on the image for a larger version.Earlier this month I had the opportunity to spend nearly a week in Arches National Park in south eastern Utah. As the name implies, there...
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