The 40 Meter Pixie (available at the time of writing for about $7 assembled on eBay) is an interesting minimalist transceiver design – crystal controlled, 2 transistors and an audio amplifier chip. And you are on the air with a unit that you can make QSO’s with! Naturally, there is much room for improvement, and it can in fact be done for only a few dollars more. Below I describe a set of additions that I think really enhances the Pixie’s usefulness.
Continue reading Project LOAP (Lipstick On A Pig) – Pixie XCVR Mods with Outboard CW Filter and Audio Amp
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The unit on the left below is the medium power BMU (Base Matching Unit) intended for 42 foot to 48 foot vertical, sloper, or Inverted-L antennas. Naturally, these antennas (like all end-fed antennas) require a decent radial system for efficient operation on the lower bands.
Continue reading 80 Meters and Up – Portable Base Matching Unit for 42 to 48 Foot Verticals and Inverted-Ls – Medium Power Version
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The unit on the right below is the QRP BMU (Base Matching Unit) intended for 42 foot to 48 foot vertical, sloper, or Inverted-L antennas. Naturally, these antennas (like all end-fed antennas) require a decent radial system for efficient operation on the lower bands.
Continue reading 80 Meters and Up – Portable Base Matching Unit for 42 to 48 Foot Verticals and Inverted-Ls – QRP Version
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As part of renewed interest in portable medium power operations, I wanted a small cheap matcher. The units below are simply standard T-Tuners. Using dirt-cheap construction technique and commonly available parts, these units perform well at a very low cost.
Continue reading Still More Medium Power T-Tuners for Cheap
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As part of project LOAP (Lipstick On A Pig ===> http://vtenn.com/Blog/?p=1348), I wanted a small cheap matching and SWR indication unit for the Pixie-based transceiver system. The T-Tuner and SWR bridge unit on the right, in the picture below, is not vastly different from others, but here it is for your consideration as a good performer at a low cost. Note however, that it has been characterized into real-world impedances with a worst-case loss of less than 0.9 dB.
Continue reading Yet Another QRP Portable T-Tuner and SWR Bridge for Cheap
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Often one sees characterization and loss measurement of UNUNs using an SWR measurement of the UNUN when terminated in it’s transformation resistance, or with the “back-to-back” 2-x-Loss method. Each method reveals something about some quality of the UNUN, but neither method tell us much about how much power the UNUN will deliver to the actual antenna.
In this article I will show a simple method of measuring actual UNUN losses into the actual load impedances that the UNUN will see in service.
Continue reading “Z-Substitution” Method for Measuring UNUN Loss Into Real-World Load Impedances
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The Pixie is a fun and popular QRP transceiver kit. However, typical output power on 40 M is only about 300 to 500 milli-Watts – a bit too QRPp at times…
In this article I’ll show cheap and easy ways to pump up the output power to around 1.2 or over 2 Watts, depending upon the power supply type and crystal activity.
Continue reading $3 to Quintuple the Output Power of a 40 M Pixie Transceiver
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Consulting RF/microwave engineer specializing in Ultra-WideBand (UWB) circuitry and Antenna design for communications and radar.
- 3 Year E-Tech ISU 1979
- Lawrence Livermore National Laboratory Full Scholarship 1988, 1989
- BSEE UC Berkeley 1990
GPA 3.98 T.O.C.
- MSEE 1999
- 35+ years Lawrence Livermore National Laboratory E-Tech, EE, and Consultant – Hardware, Design, Modeling, Patents, and Applications in UWB Comms, RF OTA Powering, Radar, Antennas
- Profesional Awards: 2008 R&D100 Secure Cargo UWB Comms + 2009 Global Security Directorate Award + 2012 Global Security Directorate Gold + Sensitives
Continue reading KD6RF Bio
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From the WSJT-X online User’s Manual ===>
– A means for synchronizing the computer clock to UTC within ±1 second
Using digital communications formats like JT65/9, WSPR, meteor scatter MSK144, or any mode that requires clock synchronization, can be tough without access to network time or a GPS unit.
Continue reading A Manual PC/Laptop Clock Sync Program for Digital Modes
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… or any signal generator for that matter in order to align the IF section, including the notorious crystal filter and phasing circuits, of Vintage Receivers like the Hammarlund HQ145 and HQ129X. It takes about a half hour once you get used to it, perhaps an hour or so the first time. I’ve aligned my Hammarlunds with this procedure and found the units to be very close to factory spec as measured with standard lab equipment.
A layout diagram, such as the one for the HQ145 below, is useful ===>
Continue reading We Don’t Need No Stinkin’ Sweep Generator …
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