Posts Tagged ‘amateur radio’

AF5HD’s L-Match tuner build

Monday, June 10th, 2019

Ryan Flowers writes,  "A fun project for every QRP enthusiast is an L-match tuner. We’ve built a couple here at MiscDotGeek and our latest build inspired Billy Dunn (AF5HD) to build a similar tuner. We have to say, this one turned out better than ours did!" More details on MiscDotGeek...

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Posted in DIY | No Comments »

WBR-Oscar regen receiver

Friday, December 14th, 2018

A nice write-up on Sheldon's (N6JJA) version of N1BYT’s WBR regenerative receiver: This article is broken into two parts. First comes the “Oscar” preselector/preamplifier. As I said, I intended it to be either part of the overall receiver or used as a standalone where desired. The second part deals with...

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Posted in DIY, RF | No Comments »

MFJ-1708SDR transmit/receive switch for SDR receivers

Friday, March 30th, 2018 Here's a demonstration of the MFJ-1708SDR transmit/receive automatic relay switch from YouTube channel HamRadioConcepts . Here is an interesting device, for use with your SDRplay or other SDR dongle for receive. You can share your current antenna with your 100 watt HF rig and an SDR for receive.

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Posted in RF, SDR | No Comments »

Homebrew dummy load

Saturday, August 27th, 2016

A simple DIY dummy load project from Flathagen: I have created a simple 50 Ω dummy load to test transmitters. I also added a simple RF diode detector so I can measure the peak voltage, and calculate the power. The dummy load consists of eight 100 Ω resistors rated at...

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Posted in DIY | 3 Comments »

WA2EBY IRF510 amplifier

Monday, June 20th, 2016

Flathagen has published a new build: The WA2EBY amplifier is a famous linear amplifier project published in QST in March and April 1999 by Mike Kossor WA2EBY. As this amplifier can give up to 50W out with 1W drive, it is a perfect pair for my Softrock RXTX amplifier. The...

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Posted in DIY | 7 Comments »

EMRFD Direct conversion 40m receiver in a tea caddy

Thursday, May 5th, 2016

Flathagen has made a DIY EMRFD Direct conversion 40m receiver in a tea caddy: I woke up one day eager to build something simple (at least I thought is was simple) and opened up the first chapter in EMRFD and decided to build the 40m direct conversion receiver. I already had...

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Posted in DIY | 3 Comments »

Directional coupler

Monday, September 14th, 2015

Flathagen blogged about his DIY directional coupler: It is simple to construct the directional coupler. The transformers are FT50-43 toroid cores with 32 turns of 24 AWG enamel wire. The primary winding is simply a piece of RG58 through the torioid (i.e., one turn). Different designs use different toroids and...

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Lowpass filter for 30m

Thursday, August 13th, 2015

Flathagen made a 30m lowpass filter for his Softrock Ensemble RXTX tranceiver: I just finished a 30m lowpass filter for the Softrock Ensemble RXTX tranceiver.  I used the schematic provided by WB5RVZ.  L200 and L201 is wound to about 0.9uH, whereas C200 and C202 is 100pF and C201 is 330pF....

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Posted in DIY | 7 Comments »

Embedded Linux APRS iGate tutorial

Wednesday, August 5th, 2015

A detailed tutorial on how to make your own APRS iGate (Automatic Packet Reporting System)  from Andrew Milluzzi: With the super cheap embedded Linux platforms (Raspi, Beaglebone, etc.) and cheap TV dongles, it is really easy to make your own APRS iGate, just like the one in the photo above....

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A signal amplifier module for HF

Monday, May 25th, 2015

Marcus Jenkins blogged about his radio frequency amplifier project he made using DirtyBoard PCB's In building QRP HF radios, having an RF signal level amplifier building block is handy. You want 50 Ohm output impedance, some reasonable gain, supply voltage of the usual 10-14V and ease of building using standard parts...

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Posted in, DIY | 2 Comments »

Using the RTL-SDR dongle to detect meteors

Thursday, January 1st, 2015

According to AMSAT-UK, "a new paper has been released by Dr David Morgan 2W0CXV on using the RTL2841 DVB TV Dongle as a SDR processor with SpectrumLab. The paper 'Techniques for using the RTL Dongle for Detecting Meteors' covers the setting up and use of the dongle to receive meteor...

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Posted in SDR, site, techniques | No Comments »

A Classie WSPR transceiver

Monday, December 29th, 2014

joesugar over at Computer/Electronics Workbench writes: Because of my location, amateur radio operations are limited to low power and disadvantaged antennas. Therefore, the WSPR (Weak Signal Propagation Reporter) protocol immediately caught my eye when I first ran across it. My primary interest is building, so I put together a stand-alone...

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Posted in Arduino, DIY | No Comments »

Listening to D-STAR digital voice with DSD 1.7

Thursday, February 20th, 2014

Brazilian amateur radio operator PU2VLW has written a post (in Portugese) detailing how to use DSD version 1.7 to decode amateur radio D-STAR digital voice transmissions. (Google translate may be helpful.) DSD can be downloaded as source from GitHub. His setup uses a Windows machine running SDR# to receive the...

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Posted in code, open source, RF, SDR | 1 Comment »

DCC/TAPR video: FreeDV, CODEC2 and “The HT of the Future”

Saturday, February 8th, 2014

In this presentation from the 2013 Digital Communications Conference, Bruce Perens K6BP discusses FreeDV, CODEC2 and "The HT of the Future". Bruce is active in advancing interest in open-source digital voice to Amateur Radio on both HF and VHF/UHF. Here he also discusses D-STAR and Yaesu's controversial new proprietary VHF/UHF...

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Posted in open source, RF, software, Videos | No Comments »

DCC/TAPR video: HackRF – A Low Cost SDR Platform

Thursday, January 16th, 2014

In this talk from the 2013 Digital Communications Conference (DCC) co-sponsored by the ARRL and TAPR, developer Michael Ossmann discussed the origins and development of the HackRF Jawbreaker SDR transceiver. This is Michael's first talk at an amateur radio oriented conference.

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Posted in open source, RF, SDR, Videos | 1 Comment »

Digital Speech Decoder 1.7.0-dev adds D-Star support

Wednesday, January 8th, 2014

DSD is a popular software tool for decoding various unencrypted digital radio protocols about which we've previously posted. We noticed that there is now a release of DSD which purports to be capable of decoding the amateur radio digital protocol known as D-Star. This is in addition to P25, X2-TDMA,...

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Posted in code, digital radio data, open source, RF | No Comments »

Ham Radio Linux LiveDVD Ver. 14 supports RTL-SDR, HackRF and more

Monday, December 16th, 2013

Andy, amateur radio operator KB1OIQ, has released the Version 14 of his Ham Radio Linux LiveDVD containing programs focused on amateur radio and SDR operations. This is a remastered version of Ubuntu Linux. As of version 13, there are 32-bit and 64-bit versions available, as well as an image for...

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Posted in Linux, RF, SDR, software | 18 Comments »

Nooelec RTL-SDR giveaway at

Friday, December 6th, 2013 has teamed up with to give away RTL-SDR packages to 10 hams. To be eligible to enter the competition, you must be a registered amateur radio operator, and you must comment on the competition page. The prizes are: Two (2) Complete HF sets including NESDR Mini receiver and...

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Posted in contest, SDR | 3 Comments »

Open source amateur radio programming software

Monday, November 4th, 2013

If you own a modern amateur radio here's an open source software project you'll find useful. It's called CHIRP, and supports programming of a large number of manufacturers and models, and provides a way to interface with multiple data sources and formats. Rigs included are ICOM (including D-Star models), Yaesu,...

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Posted in open source, RF, software | 2 Comments »

Free download: SSTV Handbook

Sunday, October 20th, 2013

Drone found this while perusing the Southgate ARC site: Here is the 176 page E-book "Image Communication on Short Waves, ham radio handbook for SSTV, WEFAX and digital SSTV", by Martin Bruchanov, OK2MNM. The book is offered as a free .pdf download. But a contribution is requested, and is well...

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Posted in #liveupdates | 1 Comment »

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