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Passive Crossfeed for iPhone
Some records just have too much stereo separation. This makes them kind of artificial to listen to with earplugs or headphones as the sound in the two ears is too different. This is where a crossfeed...
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Unusual HF Propagation Phenomena
Earthrise from Apollo 8 (NASA)My blog has just been updated by migrating posts from my old web site containing a collection of audio samples from unusual HF propagation phenomena. They range from...
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Will I ever complete "Worked All States"?
Here's my map of confirmed US states as it has slowly been filling over the last 10 years. 41 states have been confirmed on CW on Logbook of the World, while 9 are still missing.In recent years...
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More long delayed echoes
4.5 metre high UK acoustic mirror used as early warning systemduring WW1. Not so relevant for Long Delayed Echos, but somethingwhich definitely reflects well. Wikipedia Commons, Paul GlazzardThe...
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Medium delayed echoes
Medium Delayed Echoes or Magnetospherically Ducted Echoes (both MDE) are radio echoes delayed from 0.14-0.3 seconds. They represent a subset of Long Delayed Echoes (LDE) and is the only one of the five...
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The 10 biggest lies in audio
Quad II Tube amplifier. (Wikipedia Commons, user Harumphy)In the fall of 2000 The Audio Critic had an article listing the 10 biggest lies in audio. The article is well worth reading even today although...
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Vintage Tektronix oscilloscopes
I first encountered this generation of Tektronix oscilloscopes in my first job at the Electronics Lab of SINTEF, Trondheim, Norway in 1978. Already at that time the main use for them was as heaters in...
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Vertical antenna on a turf roof
A vertical wire antenna based on a MFJ-1904H 6.7 m (22 feet) telescopic fiberglass pole as shown here is easily tuneable for all bands from 40 m to 10 m. Here it is placed on top of a turf (sod) roof...
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Nostalgia from LA3ZA in 1949
Those who are familiar with me will know that I wasn't even born when this LA3ZA QSL-card was issued in 1949. This is because I am second generation LA3ZA after my father. When the callsign was...
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Transformerless tube power supply
In 2012 bulky power transformers that work directly from the power grid at 50/60 Hz have mostly disappeared. My objective here is to modernize the power supply for a one-tube transmitter in the same...
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Fixing my Lithuanian oscilloscope
I visited Riga, Latvia with a youth group which we as a family were involved with in 1992, and there I stumbled upon a Soviet oscilloscope in a department store. It was from the neighboring country,...
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Noisy Designer Lamp
Herstal pendant lamp,type 06Some years ago I had this annoying noise that made listening for weak signals on several of the shortwave radio bands virtually impossible. In the end I was finally able to...
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Altoids Projects
Press image for magnificationI like to build small electronics projects and like many others I have found the small Altoids tins to be excellent enclosures. These tins are inexpensive, well shielded,...
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My first 24 hours on WSPR
My first beacon on 30 m, a free-running Ultimate QRSS kit (no GPS) has now been running for a full 24 hours using the Weak Signal Propagation Reporter (WSPR) mode. The figure comes from the WSPRnet...
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The useless machine or ultimate machine originates from Claude Shannon, the scientist who figured out how to find the channel capacity in a communications system. I bought the basic machine as a kit...
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Visiting 409shop in Hong Kong
A stop-over on my way from Sydney to Oslo gave me the opportunity today to visit Apliu street in Hong Kong. This is where all the electronics products are found. As I had purchased a Baofeng UV-5R from...
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F/LA3ZA on Long Delayed Echoes
Laurent, F6GOX, who is one of the primary forces behind the ARP, Radio-Club de Paris, has written a nice little French-language presentation of me since I am a former member of the club. It also...
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The most interesting contact in the CQ WW Contest
Sometimes looking up remote stations on QRZ.com or other sites gives a glimpse of the person behind the callsign. I did this for the Chinese station BY5CD which I contacted on 40 m during the CQ...
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Half a year of APRS temperature monitoring
My APRS-based temperature monitor has now worked flawlessly for half a year. APRS stands for Automatic Packet Reporting System so it can send much more than temperature data, the chief usage is really...
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GSM phone power control and signalling
When you measure the energy out of a GSM cell phone at the moment of initiating a call, you get the picture to the right. It shows the first 15 seconds.For the first 3.5 seconds there is the signalling...
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