Tag: radio


Igloos on the Air

Operating the 2016 ARRL DX CW contest from inside an igloo at the summit of Witt Hill in Norway, Maine.

You can see the dipole feedline entering the air hole near the top right of the igloo – in the above photo.

Inside the igloo, the rig is balanced on a board, supported by plastic storage containers. I ran full power, 100 watts, from an IC-7300, using Bioenno LiFePo batteries. The temperature inside stays a few degrees above zero Celsius. I thought the rig would help heat up the igloo, but instead had to rely on wool blankets.

All of the gear was pulled up on sleds using human power.

About 3 feet of snow fell in the week before the contest.

Results: KA1IS – 40 meters SOSB LP claimed score: 86,286 (394 QSO’s + 73 countries)


Live at Zebrafarm

Six new releases from Schwwaaa

Produced by Christopher Konopka


A 2016 collaboration of Christopher Konopka (analog video synthesis, audio sampling, analog audio synthesis) and Tom Zicarelli (shortwave radio, audio synthesis, and saxophone). Here’s track one:


Computer controlled phased arrays

Designing antenna arrays with adjustable beam width, azimuth, and elevation angles.

by Jim Lux, w6rmk



Mac OS Wifi Diagnostics

“Wireless Diagnostics” is a builtin signal monitoring app.

Screen Shot 2016-04-28 at 2.51.13 PM


  • Press the option key and click on the Wifi icon in the task bar.
  • Select “open wireless diagnostics.”
  • Diagnostic screens are accessed from the Window menu.

More information from Apple: https://support.apple.com/en-us/HT202663


RF noise reduction



More notes

Noise reduction with Max and Pd

Ladder-line antenna tuner

Impedance matching by adding/subtracting open wire transmission line

A simple antenna tuner made from switches. How to determine the “best” transmission line lengths for multi-band center fed wire dipoles.

by Cecil Moore, W5DXP


Screen Shot 2016-04-28 at 1.55.42 AM


Transmitting FM, AM, SSB, SSTV and FSQ with a Raspberry-PI

By @F5OEOEvariste (article at: rtl-sdr.com)



Reverse beacon network

A network of Internet connected CW skimmers that display detected signals in real time.

Send a CQ and immediately get a list of reverse beacon stations that heard your call, from around the world, with time and signal report data.


CQWWCW low and high bands

Logs are collected in a database that is accessible for research.

Blog: http://reversebeacon.blogspot.com/

Radio music

Sampled shortwave signals

SDR Panadpter, logger, and skimmer

With a TenTec Eagle transceiver, Managed by N4PY software.



N4PY acts as router, distributing CAT commands to other applications.

The applications are connected using virtual serial port bridge pairs. For each of the applications, N4PY emulates a K3 transceiver on one side of the bridge.

  • Panadapter: NAP3
  • Logger: N1MM
  • CW Skimmer

The CW keyer is a K1EL Winkeyer USB controlled solely by the N1MM logger.

The routing of IQ signals from LP-PAN2 SDR is done through a MOTU 828 mk3 interface, simply to be able to split the signal so that both NAP3 and CW Skimmer can use it.

CW Skimmer gets the IQ signal directly from the MOTU. NAP3 doesn’t not recognize multiple ports on soundcards. So one end of the split from the MOTU is sent through another audio interface (Focusrite 2I2). NAP3 uses the 2I2 as an input device.

LP-PAN frequency adjustments

Notes on configuration for correct zero-beating.

When setting the Eagle BW or PBT, the IF will shift in frequency, so the numbers below assume a centered PBT and a BW of 700.

The sidetone pitch is 523 Hz.

Settings may also depend on which roofing filters are installed in the Eagle.

NAP3 settings

Set the global offset to -8200. Leave everything else at 0.

CW Skimmer settings
  • CW pitch: 523
  • Audio IF: -7520
  • Sample rate: 96 kHz
  • Hardware: SoftRock-IF

This post is about ham radio.