The KØLR Antenna Farm (winter and summer)
click on the pictures to see a bigger image

Lyle Koehler, KØLR
30141 Oriole Ave.

Aitkin, Minnesota, 56431
46.45 N 93.62W, Grid EN36ek


This page is dedicated to experimental circuits and homebrew projects. Last update: 2/3/07

This page is no longer maintained on a regular basis. I apologize for the broken and outdated links.

Longwave Club of America Your best source of information on Low Frequency radio.
Web Site of Reg Edwards, G4FGQ Excellent free software collection including design aids for receiving and transmitting loops and verticals.
Web Site of Johan, SM6LKM Longwave and QRP projects, including a PIC controlled LF transmitter and a DDS VFO.
BPSK Basics An introduction to Binary Phase Shift Keying. (12/7/98)
Wolf for Beginners Notes on using KK7KA's WOLF weak-signal mode. (3/11/01)
Simple LowFER Transmitter Easy way to get started on LF. (11/10/98) Calculates wire diameters and loading coil properties. (1/10/98) Excel and Works spreadsheets to calculate bearing and distance between lat/long coordinates. (12/11/00)
High-Gain Preamp Works with loops from LF through the low HF range. (Remote-tuned loop option added 3/16/98)
A Clamp-On RF Current Probe Measure RF current from 100 kHz to 10 MHz. (1/20/98)
Using a PC as a Beacon Message Generator Don't throw away that old PC! Put it to work as a beacon identifier. (two-speed version added 12/10/00)
A PC-Based Frequency Synthesizer Another use for that old PC. (QRSS fix added 11/27/00)
The LEK LowFER Antenna Picture and description. (11/10/98)
Listening for LowFERs, Part 1 Longwave receiving antennas. (updated 3/29/00)
Listening for LowFERs, Part 2 WAVE files and pictures of LowFER beacons (QRSS spectrograms and WAVE files added 11/24/00 and 11/26/00)
A Tunable LowFER Test Transmitter Simple test transmitter with variable-frequency oscillator (7/26/98)
Computer Modeling of LowFER Transmitting Antennas Using MININEC for LF antenna designs (new 3/29/00) MFJ-259 analyzer modifications by Dave, WB6VKH -- extends range down to 100 kHz (added 11/16/98)
Balanced Loop Preamps More high-gain remote-tuned preamp designs (notes on non-center tapped loops added 5/22/01)
All-In-One Transmitter Synthesized LowFER transmitter with built-in BPSK/CW keyer (parts list corrected 7/22/00)
Epson Programmable Crystal Oscillators A brief test report (added 7/23/00)
Solderless Homebrew Projects Using solderless breadboards for homebrew circuits (HiFER transmitter schematic added 5/27/01)
Weak Signal Techniques A comparison of weak signal modulation techniques for LowFER beacons. (added 12/12/00)
Audio Beacon An inexpensive "navigation aid" for the blind. (motion-activated option added 8/3/02)
DDS Exciter My version of the ZL1BPU direct digital synthesis LF exciter. (Futurlec development board version added 1/12/04)
A Really Simple LF Receiving Loop Tree-supported, single- turn loop construction. (new 11/23/02)
"Lightweight" LowFER Verticals Two ideas for LF transmitting antennas that are relatively easy to erect. (link added 3/30/03)
A LowFER Receiver Using a "Software" IF A complete receiver using two ICs and the DL4YHF Spectrum Lab software. (link added 11/13/03)
A 3-D multimode QSL You'll need red and green 3-D glasses to view this! ( added 1/27/03)
Brainerd (MN) Area Amateur Radio Club A great club and a nice web site! (link added 12/24/01)

Thanks for the QSO -- Visit again soon!