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John K. Andrews   Holden, MA FN42ch  

Many of the articles below refer to operation at LF and MF under Experimental Service authorizations from 2004 - 2017. The FCC has now created Amateur Radio bands at 2200 and 630 meters. To prevent possible interference with power line carrier services which may operate in those bands, you must file your geographical information with the Utilities Technology Council. Go to: https://utc.org/plc-database-amateur-notification-process/ for more information. If they do not object within 30 days, you are clear to begin operating according to FCC Part 97 rules.

LF/MF Transmitting

137/472 kHz Power Amplifier
137 kHz 5 Watt Amplifier
137 kHz Exciter
472 kHz Exciter
185 kHz Lowfer 1 Watt Amplifier

LF/MF Receiving

Use of Balanced Transmission Lines for LF Receiving
518 kHz Elliptical Filter
LF AC Line Filter for Switching Supply

LF/MF Antennas

LF/MF Transmit Loop Antenna
MF Transmit Loop Antenna
LF/MF Receiving Loop Antenna

LF/MF Test and Measurement

Sampling Rate and Receiver Frequency Calibrator
LF Field Strength Measurement
Homemade RF Ammeters
GR 516C Calculator
Receiver Calibration with Loran Lines
Use the WOLF GUI and Loran to calibrate your sound card sampling rate.

LF/MF Operating Modes

Modes for LF Use
Modes for MF Use
WSPR-15 vs. WOLF Comparisons

LF/MF Experimental Operation

WD2XES License
WE2XGR License
WE2XGR/3 Log

AM Stuff

2-Tone Test for AM Modulation