Amateur radio projects from 73kHz to 447THz
old favourite revised with modern SMD coils. Ready built preamp for 136kHz
and a new version for the 472kHz band.
Middle: A 300W Class D Amplifier for 630m. Includes over current and hi ref power protection
Right: A 5W linear amplifier for 136 or 475kHz. (70k - 2MHz)
Kits and components Index.
to Canada on 136k 4300km crossband
Quarter kilowatt linear amplifier for L.F.
A 100W LF Class D Amplifier from 13.8V
LF - HF Reflection Coefficient Bridge
300 Watts on 136kHz. A class D TX. (Jan/Feb 2003 Rad Com)
300 Watts on 472kHz /630m with over current and SWR protection Kit available
A broadband 5Watt linear amplifier for 136 and 475kHz Kit now available 09/2018
AMSAT Oscar 40. Worldwide satellite communication
Helix dish feed kit for 2.4GHz
Gemini : S Band to 10m converter with 0.6dB NF
Laser transmitters / Receivers - 6 pages updated
LF PreAmp and BPF. Make your black box work on LF and MF. New Version. Feb 14
LF On-the-Air Antennas, Photo's, Coil's etc
L.F. Dx-pedition to the Isle of Man.
VSWR Bridge for LF Forward and reverse power at a glance
Where a project has been published, the original
text is reproduced.
Up to-date developments / modifications to circuits are also included.
300W Amplifier for 472kHz / 630m - A 2016 design using 2 FETs in push pull. Ideal for WSPR beacons and CW QSOs
A 5Watt linear amplifier that works from 70kHz to 2MHz. Ideal for that low level from your Kenwood Icom or SDR Radio
The ESEO project. An inside view from an AMSAT perspective on this 49kg satellite from ESA Education
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If you have any questions or comments please e-mail
David Bowman G0MRF Site last updated 19th/November/2018