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Technical Topics => The RF Workbench => Topic started by: Quinta on July 25, 2023, 1955 UTC

Title: Dual (multiple) frequency beacon
Post by: Quinta on July 25, 2023, 1955 UTC

Because propagation changing from day to night i try to make dual frequency and simple transmitter for qrp beacon. I try diode commutator and it works.
Beacon powered from 5v 350 ma solar panel and 3V 6A/H lifepo accumulator. Because my controller know voltage on solar panel he will switch frequency on twilight and dawn, it even can be done by primitive voltage comparator, without any programming

(https://sun9-30.userapi.com/impg/WLmnSOFn14r3GdYUmrzQwxLb-VhF3InyK_6VMg/z7FXUK_SJt0.jpg?size=1620x2160&quality=95&sign=688f7b3b034fcce55de76083dfea6210&type=album)

Title: Re: Dual (multiple) frequency beacon
Post by: Teotwaki on September 09, 2023, 1535 UTC

Possibly use a half wave end fed that could resonate at a few frequencies. Also try a simple AD9833 DDS board instead of crystals to allow for multiple frequencies to be controlled by the ATtiny chip
(https://m.media-amazon.com/images/I/41wDgG8+RgL.jpg)