Raspberry Pi

C4FM – YSF Reflector

YSF is de afkorting voor YAESU System Fusion. Dat is misleidend. YAESU wil niets van deze reflector techniek weten. Zij hebben immers zelf Wires-X rooms. Oorspronkelijk was het idee deze technieken te koppelen, echter heeft YAESU dat afgehouden…

WSPR setup - RPi - 40m LPF

As you can read in WSPR setup - RPi - no filter the WSPR Tx output of GPIO4 is more or less a square wave signal which can't keep up the speed. So a filter is needed.


The WsprryPi program is able to transmit on all Ham bands up to 2m. So it would be nice to develop a Raspberry Pi shield which is able to transmit on more than one band.

WSPR setup - RPi - no filter

Don't do this at home... it may brick your Pi

First experimental setup. Just to see how it works.
No band filter. So a lot of harmonics... and QRM.

No buffering on GPIO4 pin, so it may brick the Pi. These GPIO pins work on 3V3 and are directly extracted from the Broadcom BCM chip. This is a so called  SOC (System On a Chip) .

For this experiment I used a Raspberry Pi 2 model B. WSPR signal set to 40m.

WSPR (Tx) on Raspberry Pi

WSPR (Whisper) stands for Weak Signal Propagation Reporter.
WSPR implements a protocol designed for probing potential propagation paths with low-power transmissions. Transmissions carry a station's callsign, grid locator, and transmitter power in dBm.

WSPR uses a two-minute time slots for transmitting and receiving. Transmissions nominally start one second into an even UTC minute: i.e., at hh:00:01, hh:02:01, ... 

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