From 0ad919e9026e07bbf51652ecd81d72b86add00ec Mon Sep 17 00:00:00 2001 From: pe1nnz Date: Thu, 28 Mar 2013 20:26:40 +0000 Subject: [PATCH] temp coeff --- README | 14 +++++++------- wspr.c | 14 +++++++------- 2 files changed, 14 insertions(+), 14 deletions(-) diff --git a/README b/README index 0d18273..f3f744c 100644 --- a/README +++ b/README @@ -19,12 +19,12 @@ Credits: To use: In order to transmit legally, a HAM Radio License is REQUIRED for running this experiment. The output is a square wave so a low pass filter is REQUIRED. - Connect a low-pass filter to GPIO4 (GPCLK0) and Ground pins on your - Raspberry Pi, connect an antenna to the LPF. The GPIO4 and GND pins can be - found on header P1 pin 7 and 9 respectively, the pin closest to P1 label is - pin 1 and its 3rd and 4th neighbour is pin 7 and 9 respectively, see this - link for pin layout: http://elinux.org/RPi_Low-level_peripherals - Examples of low-pass filters can be found here: http://www.gqrp.com/harmonic_filters.pdf + Connect a low-pass filter with decoupling C to GPIO4 (GPCLK0) and Ground pins + on your Raspberry Pi, connect an antenna to the LPF. The GPIO4 and GND pins + can be found on header P1 pin 7 and 9 respectively, the pin closest to P1 label + is pin 1 and its 3rd and 4th neighbour is pin 7 and 9 respectively, see this + link for pin layout: http://elinux.org/RPi_Low-level_peripherals Examples of + low-pass filters can be found here: http://www.gqrp.com/harmonic_filters.pdf The expected power output is 10mW (+10dBm) in a 50 Ohm load. This looks neglible, but when connected to a simple dipole antenna this may result in reception reports ranging up to several thousands of kilometers. @@ -43,7 +43,7 @@ To use: Frequency calibration is REQUIRED to ensure that the WSPR transmission occurs within the 200 Hz narrow band. The reference crystal on your RPi might have - an frequency error (which in addition is temperature dependent). + an frequency error (which in addition is temperature dependent -1.3Hz/degC@10MHz). To calibrate, the frequency might be manually corrected on the command line or by changing the F_XTAL value in the code. A practical way to calibrate is to tune the transmitter on the same frequency of a medium wave AM broadcast diff --git a/wspr.c b/wspr.c index e0a88b1..760c89b 100644 --- a/wspr.c +++ b/wspr.c @@ -35,12 +35,12 @@ Credits: To use: In order to transmit legally, a HAM Radio License is REQUIRED for running this experiment. The output is a square wave so a low pass filter is REQUIRED. - Connect a low-pass filter to GPIO4 (GPCLK0) and Ground pins on your - Raspberry Pi, connect an antenna to the LPF. The GPIO4 and GND pins can be - found on header P1 pin 7 and 9 respectively, the pin closest to P1 label is - pin 1 and its 3rd and 4th neighbour is pin 7 and 9 respectively, see this - link for pin layout: http://elinux.org/RPi_Low-level_peripherals - Examples of low-pass filters can be found here: http://www.gqrp.com/harmonic_filters.pdf + Connect a low-pass filter with decoupling C to GPIO4 (GPCLK0) and Ground pins + on your Raspberry Pi, connect an antenna to the LPF. The GPIO4 and GND pins + can be found on header P1 pin 7 and 9 respectively, the pin closest to P1 label + is pin 1 and its 3rd and 4th neighbour is pin 7 and 9 respectively, see this + link for pin layout: http://elinux.org/RPi_Low-level_peripherals Examples of + low-pass filters can be found here: http://www.gqrp.com/harmonic_filters.pdf The expected power output is 10mW (+10dBm) in a 50 Ohm load. This looks neglible, but when connected to a simple dipole antenna this may result in reception reports ranging up to several thousands of kilometers. @@ -59,7 +59,7 @@ To use: Frequency calibration is REQUIRED to ensure that the WSPR transmission occurs within the 200 Hz narrow band. The reference crystal on your RPi might have - an frequency error (which in addition is temperature dependent). + an frequency error (which in addition is temperature dependent -1.3Hz/degC@10MHz). To calibrate, the frequency might be manually corrected on the command line or by changing the F_XTAL value in the code. A practical way to calibrate is to tune the transmitter on the same frequency of a medium wave AM broadcast