// Remainder is the last call char

        call[5] = 'A' + subalt;

        ////////////////////////////////////////

        // Composite temp/batt/speed/gps 

        ////////////////////////////////////////

        // Encode value from -50C to 39C => 0-89. TODO: Bounds!

        uint32_t temp_enc = adc_get_dietemp() + 50;

        if(temp_enc > 89)

            temp_enc = 89;

        // Encode value from 0-39 with some scalar/offset/etc

        uint32_t batt_enc = adc_get_vbatt();  // Hopefully in decivolts

        if(batt_enc > 39)

            batt_enc = 39;

        // Encode speed in knots from 0-82 to 0-41

        uint32_t speed_enc = gps_getdata()->speed / 2;

        if(speed_enc > 41)

            speed_enc = 41;

        // Encode GPS status

        // We always have a fix if we got to this point; and I think we zero out that we had a fix when turning the GPS off before entering this function

//        if(gps_getdata()->fixtype == 2 || gps_getdata()->fixtype == 3)

            gps_status = 0b1;

        if(gps_getdata()->sats_in_solution > 5)

            gps_sats = 0b1;

        uint32_t engdata = gps_sats + 2 * (gps_status + 2 * (speed_enc + 42 * (batt_enc + 40 * temp_enc)));

        ////////////////////////////////////////////

        // Encode temp/batt/speed/gps

        ////////////////////////////////////////////

        // Mask off fields

        chunk = engdata / 18 / 10 / 10 / 19;  

        // Encode to grid locator

        loc[0] = 'A' + chunk;

        // Subtract off previous portion 

        engdata -= (chunk * 18 * 10 * 10 * 19);  

    htim1.Init.Period = ctc; // Count up to this value (how many 64uS ticks per symbol)

    htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;

    htim1.Init.RepetitionCounter = 0;

    HAL_TIM_Base_Init(&htim1);

    HAL_TIM_Base_Start_IT(&htim1);

    HAL_NVIC_SetPriority(TIM1_BRK_UP_TRG_COM_IRQn, 0, 0);

    HAL_NVIC_EnableIRQ(TIM1_BRK_UP_TRG_COM_IRQn);

    // TODO: Bring up TCXO sooner! Gotta let it warm up or something

    HAL_GPIO_WritePin(OSC_NOTEN, 0);

    HAL_GPIO_WritePin(TCXO_EN, 1);

    HAL_Delay(100);

    // Bring up the chip

    i2c_init();

    si5351_init(i2c_get(), SI5351_CRYSTAL_LOAD_8PF, 0);

    si5351_set_correction(0);

    //si5351_set_pll(SI5351_PLL_FIXED, SI5351_PLLA);

    //si5351_set_ms_source(SI5351_CLK0, SI5351_PLLA);

    si5351_set_freq(WSPR_DEFAULT_FREQ * 100, 0, SI5351_CLK0);

//    si5351_drive_strength(SI5351_CLK0, SI5351_DRIVE_8MA); // Set for max power if desired (8ma max)

    si5351_output_enable(SI5351_CLK0, 1);

    //si5351_pll_reset(SI5351_PLLA);

    // Make sure the other outputs of the SI5351 are disabled

    si5351_output_enable(SI5351_CLK1, 0); // Disable the clock initially

    si5351_output_enable(SI5351_CLK2, 0); // Disable the clock initially

    // disable clock powers

    si5351_set_clock_pwr(SI5351_CLK1, 0);

    si5351_set_clock_pwr(SI5351_CLK2, 0);

    // Encode message to transmit

    wspr_encode(call, loc, dbm, tx_buffer);

    // Key transmitter

    si5351_output_enable(SI5351_CLK0, 1);

    // Loop through and transmit symbols TODO: Do this from an ISR or ISR-triggered main loop function call (optimal)

    uint8_t i;

    for(i=0; i<symbol_count; i++)

    {

        uint32_t freq2 = (freq * 100) + (tx_buffer[i] * tone_spacing);

        si5351_set_freq(freq2, 0, SI5351_CLK0);