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How to convert binary fractions to decimal ( fixed point arithmetics )

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Example for n = 110.101

Step 1: Conversion of 110 to decimal
=> 1102 = (1*22) + (1*21) + (0*20)
=> 1102 = 4 + 2 + 0
=> 1102 = 6
So equivalent decimal of binary integral is 6.

Step 2: Conversion of .101 to decimal
=> 0.1012 = (1*1/2) + (0*1/22) + (1*1/23)
=> 0.1012 = 1*0.5 + 0*0.25 + 1*0.125
=> 0.1012 = 0.625
So equivalent decimal of binary fractional is 0.625

Step 3: Add result of step 1 and 2.
=> 6 + 0.625 = 6.625
Example for n = 4.47 k = 3

Step 1: Conversion of 4 to binary
1. 4/2 : Remainder = 0 : Quotient = 2
2. 2/2 : Remainder = 0 : Quotient = 1
3. 1/2 : Remainder = 1 : Quotient = 0

So equivalent binary of integral part of decimal is 100.

Step 2: Conversion of .47 to binary
1. 0.47 * 2 = 0.94, Integral part: 0
2. 0.94 * 2 = 1.88, Integral part: 1
3. 0.88 * 2 = 1.76, Integral part: 1

So equivalent binary of fractional part of decimal is .011

Step 3: Combined the result of step 1 and 2.

Final answer can be written as:
100 + .011 = 100.011
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Arduino not visible on COM port. Cannot upload a sketch even if you have flashed a fresh booloader. Solution.

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If your Arduino does not show up on any USB COM ports even if you flashed a fresh bootloader, it may be because the sketch you flashed has messed up your USB serial settings on the Arduino. This sketch will prevent the Arduino showing up as a com port in Windows because the flashed sketch starts immediately upon reset and “blocks” the normal USB COM operation.

Solution:
1) re flash the bootloader with an ISP connected to the 6 pin header. I use a USBasp (cheap ISP clone).

2) Just so you KNOW the bootloader is installed. You can check that the bootloader is operational by plugging in the board thru the USB COM port (when you already have an open hardware manager windows in Windows).
You should see briefly a new COM device named “Arduino [name of board] bootloader”. This  COM device will quickly disappear again if you have a sketch messing up the serial settings.At least you know the bootloader should be OK.
3) Upload a completely empty sketch WITH THE ISP device. Important!:Do that upload with the ISP and NOT via the USB serial cable.

This is a completely empty sketch you can use:

void setup() {}
void loop() {}

I have fixed several dead Arduino boards that I suspected had hw problems this way. In fact the boards were OK. The problem was that a sketch already installed messed up the serial settings. The bootloader and hw was completely ok.

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RTOS on Arduino

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FreeRTOS Task for Blink LED in Arduino UNOProfessional software developers of time critical code often use a real time operating system (RTOS) in their work. The reason is that the OS is taking care of timing and scheduling tasks with higher priority. Now you can easily use an RTOS on your Arduino as well! Read Jain Risbah’s article over at circuitdigest: https://circuitdigest.com/microcontroller-projects/arduino-freertos-tutorial1-creating-freertos-task-to-blink-led-in-arduino-uno

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Finn posisjonen til masten som ditt 4G / LTE modem er koplet til med Celle ID! (4G / LTE Cell ID database with position info., Norway)

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Lurer du på hvor masten som ditt 4G / LTE modem er koplet til er lokalisert? (LTE Cell ID database with locations, Norway). 

Maybe this can help: I found a comprehensive database that contains approx 147000 lines at https://opencellid.org/ This dataset is made publicly available by Opencellid for download.

Here is the cell id data I downloaded for Norway:

 242.csv

Rename the file to 242.csv (it has a txt extension) and open it or import it in Excel.

You can then find lat and long position from the Excel cheet

Then enter that lat / long (with decimals and add E and N after the numbers) into the search field of Google maps

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How to adjust your parabolic antenna for QO-100 / Es’Hail amateur radio geostationary satellite

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VIDEO. How to adjust your dish for QO-100 geostationary satellite:

  • Find Astra 28,2 degrees (strong signals in Northern Europe and Central Europe) with a low cost satfinder with sound / analog meter
  • This is one of the most eastern TV satellites that are very strong, so you can start east and move towards south until you find the first strong satellite on your satfinder (you should find Astra 28,2)
  • Now move a slight bit more to the south until you are out of the strong Ku band lobe of the Astra 28,2
  • You should point in the correct direction (elevation is the same in practice)
  • If you have a generic LNB the IF should be on 739,7 MHz. Your SDR should be able to tune to that QRG

Join our FB group (exclusively for licenced radio amateurs by the respective government administrations) https://www.facebook.com/groups/252645695661305/members/