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Mr.RC-Cam

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About Mr.RC-Cam

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    RC-Cam Mentor

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    http://www.rc-cam.com
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    USA
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    R/C, FPV, Embedded Programming, Electronic Design.

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  1. Thanks for the positive feedback on the Oracle Diversity controller. Many users find that about a wavelength in separation (9-inches) is fine for typical 1280MHz RF spatial diversity. But sometimes 3X wavelength (or larger odd numbered distances) is better. There are a lot of opinions on it, so do some experimentation to find the best distance for your installation. BTW, I'm not an exact antenna placement type of diversity user. I just put one antenna (and its receiver) in a convenient spot, and put another a few feet away, and connect them to the Oracle (or Diversity Demon) controller with some A/V cables. Might not be optimal antenna placement, but my thoughtless method works pretty good for me. - Thomas
  2. 1. The Arduino's ADC performance, including accuracy of Vref, is involved too. So even if your power sensor is a perfect match to the one I used, the measurements may be different. The default AD8317 cal values in the Arduino code were determined from my build. The default AD8318 cal values are estimations. In either case, calibration is required if measurement accuracy is important. 2. The sensor detects RF power by measuring RF current. It cannot determine frequency. For budget friendly frequency measurements I suggest a low cost SDR dongle. For example: https://www.rc-cam.com/forum/index.php?/topic/3891-20-spectrum-analyzer-for-testing-fpv-systems/
  3. It's up to you. I didn't add a shield and no issues have been encountered.
  4. Your TBTE6CP26B3 tuner is the same module that is mentioned in the original post of this discussion. The China manufacturer was never identified. It worked OK, but Comtech performance was generally more consistent. Also, some had an undesirable metal ridge at the end of the SMA that often caused poor connection to the antenna and/or coax feedline. A 4.6mm diameter ream can be used to remove the ridge on the SMA connector. Note: Comtech tuners do not need this rework.
  5. Calibration wouldn't be necessary for those users that only do SWR measurements since it is a relative comparison. But beyond that, calibration would be prudent.
  6. They are similar in performance, but with subtle differences. Download the datasheets for the specs. https://www.analog.com/media/en/technical-documentation/data-sheets/AD8317.pdf https://www.analog.com/media/en/technical-documentation/data-sheets/AD8318.pdf
  7. The sensor's voltage output has a slope and intercept that are dependent on the measured frequency. The datasheet has the full details.
  8. Causing interference and failing to provide station identification on amateur radio frequencies. All that for the low price of $18,000. https://www.fcc.gov/document/eb-imposes-18000-fine-against-amateur-radio-licensee
  9. Yes, be careful with the hot air. The nearby components may reflow; Then they can move off their pads while you wrestle with the SAW chip. That's exactly what happened to one guy that messed up his SAW chip upgrade.
  10. Low risk for heat damage. The SAW construction is similar to a crystal oscillator and can take normal rework / soldering temperatures. Besides the three pin legs, the bottom side of the filter is also soldered to the PCB. It takes a lot of heat to reflow this hidden region. After fully desoldering the three legs with your Hakko vacuum tool, you can move on to the hard part. I suggest using two soldering irons, one on top of the SAW's metal case and another on the bottom of the PCB (on the copper area that is under the component's center area). Apply extra flux and when the PCB is hot enough to reflow the hidden solder the SAW will come right out with a gentle pull. Don't force it, you don't want any PCB damage.
  11. If it has a 27MHz SAW filter then replacing it with the ECS-D480A filter will add a couple dB of gain. But be aware that removing the old filter is difficult. Some people that tried it caused some damage that reduced RF performance (or killed it). So don't attempt it unless you have strong PCB reword skills.
  12. It seems unlikely that resetting cleanflight would prevent binding the radio (transmitter) to the receiver. Do you mean you can't arm the drone? If that's the problem, then I suspect you need to correctly set up the channels in cleanflight. Some suggestions are discussed here: https://blog.dronetrest.com/quadcopter-not-arming-how-to-solve-in-betaflight/
  13. You are welcome. Thanks for letting me know you got it working.
  14. That might be the reason. The R/C servo signal must be present when RCFS boots up. If the servo signal is delayed when the receiver is turned on then RCFS will ignore programming mode. Try the test again. But disconnect RCFS from the receiver before starting the test. After the receiver is powered up and confirmed working, plug in RCFS while holding the programming button. Confirm the flashing LED while the button is held/pressed. Then proceed to step 2 in my previous post to see if the problem is resolved. BTW, what brand/model receiver are you using? It should be an old analog design with simple shift register decoding (no microcontrollers) that uses 50Hz framerates. That's what was commonly available in 2005 when this project was created. AKA, the good old days. Also, if you have an oScope then please post a screenshot of the servo pulse waveform.
  15. All your observations seem reasonable. As a test, follow the steps below and provide feedback. The RCFS will be set to Hold mode with Impulse Filter data averaging. 1. Turn on R/C transmitter. Remove power from receiver & servos. Press and HOLD the button on RCFS. Apply receiver power. The LED should flash. It should continue to flash until the button is released, then turn off. Is this what you see? 2. Next, press the button TWO times to enable the hold mode. This must be done within five seconds of entering programming mode. Did you see the LED blink after each press? 3. After the second press wait five seconds. At the end of the five second wait the LED should change to a continuous rapid flash. Do you see this? 4. As soon as you see the flashing LED, press the button once. This enables the filter mode. The LED will acknowledge by a single LED blink and programming mode is exited. 5. R/C system operation should be normal at this point. Confirm the servo operates correctly when the radio's stick is moved. 6. Press RCFS button once. It will blink a pattern that reports its configuration. What do you see? During normal operation (Tx on), pressing the PB Switch will blink out the active Failsafe mode. 1-Blink = Idle mode (servo signal turns off) 2-Blink = Hold mode 3-Blink = Fixed Position mode. After a short delay (about two seconds), the LED will blink one more time if the Impulse Filter (averaging) is turned on.
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