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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.

 

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You can build the meter without a fancy enclosure.  But if you have access to a 3D printer then I recommend making the custom plastic case. The case was originally created/published by contributo

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I want RF power measurement. Without calibration, it makes no sense and I think the webshop verison should also be calibrated if we want to see real values.

I don't know if the AD8318 has default settings (factory calibration), but I don't think so.

A silly question: does the AD8318 module not need to be covered with metal shield?

Edited by Wreg
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A silly question: does the AD8318 module not need to be covered with metal shield?

It's up to you. I didn't add a shield and no issues have been encountered.

 

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Does anyone have any info on my other question?  (The AD8318 have factory settings and without calibration did anyone take measurement to see how much error there is?)

And one last, then I promise I finished: can this be used to perform an automatic frequency search in some way (say with an arduino program modification)? This can be useful if we do not know the exact frequency.

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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/

 

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  • 2 months later...

After boot

the blank line is not present at the display of course but for unknown reason added by this app 

RF POWER METER

1MHz - 8GHz

VERSION  2.3

SENSOR  AD8318                  (thats the type i use that is the chip is marked: 8318

HARDWARE PROBLEM

OVERLOAD WARNING 

DISCONNECT NOW!

and thats it

I have exactly connected the AD8318 as in the document

A0  3k3 gnd          measuring 2.57V and changing with key pressed to other levels for kepad

 A1 470R gnd   to ad8318 output   100p is placed    level 0V with AD8318 opern or terminated with 50Z

using LCD Keypad shield  plugged on AT MEGA 2560  A0 aligned with A0 

do i miss anything ?             it just hangs atm

can not show a picture that fits in the max 200k

 

 

 

 

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The A1 voltage should be 2.0V to 2.1V with no RF signal. If you measure 0V then there is definitely something wrong with the AD8318 sensor (or the wiring to it). This voltage represents the measured RF power and should range from approx 0.6V (~0dBm) to 2.0V (~ -65dBm).

My first thoughts: The 0V reading could mean that A1 is shorted to ground. Or a power supply issue related to the AD8318 board.

 

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