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DL4JAL mW-meter

I suggested a new PCB in KiCad, orderd necessary parts and started to build mW-meter. Complete schematic is visible here. It contains two main blocks - PIC with 18F4520 and Amplifier with precious Zero-Drift Operational Amps LTC1050 from Linear Technology. Andreas developed an excellent and premeditated software, which is available on his web. Great job, Andreas!



I am using 3 different measuring heads. One with AD8362 detector, which is more accurate in very wide frequency range, and two detectors with AD8307 - one for RF range and one for Low frequency range. Parameters are visible on the stickers.

Couple of next pictures shown complete set with one head (AD8307) and measuring results from VHF/UHF portable radio VX-6, using TX mode with all 4 power levels  - LOW1, LOW2, LOW3 and HIGH. For the power level higher than +30dBm (1W) attenuation of 20dB was set and 20dB/5W attenuator was inserted between radio and measuring head input.


Basic screen with AD8307 measuring head. Left side for RMS average results, right side for PEP results.

View of an opened measuring heads.

Four TX power level measuring results (VX-6 handy).

Opened mW-meter is visible on the next picture. It is installed into Fisher ALU box 160 x100 x85mm, ordered from Reichelt Elektronik. I have put one 1800mAh battery inside the box for poratble use. Battery charging is accesible trough the rear connector. Another connector is using for external powering (14 - 18 VDC).


Next pictures show FT1000MP output power measuring results. Attenuation in mW-meter was set to 20db, between transceiver and mW-meter an external attenuator 20dB / 500W was inserted. 

 

DL4JAL mW-meter is really valuable tool. I am using it for many different purposes. For example, with direct connection at the BFO output I can check CW, USB and LSB and set proper levels. It was possible to set exactly necessary level for the using mixer (+17dBm). Or, I can set right level from IF amplifier (plus AGC) to the RX detector, etc. etc. I sincerely recommend to build this tool for every ham radio enthusiast, who likes to play with electronic circuits. Easy it is to make, easy to use, easy to carry, easy to maintain......THANKS, ANDREAS!

Remark. If somebody has interest to empty PCB, let me know. I have couple of them available, because minumum manufacturing amount was 3, resp. 5 pcs. I used just one.....


 
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