Chinese RF Power Meter

  • Hallo Oms,

    please remember, any infomation about power should be combined with attention to linearity. One can watch the transmit Signal with the Pluto itself. Use a dummy load and/or directional couplers with the right attenuation and look to the spectrum. The Console in combination with the Pluto gives a rather clean two tone signal with 0dBm PEP. This all is possible without a spectrum analyzer.
    At least the transponder will show if the transmitted signal is ok. From my point of view there is a great general improvement compared to the beginning more than a year ago. Don't forget the equalizer and the compressor.

    The goal must be to find a transmitter chain without unneccessary intermodulation. The Pluto followed by the CN0417 delivers +20dBm
    (100mW) with good linearity.
    @Oliver: Why don't you stick all the attenuators together and place it behind the last amp? With 36dB of gain of a two tone signal there is no danger for the attenuators. From 0 dBm of the Pluto you achieve 36dBm PEP (4 Watts PEP), the 2 W dummy load will withstand it keeping the transmission short. I would try to bring an damped signal back to the receiver to control intermodulation.

    73s
    Andreas

  • Hallo,

    CN0417.
    There are differences between Rev B and C. My board (RevC) shows more components U2 and U3 on the backside. My idea is to use the enable Pin2 of the ADL5606 to reduce standby current. The AD-Documents "Design-Support" show Rev B. No infos for Rev C.
    In Rev B Pin 2 is grounded, very clear. Not so in Rev C.
    May be, the circuit to use the enable function is there already but I can not use it without any info about U2 und U3. I think it is difficult to find the right person at AD which can help. I will try parallel.
    I am pretty sure, there is a chance to switch the amp on and off. It is designed for mobile communication with fast time slot operation.

    Does anybody have infos about Rev C? Circuit or layout?

    Thanks in advance

    73s Andreas

  • The goal must be to find a transmitter chain without unneccessary intermodulation. The Pluto followed by the CN0417 delivers +20dBm
    (100mW) with good linearity.
    @Oliver: Why don't you stick all the attenuators together and place it behind the last amp? With 36dB of gain of a two tone signal there is no danger for the attenuators. From 0 dBm of the Pluto you achieve 36dBm PEP (4 Watts PEP), the 2 W dummy load will withstand it keeping the transmission short. I would try to bring an damped signal back to the receiver to control intermodulation.

    73s
    Andreas

    Hello Andreas,

    I try to keep drive the PA EP-AB003 with 5-15dBm input signal to be on the save and linear side. So Pluto =>CN0417 => attenuator ( to drop in the right entry level of 5-15dBm) => PA EP-AB003. I need about 500mW from the EP-AB003 to drive the final PA (SG-lab). SG-lab PA is ordered and should come soon. So I have different ways to keep the devices in a stress free and linear level. You are right I could also have the attenuaor behind the EP-AB003 but then I burn the power instead of smoothly control it . Hope I am right ;-) .

  • Hallo,
    CN0417 Cool Down.
    With the help of a very kindly Applications Engineer of AD the Rev C of the CN0417 is clear to me now. The additional chips are a temperature switch U2 and a tri state buffer. The buffer U3 has an output enable pin. It is clamped to 5P.


    This is the backside of CN0417. Remove R6.

    Patch 1k from Pin1 of U3 to GND. Patch a pull up from Pin4 to 5P. The PTT-Signal to pin1 of U3 changes between 0 (Rx) and 5P (Tx).
    The current consumption goes down from 600 mA to 40mA and is good for stby.


    Again, the help of the Applications Engineer from Analog Devices must be higly appreciated.

    Save current, avoid heat.
    73s
    Andreas

  • Hi Andreas,

    this is a great solution as my CN0417 was the 'hottest' device in the set-up.

    Especially the TX chip on the backside even when cooled with a little Raspberry-Alu-block.

    I guess I will follow your solution.


    Thank you!!

    73, Oliver

  • So Pluto =>CN0417 => attenuator ( to drop in the right entry level of 5-15dBm) => PA EP-AB003. I need about 500mW from the EP-AB003 to drive the final PA (SG-lab).

    I think the CN0417 is rated 1 watt so should be good for driving the SG Lab PA, so I did Pluto=>SPF5189 Amplifier=> 3dB attenuator=> CN0417=>SG-Lab PA . This would need less space than using the EP-AB003. I think the PA output is about 17W but can't measure accurately, but is enough for me.

  • I think the CN0417 is rated 1 watt so should be good for driving the SG Lab PA, so I did Pluto=>SPF5189 Amplifier=> 3dB attenuator=> CN0417=>SG-Lab PA . This would need less space than using the EP-AB003. I think the PA output is about 17W but can't measure accurately, but is enough for me.

    @G4MBQ , the CN0417 get 0dBm from the Pluto and increase it to around 20dBm which is 100mW not 1 Watt. As this device is powered by a standard USB port the entire DC power consumption shout be max 2,5 W on 500mA . So you can drive with the CN0417 direct the new SG lab PA version 3 as this new PA require 40mW (only an attenuator needed). For the version 2 device of the SG-lab PA you need an addition PRE-PA (I took the EP-AB003) to bring it to 500mW. The EP-AB003 is too strong for that job but worked perfect. Other Pre-PAs can do it maybe more efficient and are smaller and cheaper.

    'Specification RF Amplifier 2400Mhz Analog CN0417

    Frequency range: 2400 - 2500 MHz

    Maximum gain: +21dB

    Impedance: 50 Ohms

    Max supply voltage: 5V / 370mA

    With circuit: ADL5606 and LTM8045

    Insertion loss: 0.4dB @ 2000 MHz


    Bottom line, I guess getting 1Watt output instead 100mW will stress the CN0417 too much. It runs hot even with 0,1W.

    73, Oliver

  • I think the PA output is about 17W but can't measure accurately, but is enough for me.

    The PA SG-LAB supplies 22 Watts when powered at 28 Volt. If powered at 20 Volt it provides 12 Watts and at 12 Volt it gives you 5 Watts abundant. You can keep everything in the house and decide how to use it, with how much cable and with what output power.

  • @G4MBQ , the CN0417 get 0dBm from the Pluto and increase it to around 20dBm which is 100mW not 1 Watt.

    Hi Oliver I agree and apologies for not writing more clearly, I was saying that I put a small SPF5189 Amplifier after the Pluto to boost the signal into the CN0417 which then puts out enough power to drive the SG-Labs PA.


    I mentioned 1 Watt for the point that as the PA only needs 0.5W then the CN0417 is not being pushed hard at 0.5W. It does get very hot though, but a 40mm fan keeps it cool.