RF Power Sensor

[krush99]

Hello,

I've got a Collins 830D driver putting out about 275 watts and I was wondering how to connect the bnc rf test output to a sine systems RCF1/b remote control to monitor power output. I know how to set it up in the remote control, but I don't have a schematic on how to make a RF to DC voltage converter.

I believe the RF test output is -30db down or so. I'd need about a 1vdc output.
Can anyone help?

Thanks in advance!
Jake

 

[jammerdave]

Take the center of the bnc, through a diode, such as a glass type 1N914,
banded end is output side. Maybe a 10 to 25 uF electrolytic capacitor to ground
to smooth out ripple. If there is too much voltage, use a 10K ohm potentiometer
, top pin to diode/cap output, bottom pin to ground, center wiper to your
R/C input. You should be able to adjust it to what you need. Use a 10 turn pot
if fine adjustments are needed.

That should do it...

dave/fmnostatic




> Hello,
>
> I've got a Collins 830D driver putting out about 275 watts
> and I was wondering how to connect the bnc rf test output to
> a sine systems RCF1/b remote control to monitor power
> output. I know how to set it up in the remote control, but
> I don't have a schematic on how to make a RF to DC voltage
> converter.
>
> I believe the RF test output is -30db down or so. I'd need
> about a 1vdc output.
> Can anyone help?
>
> Thanks in advance!
> Jake
>

 

[CW]

> Hello,
>
> I've got a Collins 830D driver putting out about 275 watts
> and I was wondering how to connect the bnc rf test output to
> a sine systems RCF1/b remote control to monitor power
> output. I know how to set it up in the remote control, but
> I don't have a schematic on how to make a RF to DC voltage
> converter.
>
> I believe the RF test output is -30db down or so. I'd need
> about a 1vdc output.
> Can anyone help?
>
> Thanks in advance!
> Jake

I am not familiar with the driver but if I read you right, you have 275 watts out of the unit and a BNC test jack that is -30dbm0 compared to the RF out?
So 30db down of 275watts is 275mw....You may get ~120 or so mV out of that across a 50ohm load....How is the test jack connected to the output stage? Is it capacitively coupled or directional coupled? You could try using a 0.1 cap in series and then two 1N914 diodes....one reversed biased from cap to ground and the other in series and foward biased...that may get you a little more DC voltage out of it..you may need a small cap to smooth out the DC...(4.7 or 10uF should work)...try that...if too high, use a resistive divider (pot or similar) to lower it..a 10 or 50K pot should be ok (dont go tooo low or it will load the recovered DC down)...but somehow I dont see a 1V DC out of that...