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863-865MHz generation and detection

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Hi all

A brief explanation of my background: I am experienced in working with microcontrollers and power electronics but I'm not experienced in high frequency electronics where I have to worry about transmission line effects. In the past I have studied things like impedance matching and reflections so I have a rudimentary awareness of these things but I have absolutely no practical experience.

What I am trying to do:

I am working on a home project which, in order to implement my idea, would involve detection of standing waves in the 863-865MHz frequency range along varying lengths of transmission line - I was thinking of making a germanium diode RF peak-detector/de-modulator probe in conjunction with my oscilloscope to measure them, like in this video:

But I am really not sure how to generate the wave:

I am not trying to transmit any information by modulating it - I only want to detect its presence. I don't want any more than 25mW of transmission power and I want to be able to operate it in a burst-mode. Where I would transmit for maybe 1-10 micro-seconds at a time. When I started on this idea, I envisioned being able to find a simple chip that would cost a few £ (perhaps with a configurable output frequency and power) which I could just pulse an enable line with a microcontroller and it would simply output the desired frequency in the "burst" fashion that I want. But I am struggling to find what I want.

Could anyone point me in the right direction? Is what I am trying to implement even realistic?

Thanks a lot

For pulse generation one of the development boards that operate a low power digital transmitter in that frequency range should work, maybe one of the LORA chips / boards for that band.
Often such chips have a test mode to send a burst of pure carrier or something like that.

There are VNAs like some versions of the nanovna that can generate a carrier in that frequency range but I doubt it can pulse it for only microseconds, but it's a handy piece of equipment to
measure your SWR in a different way.

There are return loss meters / bridges which are intended to measure the SWR for a particular frequency and probe amplitude range but never really in burst mode.

TDRs can measure in real single pulse mode but that's not a tuned carrier.

VNAs can measure a RF impulse / reflection, but not usually in microsecond tone bursts.

Analog devices has a frequency selective power detector which has a LO input which is mixed with the received signal to determine the power coming back at that LO frequency, so a bridge to measure the return given an excitation burst that's wide enough to look like a narrowband enough carrier could work.

They also have evaluation boards based on this:

Which should be able to do it given external directional couplers.

And yes some of the old SWR meters on parallel transmission lines or slotted waveguides or similar could be used by sliding a diode detector along the line and looking for the standing wave peak / valley points and taking the envelope voltage values along the line.

Just an ordinary UHF capable schottky mixer / hot carrier diode would do to make a detector for 850 MHz. 

Here's some relevant application notes about diode detectors.

Thank you, very much appreciated. I shall have a look at these. :)

Wallace Gasiewicz:
There are several different cell phone and cell tower service monitors that work very well in this freq range.
I have two HP 89935 and Agilent 7495.

I do not know anything about the burst detection issue however. Maybe there is a way to detect bursts with this type of equipment.
Perhaps someone here might know?

Fantasic ,more noise clogging up the  the license exempt radio mic band  here in the uk.


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