On 10/6/21 10:09 AM, Roger Need via groups.io wrote:
Mark,
Since you only want to transmit one of the harmonics from the NanoVNA you will require a bandpass filter for the 900 MHz. band. Here is a link to a good online tool that can design many types of filters with standardized component values.
Once you try it out you will see that the LC component values are small values and PCB layout will be critical.
I suggest you use an off-the-shelf component. You can buy these for a few dollars and most have specs for the PCB layout.
Here is one example...
If you don't want to design and build your own PCB and enclosure you can buy filters that come in a box with appropriate connectors. Google will find quite a few in short order.
yes, that's the kind of thing I was thinking of.. 40dB isolation - so you might need 2 or 3 of them, and packaging will be important.
There are inexpensive off the shelf boards with a couple SMAs and the solder pads for the filters. If you can't find them, let me know and I'll ask someone who bought them recently.
