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Hello, This email message is a notification to let you know that the following files have been updated in the Files area of the [email protected] group. * /Tiny Spectrum Analyzer/Build instructions for

The drive capability of the GPIO outputs is rather limited. When loaded with 50 ohm the output is? between -21dBm and -22dBm. Excellent level for power calibration -- HBTE Files section:

To get some confidence in what you are measuring with the tinySA it would be nice to have a well known signal that you can quickly use as input to check if everything works as expected. It turns out

Hi all, I think that my experience of using screening with the Arduino NANO might be of use: Working with Tony Fishpool I recently built an attenuator using the parallel non latching version of the

A few minor clarifications and addendums to my previous post: Looking into one of the two ports of a B3550 SAW filter element, we would encounter an impedance of 31.59 - 65.87j We might say that's the

For those curious about how impedance matching works, here's the algebra for what is going on when putting two SAW filters in series. I believe this is correct, but would be interesting to verify it

Them mixers create a whole career's worth of complications to figure out. My understanding is that a diode ring mixer has no specific impedance, it simply passes the impedance it sees at the incoming

After some more testing I discovered my nanoVNA was not correctly calibrated when measuring the SI4432 input impedance. The SI4432 input impedance turned out to be fairly ok at 434MHz, about 45ohm.

Joerg, Thanks for this excellent input. I also added a LCL (33nH, 12pF, 33nH) network between the two SAW filters and the S11/S21 went from to Roughly 5dB S21 gain which is always nice! Unfortunately,

Two capacitive ports in series makes for a really capacitive connection there. These SAW filters are not designed for that, as post 666 has shown. They need a conjugate match, which means adding

I've been wondering about noise from the Arduino as well. I'm working on a Kicad pcb layout and thought the Arduino pro mini 3.3V, 8MHz version would work best since it doesn't have a USB connector

Yes. Good job! That passband graph looks great! To be clear, it looks like each of the individual SAW filters has the recommended impedance transformation network on each side of the SAW filter. So a

I finally added a MAV-11 MMIC between the filters: With this I reached an overall gain in the passband of 5.3 dB: BTW: The peek at 437.8 MHz is pretty exactly, what is shown in the datasheet. --

I noticed the same extreme ripple in the passband and the high loss, when I DIRECTLY coupled the SAW filters (EPCOS B3555 from the German "expensive" supplier on eBay, that I received 3 weeks ago):

That's an extremely good price! Especially if they work well enough. Here's a datasheet, note the peak at 438mhz: https://www.mouser.ec/datasheet/2/842/B39431B3555U310-1217831.pdf They look pretty

Hi Jerry, These are the filters I ordered.... ** (

Tony, Are these the same B3550 filters that Eric was using? Here's a datasheet, the B3550 is in the first section: http://www.farnell.com/datasheets/39097.pdf Page 7 of that datasheet shows a graph of

Tony, Good to see these results. My SAW filters have exactly the same ripple and loss. It's a pity but my tinySA does not seem to bother much Out of curiosity you could try to measure a single saw

Niels, That may work as is. Or it may need a few iterations of the layout to work well at these frequencies. A few things I'd be scratching my head about: How solid is the ground plane? Can the

I'm still waiting for some of the other modules to arrive. However the filters arrived from the Polish EBay source (that has been previously mentioned) so I set about building that module first. It