To protect my SDR UHF receivers on hilltop sites, I needed some filtering to reject local FM broadcast and repeaters.
I looked on Aliexpress what bandpass filters were available. Most of them are SAW filters.
Here are the results of my findings and testings.

 filter 403MHz pic The first filter I bought was a 403 MHz bandpass for my radiosonde receiver.

 Advertised for less than 2.5 dB insertion loss
+20 dBm maximum admissible power

This measurings confirmed the good advertised characteristics.
The insertion loss is within characteristics and the return loss is quite good for such a low cost filter.
Very low ripple within the bandpass.
This filter makes its job !

Filtre 403 MHz


Being confident in these filters, I than bought a similar filter for the 433 MHz band in a different shop.
Big disappointment ! Bad mechanical and electrical quality as can be seen on the pictures.

 filter433 2  433 saw 2  

Both filters I bought from this seller had the same very bad characteristics. Almost no bandpass and bad return loss.
Did I get a bad batch or are they all like this ?
Don't buy here ! The seller was very relunctant to refund me and I had to return the filters at y expense despite the Aliexpress rules.
Bad seller :

I decided to try another 433 MHz SAW filter :

 I500309861 6f This 433 MHz SAW filter advertised on Aliexpress, was given for less than 3 dB insertion loss.
For the price, it looked to good to be true.

Once measured, it apperead to be much more lossy and with a high ripple in the bandpass.

Forget this one !

Here the measuring results. (click to enlarge)
As can be seen, the insertion loss is at least 5.5 dB and return loss is very bad.

filter 433

Conclusion :
The first SAW filters are quite good, but you have to find a good seller !