Based strictly on my experience, 100ppm was/is a good number. The worst of my no-name dongles was 75ppm off, after warm up.
That’s what I’m seeing.
Of the generic dongles I’ve characterised, I’ve seen offsets ranging from 15 to 80ppm.
Is there any valuable measurement in number of flights/positions change recorded?
Did anyone record the change for a longer period of time?
Not sure if it’s a valid comparison, but I have been using a no-name dongle and an FA Pro+, almost side by side, for a few months now. The difference in the number of aircraft decoded is between 5-10% less for the no-name dongle.
The Pro+ is connected directly to an FA antenna. The no-name is connected to another FA antenna through an RTL-SDR Blog LNA filter combo.
The antennas are about 2 feet apart, with the no-name more inward. Based on my past experience moving the antennas around, my guess is that the difference in the number of aircraft received is due to this antenna positioning, not to frequency drift. The other reason I say this is that I also saw similar performance differences with a RadarBox and RTL-SDR Blog v3 dongles. If that is not enough, I also switched places between the FA Pro + and the no-name dongle.
If the change you refer to is PPM, no, I did not record for longer periods of time. The shorter periods I observed, it did not change much or at all after warm up. However these short observations were made with the dongle indoors. I would not be surprised if the PPM changed overtime when exposed to the elements/environment.
My receivers are in the garage, where temperatures can vary from -20 to +30 degrees Celsius during the year. Still, if I recall correctly, the 5-10% difference did not change.
For entertainment purposes only. All unscientific and anecdotal since the ‘scientific method’ was not adhered to. 
1 Like
I could imagine that the FA stick delivers a better performance with less deviation from the cheap ones.
I am more interested in a mid-term comparison having different PPM values on the same stick for over a period of time.
@obj has commented that the difference, up to a point (100 ppm having been mentioned), is not major. The main benefit of the FA dongle, I think, is the built-in LNA, and perhaps better quality control.
Frequency stability is critical for some narrow mode applications. In my experiments with some of these narrow modes, specially the ones that required long integration times for decoding, frequency stability is the most important factor. Deviate a few Hertz, and decoding fails.
@obj, any news on new dongles/sticks?
Yes, i’ve read that. Therefore the question if it would even make any difference
We have a few things cooking but nothing beyond the prototype / small batch stages at the moment.
1 Like
OK… ‘slow cooking’ is fine, but I like it ‘well done’, please. 
Thanks for replying.
This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.