Dongle R820t2, how much of an upgrade to the R820T?

[Your_account]

yes i looking for a comparison to. But now with an Upconverter. For me is PMR446 and ACARS intersting.
(Maybe you can use ACARSDECO2 for both.)

 

[DK327]

An antenna multicoupler would be much better - eliminates all antenna issues.

That's true... I suppose he can swap the new antenna between the two dongles to see how much of a difference it makes, if any, but to strictly test the performance of the dongle, a single antenna would be best.

 

[Your_account]

take some T splitter...

 

[Flatliner]

Someone did that test with an old airspy prototype:
Simple Airspy and RTLSDR Comparison

That's with the dongle with the R820T, not the R820T2.

Just use a t connector. The impedence is mismatched with our transmission lines and antennas anyway.

 

[Voyager]

Nick,

I got my two yesterday, the Offset of my original NooElec is at 59ppm and one of the new ones is at 70 something and the second one is around 30 or so if I recall. I will double check when I get home but I do recall a good spread between the two new dongles, thought that was a tad strange. but they do seem to work well.

The PPM setting is just to compensate for the crystal frequency (no two crystals will have the exact same characteristics). I have several of the 820T dongles with PPM ranging from about 12 to about 64 with most much closer to the 64 figure. (odd thing is I've never had one with a negative correction factor). A PPM calibration of 0 would mean the crystal is exactly on frequency. But, this all has very little to do with drift. A crystal that is on frequency may drift 10 ppm while one that is off by a correction factor of 50 may drive only 3 ppm (or vice versa).

In other words, all you are doing with the correction factor is netting the crystal on-frequency. It is not an indication one crystal will drift any more of any less.

 

[Voyager]

Would love to see the same test using a production Airspy (which should be better than the prototype) vs a dongle with the R820T2.