Thanks Joanne.  I ran some more tests this morning and I was able to get the dongle to run at greater than 3.0 MHz sample rates. Yesterday, when I was testing the upper limits, I must have put the 2832 into a bad state and wasn't able to get it to output anything higher than ~2 MHz. When I compare the settings in my spreadsheet to what rtlsdr setSampleRate() method is producing, they're not too far apart.  I think I'm just using a different approach to get the setting versus what the rtlsdr library is using ( 2^22 * oscillator / sample rate). On the bright side, I'm able to use a whole new set of (lower) sample rates with the 2832. Denny On Sunday, January 12, 2014 7:07 AM, Dennis Sheirer <dennissheirer2002(a)yahoo.com> wrote: Does anyone know if you can check the crystal frequency from one of the RTL2832 registers? Or, has anyone seen an early version E4000 dongle using a crystal other than 28.8 MHz? I've been measuring the sample output rates of my E4000 and found the output rates differed from the expected rates that I'm setting using the rtlsdr library method. https://groups.google.com/forum/#!topic/ultra-cheap-sdr/r_BLWQ5C4mw Denny