One more (but completely different) topic, hence a separate mail:
Has anyone experimented with using the R820T above 1.77 GHz?
Hi Per,
mine goes up till almost 1.9GHz with no harm. I don't know if you already had a look on https://github.com/stsydow/rtl-sdr.
I've changed the PLL code a lot. From your last mail I get that we had similar ideas. If you find bugs in it I would be glad to hear about.
Stefan
Thanks for your reply, Stefan.
You wrote:
mine goes up till almost 1.9GHz with no harm.
Mine does go up there around too, if I'm using your repository.
I've also had a look at your code, and I can see you have removed the same lines of code too. However, when I build it here and install it on my machine, there is a big difference in the performance -- for instance, tuning to some of the lower bands (just try 24 MHz) shows a lot of spikes/spurs that are not present when using the "official" repository, even though the settings are the same in the testing application (in this case gqrx).
Not sure why, though -- did you change the gain parameters somehow? If not, then there might possible be some bugs introduced that are causing the spurs? They seem to be somewhat stable in the spectrum, despite the tuned-to frequency.
-- Per.
Hi Per,
I guess I changed to much to find the bug by looking at the diff. My motivation was to rewrite the driver, understand what's going on inside.
I've seen that spurs at 24MHz and there are also mirror images form FM-radio, but it did not raise my suspicion until now. I'm wordering if I disabled a filter or something.
To get to 1.9 GHz, you need to adjust the PLL charge pump register if the PLL doesn't lock.
Stefan
On 04/16/2013 12:32 PM, Stefan Sydow wrote:
My motivation was to rewrite the driver, understand what's going on inside.
Yep, the code in your repo looks much cleaner -- and some of the really weird and non-intuitive parts have been streamlined, making it easier to read!
I've seen that spurs at 24MHz and there are also mirror images form FM-radio, but it did not raise my suspicion until now. I'm wordering if I disabled a filter or something.
Might be the case, yes. Or some some other setup is missing -- I guess we're still missing a more complete description on how the device functions.
-- Per.
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Per Baekgaard -
Stefan Sydow