From pczzs at yahoo.com Sat Jun 1 02:00:33 2019 From: pczzs at yahoo.com (P C) Date: Fri, 31 May 2019 21:00:33 -0500 Subject: RTL_SDR "output_block_size (default 16*16384)" In-Reply-To: <8eda73b0-9d71-c0d3-8402-804776140f97@gmail.com> References: <2ff66056-843d-b403-6233-e375ee0228dd@yahoo.com> <8eda73b0-9d71-c0d3-8402-804776140f97@gmail.com> Message-ID: Vasil, Thank you for the prompt reply. And thank you for not chastising me for saying I searched but you found the links for me. Unfortunately, had already found that page.?? Maybe I am dense as a box of rocks but I couldn't find what I was looking for there. I was hoping for something like, The size of the buffer is used while capturing in synchronous mode.?? It is adjustable so that (insert the reason here).?? Make it larger if (insert reason here) but that will cause (insert result here).?? (more explanation......). Would you know where can find that kind of information? Thanks again, Pete On 5/31/2019 3:14 PM, Vasil Velichkov wrote: > Hi Pete, > > On 31/05/2019 19.59, P C wrote: >> In RTL_SDR, option -b >> >> What does: >> "output_block_size (default 16*16384)" mean? >> >> I have been searching and I just can't find that explained anywhere. > It's the size of the buffer that's used while capturing in synchronous mode. > > http://git.osmocom.org/rtl-sdr/tree/src/rtl_sdr.c#n143 > http://git.osmocom.org/rtl-sdr/tree/src/rtl_sdr.c#n174 > http://git.osmocom.org/rtl-sdr/tree/src/rtl_sdr.c#n236 > > Regards, > Vasil -------------- next part -------------- An HTML attachment was scrubbed... URL: From vvvelichkov at gmail.com Sat Jun 1 15:38:26 2019 From: vvvelichkov at gmail.com (Vasil Velichkov) Date: Sat, 1 Jun 2019 18:38:26 +0300 Subject: RTL_SDR "output_block_size (default 16*16384)" In-Reply-To: References: <2ff66056-843d-b403-6233-e375ee0228dd@yahoo.com> <8eda73b0-9d71-c0d3-8402-804776140f97@gmail.com> Message-ID: <66ef9d99-128b-ada1-e5f3-882515de18de@gmail.com> Hi Pete, On 01/06/2019 05.00, P C wrote: > Unfortunately, had already found that page.?? Maybe I am dense as a box of rocks but I couldn't find what I was looking for there. > I was hoping for something like, > The size of the buffer is used while capturing in synchronous mode.?? It is adjustable so that (insert the reason here).?? Make it larger if (insert reason here) but that will cause (insert result here).?? (more explanation......). > > Would you know where can find that kind of information? Sorry, I don't know. In my opinion smaller buffer sizes would remove latency as the buffer would fill faster and rtlsdr_read_sync would returns sooner but this would add an additional overhead as rtlsdr_read_sync would be called more often, and bigger buffer sizes would add latency but remove the overhead. Hope this helps. Regards, Vasil From pczzs at yahoo.com Sat Jun 1 17:04:25 2019 From: pczzs at yahoo.com (P C) Date: Sat, 1 Jun 2019 12:04:25 -0500 Subject: RTL_SDR "output_block_size (default 16*16384)" In-Reply-To: <66ef9d99-128b-ada1-e5f3-882515de18de@gmail.com> References: <2ff66056-843d-b403-6233-e375ee0228dd@yahoo.com> <8eda73b0-9d71-c0d3-8402-804776140f97@gmail.com> <66ef9d99-128b-ada1-e5f3-882515de18de@gmail.com> Message-ID: Vasil, Nothing to be sorry for. You give me a lead to follow. I'm not using synchronous mode but maybe I should. The last time I did anything with PLLs was the Signetics NE5xx family. Ouch, that dates me. Thanks Pete On 6/1/2019 10:38 AM, Vasil Velichkov wrote: > Hi Pete, > > On 01/06/2019 05.00, P C wrote: >> Unfortunately, had already found that page.?? Maybe I am dense as a box of rocks but I couldn't find what I was looking for there. >> I was hoping for something like, >> The size of the buffer is used while capturing in synchronous mode.?? It is adjustable so that (insert the reason here).?? Make it larger if (insert reason here) but that will cause (insert result here).?? (more explanation......). >> >> Would you know where can find that kind of information? > Sorry, I don't know. > > In my opinion smaller buffer sizes would remove latency as the buffer would fill faster and rtlsdr_read_sync would returns sooner but this would add an additional overhead as rtlsdr_read_sync would be called more often, and bigger buffer sizes would add latency but remove the overhead. > > Hope this helps. > > Regards, > Vasil -------------- next part -------------- An HTML attachment was scrubbed... URL: From yaron at rontalcolour.ca Mon Jun 24 13:40:10 2019 From: yaron at rontalcolour.ca (Yaron Haddi) Date: Mon, 24 Jun 2019 13:40:10 -0000 Subject: Receiving UTAs on 978 Mhz Message-ID: An HTML attachment was scrubbed... URL: From bwalker at musings.com Mon Jun 24 22:34:23 2019 From: bwalker at musings.com (Brad Walker) Date: Mon, 24 Jun 2019 22:34:23 -0000 Subject: ADS-B reed-solomon ? Message-ID: I've been studying the rtl_adsb.c code and it's very interesting how it works.. But, I have question. I noticed that if I request verbose output using the "-V" option, then the CRC is printed out. But, it doesn't look like the code actually does any Reed-Soloman error correction to the data the ADS-B specification documents. Am I reading this correctly? Thanks. -brad w. -------------- next part -------------- An HTML attachment was scrubbed... URL: