[TangerineSDR] Uploading of spectrum data from TangerineSDR to Central Control

John Gibbons jcg66 at case.edu
Tue Jun 9 14:25:25 EDT 2020


If the DRF data is being taken in, let's say,  1 minute epochs and the
request for data from the Central host is for a 'set of 30' 1 minute data
blocks makes perfect sense.  The data already exists and is packaged and
sent back to the Central Host without any data manipulation.

IF the blocks are not refined that small, will the request for data
(presumably after the fact) from the Central host be in a block / time
segment size that it has already been collected in or will the node have to
massage the data to comply?

I guess what I'm getting at is if the data sets are pre-recorded in 5
minutes long blocks synced to 00 minutes (0,5,10,15,20, etc data blocks
being collected), will the host ever ask for data from 00:02 to 00:08 (8
minutes of data imbedded within 2 already existing data blocks) and force
some data crunching to reply?

Or am I trying to read tooo much into this....

John N8OBJ

John C. Gibbons
Director - Sears Undergraduate Design Laboratory
Dept. of Electrical Engineering and Computer Science
Case Western Reserve University
10900 Euclid Ave, Glennan 314
Cleveland, Ohio  44106-7071
Phone (216) 368-2816 <216-368-2816> FAX (216) 368-6888 <216-368-6888>
E-mail: jcg66 at case.edu

On Tue, Jun 9, 2020 at 12:38 PM Engelke, Bill via TangerineSDR <
tangerinesdr at lists.tapr.org> wrote:

> Hello All:
> I have a prototype of a process working for moving (raw) spectrum data
> from the TangerineSDR to the Central Host; I would like any interested
> colleagues to review and comment on it, since it is such an important piece
> of the system. I have a mockup running in Ubuntu on a virtual server, but
> the final Central Host process will run under CentOS and Django. Here’s how
> the process works:
>    1. When in Ringbuffer mode, the TangerineSDR collects one to 16 bands
>    of spectrum data, saving it in a ring buffer in Digital RF format. (Typical
>    actual use would probably be the ~ 5 bands of WWV).
>    2. Every so often (say, 120 seconds), the TangerineSDR sends a
>    heartbeat packet to the Central Host.
>    3. If the Central Host has been given a data collection command (by a
>    superuser), it will reply to the heartbeat with a Data Request that has a
>    start and end time.
>    4. The TangerineSDR finds all the files and metadata collected during
>    the requested time frame and uses tar to put into a single file (optionally
>    compressed).
>    5. The upload file gets named according to the (still being refined)
>    CWRU naming convention (except that band info will not appear in the file
>    name since a DRF file will usually contain multiple bands).
>    6. The TangerineSDR optionally sets the maximum upload rate
>    (“throttle”) and uses the utility lftp to send the file to the sftp server
>    running on the Central Host. Each user has their own “incoming” directory.
>    7. The Central Host checks the incoming directories at certain
>    intervals; when it finds a file package, it moves it to a central
>    collection and puts a cross-reference into the relational database.
> Notes: I thought about a number of different ways of moving the data from
> TangerineSDR to the Central Host; this way seems promising because it
> offers the following benefits –
>    - lftp is restartable in case the upload is interrupted. Some uploads
>    will run for a long time.
>    - Using sftp as the protocol protects the data in transit.
>    - The Central Host can handle a lot of uploads at once without
>    burdening the website.
>    - Since each user has a unique UID and password, and data travels
>    encrypted, we should be able to minimize hackers uploading garbage.
>    - The TangerineSDR has another mode (“snapshotter”) which
>    pre-processes raw spectrum into frequency domain data – this will be
>    handled differently (more to come on that).
> I’m sure I have not thought of everything though;  if you have a
> suggestion on how to do this better, it is most welcome – thanks for your
> help!   -73- Bill  AB4EJ
> --
> TangerineSDR mailing list
> TangerineSDR at lists.tapr.org
> http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
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