Re: New to the list


VE7VXO
 

Yeah you are still not getting what I'm proposing Glenn, but Rob's message just now answered my question that it should be possible.  In the scheme I'm proposing there is no second hardware connecting to the SDR.  The wspr daemon code is executing in the same CPU as the KiwiSDR code concurrently.  This might be possible on a RaspberrySDR which I should have said instead of calling it KiwiSDR.  So I would just have a RaspberrySDR with WD running on it in the background sharing the same local port :8073. Get it?

Joe

---------- Original Message ----------
From: Glenn Elmore <n6gn@...>
Date: July 14, 2021 at 8:11 PM


To access the Kiwi you have a choice of a  wired LAN connector (static
or DHCP), USB A connector (port number statically assigned by BB). 
Either of these *might* be connected to a router/dongle or directly to a
host computer such as the RPI.  If the connection is not wireless, then
the device it is connected to must have a power source. That power
source *could* be it's own separate PS or it could be something in
common with the Kiwi's.  IF it's in common then there is either an
actual ohmic COMMON path as in the case of USB or there's finite CM
rejection as in the case of the LAN/RJ45 PHY.  Either of these paths
might create a current loop with data path. Edges from the data can end
up  generating non-zero current through Kiwi/BB "grounds".  These paths
are imperfect and have the danger of generating signal energy within the
Kiwi's large measurement range.  This can sometimes be a bit insidious
because the currents may increase due to finite CM impedance on antenna
feed line or LAN line (if either present).

The Kiwi *can* be run with either a direct connection to the host,
through a router wired or wireless or USB.

I'm only cautioning against these somewhat 'invisible' paths. Ground is
not ground. Edges have families of spectral lines. The Kiwi has a low
noise floor. Watch out.

I tried to document a USB/Wifi solution to this on the forum. For that I
provided WiFi router PS over the single USB A cable connecting the
Kiwi/router. There was therefore no opportunity for a current loop
within the kiwi/BBG or current injection from the LAN cable.



On 7/14/21 5:59 PM, VE3VXO wrote:
> I think I'm missing something here.  You keep mentioning wired LAN
> connections.  I'm talking about running the SDR stand alone with wspr
> daemon running on the same pi that is connected to the SDR hardware
> and no LAN connection at all, but just logging spots to an internal
> file for upload at a later time.  I still don't know if it is possible
> to run wspr daemon the way I propose and how wspr daemon software
> would connect to the SDR software in this case, ...I suppose through
> defining a common port or using a third application which acts as a
> virtual port, I am no expert on the like but wouldn't this get around
> virtually (no pun) all the connectivity issues that cause ground loops
> and common mode noise injection?




>

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