[time-nuts] Re: SDR radios - Loran-C & WWV

[Scott Newell]

At 08:42 PM 3/12/2024, John Ackermann N8UR wrote:

>There are two or three different activities going on. One uses 
>dedicated receivers called "GRAPES" while others use the wsprdaemon 
>network I mentioned.  You can participate no matter how close you 
>are to totality -- the ionospheric effects extend over a pretty 
>large area.  'm not up on all the details but the https://hamsci.org 
>site has a bunch of information on all of this and I'd suggest checking there.

I did read through a bunch of the hamsci google groups messages and 
am considering a GRAPES1 (from the emails, it sounds like they're 
really cutting it close on GRAPES2), but I'd have to rig a GPS locked 
LO. The RX888 is appealing due to grabbing all the WWV/CHU frequencies.


>horsepower, but I've run the RX888 with ka9q-radio at 64 msps (32 
>MHz bandwidth) on an Orange Pi 5 and similar SBCs like the RPi 5 
>should work.  The RPi 4 is probably just at the edge.

I do have an uncommitted RPi4 on hand.


>(though whatever is consuming the data might).  And, with 
>multicasting you can have receiver processes on other computers on the LAN.

I'm wired gigabit here at the house, so that shouldn't be an issue for me.


>Did I mention that it's cool? :-)

Yeah, I think you and Mr. Bulte have convinced me to see if I can 
find an RX888 vendor that can deliver in time.


At 02:07 AM 3/13/2024, Wilko Bulte wrote:

>I found that having a fast USB3 interface (as in a sensible datapath 
>on the  mainboard, not just a blue USB connector)more important.

I've been there before with a Saleae Logic Pro 16 USB3 streaming 
logic analyzer--USB3 card wouldn't keep up, and they tracked it down 
to the PCIe slot not being fast enough.


>So, I would stay away from the Atom boards, the i3 and probably the 
>Xeons (are those server mainboards). Pick the i7 boards and try.

The Atoms are cute little Compulab Fitlet2 and Fitlet3 mini-PCs that 
we use for industrial automation projects. The Xeons are 
decommissioned CAD boxes (Dell Precision workstations--I still like 
'em for daily drivers and fileservers due to the ECC memory). The 
i7-5500U is a busted up laptop, but the i7-4790 is a decent desktop 
(not sure why it was retired...maybe someone wanted a new PC?).


Thanks for the advice!


-- 
newell  N5TNL