[Skimmertalk] Follow-up on Skimmer with rtl_hpsdr (dongle driver)

[John Ackermann N8UR]

Good news --

I've been exchanging emails off-line with N1GP and he's pushed updates 
to the librtlhpsdr github that fix my problem.  With the latest code, 
Skimmer Server now connects to rtl_hpsdr just as it should (you get one 
Skimmer error at the beginning, but on the second try it connects and 
works fine).

I'm hoping to have a proof-of-concept system running during the VHF 
contest this weekend.  We won't have great antennas, and the poor 
dongles will have to deal with KW amps in the same building (at the N8ZM 
contest site in SW Ohio), but hopefully we'll get a chance to at least 
try things out.

Thanks, Rick!

73,
John
----

On 01/16/2018 03:47 PM, John Ackermann N8UR wrote:
> Update:
> 
> I was able to contort things into working, and actually capturing a 
> spot.  The condition was:  Skimmer was running but rtl_hpsdr was not, so 
> Skimmer was reporting "No HPSDR Receiver Found".  Then I started 
> rtl_hpsdr and on the next attempt, Skimmer found it and connected.  I 
> sent a CQ (into dummy load) and it was spotted.
> 
> I have not been able to reproduce this, though. :-(
> 
> Right now, I'm working on capturing the ethernet packets between the two 
> machines in the hopes that might help the developers figure out what's 
> going on, because I'm at a loss.  Stand by.
> 
> John
> ----
> 
> On 01/16/2018 01:52 PM, John Ackermann N8UR wrote:
>> Well, I think that Skimmer Server and the N1GP/NO1D rtl_hpsdr driver 
>> *want* to work together, but just can't quite make it work.  Here's 
>> where things stand now.
>>
>> 1.  I was able to connect the Skimmer Server to a Red Pitaya and 
>> capture spots, so the Skimmer (and RBN Aggregator) functionality works.
>>
>> 2.  I was able to connect to the rtl_hpsdr box (Raspberry Pi 3 with 
>> from 1 to 4 RTL-SDR.com dongles connected) with the HDSDR receiver 
>> software and successfully tune and listen to various frequencies with 
>> one dongle (though the tuning was a little flaky -- sometimes I had to 
>> stop and then restart HDSDR to get a new frequency to "stick".
>>
>> 3.  I was also able to receive 4 bands simultaneously from rtl_hpsdr 
>> and 4 dongles using a Gnuradio with the N5EG Hermes receive block.
>>
>> So, both ends of the system seem to work.  But when I try to connect 
>> Skimmer Server to rtl_hpsdr, this is what happens:
>>
>> 1.  On the first attempt after a reboot of both systems, Skimmer 
>> Server says "Too Many Receivers Connected".  rtl_hpsdr shows a 
>> discovery request, and receipt of a "Stop" command (but not frequency 
>> set or "start" commands).
>>
>> 2.  If I close Skimmer Server and restart it, on the second attempt I 
>> usually get a "divide by zero" error window, but Skimmer starts.  This 
>> time it usually says "No HPSDR Device Found".
>>
>> 3.  If I then restart rtl_hpsdr and restart Skimmer (without rebooting 
>> the machine), Skimmer will usually connect.  BUT -- as far as I can 
>> tell, it's not receiving/decoding any data.  I send CQs (into a dummy 
>> load) but nothing shows up.  I don't know how to tell anything further 
>> about where the receiver is tuned, or whether Skimmer is actually 
>> receiving spectrum.
>>
>> I suspect there is something in the startup handshake sequence between 
>> the two programs that is not correct.  If I can get Wireshark to work 
>> on the Raspberry Pi, I'll try to capture the connection sequence to 
>> see what's going on.  Wish me luck...
>>
>> 73,
>> John
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