[Skimmertalk] My QS1R died during CQ WW CW

Jeff Maass K8ND jmaass at k8nd.com
Mon Dec 8 04:06:03 EST 2014


For the PJ2T Skimmer Server, Jim W8WTS added vent holes and a fan to the
QS1R case. This receiver (and its associated PC) ran for 5 years in a space
that did not normally have air conditioning (in the Caribbean), with ambient
temperatures cycling between 85 and 95 degF. No failures.

There are some photos of the modified case among the assembly photos for our
hardware at: https://www.flickr.com/photos/jmgalm/sets/72157625138658540/ .

The PJ2T Skimmer Server was relocated this past month to a new location in a
private business' data room, where the temperature is consistently < 70 degF
(and where the tower is ~50 feet higher!) 

73,  Jeff  K8ND

-----Original Message-----
From: Skimmertalk [mailto:skimmertalk-bounces at contesting.com] On Behalf Of
Bob Wilson, N6TV
Sent: Sunday, December 07, 2014 10:19 PM
To: SkimmerTalk Reflector
Subject: Re: [Skimmertalk] My QS1R died during CQ WW CW

Update:  local SDR expert WA6KBL determined that the 1.2V voltage regulator
chip on my QS1R board, which feeds the FPGA hardware, seems to have failed.
  The measured output voltage was only about 0.8V.

Apparently this is not the first time this chip failed when someone was
running Skimmer Server, which really taxes the hardware.  This chip gets
really hot.

WA6KBL is going to experiment by replacing it with a different voltage
regulator, perhaps one with a heatsink bolted to the side of the case.  If
anyone has already gone through this exercise, or added a cooling system to
the QS1R, please share.

I'm encouraging WA6KBL to write up the modifications once testing is

Bob, N6TV

On Tue, Dec 2, 2014 at 8:21 AM, Bob Wilson, N6TV <n6tv at arrl.net> wrote:

> It appears that my QS1R had a hardware failure just after 0947z 
> November 30th (during CQ WW CW), after it ran Skimmer Server 
> continuously for a couple of days.
> Rebooting Windows and power cycling the SDR makes no difference.
> Skimmer Server reports an error and repeats "Reloading FPGA."   CW Skimmer
> reports "FpgaCommand/usb_control_msg failed."  HDSDR reports "Cannot 
> read from SDR".
> The red PWR LED on the QS1R is lit, and the USB device is detected OK 
> by the Windows device manager (under "libusb-win32 devices/QS1R Direct 
> Sampling Receiver", so I suppose the power supply is OK (it's the 2A 
> supply).
> Maybe it overheated?  Time for a new QS1R board?  It's an older one, 
> not of recent generation.  Has anyone else on this list experienced a 
> similar failure?
> 73,
> Bob, N6TV
Skimmertalk mailing list
Skimmertalk at contesting.com

More information about the Skimmertalk mailing list