The generator running the Spectrum Sweep has a loading error (LE::w23160342572). I only have this issue when running the Spectrum Sweep - so far I have not encountered it with any other protocol.

1. When you start a fresh frequency set the Serial port used is very busy for a few seconds loading the waveform. The sweep also puts a loading on its serial port. Sometimes this can mean that one will slow down a little, but not stop a generator. You have a top quality USB hub.

The only thing I can suggest from here is to try the sweep generator plugged direct into the computer if possible.
I have occasionally found some redundant program running in the background that polls the USB, but because you can reproduce your problem I think the serial ports are just not keeping up. Is there a driver for the USB hub that can be updated?

I use Process Explorer to check processor use in case something is grabbing too much of the CPU, free downloadable and does not need installation.

If your channel numbers (Com port numbers) are not consecutive then sometimes "Phantom Ports" can cause a problem, I posted a fix for this several months ago.

2. With a normal program, Spooky2 issues on average one update every 3 minutes to a generator -- the update being to switch to the next frequency, the 3 minutes being the standard default dwell.

With the spooky spectrum sweep, it will be issuing a command update 8 times a second (default), or twice the # you have as the gate rate -- even if the gate is not in use. This is because it is constantly moving the target frequency through the sweep.

When you search the database, make changes to another generator, or do anything that adds load the the CPU or communication channels (like starting a new program which first uploads the waveforms), it can saturate your computer's resources and cause one of the commands to go unanswered by the generator. This has a lot to do with the fact that the serial communications in use over the USB port, is not governed by any hardware flow control.

The LE field just shows you what the last command was that was sent that resulted in an error. The RE field shows how many have errors have occurred since Spooky2 was started, or since last time errors were cleared. The CE field will show what generator was last in error.

When a command is missed, usually Spooky2 will re-issue the command. In the case of the sweep, nothing was lost if it was just one command missed.

For more details, please check the link:
http://www.spooky2.com/forums/viewtopic.php?f=39&t=5387