The idea behind QRSS stacking is simple: If you have a bunch of QRSS grabs (signal + random noise), averaging the images
together will cause the signal to pop out above the noise. This is because noise is random, and averaging randomness
eventually produces zero. Averaging a small, weak signal eventually produces something "a little more than zero". Think of
QRSS stacking as helping weak signals pop out above the noise.
For QRSS stacking to work, each image has to be perfectly aligned. The tradition in QRSS is to (a) tell the QRSS keyer to
repeat exactly every 10 minutes, (b) configure the QRSS listening software to make 1 full screen scroll every 10 minutes, and
(c) upload the grabber file every 10 minutes. With everything aligned to 10 minutes, it's easy to download the grabber file
every 10 minutes and average them together -- they will already be aligned!
So, if you haven't already, consider configuring your grabber to capture and upload images
aligned to 10 minutes.
Bill (W4HBK) has a great tutorial on how to set up a 10-minute grabber using Spectrum Lab:
Peter (Zl2iK) sent me a Spectrum Lab
user file designed to create grabs 10
As of this moment (July, 2016) it seems Argo is incapable of producing 10 minute grabs
suitable for image stacking :(
Here are examples of single (left) and 1-hour (6) stacked grabs (right).
I think the advantages for seeing weak signals are obvious!