A customer responded that he was using a “…direct to ground connection with a ground rod. The direct to ground connection seemed to [quiet] some of the extra noise on the receiver.” I assume that he had tried using just the counterpoise first and it was noisy.
If you are using the matchbox with a counterpoise or just relying on your coax to provide the counterpoise for RF and you notice the antenna seems noisy, try the ground rod method. Besides the potential noise reduction benefit, you’ll also provide a path to ground that will bleed off any static buildup on the antenna–a good safety feature.
As always, it it good to experiment.