The modules you have, that is without both the PA and LNA, are normally the least troublesome of the 2 variants.
Are both modules powered by a USB cable derived from the same PC ? If so, it would be interesting to know if powering say the Transmitter part with a smart phone charger or similar would give different results.
Both modules are very close to your notebook PC and the WLAN frequencies can clash. Can you also try switching off the WLAN on the PC ?