It is always wise to backup your SHSH's, either using the "make my life easier" option in Cydia or by downloading tinyumbrella if you want to save them locally to your PC. Search for further details and instructions.
As regards your "slight signals issues", you could do with providing more info. Do you mean 3G or WiFi?
It is highly unlikely the jailbreak caused anything to happen to your "signal". JB is just a way to provide root access to your device. It doesn't mess with things like wi-fi and 3G.
If you installed a specific jailbreak application with accesses the signal, then perhaps, but unless you provide more details it is difficult to help further.