It sounds like you may have a dual band set up or the wifi chip in either device is creating a network that the other chip is unable to communicate with. If it is not visible at all it is likely a hardware limitation.
Mac's and Ipad's both support the 5GHz range I believe and if that is the case, and you android device doesn't, then this is why your network is not visible to your android device.
5GHz was originally used for 802.11a (before b, g, and n) which supported 54MBps and has more recently need adopted to be usable for 802.11n at 150MBps+. If your n capable device doesn't also support a then it won't be able to see the 5GHz band (this may have changed more so recently since a is outdated and some n's could simply have been adapted for use with 5GHz).