On what frequency range do keyless entry fobs transmit?

Automotive keyless entry systems typically operate at either 315MHz or 433MHz. If you use an RTL-SDR you can pickup the signals. There are also aftermarket antennas specifically tuned to pickup these signals. Depending on the transmitter, you may also be able to get an antenna+decoder pair that will decode/decrypt the (probably) encrypted signal.

Despite these systems typically being encrypted, they very well may be vulnerable to practical attacks. Theese systems are generally designed to hinder sniffing and/or forging a valid message (given the proper hardware), but many implementations are flawed. KeeLoq is popular a popular algorithm, but it's vulnerable to replay attacks as well as being weak enough to be reasonably brute-forced.

160mhz on FM analog will pick up frequency