Their frequencies are:
127.3 153.890/154.310 *FIRE Houston (backup system?)
none 154.160 *FIRE Houston Pager (decreased usage)
127.3 453.425/458.425 *FIRE/EMS Houston Ch.A1 Dispatching, D1-simplex
127.3 453.500/458.500 *FIRE/EMS Houston Ch.A2, D2-simplex
127.3 453.675/458.675 *FIRE/EMS Houston Ch.A3, D3-simplex
127.3 453.950/458.950 *FIRE/EMS Houston Ch.A4, D4-simplex
127.3 460.575/465.575 *FIRE/EMS Houston Ch.A5-Secondary TAC, D5-simplex
127.3 462.950/467.950 *FIRE/EMS Houston Ch.A6-Secondary TAC, D6-simplex (radio check 6:00am-7:30am daily)
127.3 462.975/467.975 *FIRE/EMS Houston Ch.A7-Secondary TAC, Lifeflight, D7-simplex
127.3 460.625/465.625 *FIRE/EMS Houston Ch.A8-Secondary TAC, D8-simplex
127.3 463.000/468.000 *MEDICAL Houston EMS Hospital-Ambulance Ch.B1 Channel assignments
127.3 463.025 *MEDICAL Houston EMS Hospital-Ambulance Ch.B2
127.3 463.050 *MEDICAL Houston EMS Hospital-Ambulance Ch.B3
127.3 463.075 *MEDICAL Houston EMS Hospital-Ambulance Ch.B4
127.3 463.100 *MEDICAL Houston EMS Hospital-Ambulance Ch.B5
127.3 463.125 *MEDICAL Houston EMS Hospital-Ambulance Ch.B6
127.3 463.150 *MEDICAL Houston EMS Hospital-Ambulance Ch.B7
127.3 463.175 *MEDICAL Houston EMS Hospital-Ambulance Ch.B8
154.890 POLICE Houston (licensed for 1 5W unit for data)
158.985 POLICE Houston (licensed for 1 5W unit for voice)
123.0 453.650/458.650 *POLICE Houston Radio Shop w/ph. patch, called "650"
none 155.670 *POLICE Houston Pager, Motocycles?, Reliant Astrodome?
123.0 460.325/465.325 *POLICE Houston Ch.A1 North/Shepard Patrol B
123.0 460.125/465.125 *POLICE Houston Ch.A2 Northeast/Kingwood Patrol C
123.0 460.025/465.025 *POLICE Houston Ch.A3 Southeast/Clear Lake Patrol D
123.0 460.050/465.050 *POLICE Houston Ch.A4 Southwest/Fondren/Beechnut Patrol E
123.0 460.425/465.425 *POLICE Houston Ch.A5,B5 Citywide (HISD trunk 02-030, STAR-NET trunk 6544)
123.0 460.100/465.100 *POLICE Houston Ch.A6 Central Patrol A
123.0 460.350/465.350 *POLICE Houston Ch.A7,B7 Special Ops M,Y,Z
123.0 460.225 *POLICE Houston Ch.A8,B8 Car-Car Simplex
123.0 460.550/465.550 *POLICE Houston Ch.A9 South Central/Magnolia Patrol H
123.0 460.450/465.450 *POLICE Houston Ch.A10,B1 Investigations/Detectives 1xxx,2xxx
123.0 460.475/465.475 *POLICE Houston Ch.A11 Northwest Patrol F
123.0 460.150/465.150 *POLICE Houston Ch.A12 West Patrol G
123.0 460.375 *POLICE Houston Ch.B2 "TAC 1"
123.0 460.525/465.525 *POLICE Houston Ch.B3 "525"
123.0 460.075 *POLICE Houston Ch.B4 "075" Narcotics surveillance
123.0 465.375 *POLICE Houston Ch.B6 "TAC 2"
123.0 460.400/465.400 *POLICE Houston Ch.B9 Vice, Narcotics, CID
127.3 453.700/458.700 *POLICE Houston Ch.B10-Bush Airport 21I10-50 (linked to 453.900)
453.550 *POLICE Houston Ch.B11 Car-car with other agencies (rarely heard)
123.0 453.900/458.900 *POLICE Houston Ch.B12-Hobby-23J50/Ellington-23J40 Airports (link to 453.700)
123.0 465.225 *POLICE Houston Ch.C8 SWAT
I got these
here