Does the LHBP Control coverage cover all the high traffic?
It varies depending on how the sectors are configured. When it's slow all altitudes are covered, then as traffic increases the airspace is split vertically by altitude as required. The radio is covering the low altitude frequencies so during peak times you are usually only hearing traffic at FL340 and below (varies). Also you can not always hear the west side controller on 133.20, must use different transmitter sites.
Personally I would not add any more frequencies to the present setup, it gets extremely busy at times and would just be too congested. The way it is set up now works well because the frequencies monitored by the radio will automatically adjust as the sectors are reconfigured as required by the amount of traffic. (all frequencies are cross coupled so you can hear the aircraft even though the radio is not monitoring that actual frequency). A better solution would be to wait for another radio dedicated to some of the higher altitude frequencies. IMO.
The last time I checked the channel setup looked like this.
West Sectors
132.300 = FL320 and below
128.105 = FL330 to FL340
127.105 = FL350 to FL360
132.055 = FL370 to FL380
135.205 = FL390 and above
East Sectors
120.375 = FL320 and below
128.955 = FL330 to FL340
135.555 = FL350 to FL360
136.380 = FL370 to FL380
132.790 = FL390 and above
Backup frequencies
130.575
133.535
By noting cruising altitudes or handoffs of climbing and descending traffic you can determine what vertical configuration the controller is using. The slow time when all altitudes are covered is usually between 22 and 03 UTC.
Thanks to the volunteers who set up the radios. If more radios can be added to cover the higher sectors I would be happy to donate to help.
Attached below is a sector map I put together of the area (must be logged into forum to see it)