I have all the sites in Colo Springs programmed in, the one closest would be Fountain Valley. I am really not interested in listening to anything but fire, so not sure on SO or anything else for that matter.
The law enforcement side was more to see if you can still monitor the system, but just aren't getting traffic from the fire side. It can be used to get a sense if you have a loose/bad connection or interference working. The
DAT symbol on your BCD536HP would also be helpful for determining if your losing your signal or have interference. If the
DAT symbol goes away, your scanner doesn't lock onto another site, and manually listening to a known control channel frequency near you (like Fountain Valley) results in white noise or no noise, then that a strong indication of interference or a bad connection as others are suggesting.
I would suggest getting rid of anything that's not a Zone 4 site (anything not 4xx), Cheyenne Mountain being the biggest one to get rid of if you have it. It's actually set to deny access to CSFD and El Paso talkgroups since the Colorado Springs area has other sites. A statewide system does not mean that traffic is carried on all sites at all times, it is very dependent on radio uses in the area and how they are programmed.
If you're monitoring from a stationary location and not being mobile, it's probably worth it to be very selective about which site you have programmed in. Not all the sites in El Paso County carry CSFD/Red at all times. I don't do much monitoring in the El Paso County area so I'm relying on data available from the sites in the area. I'll try list them starting from best to good sites. You can test them by trying to listen to the red control channel frequencies listed in the database and figuring out which sound clearer (I liked to describe the sound as if it were "grinding"). Anything outside of the sites below is likely are not worth being programmed.
Generally the best site for El Paso County overall is
Stanley Canyon if you can pick it up. It's a bit north so there's a fair chance you won't be able to monitor it, but it should pretty much cover most of El Paso County at all times.
Templeton Gap doesn't look like a bad choice for CSFD/Red if you can hear it. Given your possible location, you might not be able to follow either of those sites so
Ski Summit and
Peterson Air Force Base would be good for monitoring CSFD (not sure about El Paso County Red).
Fountain Valley is a maybe due to it's location. It looks like it carries CSFD and Red a majority of the time give the data I've seen, but I'm not 100% sure of that. The last sites to consider would probably be Cedar Heights and Austin Bluffs if you're looking to experiment a little with finding optimal sites.