On Tuesday afternoon, an old problem resurfaced in regards to the OEMC CFD Fire consoles and the city's P25 trunking system. One of the dispatchers started noticing on EMS North that she started having issues hearing ambulances responding. The first thought (I'm sure this was thinking from the P25 UHF conventional system), was to have everyone use the portables instead of the rig radios. That shortly turned out to be not the issue. What I was noticing, is this issue was isolated to a certain area. Instead of using a portable at the OEMC when this occurs, they started going into panic mode and told everyone on EMS North to switch to the "back-up/old" EMS North channel. This soon followed to fire, then south EMS and Fire.
As I mentioned in previous posts, Harris consoles are used and linked to the Motorola system. I learned this personally when I was at Midway Airport and it was explained to me by a Harris tech who was there when we were having connectivity problems. He was able to reset the ISSI link, called the OEMC and had them also rest the link there.
Time passed on, I left there and started hearing CFD test without a radio ID showing (one of the signs the dispatch is using a Harris console) on a Motorola system. CFD started having interference issues, and they started using the city's 800 system as primary.
Some of problems do continue on the 800 system, but it's more user related than system related. Some of the dispatchers have a tendency to be very low, while others sound good. One possibility is certain consoles are being used which were set to lower transmit audio, while others were not touched, but not sure. I also notice channel selection is still problematic...."switch to fireground, you're still on Main/Englewood.". This surprises me until I realize many new promotions have happened in the last year, and firefighters being promoted to Lieutenant aren't normal radio users and get caught up in the moment when you're looking at a house on fire.
As of this morning (I just posted on the other 460Mhz thread), they tested with the Command Vans on the Citywide Fire Back-up channel. This channel is in the FD800 code plug, and would be a better choice if the ISSI issue happens again instead of having everyone scrambling looking for the Zone selector switch (in my opinion). I don't have any solid opinions/rumors if/when they're going to go to the new 460 Mhz. Some of the things heard: Sept 2023 (nope, not then), to Jan. 2024 (nope, not then), to "put on hold indefinitely" (well, ok), to a user reported "maybe July 2024" to a friend telling me he heard from a chief "sometime after the DNC" (the latest opinion/rumor). I've yet to hear any testing of the new digital frequencies since last year, have heard the back-channels in use now and then, but no grid testing, console testing etc. that I previously heard when we went from analog to digital which took 6 years to go on line. Chicago politics have changed, the VHF analog system had some racial slurs, open mics which moved things along. This isn't the case now since the system is generally working. But...ya never know what is in the works!
ISSI Information:
