When I worked for Metro West Amb in the early 90's, I remembered seeing both call signs, I think it might be the old UHF Medical Channels. Med 9 462.9500 / 467.9500 -Multnomah County EMS and Med 10 462.9750 / 467.9750. Not to age myself but I think Med 9 was Portland/Multnomah County EMS Dispatch and Med 10 EMS Dispatch for Washington County. Lifeflight used one of them as well -Med 10 I think.
--- Does any agency still use the UHF med channels anymore?? They are listed in the NIFOG (Natl Interoperability Field Operations Guilde. 1/2011 edition.
Hmm, the licenses show 460.15 and 465.15, 460.375 and 465.375 with repeater locations at each of the main sites in Washington County, first licensed in 2005 and set to expire in 2015.. There's no text in the narratives or anything listed in the ULS. Just that they are public safety. So I guess it could be a backup?
Dunno... last time I was over in Tillamook during the summer they were dispatching ambulances on the county fire freq. Didn't hear so much as a peep over the UHF Med channels, but was only monitoring for a day. Perhaps they are using them for ambulance to hospital comms if needed.
Metro West IS VHF - both emergency and non-emergency dispatch. A few years back, they got into a scuffle with the FCC over an expired license. Their repeater (if I recall correctly) is up in the west hills, near the KOIN TV and other broadcaster towers. Sometimes you can hear them on the UHF channel, too, but it's been a while. Since I'm so far south, I usually only get the dispatcher and not the units' traffic.
The UHF licenses are indeed from the pre-trunked 800 MHz days. The licenses are maintained as a backup, but are regularly used for Search and Rescue by the sheriff's office explorer post. They are also available for use as an emergency "bandwidth expander" should the need ever arise. This used to be a voting system, but now the repeaters are all stand-alone units.