This is the place to discuss generalized scanner questions and information for San Diego County. Whether it's radios, antennas, or other general scanner related topics, you can talk about it here.
It could be a ambulance from another city/etc. With a radio in this area.
bringing up the repeater site in San Marcos.
I belive that is part of the fisherwireless.com 'Passport' system.
since you should hear the 'handshake(Data Stream)' every 3-5 seconds.
It's a very nice system!