Phx FD issue?

[chrisareston]

All
I still have not purchased a digital scanner yet, waiting for the money. From what I read though the fire has not gone digital because of issues of signal in buildings. I have put the following freqs in my Pro 97 and I can hear all the dispatches, but I never hear the actual units on scene, are there other freqs I need to put in to hear the units at the scene?

These are what I have in right now, I got them from this site.

Frequency License Type Tone CH Description Mode
154.19000 KBH507 BM 173.8 PL A01 White-1/Blue-11 Dispatch (Phoenix) FM
154.25000 KBH507 BM 173.8 PL A02 White-2 East Phoenix FM
154.07000 KBH507 BM 173.8 PL A03 White-3 West Phoenix FM
154.28000 KBH507 BM 173.8 PL A04 White-4 Mutual Aid FM
153.83000 KBH507 BM 173.8 PL A05 White-5 Northeast Phoenix FM
154.31000 KBH507 BM 173.8 PL A06 White-6 Northwest Phoenix FM
154.14500 KBH507 BM 173.8 PL A07 White-7 Tempe FM
153.77000 KBH507 BM 173.8 PL A08 White-8 South Phoenix FM
155.67000 KOA519 BM 173.8 PL A09 White-9 West Phoenix FM
151.37000 KOA519 BM 173.8 PL A10 White-10 Far North Phoenix FM
154.02500 KOA519 BM 173.8 PL A11 White-11 Scottsdale FM
155.77500 KOA519 RM 173.8 PL A12 HAZMAT FM
154.43000 Blue-1 Chandler FM
155.95500 Blue-2 Chandler FM
154.08500 BM 173.8 PL B12 Blue-12 Buckeye FM

Thanks

[Duditz511]

Unless your close enough (within a few miles from the unit transmitting) - you are not going to be able hear the actual units, only dispatch. I forgot the exact reason for this, but unless your listening on the digital side, your only going to be able to hear dispatch.

-Dylan

[Exsmokey]

The VHF system uses simplex with many satellite voting receivers, many of them located at fire stations throughout the city. The digital system uses several repeaters in a complex way I can't remember right now. I don't think the issue of using digital vs. VHF analog is so much about tall buildings, it is about units in tactical situations not being able to hear each other on the new digital system because even the tactical traffic has to go through a repeater. Sometimes two units can be line of sight with each other and only one or neither will be line of sight with a repeater, tempting the question "why don't we just shout at each other or use hand signals?"

I think there are some issues with digital when using simplex as well. The original question concerning high buildings cites a legitimate issue as some radio systems have had to employ low powered repeaters or antenna systems that act somewhat like a repeater by carrying the signal to the exterior of building.