A common issue, due to multipath interference issues with the simulcast sites.
Surprise PD is on both Simulcast G, and the White Tanks IR site. You're picking up the White Tanks site clearly, because there is no multipath interference from it. Simulcast G has multiple sites, all transmitting on the same frequencies. If the signal from multiple sites doesn't arrive at your antenna at exactly the same time, and they won't due to varying distances from the sites to your antenna, the signals can, and frequently do, cancel each other out. (Kind of like what happens when two users key up at the same time on an analog conventional channel, and one user isn't sufficently stronger than the other.) Commercial grade radios costing several times what our scanners do, can better handle this.
El Mirage PD and Phoenix FD are not carried on the White Tanks IR. They're on Simulcast G. Without finding the "sweet spot" inside your home, or using a directional antenna and experimenting with the best direction to point it in order to minimize the multipath issues, you're not going to have much luck. (I have the same problem here trying to listen to Glendale PD, El Mirage PD and the FD K-deck TG's, as well as Phoenix PD 800 and 900, Avondale PD and Goodyear PD, all of which are carried on G. Peoria PD is on both G and the White Tanks IR as Surprise is. Phoenix PD 200 is carried on the Thompson Peak IR which has no multipath issues.)
K-6, the primary TG used for EMS calls by the Northwest Valley FD's, is sometimes carried on the Towers Mtn IR, but it is not consistent. (Similarly, K-2 is sometimes carried on the Thompson Peak IR.) However, the more exciting EMS calls, such as mountain rescues and multi-victim car wrecks, are on K-10, K-11, and K-12, which I haven't yet caught on the Towers Mtn IR.
All of the K-deck TG's used to be carried on the various IR's (Towers Mtn, White Tanks Mtn, North Mtn, South Mtn, Thompson Peak) full time, however, they were taken off them right before the Superbowl in Glendale, and have not returned.
John
Peoria
