As I previously stated Strawberry only provides partial coverage of the high desert. San Bernardino County Fire transmits at 35 watts into a 6db gain antenna from 1860m (6100ish feet). Using the standard 90% coverage standard (90% coverage 90% of the time) you will see that Strawberry does not provide a 90% coverage using HT's. HT's are the primary radio when used on scene. Thus, Quartzite is the high desert primary site. Strawberry can only handle a portion of the populated land mass.
The radio coverage prediction map previously shown is based on handheld receive signal strength at the repeater site. Handhelds are the primary means of communications on scene. Fireman and Deputies don't go back to their unit to speak with dispatch. In most cases they use their handheld on their hip with a microphone that comes up and over their shoulder.
The profile used to represent this map was a handheld 1.8m above ground (5' 10") with a zero gain antenna and 3 Watts RF output. This is the standard profile for 90% coverage 90% of the time. The APCO standard. Of course a 15 watt mobile with the 3dB gain antenna would do much better.
When the radio is on the hip the body can act as a wall between the user and the repeater site they're talking into thus decreasing the signal strength even more than what the prediction map shows.
Research has shown that the body acts as it does because positioning a large human body between the transmitter's antenna and the receiver's antenna can cause a degradation in RF performance. The human body is made up primarily of "salt water." Salt water is an effective absorber of RF energy. That's why submarines need to surface to send out a radio signal.
If you put an HT on your hip and do a 360° turn while listening to the transmitter you will hear in most cases the transmitter fading in and out as you turn. This has been well known for years. It's more prevalent at the higher frequencies. In fact on transmitter hunts that ham radio operators do they routinely hold an HT to their body and turn their body until they can peak or null the radio signal that they're hunting for.
Overall, this is why there is a need for more transmitter locations than might normally be required. I can tell you that on BDC V2 and V3 they work fantastic in the desert because they are VHF. The 800MHz system requires more repeater locations. BDC V2 transmits from Heaps Peak, the Big Bear sheriff station, Onyx Summit, and San Savine, which is Lytle Creek. Heaps peak in particular provides excellent coverage of the high desert. I speak from experience. I can't say whether or not the Onyx Summit repeater is on the air yet since a fire recently destroyed the main building and a second outbuilding. Once firefighters got on-scene they reported that both structures were burned to the ground.
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