Why does KIPA have spotty reception on Oahu?

[IBadget]

I have been noticing that the Big Island's KIPA AM 620 has spotty reception on Oahu. I can pick up KIPA in Waipahu, Manoa (where the University of Hawaii is), Waikiki, Kailua, and eastern Oahu. However, I can't pick up KIPA in downtown Honolulu, e.g., King and Punchbowl, or Kalihi. Does anyone have any idea why KIPA can't be heard in downtown Honolulu nor Kalihi yet can be heard in Waipahu, Manoa, Waikiki, Kailua, and eastern Oahu?

I would also like to predict KIPA's reception on other islands. I expect KIPA to have a better signal on Maui because Maui is closer to the Big Island. I also expect KIPA's signal to be worse or nil on Kauai because Kauai is farther from the Big Island than Oahu is. Because of the nature of AM signals, I expect KIPA to reach Kauai and all other islands at night. Is my prediction correct?

[craigwatanabe]

Re: Why does KIPA have spotty reception on Oahu?

I would imagine that Downtown Honolulu's tall buildings create a lot of shadow for a signal from the Big Island to overcome. Of course the two biggest shadows would be Mauna Kea and Haleakala. Mauna Kea effectively isolates Hilo from the rest of the broadcast world so I would imagine the same would hold true for Oahu.

[mel]

Re: Why does KIPA have spotty reception on Oahu?

Doesn't KIPA also have a transmitter in Kona? I know I have caught it on the Diamond Head lookout. The station has been off and on over the past couple of months. When I was in Honokaa for about 2 weeks earlier this month, I got nothing, even when I was in Hilo.... not that I went out of my way to listen. Fact is I ended up listening to Mynah Bird on KHBC when I drove into Hilo one Tuesday morning. In Honokaa the AM reception is not as good as it used to be for some reason. KLEO FM really dominates the airwaves in Honokaa... more so that KAOI which has long been a fixture in that area.

As for Downtown Honolulu, I concur on the poor reception of KIPA or any other neighbor island radio station... tall buildings and other interference.