Monday, April 30, 2007

AM frequency change in Hawaii

Honolulu, Hawaii: 880KHz:
KHNR has moved from 870 to 880.
2,000 watts fulltime, non-directional


Anonymous said...


870, KHNR, HI Honolulu - Licensed for U3 50000/50000, KHNR has a CP to move to 880 kHz with U1 10000/10000, sharing the tower with co-owned stations KHCM, KGU, and KZOO. This amendment requests U1 2000/2000. A special condition of the KHNR construction permit limits the field strength that may be present at the FCC’s Waipahu, Hawaii monitoring station, which limits the KHNR antenna input power to approximately 2600 Watts. So the licensee has reduced the requested power to 2000 Watts (Bill Hale, AM Switch, NRC DX News May 16 via DXLD) However, we recently had a report they had already moved to 880 (gh, DXLD)

Glenn, Both 870 and 880 are silent at this time. I don't think they have been diplexed (quadplexed?) into the 690, 760, 1210 tower yet. Funny that they have to reduce power to 2,000 watts, as both 690 and 760 run 10,000 watts on the same tower. It could be because of the FCC monitoring station, but it could also be a reduction to protect mainland stations on 880, without having to run a directional antenna, as it is a change in frequency, and a whole new set of protected contours on 880 comes into play. Regards, (Brock Whaley, HI, May 6, DX LISTENING DIGEST) (via Glenn Hauser)

Doug Smith said...

My guess is 690 and 760 get to keep 10kw because they were already using it when the policy was adopted. But that's a guess...

The amendment application specifically confirms Bill Hale's comment, that the power reduction is due to the Waipahu Monitoring Station and that the original 10kw permit already met all provisions of 73.37 and 73.182 with regard to interference to existing stations/applications.

There is a typo somewhere, the limitation is 2,060 watts. (not 2,600) 73.31 provides for rounding of power levels, and this is where the 2,000-watt figure comes from.

It is of course impossible to keep a transmitter precisely on authorized power. The FCC allows a tolerance of 90-105% of authorized power for radio stations. (it's 80-110% for TV) 2,060 watts is well within this tolerance for a station licensed for 2,000.