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The new NOAA satellites, NOAA 18 and NOAA 19 are using new transmission frequencies for APT transmission. The new frequencies, 137.100 and 137.9125 MHz are not programmed into the 2716 EPROM of the WEPIX 2000B receiver, so I have calculated the required programming data for them, as shown in the table below.
Since the design of the WEPIX receiver will only accept frequency steps of 5 KHz or 10 KHz, the new 137.9125 frequency cannot be exactly programmed, so I chose the closest values above and below that frequency. The error is only 2.5 KHz, so either channel should be able to receive the APT signal with minimum degredation. Due to doppler shift, the recption may be slightly better on one channel while the satellite is approaching, and it may be better on the other channel as the satellite moves away from your location.
Bank 2 of the EPROM does not need to be changed, if you are happy with the existing frequency programming.
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