KVM70 NOAA Honolulu, Hawaii Radio Fax

Another good radiofax station for DXing is the KVM70 station at Honolulu, Hawaii run by NOAA. This station sends faxes almost continuously around the clock and at least one frequency is usually observable, although sometimes interfered with and or weak. The transmission centre frequencies are as follows (all of them have been observed at home):

  • 9982.5khz at 4kW
  • 11090khz at 4kW
  • 16135khz at 4kW

Signals from Hawaii are often affected by doppler spreading giving straight vertical lines a “jagged” look – that’s the nature of the analog transmission system.

All transmissions from KVM70 have some unusual characteristics. For example – the shift seems to be slightly reduced from the 800hz standard shift being somewhere around 700-720hz shift. All the faxes begin with a black thick line which extends about 80% of the way across the image before the actual image data begins to be sent – this seems to be common to all NOAA transmissions. No tuning tone is transmitted before the fax – the fax begins directly with a start tone, and once completed, the signal goes off air without sending any white/black trailer. The sync pulse is a black area as well, which is the reverse of what I’m used to from VMC/VMW.

Here are some faxes from KVM70 received very recently … with any luck, I may be able to claim a QSL from NOAA.

26th January 2013 – KVM70 11090khz ending 2005EDT (UTC+11)

wefax_20130126_200507_0_gui

26th January 2013 – KVM70 11090khz ending 2014EDT (UTC+11)

wefax_20130126_201430_0_phasing

26th January 2013 – KVM70 11090khz ending 2029EDT (UTC+11)

wefax_20130126_202922_0_nocorr

26th January 2013 – KVM70 11090khz ending 2042EDT (UTC+11)

wefax_20130126_204221_0_nocorr

28th January 2013 – KVM70 11090khz ending 2107EDT (UTC+11)

wefax_20130128_210715_0_nocorr28th January 2013 – KVM70 11090khz ending 2119EDT (UTC+11)

wefax_20130128_211926_0_nocorr

28th January 2013 – KVM70 11090khz ending 2201EDT (UTC+11)

wefax_20130128_220115_0_nocorr

28th January 2013 – KVM70 11090khz ending 2213EDT (UTC+11)

wefax_20130128_221358_0_gui

28th January 2013 – KVM70 11090khz ending 2227EDT (UTC+11)

wefax_20130128_222709_0_gui

28th January 2013 – KVM70 11090khz ending 2239EDT (UTC+11)

wefax_20130128_223909_0_gui

As you can see, the propagation is stable – although affected by doppler shifts. Unfortunately, where I am, I can’t get a larger antenna in to get a better signal …

UPDATE: This appears to be what happens when they aren’t able to fax …

wefax_20130203_042435_0_phasing

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