{"id":653,"date":"2026-07-15T12:21:36","date_gmt":"2026-07-15T11:21:36","guid":{"rendered":"https:\/\/ei4hq.ie\/test\/?p=653"},"modified":"2026-07-15T12:21:36","modified_gmt":"2026-07-15T11:21:36","slug":"ei4hq-navtex-spectrograms-for-2026-07-july","status":"publish","type":"post","link":"https:\/\/ei4hq.ie\/test\/2026\/07\/15\/ei4hq-navtex-spectrograms-for-2026-07-july\/","title":{"rendered":"EI4HQ NAVTEX Spectrograms for 2026-07 (July)"},"content":{"rendered":"\n

Here’s you’ll find links to a daily spectrogram for the NAVTEX MW sub-band, recorded at Cobh, Cork Harbour, Ireland, IO51uu during July 2026. I started saving these in June 2026. Spectra for previous months are available on the NAVTEX<\/a> page.<\/p>\n\n\n\n

Each spectrogram covers a 16h 44m period, that being the length of the longest night of the year here, with 15m added before sunset and after sunrise to capture enhanced reception that sometimes occurs around sunset or sunrise. Each spectrogram starts at 1608z and ends at 0852z the following morning.<\/p>\n\n\n\n

Along with each image, there is also a processed version courtesy of my radio friend and keen NAVTEX DXer, SWL Tobias. Tobias has written software that takes my spectrogram as input, and processes it to create a high contrast version, to convert the timescale to UTC and to add NAVTEX slot letters. Thanks Tobias!<\/p>\n\n\n\n

Each unprocessed spectrogram image is 2556×1569 pixels in size. Tobias’ processed images are 2048×2048 pixels in size:<\/p>\n\n\n\n