June 02, 2003
The graphs below were recorded by the Elfrad Group in the Netherlands and are another enigma. Dave is using the exact same type of equipment and antenna setup as used at ELFRAD NC. The first graph shows the entire selected area, 1 hour long, and focusing on the P & S section. The signals were sampled at 100 S/per second. This type of pulse chain is quite frequent although differs in sections and timing. Sometimes it appears that not one transmission is the same as the last, and are not exactly repeated.
This second photo indicates the FFT for the whole 60 minute time period.
The next photo shows the expanded view of the shaded P & S area shown in previous graph indicating timings etc. For instance, the first block in the chain could be the "Start" pulse for the beginning of the transmission
The next graph shows an expanded view of segment A, clearly showing the difference in the pulse blocks.
This next graph shows section B, the first block in section A, with much faster pulses lasting almost 5 seconds.
next photo is the FFT for this section. Strong single pulses for the
duration at 16 hertz
The next graph is an expanded view of the second pulse in section A, with a duration of 6.4 seconds.
FFT below is of the above graph, multiple frequencies are visible, with a
primary freq of 1.6 hz.
have seen 100's of these type of pulse chains over the last several years. They
are increasing in frequency of sending and improving their pulse shapes.
We still have no idea where they originate from or what they are used for. There
are several combinations and more information will become available from data
stored and constantly being recorded.