Recently I've looked at two other ways to observe pings. The web site LiveMeteors.com uses a well established technique which listens to the carrier signal from a Canadian TV station with a VHF receiving station in Washington DC. I've had good results in using the audio piped into a PC sound card then to a waterfall spectrum analyzer, Spectrum Lab. Figure 1 is a typical recording.
|Figure 1. Typical Ping Recording for One Hour|
|Figure 2. Luminosity Histogram|
|Figure 3. Frame Selection for Pings Histogram|
This procedure was applied to a 24 hour set of grabs made in one hour increments during a recent meteor shower and plotted to produce Figure 4. The results shows the expected variation with maximum pings around Sunrise and minimum around Sunset.
|Figure 4. Results Obtained with Mean Luminosity Assessment of Pings per Hour|
It is by far the quickest way to analyze pings I have tried. Once the workflow was established I found it took only a few minutes to determine the histogram data for each one hour grab. Any method of quantifying meteors is relative since any measurement scheme counts pings only in a given field of view. What I like about this method it that it takes into account pings of all size and strength right down to the background noise..
A second method utilizes receiving stations on the KIWI network which are tuned to strong stations such as WWV and CHU. The audio is fed into my PC as described above and produces similar output. . Both stations emit strong, omnidirectional signals which are on the air 24/7 day in and day out. The KIWI receiver network consists of dozens of KIWI-SDR receivers located around the World and controllable by the user via an Internet connection. Figure 5 is a compilation of several combinations made back in late April as a first look at the feasibility of the method. I have lately explored this in more detail with CHU on 14700 kHz using the KIWI receiver of W1NT in New Hampshire. The antenna at W1NT is a 500 foot Beverage aimed northeast
|Figure 5. Feasibility Study of Using KIWI Receivers to Measure Pings from WWV and CHU|
Note the two horizontal lines at the center shown at higher resolution in Figure 6 where we see there is actually a third line in between. This is the well known and commonly seen effect of backscatter