A group of hams here in the Northwest are using the incoming weather from the Pacific ocean as a scattering medium of UHF signals for making 10 GHz and 24 GHz contacts.  This is being done from the comforts of our homes in normal ham settings, not on hill tops. Two stations aim their antennas at a common spot of sky.  This spot is a Common Volume and is usually ( but not necessarily) half way between the two stations and from 10k to 30k feet in altitude. 

    This propagation is called scattering and is been observed often by UHF hams and all we need is some sort of weather related signal scattering media.  This is what we are studying.  This is the same scattering media observed in the middle of the US during their large thunderstorm build ups.  But alas, here on the west coast, we don't get this type of weather very often.  The one thing we do have is eastward flow of Pacific storms into our area to provide the media to scatter our signals. More information on this subject is available in a pdf file from the July/August 2003 QEX article , authored by W7PUA, W7LHL  (SK) and W7SZ

     We also have the main west coast north south commercial airplane traffic pattern inline with our test area and an occasional airplane flying through this common volume makes for a large signal reflector of our signals back down to let us know our equipment is up and operating.  This provides peace of mind when no signals have been observed for a long time and we start to think the equipment on either end may have failed.

    This group of hams, W7PUA, W7SZ, KD7TS, W7SLB (SK)  W7HXM, W7YOZ, KK7B, and W7CQ meet almost every morning at 8:30am on 3,818 kHz  to discuss ideas, what is going on, and what we have observed and the weather.  That brings us to the reason for this page.

    Here on this web site we are gathering weather data to try and make some sense of the signals we are seeing or not seeing and making this data available to the group.  Some of these observations come from just looking out the window, and other data is gathered from weather balloons KUIL and kSLE that are launched from several spots around the northwest every 12 hours.  Other gathering is done with the 4km and 2km Green GOES satellite pictures, Isobar Maps of the most of the Northern Hemisphere, Portland Rain Radar, and Composite West Coast Radar.  Until it switched to a digital format in February 2009 the signal strength data from TV station channel 24 in Portland, Oregon (on 531mhz, about 125 miles away) was being gathered and saved by an automated program on an old DOS computer.  We have to figure out a new plan for this operation. Any ideas on how to monitor digital tv signal strength would be helpful.

We use information from the above data on this page,  signal data from our DSP-10's, a Software-design Radio by W7PUA, and audio files saved from Spectrum Lab by DL4YHF to gather info.  Many hours of semi automated  transmitting and receiving are required.  Lots of Excel files and charts are being passed back and forth. Screen grabs of signals on the DSP10 saved to study.  All these go together to help us in our search for information and understanding of the relationships involved.

     However our most useful observations have come from the GOES West satellite pictures shown at the top of this page. Satellite computer generated pictures  WV4 4km gif  and  WV4 2km gif  files are updated every half hour.  After many years of looking at these satellite pictures, as we now call them Green GOES,  we have now decided to analyze the data contained in the pictures to our advantage.  The pixels of the gif files are color coded by temperature so we have chosen to calculate the temperature of the cloud tops of the Common Volume to see if there is any relationship between signals and temperature in scattering medium we are using.  The real understanding will come from analyzing the transition from no signal to that of marginal signals. Though most of our work is in the 10 GHz and 24 GHz bands,  we are looking at any vhf to uhf freq to help in obtaining this understanding.

    Below is a cropped picture of a GOES satellite 4km file like the one at the top of the page.  If you look closely you will see I have placed colored dots on the photo that represent a 4km pixel from the original gif file.  A yellow dot is placed to the left of each of the ham call letters, and a white dot to the right weather balloon call letters.   The two white pixels are the launch sites of weather balloons from Salem, OR (KSLE) and Quillayute, WA (KUIL).  The red pixels represent the calculated common volume between ham stations.  Currently we are gathering temperature data from the two white pixels and the six red pixels for the temperature data file described below. The yellow dots represent the home QTH of the five hams involved in this experiment. The data gathering points we are using are all subject to change at any time. Other interested hams are welcome to join in this process.  Contact me by clicking on the airplane e-mail at the bottom of the page.

    A computer program, written by W7PUA, locates and calculates the Celsius temperature, using the color / temperature chart below, of each desired pixel location on the new half hour satellite WV4 gif file.  The program then records the data in temperature data file called get_wv4_degc.txt  (described  here)  The last 72 hours of data (144 lines) from that file are then uploaded every half hour to this web site.  As this program runs, and a complete data set is archived on my old slow 486 DX66 ham shack computer.  There is a place for "old" computers other than the garbage pile.  Reuse is the better form of Recycle.

This color chart shows the Celsius temperature used for the WV4 km file.

    The GOES weather satellite measures temperatures at the top of the cloud cover. These temperatures, in Celsius, are calculated and their colors are displayed in the 4km Green GOES gif file box we display at the top of this page.

  Taking into consideration the curvature of the earth,  the calculated Common Volume between KD7TS and W7CQ, a distance of  239 miles (385km),  is located at an altitude of  9500 feet (2.9km) and at a distance of 119 miles (192km) from each station when their antennas at  0º of elevation and aimed at the horizon.  If KD7TS were to elevate his antenna the intersect point in the common volume will move higher in altitude and closer to him. This allows KD7TS, with his elevation control, to choose a point in the sky that possibly has better reflecting media.  Maybe a higher cold front that is closer to him as seen in the current  green GOES satellite pictures of the moment.  W7CQ would not have to move his elevation control. This very situation is being used with the 10ghz W7CQ/b beacon presently aimed at Seattle where KD7TS lives.