some radio goals visual module based construction technique module start: top layer - simple block diagram of the part encapsulated as a module as a clear color-coded graphic pass-through interfaces to LED power and function indicators pass-through interfaces to test probe points next layer - wiring diagram in block schematic form as in SDR paper radio. as a clear color-coded graphic pass-through interfaces to LED power and function indicators pass-through interfaces to test probe points next layer - physical devices, PCB, wiring and interconnects next layer - interfaces to power, global grounds and signal I/O module end. tray start: next layer - interfaces to power, global grounds and signal I/O next layer - test probe layer next layer - structural support layer next layer - cosmetic appearance layer next layer - connection to other trays layer tray end. trays that test specific modules "written in itself" so to speak instrumentation and visualization of function at each step. tablet based oscilloscopes and function generators ------ implement hartley oscillator, colpitts oscillator, pierce oscillator, czeck oscillator as part of regenerative, heterodyne, superregen and superheterodyne radios. use these as soft radios by connecting I/Q to downsampled RF output sections. create corresponding transmitters and web-interface radios. ------ what i really want is this, and I'm doing everything above to visualize its expression in an understandable way to share with others. i want to be able to tune into any modulated RF signal from DC to daylight and determine, with a network of similar receivers, the origin of that RF signal so I can map its location, its origin and its content. this includes signals reflected from the space fence and aircraft radars and multipath bounces. i want to do this in a specific way. i want two stations, A and B to listen to two frequencies simultaneously. The first signal, the time base, is continuously available to A and B and radiates from a known location. The second signal, the unknown, radiates from an unknown location. A and B each digitize RF coming from each of the two RF frequency sources. === They then exchange datasets. === They COULD exchange datasets, but that would be very resource intensive, since digitized RF is so voluminous. INSTEAD they agree on a feature in the RF pair they heard and compare the timings of the appearance of the feature. See "Feature Extraction from RF below" They then determine the time offset of the unknown through a compact iterated time computation accomplished through the exchange of messages. They then report to each other what the time offset was of the unknown. This reporting can be done via transmitted RF, or the internet, preferably both, preferably simultaneously. One of the design goals is redundant modalities. With four such stations the location of the unknown can be ascertained according to the intersecting hyperboloids equations of time of flight. (work this). Known stations can be GPS, another WWV, another unknown broadcast sources. I do not want to rely only on GPS, but I want it supported because of its accuracy. I want to establish high accuracy using other known sources and path calibration techniques. Unknown stations can be broadcast radio, shortwave, space fence reflections, astronomical sources, etc. It may be that the shared station varies between pairs of listeners, in this case the listeners may listen to three frequencies simultaneously and so on. Calibration. Measurements can be calibrated by listening to two knowns and studying the variation in time of arrival to determine the certainty of position. This calibration can be continuous or intermittent as precision requires. I want to build several of these stations to build a proof of concept and demonstrate it as a education, scientific and motivational tool. I want the deployment platform to be packaged as in the construction techniques section above. I want to deploy it in kit form to develop skills in building and understanding. I want to be the Dan Poynter of electronic kits, the designer's designer, the butler's butler as it were. ---- Feature extraction from RF Lets say A and B each take their pair of digitized RF signals. Let's say they transmit to each other a time to start listening and a time to stop listening, (see ping pong calculation) OR that they use an agreed upon third party time to start listening and a time to stop listening, (WWV or GPS) (they can either transmit this or agree upon it a priori) OR that they agree to use a trigger in the known or unknown signal to start listening for a specified interval AND in that case, they agree to EITHER a) listen for a specified time OR b) agree to use a trigger in the known or unknown signal to stop listening AND that this trigger can be EITHER i) an above threshold event OR ii) a falling below threshold event AND that this trigger can be in the space of A) amplitude OR B) frequency OR C) phase Now consider a few concrete examples 1) A mixes its signals S1 and S2 to produce sidebands at S1 + S2 and S1 - S2 Algorithm Given two overlapping events, each of 5 seconds duration from two observers A and B stored as an audio buffer: Find the region of overlap and characterize it. Find all the common features in clip A and clip B Determine the time interval between the features.