From 325022580392dd8c217deeb192e1b31f4b66ed10 Mon Sep 17 00:00:00 2001 From: Mark Allyn Date: Sat, 9 May 2026 21:15:26 -0700 Subject: [PATCH] change order of sections --- CLAUDE.md | 71 +++++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 53 insertions(+), 18 deletions(-) diff --git a/CLAUDE.md b/CLAUDE.md index 10298ad..ce87cdf 100644 --- a/CLAUDE.md +++ b/CLAUDE.md @@ -1,6 +1,5 @@ This is a project for a museum to demonstrate a simulation of a 1940's to 1960's vintage radar, including the Chain Home radar from early World War 2, marine radar, -and air traffic control radar The project will be implemented on a Geekom A8 Max 32 GB RAM @@ -53,6 +52,8 @@ This is a museum exhibit displaying and providing some interaction of vintage 1940's, 1950's, and 1960's radars. A key objective is to provide interaction with and viewing of radars from that era. + + There will be three main areas of the screen. On the right hand side will be the radar scope. @@ -67,7 +68,7 @@ Scopes in the right panel 1. Introduction of Exhibit (Explanation of the project on the left hand text panel. 2. A-scope for Chain Home Radar in the 1940's (first radar and could be tricky) -3. A-scope for marine radar in the 1950's (Before PPI radar); was a bit tedious to operate +3. A-scope for marine radar in the 1940's (Before PPI radar); was a bit tedious to operate 4. PPI scope for marine traffic control (uses beam sweeping in all 360 degrees of rotation); Easier to use than a scope 5. PPI scope on board a boat. Shows how movement of a boat affects the radar display @@ -134,13 +135,20 @@ There will be three abstracts for scopes: null points for each target. Since we do not have a physical calibrated knob, we can put the bearing as a text indicator below the A Scope. + There would be four other controls. 1. Intensity 2. amplifier gain 3. STC gain 2; stc + range + The range is 200 miles. - There is a glass or plastic graticule that is etched with vertical lines - representing range. This is edge-lit with incandescent lamps. + There is no graticule. Photos only show crystal oscillator generated 'pips' for + every 20 miles. + Marine A Scope + Utilization of A scope marine was limited to military use prior to PPI scope + invention. An example is British Type 271 radar, introduced in 1941. + Marine radar frequencies allowed the use of much smaller antennas; dishes or horns. Those antennas would be mounted on the shaft of a servo motor. The servo motor would be driven by another servo that is attached to the bearing control @@ -162,23 +170,50 @@ There will be three abstracts for scopes: Following the width, the pip has a finite fall time as the transmitter stops. This creates a curved waveform; not just a line. - Range and range lines on graticule + A photograph for this display show no graticule at all. Only range pips formed by an oscillator. - Please note that the graticules are plastic overlays over the screen. They need to be removed - and replaced when the operator changes the maximum range. This can be simulated with the graticule - being lifted toward the top of the scope as it is removed. Then the new graticule would be slid - down until it covers the scope. The graticule will be edge-lit with an incandescent lamp. - - Here is a table of the available ranges and what markings will be on the plastic graticule. - - 1. 1.5 miles; markers every 0.25 miles - 2. 3.0 miles; markers every 0.5 miles - 3. 6.0 miles; markers every 1.0 miles - 4. 12.0 miles; markers every 2.0 miles - - There would be four available plastic overlays. + 1. 1.5 miles; marker pips every 0.25 miles + 2. 3.0 miles; marker pips every 0.5 miles + 3. 6.0 miles; marker pips every 1.0 miles + 4. 12.0 miles; marker pips every 2.0 miles Range can be selected with two keyboard keys or two buttons on the panel, and is indicated in the text status panel below the scope. + Controls: 1. intensity 2. receiver gain 3. STC (I think) that reduces gain close in. 4. STC effective + range for STC effect. + 2. PPI Scope - still being worked + + + +================================== + +RADAR EQUATION + +Lets start here by mentioning the radar equation that sets the perceived strength of any +radar echoes, no matter what kind of radar. + +Summary of radar equation: + +The fundamental radar equation describes how much power returns to a radar system +after bouncing off a distant target. Physically, it follows a "round-trip" journey +of energy: the radar transmits a signal that spreads out as a sphere (losing strength +by the square of the distance, $R^2$), hits a target that reflects a portion of that +energy (the Radar Cross Section, $\sigma$), and that reflection then spreads out +again as a second sphere on its way back (losing another factor of $R^2$). Mathematically, +this results in the received power being inversely proportional to the fourth +power of the distance ($1/R^4$), meaning that if a target moves twice as far away, +the returning signal becomes 16 times weaker. To calculate the final received power +($P_r$), you multiply the transmitted power ($P_t$) by the antenna's ability to +focus that energy (Gain, $G$) and its physical size (Aperture, $A$), then factor +in the target's reflectivity ($\sigma$) and the wavelength of the signal ($\lambda$), +all while dividing by the spreading losses $(4\pi)^3 R^4$. +$$P_r = \frac{P_t G^2 \lambda^2 \sigma}{(4\pi)^3 R^4}$$ + + +Since we had four distinct radar types, and each one has it's own hardware loop gain +that does not change, we can set that as a constant in each radar's target handling shader set. + + +======================================