shave 50 mils off SMA end of PCB to allow for SMA flange to be inside box

diff --git a/Notebook b/Notebook
index 7deb6349bdc9ebe0d0ee33ed8d2ea7b4701354d5..1b9250391473d22640746dfb9f57ddbbb809b068 100644 (file)
--- a/Notebook
+++ b/Notebook
@@ -39,3 +39,35 @@
 
   Rough estimate of cogs puts us at retail price of $150
 
+2011.04.13
+- Pondering how much to clip off the SMA end of the PCB to ensure the SMA
+  flange fits inside the box.  
+
+  Our connector needs 3.81 mm "above" the PCB which for TeleBT actually 
+  means between the PCB bottom surface and the base of the box.  The box 
+  boss height is specified as 4mm, so that fits in a purely vertical sense,
+  but I'm worried about the box wall to base radius, and the fact that the
+  box walls aren't exactly vertical.
+
+  Hammond doesn't specify the radius between the wall and base of the 1551K
+  box.  Given other things they do specify, it might be that 1 mm is a
+  conservative guess.  The specification for the inside dimensions of the lip
+  around the lid is 10 mils smaller than the max PCB dimensions, and it *looks*
+  like that inside edge might be about where the wall radius ends.  The drawing
+  shows the lid inside as 6.73mm less than box outside dimension, which seems
+  reasonably consistent with my estimate of a 2mm wall thickness, about 1mm
+  for the lid lip, and some mold tolerances.  So, let's use the box lid lip
+  inside dimensions as a proxy for the box base inside dimensions until proven
+  otherwise.
+
+  So we need to peel 5 mils off to account for the box radius.  The flange
+  itself is 40 mils.  And I'm nervous about the guesstimates so I'll add 
+  another 5 mils of margin.  So we need to take 50 mils off the SMA end of
+  the PCB.
+
+  As a sanity check, on TeleDongle the closes screw hole is 78 mils from the
+  SMA edge of the PCB, which is 50 mils less than a maximum-size PCB would
+  have.  If anything, the TeleDongle SMA ends up inside the wall a bit more
+  that necessary, such that tightening the SMA nut deflects the wall inward.
+  So, 50 mils might indeed be a good choice for TeleBT.  We'll give it a try!
+

diff --git a/telebt.pcb b/telebt.pcb
index 81b57eb0bc59d5316e44b8eae14edb541be45f84..0e965c1fcd391e1dff7c02f7e4c8cf94042faa0b 100644 (file)
--- a/telebt.pcb
+++ b/telebt.pcb
@@ -1565,17 +1565,16 @@ Rat[169274 42907 1 192094 110098 1  ""]
 Rat[192094 110098 1 241801 119108 1  ""]
 Layer(1 "top")
 (
-       Line[287402 133854 24606 133854 100 2000 "clearline,lock"]
+       Line[286338 24606 286338 133854 100 2000 "clearline,lock"]
+       Line[286338 133854 24606 133854 100 2000 "clearline,lock"]
        Line[24606 133854 24606 121063 100 2000 "clearline,lock"]
        Line[12795 109252 0 109252 100 2000 "clearline,lock"]
        Line[3927 0 266732 0 100 2000 "clearline,lock"]
-       Line[291339 24606 291339 129921 100 2000 "clearline,lock"]
-       Line[278543 24606 291339 24606 100 2000 "clearline,lock"]
+       Line[278543 24606 286338 24606 100 2000 "clearline,lock"]
        Line[266732 0 266732 12795 100 2000 "clearline,lock"]
        Line[0 109252 0 3937 100 2000 "clearline,lock"]
        Arc[3937 3937 3937 3937 100 2000 270 90 "clearline,lock"]
        Arc[278543 12795 11811 11811 100 2000 0 90 "clearline,lock"]
-       Arc[287402 129921 3937 3937 100 2000 90 90 "clearline,lock"]
        Arc[12795 121063 11811 11811 100 2000 180 90 "clearline,lock"]
        Polygon("clearpoly,lock")
        (
@@ -1589,16 +1588,15 @@ Layer(3 "outline")
 (
        Line[3927 0 266732 0 1000 2000 "lock"]
        Line[266732 0 266732 12795 1000 2000 "lock"]
-       Line[278543 24606 291339 24606 1000 2000 "lock"]
-       Line[291339 24606 291339 129921 1000 2000 "lock"]
-       Line[287402 133854 24606 133854 1000 2000 "lock"]
+       Line[278543 24606 286338 24606 1000 2000 "lock"]
+       Line[286338 133854 24606 133854 1000 2000 "lock"]
        Line[24606 133854 24606 121063 1000 2000 "lock"]
        Line[12795 109252 0 109252 1000 2000 "lock"]
        Line[0 109252 0 3937 1000 2000 "lock"]
        Arc[3937 3937 3937 3937 1000 2000 270 90 "lock"]
        Arc[278543 12795 11811 11811 1000 2000 0 90 "lock"]
-       Arc[287402 129921 3937 3937 1000 2000 90 90 "lock"]
        Arc[12795 121063 11811 11811 1000 2000 180 90 "lock"]
+       Line[286338 24606 286338 133854 1000 2000 "lock"]
 )
 Layer(4 "silk")
 (