X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=Notebook;h=a888776dd20edbeceda1b3c9a16676eddac11a1e;hb=9b056f1d2c0a94ec3dafb4c119c4e5c36f1f1804;hp=c9e696478a784ea12a17f321ee898c853a16a405;hpb=eca9452fefe5f9fbdf6924b18cad25f93997138a;p=hw%2Ftelemega

diff --git a/Notebook b/Notebook
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+++ b/Notebook
@@ -112,4 +112,76 @@
 								i2c2
 						bootloader intf	usart1
 								usart2
+To Do
+
+- tweak up the paste mask dimensions and so forth on BMA250.py, which is sort
+  of crude at the moment .. see page 68 of the BMA250 data sheet
+
+2011.11.29
+- Eleazar Zuniga <ezuniga@taoglas.com> says in email of 28 Nov 2011 that we 
+  should be able to use any of the pin or SMT patches other than the 35mm ones,
+  as long as we have ground plane under the patch itself that's as large as the
+  patch or bigger.  I'm not sure I believe that, but adding an 0402 site to 
+  ground for a tuning cap ala what the chip antenna docs call for might be a
+  reasonable thing to try?
+
+  pinned versions
+
+    GP.1575.12.4.A.02
+	12x12x4 mm, pin plus adhesive
+	gain towards zenith -0.5 dBic
+
+    GP.1575.15.4.B.02
+	15x15x4 mm, pin plus adhesive
+	1.0 dBic at zenith
+
+    GP.1575.18.2.A.02
+	18x18x2 mm, pin plus adhesive
+	gain towards zenith -0.5 dBic
+
+    GP.1575.18.4.A.02
+	18x18x4 mm, pin plus adhesive
+	gain towards zenith +3.5 dBic
+	$4.13 at q100				*** 50% the mass of 25mm
+
+    GP.1575.25.2.A.02
+	25x25x2 mm, pin plus adhesive
+	+2.0 dBic gain at zenith
+
+    GP.1575.25.4.A.02
+	25x25x4 mm, pin plus adhesive
+	gain towards zenith +3.5 dBic
+	$4.05 at q100
+
+  surface-mount versions
+
+    SGP.1575.12.4.A.02
+	12x12x4.5 mm
+	-2.0 dBic at zenith, 4dB axial ratio, 6Mhz bandwidth
+
+    SGP.1575.15.4.A.02
+	15x15x4.5 mm
+	+1.0 dBic at zenith, 3dB axial ratio, 6Mhz bandwidth
+
+    SGP.1575.18.4.C.02
+	18x18x4.5 mm
+	+1.0 dBic at zenith, 4dB axial ratio, 5Mhz bandwidth
+	$4.94 at q100
+
+    SGP.1575.25.4.C.02
+	25x25x4.5 mm
+	+2.0 dBic at zenith, 3dB axial ratio, 5Mhz bandwidth
+
+  By comparison the data on the chip antenna from Pulse Engineering we're
+  trying out on TeleTerra is:
+
+    W3011A
+	required PCB surface around around 6x8 mm on a board edge
+	+1.0 dBic peak
+	$1.28 at q100
+
+  From all of this, GP.1575.18.4.A.02 would seem to be the clear winner.  It
+  has 2.5 dB more gain than the chip antenna at the expense of a bit more 
+  mass.  However, if the chip antenna performance is "adequate", it saves
+  surface area, mass, and BOM cost.