Carl Blare - Start Date: June 4, 2011
Recent Updates: July 23 / July 26 / July 29 / Aug. 2 / Aug. 24, 2011
Outgrown from the Talking Pixie2 SW Project
The web location for the continuing thread for this project is http://www.part15.us/node/2870
| F.C.C.
Part 15.225 Operation within the band 13.553-13.567mHz. United States Only 15.225 Operation within the band 13.110-14.010 MHz. |
At the outstart this was not a complete proven circuit. The project opened with a wish list of features and an estimated circuit.
The objective was to refine the circuit until it met the requirements of 15.225.
Participation via Big Talker Blog at part15.us - Please do not e-mail this website regarding this project.
Wish List of Features
¤ Proven oscillator circuit from Pixie2 Transmitter
¤ Buffer Amplifier Stage
¤ Class C Final Amplifier
¤ User Variable Output Power Control
Big Talker Version 1.0.0 Starting Circuit
SPECIAL -- ONGOING CHANGES TO MODULE 2 - Q2 BUFFER AMP
V 1.0.0
V 1.0.1
V 1.0.2
V 1.0.3
SPECIAL from Radio 8Z - The actual simulation
V1.0.3_8Z
V 1.0.4
Power Supply V1
NOW...PRESENTING...TWO FINAL VERSIONS THAT PASS ALL TESTS !!!!!!!!!!
The schematic here shown contains TWO renditions of the Buffer Amp Q2
Parts List - Version 1.0.3b and V 1.0.4c
Updated 8/24/11
ALL VERSIONS
C1 = 100pF
C2 = 220pF
C3 = 82pF
C4 = 1uF 50V
C5 = 470uF/50V [ not installed in the test models at this time ]
C6 = .01 [Also suggested are .047 or .1 ; this part is an RF supressor but might roll off high audio frequencies.]
C7 = .01uF
C8, C9 = 270pF
C10 = .1
C11, C14 = 1uF
C13 = 10uF 50V
R1 = 47k
R2 = 1.2k
R4 = 240 ohms
R5 = 5k variable
R10 = 50 1-Watt non-inductive
R12 = 50k Audio Taper Potentiometer
R13, R14 = 47k
R15 = 20k
-----------------------------------------------------------------------
MODULE 2A - The Radio8Z Q2 Buffer
R3 = 820
R6 = 4.7k
R7 = 1k
R8 = 220
R9 = 39
R11 = 22
C12 = 560nF / .56uF
D1 = 1N914 / 1N4148
-------------------------------------------------------------------------
MODULE 2B - The PhilB Q2 Buffer
R3 = 820
R6, R7 = 50k
R9 = 560
C12 = 560nF / .56uF
ALL VERSIONS
L1 = 22uH
Submitted by scwis
on September 18, 2009
In the document linked in the Talking Pixie post above the
output filter is shown in the XMTR schematic and the component values
are supposed to be shown using the fliter page link. That link is dead
but even if it wasn't it's no help - I checked it on the Internet
Archive and none of the values specified were for 13.5x anyway. John
Smick suggests a better design and calculated the proper values, shown
below. Figure
10 - 13.560 LP Filter
L2, L4 = 1uH
L3 = 1.5uH
T2 = 70.7V Sound System Type Audio Transformer 1-to-4 Watt Atlas Sound LT-72-4W
X1 = 13.560mHz Crystal ICM Catalog# 434368
Q1, Q2, Q3 = PN2222A
IC1 = Velleman P1823 1A Power Supply & Regulator
IC2 = LM 317 [Pin Diagram] and Heat Sync (see below)
IC3 = Velleman K4001 7-Watt/8-18VDC/0.5A Audio Amplifier
S1, S2 = Standard Toggle Switches
F1 = Fuse Resettable, 9.75A-H, Jameco Part# 199891
BNC Female R58 Chassis Mount Connector Jameco Pt.# 658427
ADDENDUM ADDED Jul. 24, 2011
Modifications to the Velleman P1823 Power Regulator Board
Bypass all four diodes with .1uF capacitors
Add Heat Syncs to all LM317s
Jameco Item# 34121 Heat Sink Mount Kit for TO-220
Jameco Item# 236823 Heat Sink , TO-220, 1-hole
OPTIONS
Metal Cabinet of Your Choice
L.E.D. Light
Meters
Safety Ground by A.C. Power Ground or Dedicated Ground Connector
A.C. Filtering
ANTENNAS & FILTERS
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