Ramsey Electronics WSR-1A User guide

WSR-1A•1
WSR-1A WEATHER
SATELLITE RECEIVER
Ramsey Electronics Model No. WSR-1A
Can’t trust the weatherman? Now you can be your own
weatherman with the Weather Satellite Receiver! Observe
weather events while they are happening, instead of waiting for
the news! A very sensitive receiver, the WSR-1A will return
sharp, clear, high contrast images with a maximum resolution
down to a mile! Be amazed at the new perspective you will
have on the weather and its ever-changing ways!
•High sensitivity front end for noise-free transmissions.
•Automatic scanning for all non-geo-synchronous VHF weather
satellites
•Decodes APT satellites. Ex: NOAA, Meteor, and Feng Yun type
satellites.
•Demodulating board and software available for the PC.
•Easy to follow assembly instructions that lead you through step-by-
step to a completed working unit
•All that is required to begin receiving is a demodulator board and
software.
•Preamp also included to increase the clarity of your images and
“stretch” the span of the received image.
•Fun to build and the results are well worth the effort!

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RAMSEY TRANSMITTER KITS
• FM-10 FM Stereo Transmitter
• FM-1,2,3,4 FM Wireless Microphones
• PB-1 Telephone Transmitter
RAMSEY RECEIVER KITS
• FR-1 FM Broadcast Receiver
• AR-1 Aircraft Band Receiver
• SR-1 Short-wave Receiver
• AA-7 Active Antenna
• SC-1 Short-wave Converter
RAMSEY HOBBY KITS
• SG-7 Personal Speed Radar
• SS-70 Speech Scrambler
• URC-1 Universal Remote Control
• SP-1 Speakerphone
• MD-3 Microwave Motion Detector
• PH-10 Peak hold Meter
• LC-1 Inductance-Capacitance Meter
RAMSEY AMATEUR RADIO KITS
• FX Series VHF and UHF Transceivers
• HR Series HF All Mode Receivers
• QRP Series HF CW Transmitters
• CW-700 Micro Memory CW Keyer
• PA Series VHF and UHF Power Amplifiers
• Packet Computer Interfaces
• QRP Power Amplifiers
RAMSEY MINI-KITS
Many other kits are available for hobby, school, Scouts and just plain FUN.
New kits are always under development. Write or call for our free Ramsey
catalog.
WSR-1 SATELLITE RECEIVER KIT INSTRUCTION MANUAL
Ramsey Electronics publication No. MWSR-1A Revision 2.3A
First printing: Sept 1995
COPYRIGHT 1995 by Ramsey Electronics, Inc. 793 Canning Parkway, Victor, New York
14564. All rights reserved. No portion of this publication may be copied or duplicated without the
written permission of Ramsey Electronics, Inc. Printed in the United States of America.

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WSR-1A WEATHER
SATELLITE RECEIVER KIT
Ramsey Publication No. WSR-1A
Price $5.00
TABLE OF CONTENTS
Introduction to the WSR-1A ............. 4
Parts list ........................................... 6
Strategy and Tips............................. 8
Circuit Description............................ 9
Construction..................................... 11
Schematic ........................................ 20
Casing it up...................................... 24
Initial Testing.................................... 25
Trouble Shooting ............................. 27
Antennas.......................................... 28
Building an Antenna......................... 30
Turnstile Wiring................................ 31
Preamp ............................................ 33
How To Receive a Transmission ..... 34
Parts Layout..................................... 35
Specifications................................... 36
Warranty .......................................... 37
KIT ASSEMBLY
AND INSTRUCTION MANUAL FOR
RAMSEY ELECTRONICS, INC.
793 Canning Parkway
Victor, New York 14564
Phone [phone]
Fax [phone]

WSR-1A•4
INTRODUCTION TO THE WEATHER SATELLITE RECEIVER
The days of guessing the weather by looking at the clouds overhead have just
ended. Now you can look at the clouds from above! This project will allow you
to receive pictures from satellites 600 km overhead. A typical NOAA satellite
can cover nearly 1/16 of the earth in a single pass! In New York, we are able to
clearly capture images from mid-Hudson bay (where there was still ice in late
spring), all the way down past Cuba, as well as spanning from Wisconsin to far
out in the Atlantic Ocean. The clarity of the image was enough to see the
individual Finger Lakes (in New York), and shadows on the underside of
thunderstorms.
This receiver kit allows you to receive weather satellite transmissions on the
VHF band, where most of the polar-orbiting satellites are located. You will
recognize these transmissions on the news when you see the time lapse of the
clouds darting across the countryside. The weather man in this case has taken
multiple images on the computer, aligned and pieced them together, and then
run through one image after the other. It is possible to do this same thing with
this kit and the proper software.
The way in which a weather satellite works is fairly simple. Just think of your
office fax machine as an example. The satellites circle the Earth going north to
south back to north again almost directly over the poles, which is why they call
it a polar orbit. This means that the satellite will cover every location on the
Earth at least twice per day. With a good antenna, and partly because of
overlap of consecutive orbits, you can conceivably receive the same satellite up
to six times a day! Notice though that the image received from polar orbits will
be upside down on every other pass.
The satellite retrieves the data in a linear fashion, one line at a time using a
scanning radiometer. The scanning radiometer transmits the equivalent of a
single television horizontal line as the satellite circles the earth. The system
uses a series of optics and a motor driven rotating mirror system to receive a
very narrow line of the image of the Earth. Each line is received at a right angle
to the satellite’s orbital track, so as the satellite circles the earth, a line is
received from west to east or east to west depending on the orbit of the
satellite. The total image is received from north to south or south to north
depending on the orbit also, and this motion is what relays the equivalent of the
vertical scan in a television. You can continue receiving this satellite as long as
it is within the line of sight.
Since all of the receivable satellites are similar, we will describe the ones you
will most commonly receive. The NOAA/TIROS satellites, during the first half of
the transmission, send visible light data to the receiver at the same time they
are taking in the view. Meanwhile during the same part of the scan, they are
recording the infrared view. During the second half of the scan, while the

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sensors are facing away from the earth, it sends the infrared data. The user
then sees the data as two images side by side, on the left the visible light data
is seen, and on the right, infrared data is seen. In between the images are
synchronization pulses that help computers to align the individual lines
precisely.
These particular satellites continuously transmit an FM signal modulated with a
2400Hz tone. This tone is very precise in frequency so the image seen is
aligned properly. The 2400Hz tone is AM modulated with the intensity of the
current view of the earth. The brighter or colder the point on the earth, the
higher in amplitude the 2400Hz signal is.
The receiver demodulates the FM signal and retrieves the 2400Hz tone. The
detector board in the computer will then find the peak amplitude of each wave
of the 2400Hz tone, and each peak, upper and lower now represents a single
pixel on the screen. For the NOAA/TIROS satellites, each horizontal line
represents 2400 pixels, since the incoming frequency is 2400Hz, and the
scanning radiometer rotates twice per second. The full 12 minute pass of a
NOAA satellite requires approximately 3.5 MB (3.5 million 8 bit pixels) of
storage! This is much more data (pixels) than can be seen on a super VGA
screen at any one time.
NOTE TO NEWCOMERS: If you are a first time kit builder you may find this
manual easier to understand than you may have expected. Each part in the kit
is checked off as you go, while a detailed description of each part is given. If
you follow each step in the manual in order, and practice good soldering and kit
building skills, the kit is next to fail-safe. If a problem does occur, the manual
will lead you through step by step in the troubleshooting guide until you find the
problem and are able to correct it.

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RAMSEY WSR PARTS LIST
Semiconductors
1 LM386 Audio Power Amplifier (U1)
1 MC13135 FM Demodulator (U2)
1 MC145170 Digitally controlled Phase Locked Loop (U3)
1 MC68HC705K1 Microcontroller (U4)
1 74HC138 3 to 8 Line Decoder (U5)
1 LM358 Operational amplifier (U6)
1 BB505 Varactor Diode (D1)
5 2N3904 NPN transistors (Q3,Q4,Q5,Q6,Q7)
3 2SC2498 or 2570 NPN transistors (Q1,Q2,Q8)
8 Red mini LEDs (D2,D3,D4,D5,D6,D7,D8,D9)
1 7805 5 Volt regulator (VR1)
Resistors
1 4.7 ohm resistor (yellow-violet-gold)(R9)
1 100 ohm resistor (brown-black-brown)(R30)
1 270 ohm resistor (red-violet-brown)(R38)
3 470 ohm resistors (yellow-violet-brown)(R2,R17,R32)
11 1K ohm resistors (brown-black-red) (R7,R15,R21,R24,R26,R29,R31,R34,R35,
R40,R42)
1 3.3K ohm resistor (orange-orange-red)(R14)
13 10K ohm resistors (brown-black-orange) (R1,R4,R6,R12,R18,R19,R20,
R22,R23,R27,R28,R33,R39)
1 22K ohm resistor (red-red-orange)(R16)
4 47K ohm resistors (yellow-violet-orange)(R3,R36,R41,R43)
1 68K ohm resistor (blue-gray-orange)(R8)
1 100K ohm resistor (brown-black-yellow)(R13)
1 220K ohm resistor (red-red-yellow)(R10)
1 1M ohm resistor (brown-black-green)(R25)
Miscellaneous
1 10.240MHz Crystal (Marked 10.240) (Y2)
1 10.7MHz ceramic filter (looks like capacitor with three leads in a row) (FL1)
1 450kHz ceramic filter (black cube with three leads) (FL2)
1 CBW 137MHz filter (large metal shielded can, two adjustments) (FL3)
1 10K trimmer potentiometer (yellow adjustment marked 103) (R37)
2 10K potentiometer (top mount stand up type, blue body) (R5, R11))
1 Ramsey “diddle stick” plastic tuning tool.
Capacitors
11 .001uF ceramic capacitors (marked .001, 102, or 1n) (C2,C6,C7,C14,C19,C24,
C26,C27,C36,C37,C39)
10 .01uF ceramic capacitors (marked .01, 103, or 10n) (C4,C25,C40,C41,C42,C46,
C47,C48,C54,C55)
3 100pF ceramic capacitors (marked 100, or 101) (C17,C18)
7 .1uF ceramic capacitors (marked .1 or 104) (C20,C22,C28,C33,C34,C35,C38)

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RAMSEY WSR PARTS LIST
Capacitors cont...
4 22pF ceramic capacitors (marked 22) (C29,C44,C45,C53)
1 15pF ceramic capacitor (marked 15) (C30)
2 10pF ceramic capacitors (marked 10) (C31,C32)
1 220pF ceramic capacitor (marked 220, or 221) (C52)
1 2 or 2.2pF ceramic capacitor (marked 2 or 2.2) (C8)
2 39pF ceramic capacitors (marked 39) (C11,C12)
9 10uF electrolytic capacitors (C1,C3,C9,C10,C16,C21,C49,C50,C51)
1 220uF electrolytic capacitor (C13)
1 100uF electrolytic capacitor (C15)
1 1000uF electrolytic capacitor (C5)
1 35pF Trimmer cap (orange top, silver adjuster) (C43)
Inductors
1 LB53303HK variable shielded coil (metal case with orange slug inside) (L7)
4 10uH inductors (blue-green body with brown-black-black-silver stripes) (L2,L3,
L6,L9)
2 4 Turn wire wound inductors (L4, L5)
1 2.2uH inductor (green body with red-red-gold-black stripes) (L1)
1 84885-5 Variable inductor (small metal case with green plastic) (L8)
Hardware, Jacks
1 2 pin header (P1)
1 2.5mm stereo jack (J5)
1 3.5mm phone jack (J1)
1 Power jack (J4)
1 RCA Phono jack (J3)
1 PC mount ‘F’ connector (J2)
3 DPDT switches (S1, S2, S3)
1 Buzzer Speaker (SP1)
1 Main PC Board
1 Daughter Board
2 16 Pin IC sockets
Case and knob parts
1 Case bottom
1 Case top
1 Case front panel
1 Case back panel
3 Decorative switch caps
2 Control knobs
4 Mounting screws

WSR-1A•8
RAMSEY “LEARN-AS-YOU-BUILD” ASSEMBLY STRATEGY
Be sure to read through all of the steps, and check the boxes as you go to be
sure you didn't miss any important steps. Although you may be in a hurry to see
results, before you switch on the power check all wiring and capacitors for
proper orientation. Also check the board for any possible solder shorts, and/or
cold solder joints. All of these mistakes could have detrimental effects on your
kit - not to mention your ego!
Kit building tips:
Use a good soldering technique - let your soldering iron tip gently heat the
traces to which you are soldering, heating both wires and pads simultaneously.
Apply the solder on the iron and the pad when the pad is hot enough to melt the
solder. The finished joint should look like a drop of water on paper, somewhat
soaked in.
Mount all electrical parts on the top side of the board provided. This is the side
that has little or no traces on it. When parts are installed, the part is placed flat
to the board, and the leads are bent on the backside of the board to prevent the
part from falling out before soldering (1). The part is then soldered securely to
the board (2-4), and the remaining lead length is then clipped off (5). Notice
how the solder joint looks on close up, clean and smooth with no holes or sharp
points (6).

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WSR-1A CIRCUIT DESCRIPTION
The Weather Satellite Receiver is a fairly complex receiver as compared to
most of the other receiver kits that are sold. This receiver contains circuitry
found in very high end receivers and transceivers. This is due to the high
accuracy of reception required to be able to continuously monitor various
satellite transmissions, and be right on frequency every time. The receiver must
also have a very sensitive front end for the satellites that are low on the
horizon, and also for antenna setups that can’t be optimally placed on the
Sears tower. For these reasons we will go through the receiver from the
antenna end to the speaker output, and help you understand what each section
is doing in relation to the flow chart.
If you look at the schematic provided, we will begin at J2, where the antenna is
to be connected. L1 and C4 are for the sole purpose of injecting DC into the
antenna feed line to power an external preamp. The circuitry directly after these
two parts from C11 all the way over to filter FL3 and C14, is a narrow band VHF
preamplifier. This circuitry prevents intermodulation problems and reduces the
general noise while increasing gain and reception.
This amplified signal is then seen by the MC13135 FM receiver chip (U2). This
chip performs the mixing between the PLL LO (Phase Locked Loop Local
Oscillator), and the incoming RF. Then using a detection scheme called
quadrature detection (performed mostly in L7), this part of the circuit
demodulates (converts to audio) the incoming FM signal. There is of course
much more than that to this part of your receiver, but nothing that wouldn’t be
covered in a communications handbook.
The demodulated audio signal is then passed through a low pass filter, which
Lowpass Filter

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allows only frequencies in the needed range to come through. By doing this, it
reduces the noise produced by a weak reception, since noise covers the entire
audio spectrum, but we are only interested in the spectrum around 2400Hz.
After the audio filtering, the audio is first tapped to go to a decoder card on a
PC. This way the adjustment of the volume will not alter the level of the voltage
going to the PC. Next the audio goes through the volume control before going
to the audio amplifier, consisting of U1. This amplifier is capable of putting out
some decent volume, especially combined with the efficiency of the buzzer
speaker provided with this kit.
If you look at pin 16 of U2, the receiver chip, you will see the squelch output.
The squelch is opened when the signal level of the current frequency is high
enough. In the Weather Receiver, this squelch output is used not only to switch
on the output audio when activated, but also to turn on a transistor switch
consisting of Q6, and Q7. This transistor switch allows you to turn on a portable
tape deck or some other recording device to allow you to store satellite images
onto standard audio tapes.
The same squelch signal is also fed to U4, the MC68HC705K1 microcontroller.
This lets the microcontroller know to stop scanning different frequencies while a
signal is being received. This microcontroller is able to send data to the
programmable phase locked loop (U3), and configure it for a different divide by
‘n’. This means that the phase locked loop is able to be adjusted to produce
any frequency within a range, by simply sending it a digital number from the
microcontroller. The microcontroller is just pre-programmed with eight different
numbers representing the eight different frequencies we wish to generate with
the PLL. This allows us to receive the eight different frequencies that the
satellites are on.
U5, the 74HC138 3 to 8 line decoder does just what it sounds like. The
microcontroller sends out a three bit number, or octal, which has eight
possibilities. The decoder takes these possibilities and outputs to only one of
the eight LEDs, therefore lighting the respective LED. These same decoder
chips are commonly used to access different devices on a computer, allowing
for up to eight different devices on this particular chip.
VR1 and the surrounding parts are simply a power supply. The 7805 is a
commonly used 5 volt regulator, which produces the five volts needed by the
microcontroller and display.
Well, we hope the description of this kit helps you to understand what is going
on in your receiver kit, and make it more enjoyable to assemble. Take your time
putting this together and make sure you follow all of the steps properly. We
have greatly enjoyed designing this project for you, and hope that you will enjoy
using it. Now it’s time to get down to it, and begin assembling this project!

WSR-1A•11
CONSTRUCTION OF THE WEATHER SATELLITE RECEIVER
Sort out all of your parts to begin with, making sure you have all of the parts
required. You can use old egg cartons to hold various parts to make them
easier to find. We will begin building the kit from the back side of the board
where all the jacks will eventually be placed. Make sure to mount parts on the
correct side! You will want to use the parts layout diagram to assist you in
finding where the parts go.
1. Install J4, the power jack. This will be our reference part and will help us
locate where other parts are located on the board.
2. Install C55, a .01uF ceramic capacitor (marked .01, 10n, or 103).
3. We will skip SP1, the speaker buzzer at this time. This will allow us to
mount other parts in this area more easily.
4. Install L6, one of the 10uH inductors (blue-green body with brown-black-
black-silver stripes)
5. Install C42, a .01uF ceramic capacitor (marked .01, 10n, or 103).
6. Install L9, another 10uH inductor like in step 4.
7. Install C46, another .01uF ceramic capacitor (marked .01, 10n, or 103).
8. Install L3, another 10uH inductor.
9. Install C41, another .01uF ceramic capacitor.
10. Install C40, yet another .01uF ceramic capacitor.
11. Install L2, the last of the 10uH inductors.
You have just completed some of the filters that are required to keep the RF
noise generated by computers out of the radio. This helps prevent a noisy
picture and improves reception capability.
12. Install R39, a 10K resistor (brown-black-orange). To
mount as a stand up resistor for best looks, bend the leads so
the resistor stands square to the board before soldering. Keep
it neat!
13. Install Q7, a 2N3904 NPN type transistor. Be sure and mount the flat
side in the same direction as shown on the parts layout.
14. Install Q6, another 2N3904 type transistor (Note previous step).
We have just completed the ‘switch’ for the tape cassette recorder. Now it is
time to begin working on the actual receiver’s PLL and demodulator.

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15. Install C26, a .001uF ceramic capacitor (marked .001, 1n, or 102).
16. Install R15, a 1K ohm resistor (brown-black-red).
17. Install R13, a 100K ohm resistor (brown-black-yellow).
18. Install D1, a BB505 varactor diode (orange glass body with printed
characters marking the part number). This varactor diode allows the phase
locked loop to operate by adjusting the reverse bias voltage on this diode.
This diode is the capacitive part of the local oscillator, and L8 is the
inductive part. As the reverse bias voltage across this diode increases, the
capacitance decreases, therefore the local oscillator’s frequency increases.
This circuit combined with a frequency to voltage converter (phase
detector) are the major components of the phase locked loop. Be sure to
mount this part in the correct direction. The cathode, or the striped end
should be in the same orientation as in the parts layout diagram.
19. Install C25, a .01uF ceramic capacitor (marked 103, .01, or 10n).
20. Install Q8, a 2SC2498 NPN RF transistor. This transistor has very good
characteristics all the way up to 1GHz and more. With low noise and high
gain as part of its repertoire, this part can almost put a GaAsFET to shame.
This transistor amplifies and isolates the VCO output from the PLL chip. Be
sure to mount the flat side in the same orientation as in the parts layout
diagram. Also check that it is not a 2N3904 transistor since the pin outs and
characteristics are not the same!
21. Install R41, a 47K ohm resistor (yellow-violet-orange).
22. Install C39, a .001uF ceramic capacitor (marked .001, or 102).
23. Install R40, a 1K ohm resistor (brown-black-red).
24. Install C36, another .001uF ceramic capacitor (marked .001, or 102).
25. Install R20, a 10K ohm resistor (brown-black-orange). Note this is a lay-
down resistor, and be sure to use the correct holes.
26. Install C43, a 35pF trimmer capacitor (orange top, silver adjustment).
This part will allow us to get the 10.24MHz crystal running at exactly the
frequency we desire.
27. Install R25, a 1M ohm resistor (brown-black-green).
Most of the parts we are installing right now are parts associated with the phase
locked loop. The next few parts will be associated with D1, the varactor diode.
This will make up the VCO, or voltage controlled oscillator, which will be
precisely controlled by the PLL chip.
28. Install C37, a .001uF ceramic capacitor (marked .001, or 102).

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29. Install C32, a 10pF ceramic capacitor (marked 10).
30. Install R38, a 270 ohm resistor (red-violet-brown).
31. Install C31, another 10pF ceramic capacitor (marked 10).
32. Install C29, a 22pF ceramic capacitor (marked 22).
33. Install L8, a 84885-5 variable inductor (smaller metal case with green
plastic.) This coil is the inductive part of the voltage controlled oscillator of
the PLL.
34. Install C54, a .01uF ceramic capacitor (marked .01, 103, or 10n),
located near J5.
35. Install C4, another .01uF ceramic capacitor.
36. Install Q2, a 2SC2498 NPN RF transistor. This transistor is part of the
preamp to amplify the incoming signal after the RF bandpass filter, and
boost it to a level that is usable by U2. Pay close attention to orientation!
37. Install R3, a 47K ohm resistor (yellow-violet-orange).
38. Install R2, a 470 ohm resistor (yellow-violet-brown).
39. Install C30, 15pF ceramic capacitor (marked 15).
40. Install Q1, the last of the 2SC2498 NPN RF transistors. This is the last
part of the PLL to get the VCO to oscillate. Make sure and place the
transistor in the correct way!
41. Install C27, a .001uF ceramic capacitor (marked .001, 102, or 1n).
42. Install R36, a 47K ohm resistor (yellow-violet-orange).
43. At this point you may want to check your assembly job. Check to make
sure all parts are mounted as closely as possible to the board without
sacrificing neatness, and check all of your solder joints for possible solder
bridges and cold solder joints. We don’t expect you to be an expert at
soldering right from the start, so if you take your time and check as you go,
you will save a lot of time later when you test this out for final operation.
44. Install R30, a 100 ohm resistor (brown-black-brown).
45. Install C24, a .001uF ceramic capacitor (marked 102, .001, or 1n).
46. Install C2, another .001uF ceramic capacitor (marked 102, .001, or 1n)
47. Install C7, yet another .001uF ceramic capacitor.
48. Install C12, a 39pF ceramic capacitor (marked 39).

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49. Install C18, a 100pF ceramic capacitor (marked 100 or 101).
50. Install C11, another 39pF ceramic capacitor (marked 39).
51. Install C17, another 100pF ceramic capacitor (marked 100 or 101).
52. Install C8, a 2pF or 2.2pF ceramic capacitor (marked 2, or 2.2).
53. Install L4, a four turn wire wound inductor (can’t miss em, they look like
tight springs!)
54. Install L5, another four turn inductor.
These two coils you just installed will later be stretched or bent to adjust the
center frequency of the RF bandpass filter you just completed. As these coils
are distorted, the inductance will change, allowing for fine tuning of the
reception and sensitivity of your receiver.
56. Install U2, the MC13135 FM demodulator IC. (24 pin DIP). When
inserting the chip into the IC socket, be sure all pins are properly seated
into the socket. It is very easy to have a pin bent under the chip, making it a
tough problem to find. Remember this when installing all chips! This chip as
we have described earlier demodulates the incoming FM signal using
quadrature detection and other neat features. Make sure that you have
inserted the IC in the correct way, so that the notch or dimple is facing in
the same direction as in the parts layout diagram.
57. Install C19, a .001uF ceramic capacitor (marked 102, .001, or 1n).
58. Install FL1, a 10.7MHz ceramic filter. This is a part that looks much like
a capacitor, but it has three leads instead of two.
59. Install C14, a .001uF ceramic capacitor (marked .001, 102, or 1n).
60. Install FL3. This is the large silver can with two adjustments on top. Be
careful when installing so that you don’t bend any leads over. This part is
known as a “helical filter” and filters the incoming RF even more than the
RF filter we completed earlier, and provides for excellent intermodulation
performance.
61. Install C1, a 10uF electrolytic capacitor. Notice this is the first capacitor
of this type. You want to be sure that you pay close attention to the polarity
markings on this part. In most cases the negative (-) side is marked on the
capacitor, while the positive side (+) is marked on the parts layout. If you fail
to mount this component correctly, the part can fail as well as prevent
proper operation of your project.
62. Install C20, a .1uF ceramic capacitor (marked .1, 104, or 100n)
63. Install R10, a 220K ohm resistor (red-red-yellow).

WSR-1A•15
64. Install R7, a 1K ohm resistor (brown-black-red).
65. Install R8, a 68K ohm resistor (blue-gray-orange).
66. Install R16, a 22K ohm resistor (red-red-orange).
67. Install C28, a .1uF ceramic capacitor (marked .1, 104, or 100n).
68. Install C33, a .1uF ceramic capacitor (marked .1, 104, or 100n)
69. Install R24, a 1K ohm resistor (brown-black-red).
70. Install TP4 with a 1/2” piece of scrap
component lead.
71. Install C34, another .1uF ceramic
capacitor (marked .1, 104, or 100n).
72. Install C35, yet another .1uF ceramic capacitor (you know!).
73. Install C38, even another .1uF ceramic capacitor.
74. Install C45, a 22pF ceramic capacitor (marked 22).
75. Install C44, another 22pF ceramic capacitor (marked 22).
76. Install Y2, the 10.240MHz crystal, (marked 10.240!). This crystal is the
reference frequency by which the PLL operates. All of the frequencies
produced by the PLL are referenced to this crystal’s operating frequency, so
the oscillations generated by the PLL are as accurate as the crystal is.
77. Install C53, a 22pF ceramic capacitor (marked 22).
78. Install FL2, a 450kHz ceramic filter. This filter isn’t even close in
appearance to the previous ceramic filter. This filter comes in a little black
plastic box with three leads, and only fits in its holes neatly in one direction.
78A. It is necessary to install a 100
pF capacitor on the bottom of the
board, under FL2. See the drawing
at right for correct placement of the
capacitor.
79. Install the 16 pin IC socket
where U3 is to go. Check step 56 for
more details. When done installing
the socket, install U3, The
MC145170 digitally controlled phase
locked loop. Observe the correct
orientation of the part’s notched
end. Make sure its the same as the parts layout diagram!
1/2"
PCB
Small loop f
o
test probes.
100

WSR-1A•16
80. Install C15, a 100uF Electrolytic capacitor. Pay close attention to the
polarity markings!
81. Install L7, the LB53303HK variable shielded coil. (silver metal case with
orange plastic). Solder all of the leads including the metal case pins
securely to the board.
82. Install R37, a 10K ohm trimmer pot (yellow adjustment marked 103).
83. Install R17, a 470 ohm resistor (yellow-violet-brown).
84. Install R6, a 10K ohm resistor (brown-black-orange).
Now we begin assembly of the audio stages. Since synchronization pulses of
satellite data have very distinct black to white transitions, we want those trans-
itions to appear correctly upon decoding of the data. To allow those transitions
to pass properly, we need to have a fairly wide audio response to our filter.
85. Install C3, a 10uF electrolytic capacitor. Check polarity before soldering!
86. Install R18, a 10K ohm resistor (brown-black-orange).
87. Install C6, a .001 ceramic capacitor (marked .001 or 102).
88. Install R43, a 47K ohm resistor (yellow-violet-orange).
89. Install R23, a 10K ohm resistor (brown-black-orange).
90. Install R29, a 1K ohm resistor (brown-black-red).
91. Install R26, a 1K ohm resistor (brown-black-red).
92. Install R4, a 10K ohm resistor (brown-black-orange).
93. Install C10, a 10uF electrolytic capacitor. Pay attention to the polarity!
94. Install R22, a 10K ohm resistor (brown-black-orange).
95. Install R42, a 1K ohm resistor (brown-black-red).
96. Install R1, yet another 10K ohm resistor (brown-black-orange).
97. Install U6, the LM358 dual op-amp IC. Make sure and correctly orient
pin one and the notch to the parts layout diagram. Verify that all pins are
through the PC board, then solder.
98. Install R27, a 10K ohm resistor (brown-black-orange).
99. Install R28, another 10K ohm resistor (brown-black-orange).
100. Install C9, a 10uF electrolytic capacitor. Again pay close attention to
the polarity markings.

WSR-1A•17
101. Install C16, another 10uF electrolytic capacitor. Check polarity!
102. Install R14, a 3.3K ohm resistor (orange-orange-red).
Now it is time to begin installing the microcontroller and associated circuitry. If
you haven't already, take a break and grab a Coke, relax, and get ready to
finish up the rest of your weather satellite receiver. Also check your previous
work for solder bridges and cold solder joints.
103. Install C52, a 220 pF ceramic capacitor (marked 220, or 221)
104. Install R35, a 1K ohm resistor (brown-black-red).
105. Install C48, a .01uF ceramic capacitor (marked .01, 103, or 10n).
106. Install R21, a 1K ohm resistor (brown-black-red).
107. Install Q5, a 2N3904 NPN type general purpose transistor. Make sure
that it is oriented properly!
108. Install R34, a 1K ohm resistor (brown-black-red).
109. Install U5, the 74HC138 3 to 8 line decoder. This chip is responsible
for lighting the eight LEDs we will be installing later. Be sure to install it in
the correct direction! Verify that all pins are through the board before
soldering!
110. Install R32, a 470 ohm resistor (yellow-violet-brown).It is necessary to
connect R32 to the trace next to it on the topside of the PC board. Carefully
scrape away the solder mask on the trace and connect it to R32 with a
scrap component lead or a small glob of solder. (see parts layout, page 35)
111. Install the 16 pin IC socket, verify that all pins are through the board,
then solder. Install U4, the microcontroller (marked with a sticker with WSR-
1A on it). Make sure and orient the microcontroller correctly, as these must
be ordered from the factory if ruined.
112. Install C49, a 10uF electrolytic capacitor. (Pay attention to orientation).
113. Install R33, a 10K ohm resistor (brown-black-orange).
114. Install R31, a 1K ohm resistor (brown-black-red).
115. Install C47, a .01uF ceramic capacitor (marked .01, 10n, or 103).
It is time to build the power supply and audio switching circuitry. The audio
switching turns off audio when there is no signal present to prevent some
computer interfaces from activating when there is no signal present.
116. Install C50, a 10uF electrolytic capacitor. Pay attention to the
orientation!

WSR-1A•18
117. Install VR1, the 5 volt regulator. Make sure the tab is facing the PC
board when it is bent over as shown in the diagram. If you wish you can
lightly solder the tab to the topside of the circuit board for mechanical
stability. Don’t worry about overheating the part, regulators and almost all
parts nowadays are very tolerant to soldering temperatures.
118. Install R19, a 10K ohm resistor (brown-black-orange).
119. Install C51, a 10uF electrolytic capacitor. Check polarity!
120. Install R12, another 10K ohm resistor (brown-black-orange).
121. Install Q4, another 2N3904 NPN transistor. This transistor is used in
conjunction with a jumper across P1 to squelch the audio when there is no
signal present. Pay close attention to the orientation of this part.
122. Install P1, a 2 prong jumper set. Install the part with the short leads
being soldered to the board. To jumper this, you can either use a jumper, or
you can bend the two leads together and solder them in place.
123. Install Q3, another 2N3904 NPN transistor. This transistor squelches
the audio from going to the speaker output when there is no signal present.
124. Install U1, the LM386 audio power amplifier chip. This chip is capable
of quite a bit of audio ‘poop’. Later when you crank the volume you will see
what that means!
125. Install R9, a 4.7 ohm resistor (yellow-violet-gold).
126. Install C22, a .1uF ceramic capacitor (marked 104, .1, or 100n)
127. Install C21, a 10uF electrolytic capacitor. Watch orientation!
128. Install C13, the large (but not the largest) 220uF electrolytic capacitor.
This and the following capacitor, if installed incorrectly, will actually self-
destruct in a not so pleasing manner. So be really careful when installing to
be sure they are in correctly.
129. Install C5, the largest 1000uF electrolytic capacitor. Note previous
step!
Now we will begin installation of the switches, jacks and various other parts.
When we’re done with that, we’re ready to roll!
130. Install SP1, the speaker buzzer. Notice on the bottom of the buzzer,
7805
PC Boar
d
Topside

WSR-1A•19
you will see some polarity markings. The pin marked with the positive
symbol (+) is inserted in the hole that is not touching the ground plain on
the top side of the board.
131. Install J3, the RCA type jack. This is where you will get the 2400Hz
audio without going through the volume control.
132. Install J1, the 3.5mm stereo jack. This jack is originally for stereo
hookup, but only one channel is being used, so a mono male jack will work
fine for connection. This is where the volume controlled 2400Hz is found.
133. Install J5, the 2.5mm jack. This is where you would connect the “push
to record” or “record” input of a cassette recorder to automatically begin
recording the signal when the squelch opens up. There is more on how to
connect this later in the manual.
134. Install J2, the PC mount type ‘F’ connector. This is where you will
connect your Weather Satellite Receiver Antenna.
135. Install S1, the main power switch. Note the switches are not in order,
so be sure to cross check with the parts layout diagram.
136. Install S2, one of the DPDT switches. This switch must also be
soldered on the top side of the board. After it has been properly placed and
soldered on the solder side of the board, turn the board over and solder the
pads on the top of the board. We will configure this switch to be a
momentary contact switch by pulling out the little metal wire right behind the
spring on the top side of the switch. Use needle nose piers or tweezers to
do this. Pressing this button will tell the microcontroller to skip to the next
channel if it is presently not scanning.
137. Install S3, another DPDT switch. When this switch is in, you will need
to press the skip switch to select the next channel. When it is out, the
receiver is in scan mode, and begins looking at all eight channels until it
finds a transmission. It is necessary to top solder this switch so once the
switch has been properly seated and soldered, flip the PC board over and
solder each pin of the switch on the top or component side of the board.
Now we will begin assembly of the second daughter board. Before continuing,
check your main board for mistakes like cold solder joints and solder bridges.
Also check for incorrect part placements and orientations.

WSR-1A•20
138. Now it is time to install the LED indicators, D2 - D9. These are a little
tricky since they will have to have long enough leads to reach the holes in
the display panel of the case and knob set. Look at the diagram to assist
you in placing these parts. If diodes are installed backwards they do not
light. Identify which lead is which in the following diagram, and make sure
and mark the cathode (k) lead of your LEDs with a marker if you are in
question. The cathode end is the shorter lead of the diode
139. Mark all 8 of the LEDs lead lengths at 1/4 of an inch from the red
plastic lens with a permanent marker. If they are all the same it helps with
neatness.
140. Install the eight LEDs so that the distance between the bottom of the
LED lens and the board is 1/4 of an inch, and that the total height of the
LED is .45 inches high from the top of the board. D4 must now be soldered
to a trace on the topside (front) of the PC board. As in step 110, scrape the
green solder mask off of the trace next to D4 and solder the lead to the
trace with a glob of solder or small scrap component lead. (see page 35)
141. Install R11, the 10K ohm squelch control. (Green cased pot with black
control post).
142. Install R5, the other 10K ohm pot for volume control. (Green cased
with black control post).
To mate the daughter board with the main board takes a little patience. We
want the two boards to be square with each other, so you may want the
assistance of a helper or a vise for the following steps.
A
K
1/4"