tent.
DEM ABPM All Band Power Meter
/Kits/ABPM.doc
1 Rev.
A

6/19/06
DEM ABPM
All Band Power Meter

10 KHz to 10 GHz low level power meter

PREFACE:



The DEM ABPM is the all band, portable power meter developed by W1GHZ and described
on his web site at
http://www.w1ghz.org/new/DEM_ABPM_kit.pdf
It is recommended reading
before you start assembly of this kit. The paper titled Portable RF Sniffer and Power Meter
discusses the compilation of designs by W7ZOI, W7PUA, WW2R, and W1GHZ then explains the
evolution of the final product. The web page explains the circuits in detail providing individual test
data of the power detector circuits. The page also discuses the methods of calibration, and the
final use of the circuit when complete. Be sure to review the references at the end of the web page
for further technical information and data sheets of the power detector chips. Other circuit designs
are available at that site that will compliment this kit. Feel free to browse around for other ideas.


CIRCUIT DESCRIPTION:




Now called the DEM ABPM in the Down East Microwave Inc. catalog, are actually two
individual power detection circuits combined through a simple switch connected to a bar graph
voltage meter. It is all neatly place in an enclosure with a self contained battery to make a
complete portable RF power detecting device that fits in your pocket. The ABPM has two
individual inputs (SMA connectors) that are limited by the frequency response of the detector chips
they are connected too. The Bar graph display can be operated as a running bar graph or as
individual ascending / descending segments to conserve battery power. The ABPM also has an
external meter connection so that more precise measurements of change device may be used by
connecting a digital or analog voltmeter directly to the detector circuits. One of the references on
W1GHZs web site describes an audio tone indicator and how it can be used with this device.


As for the kit in general, all components, hardware, connectors, and assembly instructions
are the responsibility of Down East Microwave Inc. Please call us if you find any components
missing, broken, or incorrect. Please do not contact W1GHZ with complaints such as fit and form
or missing or damaged components. He is not employed by DEMI and has no control of the
contents of this kit. DEMI has agreed to compile and distribute this kit with the original circuit board
and components available from the DEMI standard inventory. If you wish to discuss circuit
functions, modifications, or further uses of the circuit, Paul will be happy to, If contacted through his
website at
www.w1ghz.org.
with any details concerning these maters. You may also drop him a
line in regard to how you enjoyed this kit or any concerns on how DEMI is managing the
distribution of this kit to the armature radio public.



/Kits/ABPM.doc
2 Rev.
A

6/19/06
CIRCUIT BOARD ASSEMBLY:

The circuit board assembly is basic and straightforward but some hints and special notes
are worth paying attention too. Use only the schematic and component placement supplied with
this kit for the best results. Some designators and placements have been changed from the details
provided on the W1GHZ web site to accommodate the components actually used in this kit. Please
review all of the following notes and read this document through before starting assembly.

Circuit Board:
1. Screen printing for U2 is backwards on circuit board. Follow the component placements
used in this kit only!
2. Surface mount versions are used for C4 and C5. Their polarity is indicated on the
component placement. The leaded version positions of both will be vacant when assembly
is complete.

3. Connectors or header pins are not used for J3 and J4.
4. R3, C7 and C9 are mounted on the bottom side of the PCB. U3 is shown on the bottom
side placement for orientation of those components. U3 is mounted on the topside.
5. The bar graph is installed on the bottom side. Examine the display carefully. One corner
is slightly chamfered to indicate pin one. The chamfer is shown on both components
placements (top and bottom). The screening on the PCB does not indicate it.
6. U1, the LTC5508, will be the most difficult part to assemble in this kit. It is found in a foil
bag. It has six leads. The lettering on it is most difficult to read but is imperative that you do
for proper alignment. Once the IC is heated with any flux during soldering, the marking is
removed making it next to impossible to verify. You get one shot at aligning it correctly.

Actual Assembly:

Use the component list with both top and bottom component placement diagrams.
1. Start by installing U1. Use a magnifying lens to verify lead placement on the PCB and
the marking on the LTC5508 for alignment. Position and solder one outside leg only. Re-
verify placement of leads on pads then solder opposite leg of IC. Be sure of placement
then solder the other four leads. Use solder wick to remove excess solder that may
bridge or bulge over. Clean with flux remover and test with ohmmeter for shorts. If you
have a short try solder wick again. If you are required to remove the IC from the PCB to
repair, it most likely will not survive. Call DEMI for a replacement.
2. Next, install the topside surface mount components.
3. Install U2-U4. Remember that the screening for U2 is backwards.
4. Install C8 with a 1 turn 3/16 loop in the lead that is installed in the pad that C7 and R3
are connected to. The loop is L1 on the schematic.
5. Install all other leaded components including VR1 and VR2.
6. Install bottom side surface mount components.
7. Install bar graph on bottom side. Remember the chamfer is pin 1.
8. Trial fit the SMA connectors before soldering (found in the hardware bag). You will need
to trim the center pin length and modify the ground pins slightly. You will also need to
remove some solder mask from the ground plane before soldering. Push the flange of
the SMA up against the PCB as close as possible or the board assembly will not fit in the
enclosure.
/Kits/ABPM.doc
3 Rev.
A

6/19/06
COMPONENTS LIST

Component Bag
: Resistors values are in Ohms and are ¼W leaded unless otherwise specified. POT =
Potentiometer. "ELC" = Electrolytic. Chip is surface mount components.

C1
8.2
F 50mil ATC
C11 0.1
µF leaded
R7
1.8K

C2
100
F Chip (0805)
C12 100
µF ELC
R8
1.8K

C3
0.1
µF Chip (0805)
C13 0.1
µF leaded
VR1
10K
Pot
C4
1.0
µF Tant Chip
C14 0.1
µF leaded
VR2
500
Pot
C5
1.0
µF Tant Chip
R1
10K

BAR 1 Bar graph display
C6
0.1
µF Chip (0805)
R2
51
Chip (1206)
U4 LM3914
C7
15
F Chip (1206)
R3
470
Chip (1206)
U1 LTC5508
C8
1000
F leaded
R4
10

U2 78L05
reg
C9
0.1
µF Chip (0805)
R5
18K

U3 AD8307
C10 0.1
µF Chip (0805)
R6
470

One
ABPM Circuit Board


Enclosure Assembly

Start by wiring the PC board using the wire chart provided below. Cut and tin all wires to
length then attach them to the From positions on the circuit board. All wiring is done on the
topside of the circuit board. There will be Red, Black, and some other color wire that is designated
odd. (Something other than red or black) Pins #1 of the J3 and J4 connectors are the holes on
the circuit board in the square pads. Pins #2 are the round pads. For the GND connection on the
circuit board, scrape some solder mask off the circuit board above the WW2R logo and attach it by
soldering. Check all connections and trim excess wire off from the bottom.


Wire Connection Table

WIRE
SIZE
FROM
TO
#24 Red Teflon
3
+V on PCB
ON/OFF switch
#24 odd Teflon
3-1/2"
J4-1
VHF/UHF switch
#24 odd Teflon
3-1/2"
J3-1
VHF/UHF switch
#24 odd Teflon
3"
J3-2
Jack
#24 Black Teflon
3"
GND
Jack
#24 odd Teflon
3
J4-2
VHF/UHF switch
Black from Battery Clip
NA

-V on PCB
Red from Battery Clip
NA

ON/OFF switch







/Kits/ABPM.doc
4 Rev.
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6/19/06
Find the half of the enclosure that has the battery compartment in it. It will also have three
round holes on three different sides. Install the two switches and jack as shown. Then install the
battery clip leads through a hole in the battery compartment side (not a top hole!) closest to the
ON/OFF switch. Position the enclosure as shown on your workbench. Place the circuit board on
the bench on the ON/OFF switch side of the enclosure with the wires up and the SMA connectors
pointing in the same direction as the VHF/UHF switch. Do not install the circuit board in the other
half as of yet. Connect the wires from the circuit board to the switches, jack, and from the battery
clip as shown below. After wiring is complete, check all connections and verify all circuits by eye for
shorts or wire clipping debris. If circuit board looks ready, attach it in the other half of the enclosure
by aligning the SMA connectors with the holes in the enclosure then inserting the circuit board in
place. Check to see that the bar graph display is correctly positioned in the machined hole of the
enclosure. There is some play in the screw holes so the display could be misaligned. Attach the
board with four sheet metal screws keeping the bar graph positioned correctly.

Ba
t
t
e
r
y
To J4-1
To J4-