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Project by:
TONY / I2TZK,
Frank
/ K7SFN , Dinesh / VU2FD
SWM3-QRP: QRP SWR METER WITH
BUILT-IN HF BRIDGE
PCB REVISION: 1021
Dual Channel LCD SWR Meter SWM2
and SWM3-USB were a great
success. Hundreds of Radio amateurs built it with success. With more
and more feedback pouring-in and many demanding an SWR Meter
exclusively for QRP users, 10W range, USB/Battery Powered, etc, Tony/I2TZK decided to
go for a scale down version of PIC18F4550 for this project.
Click picture for enlarged view (Thanks to Ben/PA2ST for nice
picture)
Click picture for enlarged view (Thanks to Ben/PA2ST for nice
picture)
(Thanks to Ben/PA2ST for nice picture)
SWM3-QRP is an USB or Battery Powered CPU. Based
on Microchip's PIC18F4550 40DIP Chip.
This new QRP SWR Meter is developed keeping in mind
demand of QRP operators looking for a small, power efficient, stand
alone SWR meter for 10W class HF Radios. This project fulfills that
objective.
SWM3-QRP has in-built QRP HF bridge. An
optional second bridge may be connected to D9M connector: A bridge
like HFB3 for HF or make your
own VHF Bridge.
Firmware for SWM3-QRP Dual channel LCD
SWR Meter presented here is developed by Tony
/ I2TZK for the ham community which is basically, a
scaled down version of full SWM3 -USB firmware.
Tony/I2TZK has removed
following capability of original firmware (SWM3) to match this hardware:
1.
No PC Connectivity
2. No Configuration
of PIC Parameters thru PC
Purpose of this project is to
encourage radio amateurs to build their own SWR Meter at a low
price.
SWM3-QRP has following
features:
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Simple, single Micro Controller:
PIC18F4550 |
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Dual
channel of Power Measurement possible. (Only one channel is used in
this hardware: Built-in QRP HF Bridge) |
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Dual
Power: USB or 9V Battery |
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CPU
Unit has: |
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2
x 16 LCD with Back light control
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Stable
Reference voltage. |
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Built-in
HF 10W Balanced Bridge |
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SWR, FWD, POWER and Actual Power to antenna
calculations/Display.
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Bar
Graph mode for SWR & Forward Power
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9V
Battery Holder on main board |
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Front
panel selection of USB or 9V battery operation |
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Project
Bases:
Project
is developed on Two Double-Sided PTH boards. The first one is CPU
board where LCD, Regulator, Battery, HF Bridge and Back Light Controllers are located.
This board is powered by 5V from either USB or internal 9V battery.
Second board is for Front panel push buttons and
ON/OFF and USB/Battery Switches.
BNC PCB Type of connectors are used for HF and
A D9 Connector is used for second optional brodge.
Kit
is intended for experienced Radio Amateurs.
Although,
rated at 10W HF, this meter & bridge may work at higher RF
Power. There is always a possibility to flash SWM3
firmware into SWM3-QRP PIC to get PC connectivity and ability to
configure this CPU for your own specific purpose.
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