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Peter Miles
Northam, Western Australia
QRZ Page: VK6YSF
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TRANSMITTER CONVERTER
FOR 630M BAND
630m band (472kHz-479kHz) Transmitter
Converter and common Low Pass Filter.
Under
development
HOME > PROJECT
> 630M
TRANSVERTER
>
The
transmit converter consists of four main elements, input attenuator to
reduce the RF power from the HF Tranciever down to a manageable level
for mixing,
ring mixer to mix the 10MHz LO (local Oscillator) with the transceiver
RF and produce a linear output within the 630m band (472kHz-479kHz), amplification
to raise the output from the ring mixer to a suitable level and
finally the low pass filter to reduce unwanted harmonics to a
satisfactory level for transmission.
Fig 1
Schematic of the
transmit stage including the input attenuator, mixer, amplification
and low pass filter. This circuit is
subject to further development.
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IF
Transmitter
RF PWR in Watts
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R1
Details
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R2
Details
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Required
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Derived
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0.5
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50 Ohm
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5 x 270R 0.5W Paralleled
= 54 Ohms
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470 Ohm 0.25W
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1.0
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50 Ohm
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5 x 270R 0.5W Paralleled
= 54 Ohms
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680 Ohm 0.25W
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2.0
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50 Ohm
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11 x 560R
0.5W Paralleled = 51
Ohms
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1k Ohm 0.25W
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3.0
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50 Ohm
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11 x 560R 0.5W Paralleled
= 51 Ohms
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1.8k Ohm 0.25W
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5.0
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50 Ohm
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11 x 560R 1.0W Paralleled
= 51 Ohms
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2.2k Ohm 0.25W
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Table
1 Attenuation network for various power levels.
Component
details
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TUF-1+
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Frequency
Mixers Module - TUF-1+
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Q1
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Transistor
- 2N3904
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Q2
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Transistor - IRF510
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C1
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Capacitor
- 10n 3kV
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C2
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Capacitor
- 10n 50V
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C3
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Capacitor - 470n 50V
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C4
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Capacitor - 470n 50V
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C5
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Capacitor
- Electrolytic - 47µF 50v
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C6
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Capacitor - 470n 50V
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C7
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Capacitor
- 10n 3kV
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C8
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Capacitor
- 4n7 3kV
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C9
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Capacitor
- 10n 3kV
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FB
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Ferrite Bead
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R1
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Resistor Carbon - 560R
0.5W x 11, See attenuation network
table
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R2
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Resistor Carbon - 1k
0.25W, See attenuation network
table
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R3
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Resistor Carbon - 68R
1W
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R4
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Resistor
Carbon - 6k8 0.25W
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R5
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Resistor
Carbon - 470R 0.5W
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R6
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Resistor Carbon - 27R
1W
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L1
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Single layer, close
wound air inductor, 5.9uH, 24turns on a 20mm former. See
air inductor design
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L2
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Single layer, close
wound air inductor, 5.9uH, 24turns on a 20mm former. See
air inductor design
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Photo 1 Assembled
transmit converter.
TOP
OF PAGE
Page
last revised 12 March 2022
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Space Weather
https://www.swpc.noaa.gov/
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Nikola Tesla, born on 10 July 1856, was one of
history's most influential inventors.
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Notice Board
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VK6YSF JS8Call and
Olivia 8/250 operations.
Current activity is generally
focused - though not restricted to - JS8Call operations on the 30m, and 40m bands.
Olivia 8/250 is used occasionally on the 20m band.
Proposed
band and mode activity
is often communicated on HamSpots: https://hamspots.net/js8/
or my profile on
X: https://x.com/vk6ysf97230
.
Post
date: 5 July 2026
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Local
Repeaters
The Local Repeaters page has been updated with expanded and refreshed information on VHF and UHF repeaters across Western Australia's Central Coast, Perth, the Avon Valley, and the Peel region.
See: https://vk6ysf.com/local_repeaters.htm
Post
date: 5 July 2026
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MARMOTSat
An exciting upcoming amateur radio CubeSat
Proposed
launch date: 7 July 2026
Expected payload includes:
145.875 MHz – AX.25 packet digipeater
436.125 MHz – Telemetry & command (digital)
29.410 MHz – CW telemetry beacon, DVB-S2 experiments.
https://marmotsat.ca
https://www.propagationlab.ca/satellite/
Post
date: 5 July 2026
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Western Australian SSTV net
Popular
Western Australian SSTV net for both digital and anolog SSTV.
Generally
found at 7214.0kHz LSB every afternoon from 08:00 UTC (4:00pm WST)
For more
details: https://www.wasstv.net/wasstv.net/index.html
Post
date: 8 December 2025
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VK6MJM LF (136kHz) and MF (474kHz) Beacon
VK6MJM is a LF/MF station
located in Manjimup, Western Australia.
Common Mode: FST4W 300 (Similar to
WSPR)
Note:
other modes and sub-modes may be used.
Station details were presented by
Peter Hall (VK6HP) at PerthTech 2024.Presentation PDF: Peter
Hall VK6HP at PerthTech
QRZ Page: VK6MJM
on QRZ.com
Post
date: 10 March 2025
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