Kenwood TS-480 60 meter activation (2025)
Ameritron RCS-4 antenna switch modification for remote QTH (2024)
Ajustable Resonant Dipole for HF (2024)
JUMA ASW2 low/high band antenna swirch for Icom (2024)
JUMA SC-2 Splitter Combiner (2024)
Simple Waterproof Coaxial Cable End for Antenna (2024)
Linear power supply for LED chains to get rid of RFI (2024)
Antennikurssi OH3AC (Antenna course presentation Part 1 in Finnish) (2024)
Antennikurssi OH3AC (Antenna course presentation Part 2 in Finnish) (2024)
Antennikurssi OH3AC (Antenna course slides in Finnish) (2024)
SRALkesäleiri (Man made noise video by OH1ON in Finnish) (2024)
Häiriöklinikka SRALkesäleiri 2024 (Man made noise slides in Finnish) (2024)
Robot Lawn Mower noise filtering (2024)
High Power Trap Dipole for 40m and 60m (2024)
SV File Sync - file syncgronizing application for Windows (2024)
WSJT-X Clublog Gateway real-time uploader for Windows (2024)
DIY Electric Motor, fun craft for holidays (2025)
FBTA Fake Bike Theft Alarm (2024)
Ultrasonic Direction Finder JUMA UDF1 (2023)
Antenniklinikka SRAL Kesäleiri 2023 (PPS slide show in Finnish)
Radioamatööri ja parisuhde SRAL Kesäleiri 2023 (PPS slide show in Finnish)
50 MHz "Door Frame" Loop Antenna construction photos (2023)
RFI Emission Measurement with Home Made LISN Setup (2023)
Radio interference from electric thermostat and repair (2023)
Military Style Bent Whip is a poor NVIS Antenna (2023)
Roof Corner Mount NVIS Mobile Whip Antenna Simulation (2023)
Roof Edge Mount NVIS Mobile Whip Antenna Simulation (2023)
Test LPF Filters (2022)
JUMA RSEL4 Remote Selector for Remoterig (2022)
30m door frame loop (2022)
Good and Bad Lead Acid Battery Chargers (2022)
Cushcraft R8 vertical antenna matching box MN8 repair (2022)
RF Splitter-Combiner (2022)
JUMA SCC Ham radio friendly Solar Charge Controller (2022)
How to find out Transmission Line Velocity Factor (2022)
How to find out Transmission Line impedance (2022)
Choke Balun Winding Style Comparison (2022)
JUMA PA Combiner (2022)
Mobile antenna location (2021)
80 meter Circular Polarization
antenna comparison (2021)
Optimal 160 meter
dipole height for NVIS (2021)
Optimal 80 meter
dipole height for NVIS (2021)
Nanocrystalline Toroidal Cores Measurements
(2021)
Dummy Load for JUMA
TC (2021)
JUMA TC Turnstile Controller Rev D for Circular
Polarization (2021)
Modern Dummy Load (2021)
40m door frame loop (2021)
160m full wave loop gain versus height (2021)
80m full wave loop impedance versus height (2021)
80m full wave loop gain versus height (2021)
160m half wave dipole impedance
versus height (2020)
160m half wave dipole gain versus
height (2020)
80m half wave
dipole impedance versus
height (2020)
80m half wave dipole
gain vs height (2020)
JUMA IC-705 Bluetooth Gateway
(2020)
The challenging UNUN Transformer
for EFHW antenna
(2020)
Takeoff angle
calculator (Excel file
2020)
OH2AP
Autumn Camp presentation
(PDF file) (2020)
Simple Foot Switch (2020)
Man Made Noise Filtering
(2020)
Coil Loaded Dipole for 80 meter
(2020)
Coil Loaded Dipole for 160 meter (2020)
Square Dipole for 160 meter
(2020)
Z-Dipole
for 160 meter (2020)
Common Mode Choke Balun for Antennas
(2020)
SRAL Summer Camp 2019 in Petäys (PPS presentation in Finnish)
OH7AA Summer day 2019 in Rautalampi (PPS presentation in Finnish)
Practical Ferrite Guide for
HF 2018
Ionosonde links near Finland 2018
Circular
polarization
presentation SRAL Äänekoski
2018 (Video in Finnish)
Coaxial Cable Repair 2018
Antennirakennuskurssi. Antenna building course in Finnish, PPS file 2018
JUMA COM HUB 2018
Circular
polarization HF antenna
with JUMA TC Turnstile Controller 2017
JUMA ASW5 Automatic Antenna
Switch 2017
External RX port for Kenwood TS-480 2017
GP5 Five Band Vertical Antenna 2016
Remoterig improvement for Kenwood TS-480 PDF file 2016JUMA HF Tuner Modules 2016
Esitelmä SRAL kesäleirillä 2016 (Presentation in Finnish)
Balun Presentation 2013 (pdf file in Finnish)
Electric bicycle charger RFI Modification 2013
Magnetic loop made of
copper tube coaxial cable 2013
Magnetic loop for 1.8MHz...7MHz 2013
JUMA FM70 70 MHz FM Transceiver 2011
JUMA TX500 500 kHz Transmitter
2009
MOHAIR ONE miniature
3.5 MHz transceiver 2009
JUMA KEYER1 Miniature CW keyer 2006
High performance SSB filter for Direct Conversion RX 2006
JUMA TX1 DDS controlled
CW transmitter 2005
Active
ferrite rod antenna for HF 2005
JUMA
RX1 Direct Conversion Receiver 2005
Five cent CW key 2005
50 ohm to 200 ohm HF wide band low level transformers 2004
Wilkinson splitter for RX measurements 2004
Windom (OCF) baluns 2001/2004
Ferrite
rod antenna for
80 meter 2004
Magnetic
Loop Antenna for 80 m 2004
Mascot Switched
PSU 9320 modification
to 8A peak current 2004
Power supply 13.8V 20A schematics (gif) 1996
PLL VFO 5.5MHz…6.0MHz for TS130S 1988