Matti Hohtola OH7SV
Amateur Radio Projects
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Ajustable Resonant Dipole for HF (2024)
Choke Balun Winding
Style Comparison (2022)
JUMA PA Combiner (2022)
50 MHz "Door Frame" Loop Antenna (2021)
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
impedance versus height (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 End Fed Half Wave (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)
OH7SV Door-frame
loops for 20m, 15 and 10m 2019 (PDF file)
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
Useful script for
AFEDRI SDR Net users 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
JUMA DFR1 Direction Finder
Receiver 2017
External RX port for Kenwood
TS-480 2017
GP5 Five Band Vertical Antenna
2016
Remoterig improvement for Kenwood
TS-480 PDF file 2016
JUMA HF Tuner Modules 2016
Esitelmä
SRAL kesäleirillä 2016
(Presentation in Finnish)
Improved
Ferrite Rod
Antenna Amplifier PDF file 2015
Enhanced OCF
Dipole (Windom) Balun
2014
Measuring
Tape
Antenna in Flag Pole 2013
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
Magnetic loop presentation
in SRAL spring event 2013 (pdf in Finnish)
Dipole impedance
2012
Common mode
1:1 balun for kW power level
2012
JUMA PA1000 Linear Amplifier
2011
JUMA FM70 70 MHz FM Transceiver
2011
JUMA TX136 136 kHz Transmitter
2009
JUMA TX500 500 kHz Transmitter
2009
MOHAIR ONE miniature
3.5 MHz transceiver 2009
JUMA PA100 100 W Linear Amplifier
2008
JUMA TRX2 High performance
CW/SSB Transceiver 2007
JUMA TRX1 DDS controlled
CW/DSB Transceiver 2006
JUMA KEYER1 Miniature
CW keyer 2006
High performance SSB
filter for Direct Conversion RX 2006
Simple CW keyer
2005
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
Twin lead telephone line "killu" RF
characteristics 2005
Direct Conversion
HF Transceiver with DDS LO
2004
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
150W MOSFET linear amplifier
for 80m 1996
Power supply 13.8V
20A schematics (gif)
1996
80 m HF SSB/CW Transceiver
1988
PLL VFO 5.5MHz…6.0MHz
for TS130S 1988