The Javornik 144/14 is a very high performance transverter for 144 MHz. It is designed in 2001 by S53WW and contains two synchronous RX converters and one TX converter. It uses 14 MHz as IF to take advantage of the better linearity on 14 MHz of most HF transceivers than the often used 28 MHz.
There is no original english manual but you will find my translation from Slovenian, schematics and pictures by following the link.
The PA4EME EME-transverter is based on the original Javornik 144/14. An extra dual channel transverter was needed for adaptive receiving on 144 MHz EME. As parts and PCB became absolete, a new transverter was designed with new PCB and finals. A TFT-screen shows forward and reflected power.
Pictures from the build, info about the TFT-screen and replaced final amplifier can be found by following the link.
Pulse generator for Linrad
For 144 MHz EME I use a single 14 element LFA yagi with 3 reflectors or 4 x 14 el XPOL LFA yagis with adaptive receiving and H or V transmitting. This is achieved by using the duo channel 144/14 transverter, an Afredi 822x SDR, Linrad and then via timf2 to MAP65.
Linrad (SDR software by SM5BSZ) has a smart noiseblanker that is very effective but only if calibrated. This pulse generator is used to calibrate that noiseblanker.
14 element Plus2 LFA Yagi
Between 1985 and 2004 I have used various antennas for 144 MHz EME up to 8 Yagis. When I moved to our new house I downsized but still wanted to do EME so I made a 14 element LFA Yagi with 3 reflectors. 50 Ohm high power full wave closed loop, high F/B ratio, exellent G/T and highly supressed side lobs and side-on signal rejection…just what I need in this urban environment. Gain 16.63 dBi, F/B 36.35 dB.
4x14 XPOL (7H/7V) LFA Yagis
After many years of single Yagi EME the number of worked DXCC’s slowed down. To keep pushing the bounderies I have build a portable stack of 4 small XPOL Yagis that I can put up easely in the garden, my roof or use during holidays and DX-expeditions.
The gain is “only” 3 dB more than my single yagi but gives me the benefit of adaptive receiving and transmitting H-pol or V-pol. I’m suffering less from Faraday rotation and spatial offset.
>PA4EME antenna controller
Johannes, OE5JFL, designed a standalone antenna controler system. Computing and tracking of the moon, sun and various Galactical sources. It can handle various types of absolute encoders including those I use: the MAB25. Selectable stepsizes, selectable offset for AZ and EL, manual or autotracking, soft start and soft stop. I extended the unit with a GPS-controller that updates the controller with the current geographic location and time adjustment in case of empty backup battery.
144 MHz 2 x LDMOS SSPA
This Solid State Power Amplifier for 144 MHz contains 2 RF powermodules using the Freescale MRF6VP61K25H. It can deliver up to 2100 Watts in continues modes (eg JT65, FSK441, MSK144, Q65). Powersupply 4 x 46,5 Volts, total 63 Amperes. Input 15 Watt. Italab Archimeds 2000 control board, Italab powermodules, Wilkinson coupler, low pass filter.
Cooling and fans are dimensioned for contest and EME.
144 MHz GS-35b amplifier
2.5 kW grounded grid amplifier using the rugged GS-35B coaxial triode. This tube was produced in the Soyus factory for the Russion military for UHF radar aplications but performs very well also on lower frequencies. First design of an amplifier for 144 MHz originates from UV1AS but this one is a W6PO style as described by DL4MEA.
Compared to EIMAC tubes (eg 8877) the GS-35b was cheap and a grounded grid amplifier is easier to build than a tetrode amplifier. Running at maximum specifications (4200V anode voltage, 1200 mA anode current, 300 mA grid current and 200 Watt drive) 3250 Watt output. Powergain 12,1 dB, efficiency 64%.
The amplifier was build in 2001 as succesor of my 1977 build 2x4CX250b amplifier. Dimensions (hxbxd): 50x60x100cm. Weight 97 kg. The picture shows the amplifier in service-mode. In 2017 this amplifier was replaced by the 2 x LDMOS amplifier and HV was banned from my shack.
144 MHz 2x4CX250b amplifier
This is the well known “pluber special” 2x4CX250b amplifier from W1SL. It is published in the February 1971 issue of QST.
Only 16 years old (1979) I started the build and it seemed to be an impossible project but two years later it was finished. Nearly all parts were surplus and the HV transformer was wound myself delivering max. 3200 V at 2 A. The most difficult in the build was the neutralisation.
Running 900 Watts in CW made me a big station in those days and my first EME-QSO’s became possible when I upgraded to a 4 x 15 el Yagi stack with elevation.
There are no photos of the build itself as these were lost including the negatives. All paperwork and calculations are still in my archive. The amplifier was put out of service in 2001 but stayed in the shack untill 2020. The power/SWR-unit is still in use.
144 MHz GS-35b amplifier
144 MHz amplifier using F1CXX design. This design looks like the original first UV1AS (RX1AS) design but uses a large diameter cavity. That diameter was easier to obtain as the 100 mm size is in use for copper drainpipes. It was build for the “EME-2009 project”; a joint venture of PA3CMC and PA4EME to escape urban noise and find a rural EME-location. An existing large HV-supply was used and a copy GM3SEK tride board was used to control the amplifier.
PA4EME antenna tower
In april 2004 we moved to our current house. With some delay a building permit was granted to rise a lattice antennatower in the garden.
The Versatower (Strumech Tower) BP60SX was found in northern Netherlands and the main advantage is that it has a special designed base plate with made it possible to tilt the tower at a hight of 3 meters and therefore could tilt on the flat roof of the garage instead of the garden. The steel wiring cables were extended to 8 mm for the topsections and 12 mm for the bottom. Original pullys have been replaced as those are 5mm wire types.
Copper grounding rods were driven 6 meters deep. My shack is located 6 meters from the tower and cables are running along a tensioned steel cable. Located on a hilltop the windspeeds can be significant and sofar the highest measured windspeed was measured on Jan. 18th, 2017, at 126 km during storm Kyrill.
The Simple Aurora Monitor (SAM) is a sophisticated semi-professional 3-axis geomagnetometer. It contains 3 sensors that are measuring the X,Y and Z components of the magnetic field of the earth.
Measuring these components can provide information about geomagnetic storms, solar events, solar winds and aurora. It uses FG3+ fluxgate sensors manufactured by Speake & Co Llanfapley (nowadays magnetometer-kit.com).
My magnetometer is used combined with a PC for logging and creating magnetometer charts. It output the values of X (noth/south), Y (east/west) and Z (vetical) and alarming when a certain K-index is reached to trigger an aurora alert.
Sensors are digged 1.5 meters into the ground below the floor of our gardenhouse. The sensors are very sensitive for temperature and digging them deep keeps them stable.
144 MHz phase shifter
As I live in an urban enviroment, the amount of noise is increasing day by day. Inspired by phase shifters for HF I started to look into a design that was using high quality components at VHF. Searching the internet I discovered that I was not alone and that IZ3KGJ went the same route. The interfering signal is injected out of phase into the receiving line.
TOA lightning detector
This is my System RED lightning detector. The detector is hooked to the private Blitzortung.org network of lightning trackers. The detector receives electromagnetical signals from thunderstriks. Combined with a timestamp, the positions of a strike can be calculated from at least 3 detectors using the TOA (time-of arrival) methode.
The detector is station 1152 and sending data since August 2014.
RX / TX sequencer
This 5-stage sequencer is used to control my terrestrial VHF-station. When my RIG is keyed a sequence of operations is triggered: isolation relay LNA, LNA relay, amplifier, transverter and finaly the TX-inhibit of my transceiver. Each sequence is delayed by 100 mS. I never lost any LNA or relay due to hot switching.
Extended RX / TX sequencer
This 5-stage sequencer is used to serve my EME VHF-station. In fact it is the same as my terrestrial sequencer but allows also to control the polarisation during transmitting (H-pol or V-pol) and receiving (H-pol, V-pol and adaptive). All combinations are possible: relays 12 V or 24 V, + to TX or – to TX, + on RX or – on RX, + on TX or – on TX. Each stage has 4 contacts which can be user defined wired to the output connectors without soldering.