Funk Amateur FA-VA4, Construction And User Manual

Page 1: ...Construction and User Manual Kit for an easy to use vector antenna analyzer for use in the frequency range 100 kHz to 100 MHz Vector Antenna Analyzer FA VA4 ...

Page 2: ...is gap It was devel oped by Michael Knitter DG5MK and is presented in 1 This is a fully fledged vector antenna analyzer for use in the frequency range 100 kHz to 100 MHz Table 1 Vector measurement means that in con trast to a scalar measurement not only is the SWR determined and displayed but al so the value of the base point impedance along with the signbased imaginary part The socalled SOL compe...

Page 3: ...where the six pin mounting strip for the programmable interface is already lo cated First of all the sliding switch S4 should be mounted on the face of the board It should rest with its underside on the circuit board with the slider able to move horizontally Table 1 Technical data Frequency range 0 1 100 MHz 1 Hz resolution Accuracy 2 f 50 MHz Measurements Complete impedance values Measurement ran...

Page 4: ...ght so that there is no gap All six connections of the two 3 pin display contacts must be soldered to the top of the LED backlight along with the two outside pins of the 20 pin connector strip Figs 6 and 7 It is advisable to use an appropriate support under the display when soldering to the LED backlight unit to fix both compo nents in the correct position The protective film on the display glass ...

Page 5: ... their hous ings on the circuit board Fig 5 When soldering some form of compensating support must be used as the socket con nections are higher The battery holders must be connected to the correct polarity the spring connection is the negative pole Fig 5 The battery holder solder tags are made from spring steel please use correspondingly robust sidecutters to shorten them To finish the BNC socket ...

Page 6: ...rom the underside of the case are to be fitted it may help to use some flat nosed pliers to pull on the thin rubber nipple from the in side while slightly twisting the foot into place after which the excess rubber inside the case should be trimmed with side cut ters to around 2 to 3 mm so that it doesn t interfere when the board is screwed into the case The board is now inserted with the socket to...

Page 7: ...ble batteries should not be used in the FA VA4 as no deep discharge nor charging circuitry is available Deep discharge can render the rechargeable bat teries unuseable or even destroy them Leak ing batteries can likewise severely damage the equipment The FA VA4 is optimally designed to use 1 5 V AA cells Used cells must be re moved from the device For the longest battery life it is recom mended to...

Page 8: ...oth am plitude and phase This change is evaluat ed to determine the impedance of the test object All other measured values e g SWR are mathematically derived from the impedance by the microprocessor n Controls and connectors The only connection to the analyzer is the test socket For operation there are three pushbuttons and an on off switch All selected parameters are saved so that at switching on...

Page 9: ...er knows two different modes of SOL compensation SOL for all frequencies It is possible to permanently save SOL ref erence values for the entire measuring range In this case with the Short refer ence element connected the analyzer runs through the entire frequency range and stores the determined measured values The same procedure is to be carried out for connected Open and Load elements It is reco...

Page 10: ...ended to perform such compensation be fore each measurement Important if the measured frequency of the analyzer is changed the determined SOL reference values for the current fre quency are indicated as invalid and the standard values of the master compensa tion will be used instead for the next mea surement The display shows which refer ence values are currently being used For example in Fig 18 t...

Page 11: ...ctual frequency SWR One Frequency SWR measurement of the actual frequency Z One Frequency Impedance measurement of the actual frequency SWR Single Sweep Single run of SWR measurement in the specified frequency range Z Single Sweep Single run of impedance measurement in the specified frequency range SWR 5 Band SWR measurements of 5 frequencies 5 band measurement SWR Cycling Sweep Cyclic SWR measure...

Page 12: ...or decreased For an eventual compensation SOL One Frequency the corresponding function in the operation mode menu must be select ed see paragraph Calibration After recording the reference values the analyz er returns to the current measurement mode Fig 18 Fig 13 Operating mode first screen Fig 14 Operating mode second screen Fig 16 Setup mode first screen Fig 17 Setup mode second screen Fig 15 Ope...

Page 13: ...d right buttons the centre frequency can be increased or de creased by some 100 kHz At the same time each button press triggers a new measurement cycle over the defined fre quency range 2 large sign overview marker val ues and frequency range selection The SWR is again shown above the frequen cy Additionally the small rectangle on the SWR curve indicates the position of the marker see Mode M Using...

Page 14: ...nce values from the master calibration Single run for impedance measurement The active resistance solid curve and the reactance dashed curve are shown above the frequency All further displays and op erating possibilities correspond to the ver sions in the previous section SWR measurement on five frequencies 5 band measurement Five SWR values are displayed in the bar graph for five different freque...

Page 15: ...ent to do this briefly press both the left and right buttons simultaneously In the subsequent menu one of five 0 4 memory locations may be chosen using the middle Dwn and right Up buttons and selected with the left button Sel The saving to memory takes a few seconds as each pixel is transferred to the EEPROM Previously stored view data in the selected memory location will be over written To displa...

Page 16: ... for an input or a change f1 To do this use the left D S button to set the position in dicator to the position of the frequency value to be changed and the plus and mi nus buttons to correct By jumping from the last point on the left to the first point on the right 1 Hz the abbreviation ENT for enter input appears Pressing the plus or minus key now stores the set value for f1 and jumps to the freq...

Page 17: ... determined After selecting the menu item Delta Frequency press the left button The value for df is then adjusted using the middle and right buttons to the determined difference 27 000000 MHz less measured frequency Press the D S button again to select the decimal place Repeated pressing of this button will dis play the abbreviation ENT If the plus or minus button is pressed now the FA VA4 will ta...

Page 18: ... the EEPROM Fig 31 Forced Reset without menu item In the unlikely event of the device becom ing unresponsive even when switched off and on again a forced reset can be carried out without recourse to the menu To do this the analyzer must be switched off Then all three buttons should be pressed and held then if the power is switched on all parameters should reset to factory default settings and the ...

Page 19: ...st be set to the range to be measured A minimum SWR can be targeted via the Marker Mode For high quality antennas e g magnetic increased attention is necessary when tak ing a measurement Under certain circum stances depending on the chosen frequen cy range the maxima and minima are so narrow that they are not displayed Here the measurement frequency can only be further limited and the span reduced...

Page 20: ...y narrow Determination of cable resonance and resonant cables The analyzer makes it easy to determine points of resonance in coax and other RF cables Connecting an unknown cable to the analyzer the other end may be open or short circuited When the cable end is open points of resonance occur at 1 4 3 4 etc of the wavelength of the resonant fre quency With the cable shortcircuited the resonant point...

Page 21: ...known physical cable length can also be determined by the above equation Have fun and enjoy building and using the FA VA4 shop funkamateur de Literature and References 1 Knitter M DG5MK 100 MHz antenna vector analyzer for everyone FUNKAMATEUR 66 2017 H 3 S 246 249 H 4 S 360 363 2 FUNKAMATEUR Leserservice Majakowski ring 38 13156 Berlin Germany www box73 de Æ BX 240 SOL 20 BX 240 Box 73 Amateurfunk...

Page 22: ...Battery holders 2 Graphic display with backlight 1 preassembled 20 pin connector 1 or 2 10 pin for display 3 pin connector 2 for display SMD mounted circuit board 1 6 pin connector strip soldered to housing printed 1 upper and lower cover Case rubber feet 4 Cylinder grub screws M3 4 4 Board fixing Cross head screws M3 4 4 Case Building instructions 1 Type label 1 for sticking to the underside Appe...

Page 23: ...handling of electronic waste Electronic devices batteries and components do not belong in household waste For further information see www box73 de Box 73 Amateurfunkservice GmbH Majakowskiring 38 13156 Berlin www funkamateur de www box73 de www box73 com Status July 2017 ...