RF2K-S Linear Amplifier
Instruction Manual
Assembly and adjustment instructions for linear amplifier RF2K-S
Dear customer,
Congratulations on your purchase of an RF-KIT linear amplifier!
RF-KIT devices offer innovative and reliable technology, functionality, and appealing design.
If, in spite of our careful quality control, you have any reason to complain or have a question about the device, please contact the dealer you trust or even directly to RF-KIT.
by 73 es gd dx de
RF-KIT Reinhard Förtsch
Heuleithe 14
91322 Gräfenberg
Germany
Tel.: 0049 9192 99 66 89
www.rf-kit.de
mail@rf-kit.de
Raspberry Pi® is a registered trademark of the Raspberry Pi Foundation.
© 2021 by RF-KIT Reinhard Förtsch
Errors and omissions excepted. The removal of the copyright notice and the use of content, even in part, violates applicable law and is expressly prohibited.
Explanation of symbols, Environment protection
Explanation of symbols
Warnings
Warnings are marked by a warning triangle.
In addition, signal words indicate the nature and severity of the consequences if the measures to avert the hazard are not followed.
The following signal words are used in this document:
- NOTE means that property damage may occur.
- WARNING means that serious or even life-threatening personal injury may occur.
- DANGER means that serious or life-threatening personal injury will occur.
Important information without danger to people or property is marked by the adjacent symbol. This information is bonded by lines above and below the text.
Important information
| Symbol | Meaning |
| ► | Instruction |
| ➔ | Reference to a position in the document |
| ● | Enumeration/List entry |
| – | Enumeration/List entry(2 nd level) |
Environment protection
Disposal of packaging
The packaging protects the device against damage during transport. The packaging materials are selected according to environmentally friendly and disposal-related aspects and thus recyclable.
The return of the remaining packaging parts, such as packaging straps, PE bags, etc., into the material cycle saves raw materials and reduces waste.
If you plan to dispose of the packing by yourself, please locate the nearest recycling center.
Before the device can be used, any necessary adjustments must be carried out!
A Raspberry Pi® 4 Model B must also be installed (not supplied).
In order to prevent the device from being put into operation without these adjustments and installation works having been carried out, suitable measures have been taken which must be reversed for operation within the scope of the adjustment and installation works.
Note:
The device is not ready for operation when delivered!
Although it can be switched on, it will not generate any HF power.
To carry out the adjustments you need some tools and measuring instruments:
- Phillips screwdriver and small screwdriver
- Reference wattmeter
- Digital Multimeter
- Soldering station
In addition, the device must be connected to a control transmitter and a dummy load:
- Control transmitter (TRX) with adjustable output power
- 2 coaxial cables (approx. 1 m) with correctly fitted connectors PL-259
- 50 Ω dummy load; load capacity min. 1 kW
For the internal cabling you need:
- 2x USB-cable (USB-Mini to USB; approx. 0.5 m)
- 1x HDMI-cable (HDMI-Micro to HDMI; approx. 0.5 m)
These 3 cables are included in the delivery, in addition to a power plug and a piece of coaxial cable with an SMA plug.
Step 1: Unpacking the device
► Open the shipping carton carefully and remove the device.
► After unpacking the device, inspect it for shipping damage.
► Report any damage immediately to the shipping company or dealer. Keep the shipping carton.
► Place the device on a stable work surface and have ready the required tools.
Step 2: Removing the housing cover
► Loosen 4 lateral countersunk screws and then remove the housing cover.
Step 3: Removing the front panel
► Loosen 2 countersunk screws each on the left and right to detach the front panel from the device frame.
► Disconnect the cable between the power supply and the power switch (1).
Step 4: Installing a current operating system on a Micro SD card
The device is supplied with a Micro SD card, which must be loaded with the current operating system for the device.
To download the latest operating system you need a so-called “FTP program“ (e.g. “FileZilla“, “WinSCP“ or similar).
You can obtain the corresponding data as a Zip file from the following addresses: Version “International“:
| Server: | Port: | User: | Password: |
| access816807157.webspace-data.io | 22 | u100014070-rf2ksi | RF2K-S-int |
Version “US“:
| Server: | Port: | User: | Password: |
| access816807157.webspace-data.io | 22 | u100014070-rf2ks_w | RF2K-S-usa |
Version “Canada“:
| Server: | Port: | User: | Password: |
| access816807157.webspace-data.io | 22 | u100014070-rf2ks_ve | RF2K-S-ve |
Save the downloaded and unzipped file to the supplied Micro SD card using the disk imager software “Win32 Disk Imager“.
“Win32 Disk Imager“ is available as freeware for Microsoft Windows as a version for installation. The free software must therefore be installed after downloading, which requires administrative rights on the computer.
Installing a version of the operating system other than that intended for your country will void the warranty.
Step 5: Installing Raspberry Pi® 4 Model B
► Remove 4 pre-assembled screws from the spacer bolts provided for fixing the Raspberry Pi® 4 Model B.
► Insert the Micro SD card preprogrammed in Step 4 into the slot provided in the Raspberry Pi® 4 Model B.
(continued on next page)
► Place the Raspberry Pi® 4 model B on the spacer bolts as shown in the picture below and secure it with the 4 screws previously removed from the spacer bolts.
Step 6: Connection controller board with Raspberry Pi® 4 Model B
Now the Raspberry Pi® 4 model B must be carefully connected to the controller board, Touchscreen (2) using the 3 cables supplied. 2 cables from the connection sockets at the rear panel for USB and AN are also to be connected with the Raspberry Pi® 4 model B.
Always take care to avoid any mechanical stress on soldered sockets of all components.
Especially the HDMI sockets of the Raspberry Pi® 4 Model B are well known to be particularly sensitive in this respect!
► Connect the USB cable already present in the device to “D lower – USB“ on the Raspberry Pi® 4 Model B.
► Connect the LAN cable already present in the device to “FLAN“ on the Raspberry Pi® 4 Model B.
Raspberry Pi® 4 Model B:
A – Micro HMDI / B – Micro HMDI / C – Power supply / D, E – 2x USB /F – LAN
Controller board: 1 – Mini USB / 2 – Mini USB / 3 – USB / 4 – USB / 5 – USB
► Connect “4 – USB“ on the Controller board to “C – Power supply“on the Raspberry Pi® 4 Model B.
► Connect “1 – Mini USB“ on the Controller board to “Dupper – USB“ on the Raspberry Pi® 4 Model B.
The socket “2 – Mini USB“ of the Controller board will not be used and therefore remains free.
Step 7: Connection Touchscreen (2) to Raspberry Pi® 4 Model B
Touchscreen: “G – HDMI“ / “H – USB“ / “K – Power supply“
► Connect “G – HDMI“ of the Touchscreen (2) to “B – Micro HMDI“ on the Raspberry Pi® 4 Model B.
Socket “A – Micro HMDI“ on the Raspberry Pi® 4 Model B will not be used and therefore remains free.
► Connect “H – USB“ of the Touchscreen (2) to “E – USB“ on the Raspberry Pi® 4 Model B.
Step 8: Connection Touchscreen (2) to Controller board
► Connect the “K – Power supply“ of the Touchscreen (2) to “3 – USB“ on the Controller board.
Step 9: Preparatory work for alignment
A suitable plug for the Power jack (9) is included in the delivery. With this plug, together with a sufficiently dimensioned mains cable and a country-specific mains plug, the user has to prepare a mains cable suitable for at least 16 A current consumption (cable cross-section >1.5 mm 2 ).
A short piece of coaxial cable with one attached SMA plug (“Pigtail“) is also included:
► Strip off approx. 15 mm of insulation at the free end of the “Pigtail“ and tin it.
In the rear area of the power amplifier module, directly in front of the rear panel, there is the free end of a white coaxial cable. This coaxial cable normally lies flat between the board of the power amplifier module and the rear panel and has been angled upwards for better visibility in the following picture.
► Solder the “Pigtail“ to the free end of the white coax cable.
► Connect SMA-plug “Pigtail“ to TX/RX-Tuner-module.
Now the power amplifier module is bypassed and the control signal is looped through. All functions of the device can be tested in this way without generating power.
► Check all plug connections for a tight fit, freedom from mechanical tension, and correct connection.
► Connect TRX to Exciter input (17).
► Connect Dummy load to ANT1 (6).
► Establish PTT connection via PTT (7).
► Connect the device to earth via the Ground connector (11) on the rear panel.
Use a cable with the shortest possible length and the largest possible cross-section.
► Connect the unit to the mains using the power cable via the Power jack (9) on the rear panel.
Adjustment
Switch on the unit with On/Off (1). Wait until the main screen is displayed on the Touchscreen (2).
The following adjustments are made using setting
Tuner Mode: Auto – Bypass:
- Adjustment voltage display
- Test of frequency measurement and lowpass filter circuit
- Forward power display, reflected power display, and SWR display.
These power-based adjustments are carried out in the 20 m band (14 MHz).
Fig. below: Position of the potentiometers relevant for the adjustment on the Controller board.
Front panel:
| 1 On/Off 2 Touchscreen 6 ANT 1 7 PTT |
9 Power jack 11 Ground connector 17 Exciter input |
Rear panel:
Position of the adjustment elements and measuring points on the Tunerboard (up to V1.2)
Position of the adjustment elements and measuring points on the Tunerboard (from V1.5)
Step 10: Adjustment voltage display
► Adjust voltage display at the Touchscreen (2)
(Menu → Calibration → Poti Config: “Indication area Voltage“) with R26 on the Controller board to 53,5 V.
Step 11: Test of frequency measurement and lowpass filter circuit
► Set the transmit power of the TRX to 5 W (CW/AM/FM) reading on your reference wattmeter.
► Connect TRX to Exciter input (17).
► Connect Dummy load to ANT1 (6).
► Operate PTT.
The frequency display of the PA should match that of the control transmitter +/- 2 kHz.
► Check whether the display of the current band filter also changes on the Touchscreen (2) when the frequency or band is changed and whether the correct band filter is displayed.
There are control LEDs on the Lowpass Filter Board:
► Check for all bands whether the band filters are also changed when the frequency or band is changed and whether the correct band filter is selected (corresponding LED lights up red).
► Release PTT, stop transmitting.
Adjustment power display
The following power-based adjustments are carried out in the 20 m band (14 MHz).
Step 12: Adjustment forward power display (low)
► Set the transmit power of the TRX to 5 W (CW/AM/FM) reading on your reference wattmeter.
► Connect TRX to Exciter input (17).
► Connect Dummy load to ANT1 (6).
► Operate PTT.
► Adjust R502 on the Tunerboard for 1.6 V at the measuring point R525 (V1.2) / TPFWD (V1.5).
► Release PTT, stop transmitting.
Step 13: Adjustment forward power display (high)
► Set the transmit power of the TRX to at least 50 W or more (CW/AM/FM) reading on your reference wattmeter.
► Connect TRX to Exciter input (17).
► Connect Dummy load to ANT1 (6).
► Operate PTT.
► Set R24 on the Controller board so that on the Touchscreen (2) (main screen) the transmit power supplied by the TRX is displayed with the correct value as forwarding power.
► Release PTT, stop transmitting.
Step 14: Adjustment reflected power display (low)
► Set the transmit power of the TRX to 5 W (CW/AM/FM) reading on your reference wattmeter.
► Connect TRX to ANT 1 (6).
► Connect Dummy load to Exciter input (17).
► Operate PTT.
► Adjust R515 on the Tunerboard for 2.7 V at measuring point R526 (V1.2) / TPREF (V1.5).
► Release PTT, stop transmitting.
Step 15: Adjustment reflected power display (high)
► Set the transmit power of the TRX to at least 50 W or more (CW/AM/ FM) reading on your reference wattmeter.
► Connect TRX to ANT 1 (6).
► Connect Dummy load to Exciter input (17).
► Operate PTT.
► Set R23 on the Controller board so that on the Touchscreen (2) (main screen) the transmit power supplied by the TRX is displayed with the correct value as reflected power.
The bar graph of the reflected power on the main screen will deflect full, but the digital power display will still show the value to be adjusted correctly.
►Release PTT, stop transmitting.
The following step is valid for Tunerboard V1.2 only!
Step 16: Adjustment SWR-measuring bridge (up to V1.2 only!)
► Switch the device to “Standby“ using the switching area “Standby“.
► Choose the 6 m-band (50 MHz).
► Set the transmit power of the TRX to 5 W (CW/AM/FM) reading on your reference wattmeter.
► Connect TRX to Exciter input (17).
► Connect Dummy load to ANT1 (6).
► Operate PTT.
► Adjust C500 on the Tunerboard to display minimum SWR at the Touchscreen (2) (main screen).
Step 17: Looping in the PA module
► Disconnect SMA plug “Pigtail“ and unsolder its free end from the white coaxial cable.
► Solder the free end of the white coaxial cable to the output of the PA module.
There are 2 bias jumpers on the PA module. On delivery, both jumpers are in position “BIAS OFF“.
► Set both jumpers to position “BIAS ON“.
Step 18: Adjustment display current consumption
► Remove SMA plug from input SMA socket PA module.
► Switch the device to “Operate“ by tapping the switching area Standby.
Now LED “53 V-On“ lights up.
► Connect TRX to Exciter input (17).
► Connect Dummy load to ANT1 (6).
► Set the transmit power of the TRX to 5 W (SSB).
► Operate PTT, whistle briefly into the microphone until both Bias-LED lights up green.
► Keep PTT pressed.
► Adjust Quiescent current with R25 on the Controller board until 3.6 A is displayed on the Touchscreen (2).
► Release PTT, stop transmitting.
► Plug the SMA plug back into the input SMA socket PA module.
Step 19: Severe Error Alarm
► Connect TRX to Exciter input (17).
► Connect Dummy load via Reference wattmeter to ANT1 (6).
► Tune TRX to a frequency in the 20 m band (14 MHz).
► Adjust R19 on the Controller board about 10 turns counterclockwise.
► Switch the device to “Operate“ by tapping the switching area Standby.
► Set the transmit power of the TRX to 5 W (CW/AM/FM) reading on your reference wattmeter.
► Operate PTT.
If a Severe Error Alarm is already triggered now, R19 on the Controller board must be adjusted further counterclockwise. This will continue until the alarm message disappears.
► Gradually increase the transmit power of the TRX until 500 W is displayed on the reference wattmeter (the power display of the PA display may still show a different value, as it will be calibrated in the next step).
► Keep PTT pressed.
► Adjust the PAF display with R19 on the Controller board until the value “1100“ is displayed.
(Menu → Calibration → Poti Config: “Indication area PAF“)
► Release PTT, stop transmitting.
Step 20: Adjustment forward power display (full power)
This adjustment is carried out in the 80 m-Band (3.5 MHz).
► Connect TRX to Exciter input (17).
► Connect Dummy load via Reference wattmeter to ANT1 (6).
► Operate PTT.
► Slowly increase the TRX transmit power from 5 W until the Reference wattmeter reads 1000 W (CW/AM/FM).
► Set R24 on the Controller board so that on the Touchscreen (2) (main screen) Forward power is displayed with 1000 W.
► Release PTT, stop transmitting.
Step 21: Fine adjustment power display via the menu
Please also note the description in the operating instructions (➔ page 14, “Offset Calibration“)
Go to
Menu → Calibration → Offset Calibration:
The unavoidable frequency-dependent deviations of the linearity of the directional coupler used for internal power measurement can be minimized for each bandpass range. The adjustment should be performed at an output power of 1 kW. Use your preferred reference wattmeter for the adjustment.
Selection of the bandpass range is done automatically during transmission.
The detected band is highlighted.
► Adjust the internal power display by tapping switching areas > (increase value) respectively < (decrease value).
Brief actuation changes the value in the indication area Forward by 0.1 W.
Longer actuation changes the value continuously.
► Press the switching area Save to store the settings.
► Repeat this procedure for each bandpass range to be adjusted.
Step 22: Optional power fine-tuning via the menu
Please also note the description in the operating instructions (➔ page 15, “Output Power Calibration“)
Go to
Menu → Calibration → Output Power Calibration:
The output power generated at a given control power can be adjusted optionally within certain limits for each bandpass range.
The 6 m bands require a higher control power than the other frequency ranges and should therefore always be set to “100“.
Selection of the bandpass range is done automatically during transmission.
The detected band is highlighted.
► Adjust the output power by tapping switching areas > (increase value) respectively < (decrease value).
Brief actuation changes Calibration Value by 1 digit.
Longer actuation changes the value continuously (factory setting: 100.0).
Display area Forward Power constantly informs you about the currently generated output power.
► Press the switching area Save to store the settings.
► Repeat this procedure for each bandpass range to be adjusted.
Reinhard Förtsch · DH3NAB
Heuleithe 14 · 91322 Gräfenberg
mail@rf-kit.de · www.rf-kit.de
Documents / Resources
 |
RF-KIT RF2K-S Linear Amplifier [pdf] Instruction Manual RF2K-S, Linear Amplifier |
