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An assembled 5W HF Amplifier kit compatible with the Ultimate3S transmitter kit, and also for standalone use in homebrew projects
R526.00
A 5W HF Amplifier kit compatible with the Ultimate3S transmitter kit, and also for standalone use in homebrew projects
R401.00
buddypole.jpg
The Buddipole HF Portable Antenna
R2,800.00
HF 20W Dummy Load Assembled
R271.00
HF 20W Dummy Load
R171.00
The basic QNC unit is a small box that is inserted in between the main antenna coax from the main antenna and the radio to reduce noise
R1,599.00
mcHF RS-918
mcHF QRP RS-918SSB Clone HF SDR
R7,250.00
5W HF Amplifier (Assembled) (5WPA(A))
Assembled and tested.

This 5Watt HF PA (Linear Amplifier) kit is fully compatible with the Ultimate3S transmitter kit, and also for standalone use in homebrew projects. It has the unique feature of onboard raised cosine envelope shaping for perfect click-free CW. There is a discrete component power modulator with foldback current limiting, adjusted by an 8-bit DAC controlled by the microcontroller to generate the raised cosine envelope shape.

This 5W HF PA kit features an IRF510 MOSFET as the amplifier. But it also includes a discrete component power modulator (like a voltage regulator), which is controlled by an 8-bit Digital to Analogue Converter (DAC). A microcontroller can load a 74HC595 shift register with a sequence of DAC values which closely replicate an ideal raised cosine RF envelope. This makes a very clean CW transmission, practically eliminating key clicks. 

Features:

  • Approx 16dB of gain at HF
  • IRF510 MOSFET PA stage providing 5W or more RF output from 200mW drive (varies by band)
  • Raised-cosine keying envelope generation
  • Option for standalone envelope shaping, without external microprocessor control
  • 80 x 37mm PCB, compatible with Ultimate3S transmitter kit
  • Discrete component power modulator with foldback current limiting
  • Designed for typically 12V or 13.8V operation
  • Large heatsink
  • Supports RD15HVF1 transistor substitution for VHF/UHF operation

The kit is on an 80 x 37mm PCB, the same size as the Ultimate3S transmitter kit and relay-switched filter kit. It can be used with the Ultimate3S transmitter kit. Firmware versions v3.12 and above are capable of generating the raised cosine keying envelope. The connections required for use with the Ultimate3S transmitter kit are described in App Note AN004. Requires Ultimate3S firmware v3.12 and above.

The kit can also be built in a standalone mode, with onboard raised cosine envelope keying generated by an optional ATtiny84 microcontroller. This is plugged into the IC socket on the PCB instead of the 74HC595 shift register chip. The ATtiny84 is programmed to produced the raised cosine RF envelope and also provides a key-out signal which can be used to key a driver stage. This application of the kit is perfect for use in your homebrew transmitter projects. It is described in App Note AN005, which also includes discussion of a 5W CW transmitter built using the QRP Labs VFO kit and this 5W HF PA kit. The programmed ATtiny84 microcontroller is available as an option when purchasing the PA kit

Finally, one or more circuit blocks may be bypassed. A simplified assembly manual details a simplified way to assemble the kit, without using the power modulator and raised cosine keying generator circuits. This may be suitable for people who wish to build a more simple PA that does not include the raised cosine keying facility.

This is a Class-C or D amplifier for CW operation or FSK modes. It is not a Linear for SSB purposes. It might be possible to bias it for Linear operation, this will require some experiment. 

An assembled 5W HF Amplifier kit compatible with the Ultimate3S transmitter kit, and also for standalone use in homebrew projects
R526.00
5W HF Amplifier Kit (5WPA)
This 5Watt HF PA (Linear Amplifier) kit is fully compatible with the Ultimate3S transmitter kit, and also for standalone use in homebrew projects. It has the unique feature of onboard raised cosine envelope shaping for perfect click-free CW. There is a discrete component power modulator with foldback current limiting, adjusted by an 8-bit DAC controlled by the microcontroller to generate the raised cosine envelope shape.

This 5W HF PA kit features an IRF510 MOSFET as the amplifier. But it also includes a discrete component power modulator (like a voltage regulator), which is controlled by an 8-bit Digital to Analogue Converter (DAC). A microcontroller can load a 74HC595 shift register with a sequence of DAC values which closely replicate an ideal raised cosine RF envelope. This makes a very clean CW transmission, practically eliminating key clicks. 

Features:

  • Approx 16dB of gain at HF
  • IRF510 MOSFET PA stage providing 5W or more RF output from 200mW drive (varies by band)
  • Raised-cosine keying envelope generation
  • Option for standalone envelope shaping, without external microprocessor control
  • 80 x 37mm PCB, compatible with Ultimate3S transmitter kit
  • Discrete component power modulator with foldback current limiting
  • Designed for typically 12V or 13.8V operation
  • Large heatsink
  • Supports RD15HVF1 transistor substitution for VHF/UHF operation

The kit is on an 80 x 37mm PCB, the same size as the Ultimate3S transmitter kit and relay-switched filter kit. It can be used with the Ultimate3S transmitter kit. Firmware versions v3.12 and above are capable of generating the raised cosine keying envelope. The connections required for use with the Ultimate3S transmitter kit are described in App Note AN004. Requires Ultimate3S firmware v3.12 and above.

The kit can also be built in a standalone mode, with onboard raised cosine envelope keying generated by an optional ATtiny84 microcontroller. This is plugged into the IC socket on the PCB instead of the 74HC595 shift register chip. The ATtiny84 is programmed to produced the raised cosine RF envelope and also provides a key-out signal which can be used to key a driver stage. This application of the kit is perfect for use in your homebrew transmitter projects. It is described in App Note AN005, which also includes discussion of a 5W CW transmitter built using the QRP Labs VFO kit and this 5W HF PA kit. The programmed ATtiny84 microcontroller is available as an option when purchasing the PA kit

Finally, one or more circuit blocks may be bypassed. A simplified assembly manual details a simplified way to assemble the kit, without using the power modulator and raised cosine keying generator circuits. This may be suitable for people who wish to build a more simple PA that does not include the raised cosine keying facility.

This is a Class-C or D amplifier for CW operation or FSK modes. It is not a Linear for SSB purposes. It might be possible to bias it for Linear operation, this will require some experiment. 

This is a kit and you will only be receiving a plastic bag with components that you have to assemble yourself using appropriate tools and skills. Assemblers may be available at additional cost for some kits. The photos are only representative examples of the completed kit. Always download the latest information from the website at http://www.qrp-labs.com

A 5W HF Amplifier kit compatible with the Ultimate3S transmitter kit, and also for standalone use in homebrew projects
R401.00
buddypole.jpg
Buddipole (Buddipole)
This is a dummy card for testing purposes and the antenna cannot be ordered at this time.

New prices are negatively influenced by the rand/Dollar exchange rate, query for the latest position.

The Buddipole HF Portable Antenna
The Buddipole HF Portable Antenna
R2,800.00
Dummy Load (Assembled) (20wDummyLoad(A))
Assembled and tested.

A useful shack accessory, this is a simple 50-ohm 20W dummy load kit using 20 individual 1K resistors in parallel. Additionally this kit has a diode-capacitor rectifier for detecting the peak voltage of the RF waveform, which may be measured using a DVM.

The dummy load kit comes with 20 1K 1% 1W resistors, a diode-capacitor rectifier for peak voltage readings using a DVM, and a BNC connector. There are two identical PCBs, and the resistors are sandwiched between them to minimise stray inductance. The PCB size is 1.7 x 1.4 inches (43 x 36mm). The sandwiched-together assembly is about 0.6 inches (15mm) thick. Please note that the BNC connector is threaded but no mounting nut is included.

Measured DVM power output indication

This is a simple and inexpensive peak voltage detector and you should not expect amazing accuracy from it. However it can give a useful indication of output power, and even a reasonably accurate one if you calibrate it using a known accurate power meter. The following measurements were made on one kit (as constructed for the assembly manual photography) and power output 0.8mW to 10W. The power measurement was made using the peak-to-peak measurement function of a 100MHz digital oscilloscope. The DVM used was an inexpensive common yellow plastic few-$ type. The two graphs below show the same data, but the second graph (blue line) is zoomed in to show the very low power region 1-400mW. 

HF 20W Dummy Load Assembled
R271.00
Dummy Load Kit (20wDummyLoad)
A useful shack accessory, this is a simple 50-ohm 20W dummy load kit using 20 individual 1K resistors in parallel. Additionally this kit has a diode-capacitor rectifier for detecting the peak voltage of the RF waveform, which may be measured using a DVM.

The dummy load kit comes with 20 1K 1% 1W resistors, a diode-capacitor rectifier for peak voltage readings using a DVM, and a BNC connector. There are two identical PCBs, and the resistors are sandwiched between them to minimise stray inductance. The PCB size is 1.7 x 1.4 inches (43 x 36mm). The sandwiched-together assembly is about 0.6 inches (15mm) thick. Please note that the BNC connector is threaded but no mounting nut is included.

Measured DVM power output indication

This is a simple and inexpensive peak voltage detector and you should not expect amazing accuracy from it. However it can give a useful indication of output power, and even a reasonably accurate one if you calibrate it using a known accurate power meter. The following measurements were made on one kit (as constructed for the assembly manual photography) and power output 0.8mW to 10W. The power measurement was made using the peak-to-peak measurement function of a 100MHz digital oscilloscope. The DVM used was an inexpensive common yellow plastic few-$ type. The two graphs below show the same data, but the second graph (blue line) is zoomed in to show the very low power region 1-400mW. 

HF 20W Dummy Load
R171.00
HF QRM Noise Canceller (QNC) (QNC1)

How Does It Work?

The basic QNC unit is a small box that is inserted in-line with the main antenna coax that comes from the main antenna to the amateur’s radio in the shack, with one small addition: It has an extra AUX Input.

The AUX antenna (“Noise Pickup  Antenna”)is simple a length of wire 6 meters long, placed lower down to catch the local noise, if it is installed too high it will pick up the far away signals which is not what we want to reduce. The focus is on the local noise, thus a lower physical installation. I ran my own wire under the eaves of my house.

The QNC unit takes the AUX signal from the local Noise Pickup Antenna inverts it, and mixes it with the Main Antenna input. The result – which contains the wanted distant signal minus the unwanted local signal – is then sent to the amateur’s radio normal input.

By adjusting the mixing the local noise on the signal can be cancelled out almost completely. The level of cancelling can be adjusted over a wide range. The best situation is where all the local stations are cancelled out and only the far away stations are audible. But then you risk talking over the local Stations trying to contact the far stations. A bit of experimentation will be required to achieve the best operation!

During the last few months I found the unit especially useful to me working the HF bands.

The QNC currently works from 1Mhz to 30Mhz, and there are plans to expand the range from 1.5 MHz to 50 Mhz.

YouTube Link QRN In Action

The basic QNC unit is a small box that is inserted in between the main antenna coax from the main antenna and the radio to reduce noise
R1,599.00
mcHF RS-918
RS-918 Color HF-SDR Transceiver (RS-918)
A Chinese clone of the mcHF transceiver project for those who don't have the eyesight to be able to construct their own
mcHF QRP RS-918SSB Clone HF SDR
R7,250.00
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