Projects for the amateur radio engineer. Hardware, software, electronics and test equipment for the amateur community.
Abstract The transmitter for this transceiver is designed to deliver a peak envelope power (PEP) of 10 watts on all bands from 80 to 15 meters. Due to its purpose (SSB amplification) it is a linear amplifier. The circuit is equipped with 5 stages where the first one is a gain control stage containing a…
Introductory article of this project This is some sort like “Copy & Paste”, a useful mean if you want to create a doctorate, like the former German Minister of Defense Mr Guttenberg once did. 😉 I don’t want to achieve a doctorate but the receiver of this radio is more or less the same I…
As mentioned in the introductory article to this radio the digital components in this transceiver are pre-manufactured modules that have only been put together in a more or less sensible way. ;-). These modules are: AD9850 as variable frequency oscillator (VFO), China made no-name board, Si5351 as local oscillator (LO) produced by “Adafruit”, Arduino Pro…
Follow-up articles published so far: Digital and analog main units: VFO, Local oscillator, Display, TX-Gain control Receiver unit Transmitter unit Abstract A compact SSB transmitter/receiver will be presented. This unit covers 5 bands within the amateur radio spectrum (3.5, 7, 14, 21 and 28 MHz). Receiver is a single conversion unit with an interfrequency of…
The receiver had to match a lot of requirements that should be described first: Particularly on the lower bands and with effective long wire antennas the receiver front end will see high signal levels that it has to cope with. IMD always is a serious topic in this case. Sensitivity particularly on the higher bands,…
This short article will describe the adapter board that is connected to analog data sources and that is converting the respective voltage data into suitable voltage levels for the ADC inputs PA0:PA4 at the microcontroller: The following data will be converted and later shown on the display: User keys (Key1:Key3) TX power measurement PA temperature…
This 6-band transceiver has several stages where band switching will occur: The band pass filter section (shared by transmitter and receiver) A first section of low pass filters (LPF) between the driver stage and the final amplifier A second section of LPFs at the end of the rf power amplifier chain. To keep the circuit…
The heart of this transceiver is an ATmega128 microcontroller (MCU). It controls the vast majority of functions within the radio. E. g.: Frequency generation of the 2 DDS systems, audio tone and AGC decay time, T/R-switching, the presets for transmitter gain on the 6 bands independently, display and panel lights etc. etc. And, due to…
The two DDS oscillators are mounted to the side of the cabinet. They are sited close to the microcontroller board to keep leads short. Right on the left you can see the small dual-tone oscillator for testing and tuning. Next is the AD9834-equipped local oscillator (LO), centered the AD9951 that serves as the VFO. Right…
Abstract An SSB radio for the HF bands will be presented. Featuring 12 to 20 Watts of output power (depending on DC supply), full DDS frequency generation, covering 6 major frequency bands (1.8, 3.5, 7, 14, 21 and 28 MHz) within the short wave amateur radio spectrum. The rig also features colored LCD and front…