István Ványi

RF Signal Generator

This signal generator is intended for realignment of radio receivers. The unit is cheap and fairly basic, but perfectly adequate for its intended purpose. However, the output is not a pure sine wave, so the unit may not be suited for more exacting electronic development work.

TR1 is a high gain FET (Field Effect Transistor) and is configured as a Colpitts style oscillator. The oscillation frequency is set by the variable capacitor (C1+C2) and the five pairs of switched inductors. There is significant overlap between the ranges, due to the limited range of readily available inductors. However even by using specially would inductors, four frequency bands would have been needed to cover the range.

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HF SDR transceiver – YU1LM

Low power SDR HF I/Q S/H (Sample and Hold) transceiver CW,SSB.- ADTRX1 from 30 kHz-35 MHz with external LO

HF SDR transceiver called ADTRX1 (analog + digital) is compilation of the results and previously published designs. ADTRX1 is working to the 35 MHz and it is a very simple and promising design all with classic size thru holes components. It is very good introduction in to the new SDR technique of the HF transceiver design. Most of demanding specification for HF transceivers are in software now, not in hardware like in classic HF transceiver design. Part 1 is giving description main ADTRX1 board, results and basic connections

Schematics diagram are available: read more

The HF all-band homebrew transceiver by jg1ead

The home made transceiver covers 3.5 to 3.6 MHz and is CW only. It has the following features:

Characteristics and composition:

• Frequency coverage : 3.5MHz-28MHz 8band
• Mode : SSB/CW
• TX-final : 2SC1947
• Power output : 1W
• RX-RF amp : 2SK125*2(Grounded Gates)
• 1stIF : 48.7265MHz
• TX/RX 1st mixer : MiniCircuit MCL-1
• RX 1st IF amp : MC1350P
• 2ndIF : 11.2735MHz
• TX/RX 2nd mixer : MiniCircuit MCL-1
• RX-2nd IF : MC1350P*2

Schematics diagram are available: homebrew transceiver

T03DSP High Performance Transceiver with DSP IF processing

The goal of this project was to build a high performance HF transceiver with DSP IF processing. I did not try to archive as high parameters as possible, I just tried to get most from the available technology (i.e. mechanical and electrical parts and assembly technology). I tried to keep the design as simple as possible. The design widely uses “software” techniques that allows easy modifications and opens new possibilities.

Features

• Amateur radio bands (160m,80m,40m,30m,20m,17m,15m,12m,10m)
• 0.25 Hz and more (two tuning speed for each mode is available), implemented adaptive tuning step (1x..20x)
• USB, LSB, CW (Normal/Reverse), AFSK, RTTY (decode only by now), (PSK31 with decoder and coder will be implemented in software later)
• Selectivity 100Hz-3000Hz bandwidth in 50Hz steps
• Automatic memory keyer (built in)
• Automatic contest number generation, 5 different number formats available
• Digital RX:S-meter and calibrated input signal power meter
• Digital TX:Output power, SWR and compression (displayed simultaneously)
• 24h real time clock (powered from ionistor during power off periods)
• AFC and tuning indicator in RTTY mode
• Adjustable voice operated squelch for SSB mode
• CAT system compatible with Kenwood command set
• Built in dual tone generator for transmitter testing

T03DSP audio amlifier

Transceiver DSP

Transceiver display

Schematics diagram are available: High Performance Transceiver