On my radiotransmitter-blog I’ve postet an article about my latest project: A compact handheld QRP transceiver for SSB with self-containing battery pack for portable use:
Here are some pictures of my recent project, a very small SSB QRP transceiver (schematics can be found here) that covers the 20 meter band. First let’s have a look to the front panel:
And here we go for an inside view:
Starting on the left you can see the AD 9835 DDS chip on the very compact breakout board by artekit.
The breakout board is mounted on a 2 x 8 pin socket row to have the possibility to change the IC ver quickly in case of damage (I set all ICs into sockets without any exception). Above the DDS there is the ATMega 8 micro. Right from the rf-shield made of brass you can see the 9-MHz local oscillator with the ssb modulator and product detector IC NE 612.
For more information on board layout and part distribution have a cursory glance on this commented picture:
By the way: Had some nice contacts today with stations from all over Europe with 5 watts out. The rig is really fun! 🙂
73 de Peter (DK7IH)
Today I’d like to present my new homemade 14-MHZ-SSB-Transceiver to my fellow radio amateurs. Some basic information should be given first before details and circuits are to be discussed:
Frequency range: 14,000 kHz to 14,350 kHz
Transmit power: 15 to 20 Watts max.
Mode: SSB only.
The main units of this transceiver are:
- SSB-Generator: LM358 operational amplifier as microfone amplifier and MC1496 Gilbert-cell mixer for signal production.
- TX-Mixer: MC1496
- Transmitter consisting of 4 stages: 1 preamplifier, 1 predriver, 1 driver, 1 final (push-pull), all equipped with bipolar transistors
- Receiver: single conversion, interfrequency 9.785 MHz, 1 rf preamplifier (dual gate MOSFET) followd by mixer (dual gate MOSFET), SSB-filter, if-pre and if-main-amplifier (MC1350), product detector (CA3028A), audio preamp, audio final amp (LM 386)
- Frequency generation: DDS with ATMega32 driving an AD 9835
- S-Meter and AGC-circuitry: ATMega8 driving led-chain for S and RF presentation an r2r-network with op for generating agc voltage.
To be continued…
(C) 2014 by Peter Rachow, DK7IH