PDF DOWNLOAD: Chapter 13
BUILDING A HOMEBREW HF RECEIVER
- Building a receiver – an unusual adventure
- What’s a reasonable goal?
- An “adequate performance” HF communication receiver
- Does it have to be so complicated?
- Planning your receiver
Direct conversion versus superhetrodyne
Why not single conversion?
Start with a single-band, single-conversion superhetrodyne
How do modern digital receivers do it?
- Receiver construction – build with shielded modules connected by thin coax.
- The 80 meter preselector
Reception on 80 meter and 160 meters is aided by a tuned transmatch
- The Variable Frequency Oscillator
- Mixer magic
Mixers will give you lots of static – and howls and squeals
A practical homebrew mixer made from discrete parts – it’s harder than it looks
Dual gate MOSFET mixers
Not all MOSFETS work equally well
A JFET alternative mixer
- Crystal ladder filters – essential for CW
All 9.000 MHz crystals aren’t equal
Using the BFO oscillator to match crystals
Switch in filters with a rotary switch
- The IF amplifier
Lessons learned from a dual-gate IF amplifier
The cascode amplifier strip – variable gain with constant Q
- Automatic Gain Control (AGC) – not a luxury7.
- The product detector
Nearly anything works at least a little
- The AF amplifier – a vital part of the signal dynamic range
Protecting your ears from strong signals
How Hi-Fi should it be?
Driving a speaker
- HF converters for the other ham bands
- Receiver power supplies
Use a linear regulator, not a switching regulator