[KYHAM] (no subject)
Bill Fuqua
[email protected]
Wed, 03 Dec 2003 10:28:30 -0500
I thought I should keep you informed of the progress in the development
of the workshop and the instructional program.
You may find the following information interesting.
Here is some more information on the Radio Theory and Construction Workshop.
I have expanded the lab manual for the AM-550K radio kit.
Following is an outline of the expanded kit project:
Radio Theory and Construction Workshop for beginning students
using the AM550K AM Receiver Kit:
I. Soldering and Safety Lesson
A. Safety glasses, fume removal, lead
B. How to solder
C. Tools Required
1. Safety Glasses or Goggles
2. Soldering Iron and accessories
3. Diagonal Cutters (4")
4. Long Nose Pliers (4")
5. Screw Driver Set
6. Calculator
7. PC Compatible Computer with Sound Interface
II. Crystal Set
A. Construct tuner and wire antenna
B. Attach *earphone (nothing heard)
C. Add diode detector between tuner and earphone
D. Listen and tune radio stations and log the stations received
and relative sound level
E. Discussion:
1. AC signals and Radio Waves
a. electrical current and magnetism
b. Frequency
c. wave length etc .
2. Antennas
3. Resonance
a. Demonstrations of resonance. Pendulum and
vibrating reed demos.
b. Discuss Inductance and Capacitance and
how they work together
to store Oscillating energy. How
Q comes about by looking at flow of
energy into the resonate system,
out and of the resonant system.
c. Discuss self sustained oscillation and
how an oscillator works in time domain.
4. Diode (rectifiers) as detectors and in power supplies
And filters (in both power supplies and AM
detectors)
5. How to measure sensitivity of radio
E. Measure sensitivity of crystal set
1. Using *Standard Generator and *10" loop antenna
2. Using direct connection to antenna and ground
terminals .
III. Audio Amplifier
A. Construct Audio Amplifier using a LM386 IC
B. Check resistance measurements
C. Static measurements
D. Buzz test (finger on input)
E. tone test (using computer)
Introduce use of *PC sound card and software
Measure gain and frequency response
F. Use *crystal earphone as microphone and demonstrate an intercom
G. Discussion:
1. Audio amplifier
2. Gain
3. Frequency response
4. Power measurement
5. How a speaker works
6. Distortion
a. Frequency domain of distorted signals
b. General discussion of signals and
frequency domain.
7. Negative feedback to improve linearity and
stabilize gain
IV. Crystal Set with Audio Speaker Amplifier
A. Connect the audio amplifier to the audio detector
B. Measure sensitivity
C. Introduce *BFO
D. Attach *BFO Zero Beat and measure AM sensitivity again
E. Listen to CW signal
F. Shift *BFO 10 KHz and observe AM spectra using a PC with FFT
program.
At this time we can also demonstrate Digital Signal
processing using the PC
And using the PC as a digital IF processor and
demodulator.
G. Discussion:
1. Amplitude Modulation in frequency domain
2. Ying and Yang of non-linearity (diodes and other
devices)
3. How a non-linear device can convert frequencies
with a local oscillator and do so
with little distortion. But introduces a
great deal of distortion when not mixing.
4. Sensitivity improvement using BFO for AM reception.
5. Advantages of CW over AM
V. Detector and AGC,( audio amplifier )
A. Add AGC to diode detector
B. Inject signal and measure sensitivity (voltage) and selectivity
C. Discussion:
1.Time constant and function of AGC.
2.Tuned IF transformers and what they do
3.The Function of IF filters
4.General Discussion of Superheterodyne Receiver theory
VI. Second IF, (Detector , AGC, audio amplifier )
A. Construct second IF amplifier
B. Tune IF transformers
C. Measure sensitivity and selectivity
D. Discussion:
1. Why is the selectivity improved
2. The effects of cascading filters and amplifiers
VII. First IF , (Second IF, Detector , AGC, audio amplifier )
A. Assemble first IF
B. Align transformers
C. Measure sensitivity and selectivity
D. Observe AGC effect
E. Discussion:
1. Further discussion of cascaded filters and amplifiers
2. Bandwidth limited noise and signal to noise
3. Imagine an infinite series of filters and amplifiers
4. Discuss the LC oscillator in terms of frequency
domain
VIII. Complete receiver
A. Construct the converter (mixer and local oscillator)
B. Align the Antenna tuned circuit and the Local oscillator
C. Measure Sensitivity and selectivity
D. Measure effectiveness of the AGC
E. Discussion:
1. Superheterodyne receiver.
2. Improvements to basic Superheterodyne receiver
a. Better IF filter
b. RF amplifier
c. Multiple conversions
d. Improved mixers and detectors
e. Digital Signal Processing
IX. Good, Bad and Ugly Oscillator and components
A. Construct a *Hartley oscillator
B. Using the receiver with *BFO listen to signal
C. Move hand near oscillator components and notice frequency shift
D. Touch cheap capacitor (ceramic) to raise temperature and then
remove
and notice temperature dependance of
frequency(frequency drift)
E. Touch expensive capacitor (silver mica) as above and compare
temperature
effect as compared to ceramic
F. Tap oscillator to observe microphonic effects
H. Musical instrument?? Theremin
The very basic concepts of electricity and electronics will be taught from the
*"Now You're Talking" text book Published by the ARRL.
Note: (*) indicates items not in the kit but are provided at the workshop.
I have some of the following kits for advanced students that have completed
the above outlined program.
1. 6 and 2 meter FM receiver kit
2. Direct conversion SSB and CW kit for any HF ham band by Ten Tec
3. Active antenna kit
4.We have also discovered some CW code practice receiver kits still in
storage. These are direct conversion crystal controlled
W1AW receiver kits.
Some advanced students like the idea of designing their own projects. I
have a large personal stock of parts that should help. Also, even if you
are not participating in the workshop and have a project in mind you may
want to check with me first before ordering parts. I may have some items
that you can use. If not I may be able to tell you where to buy them at a
lower prices than the usual sources.
73
Bill wa4lav
--- StripMime Report -- processed MIME parts ---
multipart/alternative
text/plain (text body -- kept)
text/html
The reason this message is shown is because the post was in HTML
or had an attachment. Attachments are not allowed. To learn how
to post in Plain-Text go to: http://www.expita.com/nomime.html ---