Hands-off Electronics: A little bit of Monica. A little bit of Erica
Read our related article: Hands-on Electronics – Signal tracing a simple transmitter
Hog Heaven at the Mailbox
The good times just keep on rolling.
Going out to the mail box I found a white envelope from CBC International. I expected more of a box – but an envelope is what I got. “You go to war with what you got.” OK, I get it.
There was my copy of The ‘Screwdrivers experts’ Guide: Do it yourself CB repair and modifications by Lou Franklin ( K6NH )
Could it get better? Yes, it was personally signed by Lou. “Best Wishes, Lou Franklin”. I am in hog heaven.
You might think this posting is from our “We wasted our money on this so you don’t have to department. Well, yes it is. In these tough economic times you have to “spread the wealth” for the good of the country. So I made this discretionary purchase – it was my patriotic duty.
But really, I wanted to see what was in this book – I could not find it in my local public library system. This book is a companion to another book by Lou Franking “Understanding & Repairing CB Radios for the Professional Technician”
Why is there something rather than nothing?
I got these books because I found a box of old CB radios. I estimated the salvage value of this box of radios to be about $0 USD. So, what better way to play around with some electronics than to mess with these radios?
“A little bit of Monica in my life. A little bit of Erica by my side”
That’s the way you do it. A little bit of this and a little bit of that. A little bit of theory and a little bit of practice. Each reinforce each other. “And if it looks like this. Then you are doing it right”
Lou Franklin as an author
Here is an observation about Lou Frankin as an author. He knows his audience. To effectively communicate one has to know the audience – you need to be able put yourself in the perspective of the readers and see the subject from the thier perspective. Lou does an excellent job at this.
Each of Lous books address a specific audience: a) the utterly clueless and b) the technician.
The Screwdrivers Experts Guide
The Screwdrivers Experts Guide is for the utterly clueless. On the back of the book it says “Finally, a Big Dummys Manual of CB Radio Repair. In the Introduction, Lou makes a fundamental statement “YOU DO NOT HAVE TO KNOW HOW SOMETHING WORKS IN ORDER TO BE ABLE TO FIX IT.”
Now that is pretty scary if you think about it – especially if someone else is working on your radio and makes this assertion. Reminds me of a “shade tree mechanic” doing a tune-up with a mallet and chisel. I will take my car to the dealer, thank you.
On the other hand, it is true from a vocational/functional perspective. In college, I saw a vendor technician repair a mini-computer by replacing boards until it worked. He arrived in a suit and tie with a large briefcase on a hand truck. This briefcase contained a replacement board for every board in the computer. The technician swapped boards until the computer worked. That person had to know nothing about computers – how they worked or what they did. He could have been repairing a refrigerator for all he knew – swapping parts until the device worked.
Lou’s Screwdrivers Experts Guide is a bit better than the story above. There is almost no electronics or radio theory in the book but it is heavy on diagnosis. Once you make the diagnosis then Lou provides the repair advice.
Almost half the book, the first half of the book, is dedicated to solving mike problems, mike wiring, antennas (loading coil types, base antennas, antenna matching, coax connectors, and Co-phased dual antennas), and discussing the myths of SWR.
The second half of the book is about common radio problems based on symptom (dead radio, burnt out protective diodes, no transmit, no receive, how to change power devices, no sound from speaker, etc). This part of the book also contains information on alignment and peaking radios.
There are six (6) appendices. These cover modifications – mostly illegal. Frequency expansion, and power adjustments. Of course, the first page of the book says that the information presented in this book is for educational purposes only.
Lou’s other book “Understanding & Repairing CB Radios for the Professional Technician” is at the other end of the spectrum. This is a very focused and technical book specifically on CB radio using real circuits that you will find in many models. Lou provides only as much theory as you need to know. In my estimation, this is an excellent direct and to-the-point book. No fluff.
One mans junk is another mans vintage electronics
Both of these books are ancient. The Screwdriver Experts Guide going back to 1977 – 32 years at the time of this writing. The Understanding and Repairing CB Radios going back to 1988 – 21 years at the time of this writing.
But isn’t this exactly what you need if you have a box of old CB radios from the 1970’s and 1980’s? Yes, perfect.
So what’s the point.
The point is this. If you find a box of CB radios laying around why not use this as an opportunity to learn something about electronics and radio? A little bit of theory and a little bit of practice. Your theory is provided by Lou – it is only as much as you need – direct and to the point – easy to read. And you have the box of radios – value approximately $0. So why not put these two together, apply a bit of intellectual effort, and discover what you can learn.
Ham Radio folks have to get over themselves in their disdain for CB radios. A radio is a radio and a CB radio is an AM radio just like vintage ham radios of days gone by. So, use that box of CB radios as a near zero cost learning opportunity about radio and electronics. Buy the Lou Frankin books, apply some effort, and you are on your way to improving yourself.
In THE “SCREWDRIVER EXPERT’S” GUIDE (To Peaking Out & Repairing CB Radios)
· How to “peak out” your transmitter, modulation, and receiver for greatest range and efficiency.
· How to wire any mike or power mike to any CB radio, or diagnose and repair mike-related problems.
· How to diagnose and repair the most common antenna/SWR problems.
· How to diagnose and replace bad “Finals” and crystals for about $3.
· Worthless gimmicks and junk products that don’t do anything.
· Tips on curing automobile ignition noise.
· The best brands to buy, and what to avoid.
· Methods of changing and adding channels for both crystal and PLL radios.
· How to add FM to many AM or AM/SSB models.
· How to unlock the Clarifier so that it also slides on Transmit.
· Specific power & modulation adjustments for hundreds of American and foreign PLL models.
UNDERSTANDING & REPAIRING CB RADIOS
Here’s a small sampling of the fact-filled contents:
CHAPTER 1 — INTRODUCTION TO CB SERVICING
The new Surface Mount technology. CB technical specs defined. Test equipment you’ll need. Inexpensive testing aids you can build yourself. Additional information sources. Includes a complete shopping section for CB radios, antennas, parts, accessories, and test equipment including names, addresses, and “800” numbers. Plus much more!
CHAPTER 2 — BASIC TROUBLESHOOTING TECHNIQUES
Block diagrams teach you theory of AM and FM receivers and transmitters. Use of the systematic approach. Testing semiconductors. Signal injection and signal tracing. Intermittents. Interpreting DC biases. Transistor amplifier circuits. Understanding device markings. Plus much more!
CHAPTER 3 — GENERATING THE SIGNAL FREQUENCIES
Crystals and crystal oscillators. Series and parallel resonance. The Colpitts Oscillator. Overtone oscillators. Oscillator troubleshooting. How to order crystals. Walkie-Talkies. The VFO, Crystal and PLL synthesizers. Elements of the PLL system. How digital dividers work. Generating the binary and BCD channel codes. ROM programming. Additional PLL functions. Expanded coverage synthesizer methods. Broadbanding methods. Evolution of the PLL using several examples. PLL alignment procedures and equipment set-up. PLL troubleshooting methods. The MB8719 synthesizer. Includes 23-channel crystal mixing charts covering 90% of all AM CBs; use these to quickly determine dead channels or 10-Meter Ham conversions. Plus much more!
CHAPTER 4 — RECEIVER CIRCUITS
RF and IF Amplifiers. Mixers. Single- vs. dual-conversion methods. IF selectivity methods plus tips on improving them. IF troubleshooting. Detector circuits. ANL circuits. AGC circuits. AGC troubleshooting. The S-Meter circuit. Noise Blankers. NB troubleshooting. FM detector circuits. FM receiver troubleshooting. Squelch circuits. Squelch troubleshooting. Scanning circuits. Selective calling. The audio amplifiers. Audio troubleshooting. LED channel displays and bar/graph displays. Delta Tune circuits. Tone controls. Receiver alignment procedures and equipment set-up. Plus much more!
CHAPTER 5 — TRANSMITTER CIRCUITS
The RF amplifier chain. Oscillators, mixers and buffer stages. Power amplifiers. Classes of amplifier operation. Biasing methods. Vacuum tube power amps. Power doubling methods. Power reduction methods. Coupling and filtering. AM and FM modulation methods. Speech processing. Mikes and mike problems. Limiters and compressors. Measuring and adjusting modulation. RF Power Meter circuit. Modulation meter circuit. SWR Meter circuit. Antenna Warning circuit. Roger Beep Oscillator circuit. CW keying circuit. Selective calling circuit. Transmitter alignment procedures and equipment set-up. Plus much more!
CHAPTER 6 — SINGLE-SIDEBAND CIRCUITS
SSB characteristics, pros and cons. SSB signal generation. The Carrier Oscillator. Carrier and synthesizer offset methods. The speech amplifier. The Balanced Modulator. BM troubleshooting. Sideband selection methods. SSB crystal filters. The mixer. Mixer troubleshooting. Linear RF power amplifiers. Biasing methods. AM/SSB power and modulation control. ALC. Testing the SSB transmitter. SSB reception methods. The Balanced Demodulator. The Product Detector. The Clarifier circuit. Clarifier troubleshooting. IF amplifiers. SSB AGC methods. SSB transceiver alignment procedures and equipment set-up. Plus much more!
CHAPTER 7 — POWER SUPPLIES AND T/R SWITCHING
The mobile DC power supply. Ground loops. Electronic and relay T/R switching circuits. Voltage regulation circuits. The base station AC/DC power supply. The solid-state base supply. Tube and hybrid power supplies. DC-to-DC power supplies. Multimode transceiver power supplies. Includes use of SAMS Fotofacts schematics for step-by-step analysis of several common power circuits. Troubleshooting the power supply. Plus much more!
CHAPTER 8 — ANTENNAS AND TRANSMISSION LINES
Mobile antenna types and mounting hardware. 27 MHz characteristics. The ½-wave antenna. Reactance and tuning. Impedance and radiation resistance. The Standing Wave Ratio (SWR). Coax length vs. SWR. Coax characteristics. Effect of in-line accessories. Coax losses vs. SWR losses. Some practical coax tips. Bandwidth. Gain and directivity. Radiation patterns and field strength. Omnidirectional antennas. Loading coils. Directional mobile antennas. The Quad and Yagi beam, including dimensions for home construction. The PDL. Antenna matching principles. Tuning and troubleshooting the mobile whip. Magnetic antennas. Co-phasing simplified. Co-phase matching tips. Use of dummy loads in troubleshooting. Matching high-Z verticals. Matching Quad and Yagi beams. Stacking beams for increased gain. Preventing TVI. Matching special CB antenna types. Plus much more!
APPENDIX A — SOLVING NOISE AND INTERFERENCE PROBLEMS
TVI and RFI. Front-end overload. Audio interference. Ignition and other automotive noise problems. Includes reference data and parts suppliers.
APPENDIX B — FCC FREQUENCY CHART
Quick reference 40-Channel frequency listings including tolerances.
Thousands of entries covering virtually every related subject. Lets you troubleshoot a specific problem by looking up its symptom here. This is the cheapest education in CB radio servicing you’ll ever get! (And most likely the only modern book on the subject you’ll ever find.) Completely illustrated throughout. Hundreds of tips to make you money and impress customers with your technical knowledge. SATISFACTION GUARANTEED!