Best methods to learn how to fix and build radios?

  • #1

Main Question or Discussion Point

I was thinking that a good way to learn a lot about basic radios and other non integrated circuit electronics would be to take them apart and fix the connections with a scoldering iron and a multimeter. My goal is to understand how radio circuits work so I can build them and fix them. Any comments on what you think of this approach would be appreciated.
 

Answers and Replies

  • #2
Doug Huffman
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It is the traditional approach, but not so easy now that IC are universal. My first radio transmitter was a seven foot tall Collins Kilowatt KW-1.
 
  • #3
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As learning instruments, vacuum tube radios were superior. It may be difficult but not impossible to find some to tinker with even today. I wager that there must be support forums on the Internet for that.

By the way, Richard Feynman once famously fixed a radio by pulling the tubes and putting them back in reverse order.
 
  • #4
nsaspook
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Go to your local thrift stores and buy old electronics castoffs if you want to understand mechanical construction and repair. Just poking around with a multimeter won't gain you much electronic knowledge about the fundamentals of radio operation, design and repair. You can reenforce book learning by this but it's not a substitution for it.
 
  • #5
Baluncore
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I would suggest that you find a local amateur radio operator or group. Getting an old edition of the ARRL handbook would be a good move, it could come from a second hand bookshop or a local amateur radio operator.
 
  • #6
Doug Huffman
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Nothing good happened with the relaxation of licensing requirements into commodities.
 
  • #7
Baluncore
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Nothing good happened with the relaxation of licensing requirements into commodities.
Relaxation of the entry requirements has not actually hurt the amateur community or “service”. If anything, relaxation has given it a reprieve from some band cancellations.

There was a time pre-WW2 when CW speed was the only important entry requirement. Following the technical training offered by the services during WW2 the technical competence of operators increased. Unfortunately the post WW2 entry requirements remained artificially high and required significant experience before entry into the field. That was a significant barrier to new membership.

The expansion of an interest in wireless technology requires books on the subject, junk radio gear, used test equipment and knowledgeable people to answer questions. Here on PF we can answer the questions, but the rest should come from the pool of books, junk boxes and deceased estates looking for a home. That is best found through what remains of the local amateur radio community.
 
  • #8
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I was thinking that a good way to learn a lot about basic radios and other non integrated circuit electronics would be to take them apart and fix the connections with a scoldering iron and a multimeter. My goal is to understand how radio circuits work so I can build them and fix them. Any comments on what you think of this approach would be appreciated.
Find an old oscilloscope on ebay, and learn to use it. Learn to read a schematic.
I showed my Son, without much trouble while he was learning to work on guitar amps.
Some of the old Schematics show what the signal should look like at different parts of the circuit.
If you have not done so, a basic analog electricity class would help. (I am not sure they still teach that)
 
  • #9
Bandit127
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(I am not sure they still teach that)
It's a good job that analog electronics are required to make digital work.

I would agree with the sentiment of a lot of responses on this thread. The OP needs to find a group of people who can teach and mentor, either formal or informal. Self teaching electronics is going to be a slow slog.
 
  • #10
I found this channel on Youtube I think it is very good:https://www.youtube.com/user/AllAmericanFiveRadio
I will try to learn how to understand circuits through that channel and hands on experience with circuits and of course wikepedia. Thank you for all the great respones!
 
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  • #11
jim hardy
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  • #13
jim hardy
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What should you learn from an RCA manual?
It is a wonderful textbook on tubes and analog circuit analysis.

You will learn what voltage to expect at every point in a circuit.
Tubes have pins that are big enough you can get a voltmeter probe onto them.
Today's IC's have such teensy pins so close together it's hopeless for a beginner to work with them. I have to use a sewing needle and magnifying glass...
 
  • #14
It is a wonderful textbook on tubes and analog circuit analysis.

You will learn what voltage to expect at every point in a circuit.
Tubes have pins that are big enough you can get a voltmeter probe onto them.
Today's IC's have such teensy pins so close together it's hopeless for a beginner to work with them. I have to use a sewing needle and magnifying glass...
Vacuum tubes are pricey but I agree.
 
  • #15
Nidum
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Do it backwards .

There are large numbers of electronic kits available from trivial to complex . Put some of them together and learn as you go .

Similarly put together some electronic circuits from hobby electronic books .

There are also school and college level electronics learning systems with a pack of components , breadboard and (usually) good teaching material .
 
  • #16
Nidum
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Purely as a bit of nostalgia - my first ever experience of electronics was making a crystal set .
 
  • #17
berkeman
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Purely as a bit of nostalgia - my first ever experience of electronics was making a crystal set .
Me too! I was about 8 years old, I think, and I still remember Dad helping me string the long antenna wire across the side yard... :smile:
 
  • #18
davenn
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Purely as a bit of nostalgia - my first ever experience of electronics was making a crystal set .
Me 3 :smile:

Seems so long ago .. was also around 8 - 10 yrs old.
Dad knew nothing of electronics, it was with my Grandad and my summer holiday visits there that I learnt about such things

Dave
 
  • #19
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You may have found all the infomation you wanted Sorry I just joined up an could recommend the following,

There are a number of Ham web pages on the internet. I think that K7QO.net is an excellent choice. His Lab book is an great source for learning. Also the ARRL Handbook is a great learning tool.
The All American 5 really refers to using 5 tubes for the set. Those tubes are hard to get today. Most are made in Russia. You can find some at a Ham Swap meet. The old radios are hard to find and getting a schematic may be harder.

There a number of places to get the manual but are getting harder. Chuck (k7QO) may have some tube stuff but you will have to look.
I had a Yaesu 101e that had a old TV Horizontal output tubes for a final amplifier the cost was about 7 or 8 dollars each. The last time I checked they were 45dollars maybe more.
If your interested some of the ham gear tube type look up "boat anchors" usually refers to the weight due the weight of the transformers.
Good luck and fun.
 
  • #20
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Before you go getting too deep into obsolete vacuum tube stuff, I recommend "Solid State Design for the Radio Amateur" by Hayward and DeMaw. A pretty good introduction to how to think about analog transistor circuits in the way that those who design such things think about them - as opposed to textbook thinking.
I don't think it's in print any more, but you can find used online.
 
  • #21
Baluncore
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Purely as a bit of nostalgia - my first ever experience of electronics was making a crystal set .
My first electromagnet did not work. I used the DCC double cotton as specified. A few months later I worked out that wire had to be made of metal and that was why my mother's button thread had not worked. DCC copper wire did work, so I had success at last. Many years later I met an electronics technician working in the science labs who had also wound his first unsuccessful magnet with button thread, probably after looking at the pictures in the same book.

I then investigated 3V torch globes that got brighter as you ran them on greater voltages. I was quite surprised at how bright it was and never did find the pieces, but I hid the evidence, repaired the damage and the fuse on that 240V light circuit was replaced.

Steam engines were next. How I extinguished the spilled methylated spirit fire in my bedroom I will never know. Again, I hid the evidence and kept climbing that learning curve. I picked my way around the many overhangs without a guide.

And then I turned 10.
So I built my first crystal set with some advice from a friend whose father had shown him how to do it. We measured the voltage on the mains to be 240VAC, but the current range on his dad's multimeter did not go high enough to measure the current from the mains. I had some idea by then and explained that we should have wired the meter in series with a load and not straight across the supply. Unlike the meter, he survived his partial honesty when his dad came home, I survived because he committed the sin of omission and left me out of the explanation to his father. A dog, alone by itself, will wait quietly until it's master returns, but two dogs will round up the sheep and kill a few in the excitement of the chase.

Apparently by the time I was 14, I had fixed more than I had broken to date and so had passed the critical “break even point”.

It became easier over the next few years as the local radio station technician dumped his old books, electronics journals and junk parts on me. I built radio receivers that were excellent and got well into short wave listening, antennas and push-pull audio amplifiers. Building my first oscilloscope was a big step forward as I could then see what was happening inside my circuits. It was certainly more interesting than watching B&W TV.

My way forward had become clear.
So I left my books and electronics junk heap with a couple of friends who both then became electronics technicians and radio amateurs. I headed off interstate to study Geology. Six years later I was up to my knees in mud, my elbows in Geophysics and my ears in 16 bit minicomputers. That lead to electronics design for medical research and then electronics design and manufacturing, interrupted by surveillance antenna work for the Government and a fair dose of radio astronomy.

Books are great. Friends with a common interest are better, especially if they lend you their books. Make more friends.
 

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