"A Simple Code-Practice Oscillator" ARRL 1968

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MARTIN MARRIS:
So I've decided to build *all* of the projects in "How to Become a Radio Amateur" ARRL 1968. That's pretty easy because there are only three of them: a simple regenerative receiver (whose building was described in my earlier thread); a "Simple Two-Tube Transmitter" which I am building soon; and the code-practice oscillator that I built today and will describe in this single post.

Wherein:
--KB1WSY manages to build something that works immediately. I think this is a first, although inevitably there was some fine tuning to do.
--WSY almost sets fire to his shack. (That caught your attention, eh?) I think I am probably exaggerating and I will let you OTs set me right if I am wrong, which I hope I am!

Here's the link: http://tinyurl.com/mbryt24

If y'all are getting tired of my incessant homebrew-related posts or feel that a humble code-practice oscillator is not worth wasting bandwidth on, let me know. I have a relatively thick skin!

73 de Martin, KB1WSY

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Martin:

First of all if anyone "gets tired of your homebrew posts" they can simply skip them! 

As for posting your homebrew projects, I find them interesting, even though I've been homebrewing for decades. 

I feel that any homebrew posts, no matter how simple, can be inspirational to those who just might not be sure which end of a soldering iron to pick up.

Homebrewing is fast becoming a lost art.  It takes imagination, dedication, patience as well as research abilities.  The final product might look like crap but when it works, it's hard to describe the feeling! Most of the time the homebrewer also learns something.  Yes, I said "learn!"  It seems that many have an aversion to this word anymore.

BTW, for whatever it's worth, you do very neat work.  One criticism: Shorten your cap leads.  While this is a non-issue with an audio oscillator, when you get into RF these leads can become a problem.  Long cap leads can become a bad habit.   ;)

There is great satisfaction in making something with your hands and mind.  Keep on building and keep on posting.

Dieter Kuespert:
Well, seems you couldn't get a vintage battery  ;D

Sorry for that remark, it just came to my mind when I noticed you really even got the original transistors.

Before soldering you could stick the leads through the holes and bend them to already hold on tight. For protection of critical components using a pair of pliers to hold the leads helps dissipate the heat.

Of course you are right about C1 and C2 being the components determining the frequency. However, your load has an influence too as you found out.

Nice job. Now I am curious to see the two tube TX.

MARTIN MARRIS:
Quote from: K8AXW on June 12, 2013, 09:16:49 AM

Shorten your cap leads. While this is a non-issue with an audio oscillator, when you get into RF these leads can become a problem. Long cap leads can become a bad habit.   ;)


Thank you for the advice! I need all the help I can get!

Quote from: KA4POL on June 12, 2013, 10:53:10 AM

Well, seems you couldn't get a vintage battery  ;D


About a year ago I bought an already-assembled vintage Heathkit signal generator applications trainer from the 1960s. It had four vintage AA batteries in the holder underneath the chassis. EverReady/Union Carbide, "Transistor Battery," "Made in U.S.A." Much to my astonishment the batteries hadn't leaked and looked brand new, even though the casing feels like thin cardboard. To my further surprise when I hooked them up to the meter, they all still measured more than 1.5V. I still have them sitting on the windowsill here. They will probably outlive me!

Quote

Before soldering you could stick the leads through the holes and bend them to already hold on tight. For protection of critical components using a pair of pliers to hold the leads helps dissipate the heat.


Yes I'm already doing the bending/crimping: see for instance the closeup of that lug with the five connections; the wires have already been bent tight prior to soldering. For fragile parts I use a heat sink of some kind. Usually an alligator clip, rather than pliers (how does one use the pliers without having three hands?). I am slowly feeling more competent about soldering!

Quote

Nice job. Now I am curious to see the two tube TX.


Looks like that project will get under way toward the end of the month. I thought I'd be able to use an old power transformer pulled from a signal generator but it turns out to be unsuitable. So I've ordered a new one, on 10-day back order. The other components are pretty much lined up at this point.

Thank you, everyone, for the encouragement. Now it's time to become a Morse Code Recluse for a few weeks. Building stuff provides huge motivation to complete the CW course! It would be too silly to build that TX but not have enough Morse to use it!!!

73 de Martin, KB1WSY

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