Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives
Support This Site: Contributors :: Advertise


It is currently Jul Wed 24, 2019 12:05 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 32 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: Components Swapouts
PostPosted: Aug Fri 24, 2018 2:27 pm 
New Member

Joined: Aug Thu 23, 2018 3:34 pm
Posts: 14
I am looking for anyone that can help me understand components.

I have built in my Ham lifetime dozens of kits. And serviced broken radios. But it has always amazed me about the components. Like Resistor 222, why is it 47 ohms and not any other value? Or Coil L 3 why is it 55 turns of 28 ga wire close spaced on a 2 inch form. what would you change if the only form you had was 2.5 inches? why not any other values or say same items that are best for 40 meters, what do you change for 30 meters? Anyone?

More or less, what my goal is to take some ultra basic old Tube designs of simple equipment, Some are super simple like two tubes and maybe a total of a dozen support components, but change it out from a Tube to a transistor. There has to be a transistor that can do the job that any tube did.

But the mystery to me is to learn What Transistor to replace tube "X" and then the support perferial components what needs to change to work with the new transistor?

Joe WB9SBD


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Fri 24, 2018 3:39 pm 
Member

Joined: Dec Fri 08, 2017 5:40 pm
Posts: 203
Location: 44141
Wow. That's a big order.
You might start out with something like TM-11-455. This is a DC theory manual used by the Signal Corp in the '50's and go on from there.

_________________
Bruce Hagen


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Fri 24, 2018 3:49 pm 
New Member

Joined: Aug Thu 23, 2018 3:34 pm
Posts: 14
Hi Bruce,

Thanks for the reply, see I'm a Radio Amateur and have built many a transmitters. But never really understood the Why a component is what it is, And I was recently turned onto a sub activity where guys put on the air extremely old designs. Like the first generation after Spark Gap transmitters, Really simple designs like this,
Image
Finished unit,
Image

I want to try to make the exact same unit but with modern components.

Joe WB9SBD


Attachments:
sch-80.jpg
sch-80.jpg [ 121.95 KiB | Viewed 1380 times ]
finished.jpg
finished.jpg [ 120.83 KiB | Viewed 1380 times ]
Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Fri 24, 2018 4:28 pm 
Member
User avatar

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 26034
Location: Annapolis, MD
It sounds like you need a crash course in the basics....

Where are you on the following?
--basic tube theory
--basic properties of resistors, capacitors, and inductors
--current and voltage relationships for both AC and DC

_________________
-Mark
"Measure voltage, but THINK current." --anon.


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Fri 24, 2018 4:48 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 7851
Location: 13 Critchley Avenue, PO Box 36, Monteith Ont, P0K 1P0
pixellany wrote:
It sounds like you need a crash course in the basics....

Where are you on the following?
--basic tube theory
--basic properties of resistors, capacitors, and inductors
--current and voltage relationships for both AC and DC


I was under the (mis?) understanding that basic knowledge of electricity, electronics including resonance and EIR relationships was an essential part of the Ham testing and knowledge?


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Fri 24, 2018 5:00 pm 
Member

Joined: May Tue 30, 2006 4:46 pm
Posts: 9911
Location: Santa Rosa, CA
Your request isn't a simple one. To design/build a radio, you need to understand how it works and what you expect from it. No simple recipe for "swapping" components.

If you want to build a simple transistor receiver, for the AM band or shortwave, search for "transistor regenerative receiver."

Here is one site: http://www.techlib.com/electronics/regen.html

http://makearadio.com/solidstate/index.php

There are lots of simple ham receivers available from China on Ebay. May be a good place to start?

https://www.ebay.com/itm/DIY-Kits-Super ... SwBLlVWj2h

https://www.ebay.com/itm/Simple-3-band- ... SwIaFZLmP0

http://www.mfjenterprises.com/Product.p ... =MFJ-8100K


Rich


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Fri 24, 2018 8:00 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 4002
WB9SBD wrote:
I want to try to make the exact same unit but with modern components.
Joe WB9SBD


If I understand your definition of "modern," in your circuit the tube is the only component that's not modern. It can probably be replaced with an FET. Here's an article on doing just that:

https://www.google.com/url?sa=t&rct=j&q ... QrYX-1lHdj

As for how worthy a project, discussion here:

https://www.eham.net/articles/30168
http://forums.qrz.com/index.php?threads ... st.394077/


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Fri 24, 2018 10:35 pm 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 37332
Location: Livermore, CA
This circuit should work but often we are looking for stability. This one isn't going to be stable.

_________________
Norm


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Fri 24, 2018 10:42 pm 
New Member

Joined: Aug Thu 23, 2018 3:34 pm
Posts: 14
what circuit?


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Fri 24, 2018 10:48 pm 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 37332
Location: Livermore, CA
The one above using a 27 tube. You could use a more modern 6C4?

_________________
Norm


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Fri 24, 2018 10:58 pm 
New Member

Joined: Aug Thu 23, 2018 3:34 pm
Posts: 14
Hi Norm,
See thats the whole, project, to take a simple circuit like that above. but no tube use a transistor instead.


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Sat 25, 2018 12:02 am 
Member
User avatar

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 26034
Location: Annapolis, MD
Typically, you cannot just put in a transistor in place of a tube......transistor circuits are normally lower impedance than the equivalent tube circuit. You could use a FET, but some changes are still required,
For the oscillator circuit, solid state designs often use as Colpitts configuration, as opposed the the Hartley shown.

_________________
-Mark
"Measure voltage, but THINK current." --anon.


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Sat 25, 2018 2:21 am 
Member

Joined: May Tue 30, 2006 4:46 pm
Posts: 9911
Location: Santa Rosa, CA
Apologies. I should have noticed that the original circuit is a transmitter, not a receiver.

As others have said:

--No plug-in swap of transistor for tube
--That circuit is primitive and not stable

Why not just build a crystal-controlled transistor transmitter?

Image

Rich


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Sat 25, 2018 4:32 am 
New Member

Joined: Aug Thu 23, 2018 3:34 pm
Posts: 14
But yes not stable, but that's the whole thing. to USE technology that was at the roots of Amateur Radio,
http://www.antiquewireless.org/bruce-ke ... -info.html


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Sat 25, 2018 2:33 pm 
Member
User avatar

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 26034
Location: Annapolis, MD
You want to build 1929 designs, use the same kinds of parts.

Were you thinking of just plugging a transistor into one of those circuit? Do you understand why that won't work?

_________________
-Mark
"Measure voltage, but THINK current." --anon.


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Sat 25, 2018 3:07 pm 
New Member

Joined: Aug Thu 23, 2018 3:34 pm
Posts: 14
Yes I fully understand why it would not work.
And thats why I thought about asking to see if anyone with better knowledge of designing might want to make something fun.

But In the few places I have asked about this, I honestly see the experimental aspect of Amateur Radio is dead and gone.

Trying things that are not common. Just for the fun of it.

Like some days I use one of these, to do CW with.
Image

I have several that fall into the CW sub bands. They have a 5 volt peak ummm "WAVE"?

It is not a sine wave, or Square wave either. AND, they only go to one side of zero, unlike a sine wave
Image

The power when measured with a watt meter is about 70 milliwatts. I have made hundreds of contacts using these things. And amaze people when I tell them what I am using.

A Straight key to turn the power to it on and off,
3 AA Batteries, 4.5 volts
and the little metal can!

That's it.

Actually a bunch of fun.

I just thought Id try again something Old but also new, with converting one of these 1929 units to modern components.

Sorry about not wanting to be only an appliance operator

Joe WB9SBD


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Sat 25, 2018 3:21 pm 
Member
User avatar

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 26034
Location: Annapolis, MD
No one is trying to discourage you from experimenting.

What will work:
Take a classic design, learn how it works, and then design the modern equivalent with modern parts.

What will NOT work:
Plugging modern parts into a classic circuit with no understanding of how the circuit works and/or no understanding of the modern parts.

Repeating an earlier question: What is your level of experience with basic theory and principles of circuit design? For example, do you understand why a junction transistor cannot be subbed for a vacuum tube?

_________________
-Mark
"Measure voltage, but THINK current." --anon.


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Sat 25, 2018 3:38 pm 
New Member

Joined: Aug Thu 23, 2018 3:34 pm
Posts: 14
Repeating an earlier question: What is your level of experience with basic theory and principles of circuit design? For example, do you understand why a junction transistor cannot be subbed for a vacuum tube?

Obviously Voltages and impedance's are totally wrong.

But what solid state device could do the job a #27 tube does, Not a clue. If the solid state device had the correct support design around it.


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Sat 25, 2018 3:55 pm 
Member

Joined: May Tue 30, 2006 4:46 pm
Posts: 9911
Location: Santa Rosa, CA
The experimenting aspect of ham radio is very much alive. It is based on knowledge of basic electronic circuits. It is not just plugging parts together to see what happens. Get yourself an ARRL Handbook or one of the ARRL QRP books and start learning about basic circuits.

Quote:
But what solid state device could do the job a #27 tube does, Not a clue. If the solid state device had the correct support design around it.


What modern engine could I put in a '29 Ford, if it had the right support design around it? Same kind of question. If you knew how to modify all the mechanical structures, pulleys, shafts, belts, etc. it could probably be done.

People have designed 'solid state' tubes using FETs. (The Fetron). They work in specific circuits to replace specific tubes. No one has ever made a universal type 27.

http://hrsasa.asn.au/docs/Fetron.pdf

Rich


Top
 Profile  
 
 Post subject: Re: Components Swapouts
PostPosted: Aug Sat 25, 2018 4:25 pm 
New Member

Joined: Aug Thu 23, 2018 3:34 pm
Posts: 14
I Guess I'll end this string now.

The spirit of experimenting may be alive, (yet to see evidence of it tho)

But the Spirit of "Elmering" is totally dead and gone I guess.


Top
 Profile  
 
Post New Topic Post Reply  [ 32 posts ]  Go to page 1, 2  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: infzqi and 7 guests



Search for:
Jump to:  


























Privacy Policy :: Powered by phpBB