Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1] 2 3 Next   Go Down
  Print  
Author Topic: "A Three-Transistor Receiver for the Beginner" ARRL 1968 -- Build  (Read 19714 times)
KB1WSY
Member

Posts: 675




Ignore
« on: May 31, 2013, 10:11:41 AM »

Greetings all,

You are going to laugh, but I am building "A Three-Transistor Receiver for the Beginner" from the book, "How To Become a Radio Amateur," 1968 edition. After which, I will build its companion transmitter, "A Simple Two-Tube Transmitter," about 10 watts input. I have no illusions as to the performance of this modest and antediluvian station; hopefully I will be able to conduct a handful of QSOs so that I can feel I have finally had the "Novice experience" that I never achieved 45 years ago. After which, I am moving rapidly on to some much beefier homebrew projects that are already partially under way (the "Novice Q5er" tube-based ham converter for the BC-453 military receiver, and the "65 Watts at Low cost" ARRL tube transmitter from the same era).

Pictures of "Chapter One" of my transistor receiver building effort are available at the URL below. This chapter describes the project, prior to build start. For the full effect, click on the first photo, then click the "Full Screen" button at the top left of the screen:

http://tinyurl.com/ktylgzn

New chapters will appear on this thread as I proceed with the project. As a total beginner, I am following exactly the instructions in the ARRL book. I'm sure lots of you will provide advice as to how I should improve this dinosaur, but that comes later, after completion of these first baby steps.

Note: I am not posting the circuit diagram because I need to ask for ARRL permission first. If permission is granted, I will post it.

73 de Martin, KB1WSY
« Last Edit: May 31, 2013, 10:57:22 AM by KB1WSY » Logged
KB1WSY
Member

Posts: 675




Ignore
« Reply #1 on: May 31, 2013, 11:59:53 AM »

Update: the ARRL has graciously given permission to post the schematic. I've inserted it into the photo gallery, near the beginning of the sequence.

73 de Martin, KB1WSY
Logged
W1JKA
Member

Posts: 1619




Ignore
« Reply #2 on: May 31, 2013, 12:10:03 PM »

I don't think anybody will be laughing,many hams started out home brewing their own gear out of sheer necessity and many of  the new appliance operators of today probably wish they had the ability to make some of their own gear and envy those that do.Once you get your receiver built  consider building a cheap HyperMite audio filter kit,I put one on my old Halicrafters S-38 and now can pick out 3 or 4 stations where I could only hear one before.Your Novice type xtmr. will put out a cw note just as well as any QRP type rig today although you may have to spend some time experimenting with the tuning and getting rid of possible chirp.GL and keep us posted.
Logged
G3RZP
Member

Posts: 4391




Ignore
« Reply #3 on: May 31, 2013, 02:51:57 PM »

Martin,

You are likely to learn far more from building and getting working a discrete transistor (or tube device) than something with one or two integrated circuits.

Go for it!
Logged
KB1WSY
Member

Posts: 675




Ignore
« Reply #4 on: May 31, 2013, 04:04:53 PM »

Once you get your receiver built  consider building a cheap HyperMite audio filter kit,I put one on my old Halicrafters S-38 and now can pick out 3 or 4 stations where I could only hear one before.

Thank you for the kind words. One of my projects is the one-tube "Audiofil" from the ARRL book, "Understanding Amateur Radio," 1963. A quote from the book: "The Audiofil has a nominal pass band of 500 to 900 cycles [eds' note: Hertz]; that is, tones above 900 and below 500 will be reduced considerably in amplitude. The pass band is wide enough so that your receiver tuning is not made critical, but the selectivity is such that you'll be able to pull through many signals that otherwise would be hard to copy through interference created by other signals near the same frequency."

Possibly the only challenge is the inductors for that project. It uses a pair of tube audio output transformers, but only their primaries, to function as chokes. "In order to increase the Qs of the chokes, their iron mounting frames should be removed. This is easily done by bending back the small tabs and then slipping the frames off the cores. Cardboard strips replace the frames, to provide a nonmetallic clamp for the cores." As is fairly typical in ARRL publications of the period, no further details are provided except for a photo where -- if you look closely -- you can see that the iron frames have been replaced with cardboard!

Once again, you might ask why I bother with a relatively cumbersome circuit from 50 years ago, but it's a lot of fun and I hope to learn a lot. But it's for later. Having, as yet, built nothing from scratch, I need to focus on one thing at a time!!! (I've built lots of kits and restored several pieces of old equipment, but that doesn't really count!)

73 de Martin, KB1WSY
Logged
KB1GMX
Member

Posts: 714




Ignore
« Reply #5 on: May 31, 2013, 05:22:05 PM »

Built it about 50 years ago.  that was a twist on the classic regen
and on 80m plenty sensitive.

It's predecessor was a three tube regen radio using 12AV6s
(a duo diode triode) from old AA5 radios.  I used that tube as
it worked ok at 30-45V and I had them from salvaged  table radios.

Had capacity will be the most annoying thing.  The second item is
strong stations filled up the dial.

Back then audio output  transformers removed from old AA5
(5 tube line powered radios) were used and seemed to work ok.

I got the best results making a coil set for 500khz and making a
two tube converter.  At that frequency with it on the edge
of oscillation it was too narrow for AM phone!

The converter was 12BA6 and 12BE6 from those old radios
using a circuit from the 1955 edition of the ARRL Mobile Manual.
The IF was fixed and the converter tuned from 3-6mhz or so.
All the coils were hand wound on plastic pill bottles.  Today
I'd use 1" OD PVC pipe.

Enjoy

Allison
Logged
KB1WSY
Member

Posts: 675




Ignore
« Reply #6 on: May 31, 2013, 06:21:25 PM »

Built it about 50 years ago.  that was a twist on the classic regen and on 80m plenty sensitive. ...Ha(n)d capacity will be the most annoying thing.  The second item is strong stations filled up the dial.

Great to hear from someone who has actually built this thing!

The ARRL text does mention problems with hand capacity: "If an inadequate ground system is used, the receiver will exhibit hand-capacitance effects." Maybe it's made worse by the mounting of nearly all components on the *outside* of the chassis? Perhaps they did this to make it easier for the novice who had limited metalworking ability? The design does include 68uH chokes on both sides of the headphone line, so that "the headset leads are kept from acting as antennas (creating hand-capacity effects on the higher bands) by being isolated from the power supply and Q3 [the final AF stage] with r.f. chokes."

On a totally different subject: This 3-transistor design first appeared in QST magazine in March 1968 where it was bylined Walter F. Lange, W1YDS, Assistant Technical Editor, QST. Well, as I only just discovered, that call is still active and still listed to Lange. It was renewed in 2008 and other info shows that Lange was born in 1936. His QTH is listed as Windsor, CT. I will write him a snailmail letter! (See no other contact method as of now.)

73 de Martin, KB1WSY
Logged
KB1GMX
Member

Posts: 714




Ignore
« Reply #7 on: May 31, 2013, 07:56:15 PM »

Hand capacity was a side effect of poor isolation of the detector from things like
ground and antenna changes.  I'd found that the same circuit with a down converter
ahead of it tended to be very stable and the small added gain of the converter allowed
coupling to the detector be looser which improved the selectivity.

It was my last shot at regens back then as I was both trying to be solid state,
small and low power and incorporate superhet design ideas for things like
stability and selectivity.   Much of the early work was done using a regen in
the 400-500khz region where selectivity was  excellent and far easier to
build then a full out 455khz IF.

Look elsewhere on the net for  Regenodyne for someone that more recently started
replaying that idea.  [see http://www.qsl.net/w/wd4nka//TEXTS/REGENf~1.HTM]
While his is hollow state it could easily be translated to transistor or FET.

More modern designs of regens that are popular is the "Kitchen Regen" and the
"Desert Ratt 2". 


Allison
Logged
KB1WSY
Member

Posts: 675




Ignore
« Reply #8 on: June 02, 2013, 06:44:10 PM »

I spent much of the weekend drilling holes (so, how many Holes Are In The Albert Hall anyway??).

Link follows. Reminder: click on the first photo. Then click on the "Full Screen" icon at top left.

Chapter Two: http://tinyurl.com/khckgdu

Oh: in case it comes up. That's it: there is no working radio yet! Just lots of metalwork. Actual radio-building is imminent, however, now that the mechanical details are taken care of.

73 de Martin, KB1WSY
« Last Edit: June 02, 2013, 07:04:00 PM by KB1WSY » Logged
KB1WSY
Member

Posts: 675




Ignore
« Reply #9 on: June 03, 2013, 04:23:56 PM »

Chapter Three. Today was spent doing some surgery to improve the action of the main tuning dial, adding the red indicator line, and dressing the chassis. Nearly all those holes I drilled are now usefully employed. The pictures are here:

http://tinyurl.com/lrpkoya

73 de Martin, KB1WSY
Logged
KB1WSY
Member

Posts: 675




Ignore
« Reply #10 on: June 04, 2013, 08:19:30 PM »

Chapter Four. Making the coils. The pictures are here:

http://tinyurl.com/lotc3ep

Haven't had so much fun in a long time.

73 de Martin, KB1WSY
Logged
AA9G
Member

Posts: 82




Ignore
« Reply #11 on: June 05, 2013, 01:31:28 PM »

I'm not laughing. I applaud your project, Martin. Go for it and thank you for sharing. This is the spirit of ham radio.
Logged

Ex KC9EEV.
KB1WSY
Member

Posts: 675




Ignore
« Reply #12 on: June 06, 2013, 03:35:30 PM »

Chapter Four (second and final part of coil making). It's the same link as before, but it's been updated (at the end of the photo gallery) with three new photos of the six completed coils:

http://tinyurl.com/lotc3ep

73 de Martin, KB1WSY
Logged
KB1WSY
Member

Posts: 675




Ignore
« Reply #13 on: June 07, 2013, 06:09:57 PM »

Chapter Five: Wiring the entire RF stage: broadcast band filter, tuning section (bandset, bandspread, coil socket) and JFET regenerative detector circuit. Photos here:

http://tinyurl.com/mubpkwk

Up next, the two-transistor audio amplifier, and then we should have a complete receiver! That will be some time next week; I'm taking the weekend off from radio.

73 de Martin, KB1WSY
Logged
W1JKA
Member

Posts: 1619




Ignore
« Reply #14 on: June 08, 2013, 04:32:19 AM »

Great Pictures and interesting project.I'm inspired,spent yesterday gathering all junk box parts for a Pipsqueak Regen receiver.
Logged
Pages: [1] 2 3 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!