JetKing DIY Radio Kits

[reubensm]

Bringing back the memories

Now this is the link I was telling . I used to read it in Manorama Book Stall near my house and drool over getting it.

https://worldradiohistory.com/BOOKSHELF-ARH/Author-Groups/G.C.Dobbs/Making-a-Transistor-Radio-Dobbs.pdf

Another link with a clearer copy. There is an option to download too

Making a Transistor Radio : G. C. Dobbs : Free Download, Borrow, and Streaming : Internet Archive

A Ladybird book, the only one in the 724 series, detailing how to make a transistor radio. Illustrated by B. H. Robinson, with ISBN 0721403247.

archive.org

Used this to introduce radio to my daughter (neck deep in iPad, iPhone, iTunes and her MBBS) a few months back.

Did not know until later that my dad had a treasure trove with him. I remember him sitting and teaching me radio basics when in 6th Std. (1979) from a book named Basic Radio Course.

Not sure if this that book https://worldradiohistory.com/BOOKS...back/Gernsback-44-Basic-Radio-Course-Frye.pdf

I don't remember the author name.

and he had these I think

https://worldradiohistory.com/BOOKSHELF-ARH/Rider-Books/Rider-Basic-Radio-Vol-1-Tepper.pdf

Alas!! in the melee of life he did not update himself from tubes and some bit of transistors.

Oh, I am seeing this book (Dobbs) after some 40 years, thanks for sharing. Our school library had this book and I have borrowed it several times, together with a book on how to make pinhole cameras. I also used to spend hours reading a book called Fun With Radio by Gilbert Davey which Dad used to bring for me from the British Council LIbrary in Trivandrum (I cant recollect how many times he renewed it). These were days before the Photocopier and I recollect copying down the whole book by hand. Here is a copy of this book for old time's sake - https://worldradiohistory.com/BOOKSHELF-ARH/Author-Groups/Gilbert-Davy/Fun-With-Radio-4-Davy.pdf

Later on I repeated the same level of interest when Dad got me the next edition from Gilbert Davey, Fun with Electronics and this was my first introduction to amplifiers - https://worldradiohistory.com/BOOKSHELF-ARH/Author-Groups/Gilbert-Davy/Fun-With-Electronics-Davy.pdf

Then Fun with Transistors by Gilbert Davey - https://worldradiohistory.com/BOOKSHELF-ARH/Author-Groups/Gilbert-Davy/Fun-With-Transistors-Davy.pdf

Followed by Fun with Hi-Fi which introduced me to the famous 3-3 Mullard tube amplifier but my Dad would not let me have anything to do with playing with electricity. So I ended up building my first transistor amplifier with AC187/AC188 outputs in 1981 (I was in 4th Standard then). Some Great memories!

Gilbert Davey's resources - http://www.daveysradios.org.uk/index.html

 

[Jolly 7]

this is great, OC45 a RF transistor used in the detector stage of old 'all-transistor' european radios, right? So that should be similar to AF117? I think OC45 had only 3 connecting legs while AF117 had 4 (the one additional was wired to the metal body of the transistor for grounding i think)

Yes. That's right. The AF117s are unreliable and can fail as many suffer from a 'tin whisker' manufacturing defect. They can be replaced with similar transistors from the later AF series which did not have this problem. The tin whiskers can be sometimes zapped away temporarily but they often return to grow back later. Here's a defective AF117 from my collection.

 

[reubensm]

Honestly, it brought great joy, just seeing you rebuild this. I could relive the same excitement I experienced in 1980. It was so nice to re-visit those memories and emotions. It was also such a big thrill to go on the air back then. I thought it was something unique to me but many years later with the advent of the internet and google, I got to know that American kids experienced the same thrill building the Knight Kit Broadcaster in the 1950s and 1960s. Electronics is such a universal hobby

PS: I have tried my best to get a hold of EFY's Electronics Projects Vol-1, that original digest which had this circuit but I've been unsucessful. I have Vol-2, 3 and 4. This circuit was original featured under circuit ideas in a 1979 monthly edition and was reprinted in Electronics Projects Vol-1 (I had both books). If anyone comes across this book, I would be interested to buy it. It also featured a 3-band radio circuit using BEL IC 700, provided by BEL Labs. My original Vol-1 was a b-day gift from Dad in 1980, I had these for many years but when I started my travels, they disappeared (probably was given away to the scrap and old newspaper guy).

 

[Jolly 7]

Took me back to my childhood exploits. I used to get some monetary support at times. Other than that my dad took me to the shops and introduced to an "uncle" who worked in Cochin Shipyard and another who repaired stuff in his shop. Shipyard uncle gave me some stuff that had a lot of power transistors..maybe some are still in dad's place.

Had a friend Thomas with whom I used to do those experiments..EFY, Elektor were always welcome. I have a treasure for you and @Jolly 7 . I will send link to you to download .

Got these now from Thailand. Alps variable caps.View attachment 72622

These are robust devices great to experiment with that have stood the test of time. I have a few of these, including one that's probably around a 100 years old. The one on the far right of your photo looks like a dual-ganged 500pF+500pF one.

 

[Jolly 7]

Oh, I am seeing this book (Dobbs) after some 40 years, thanks for sharing. Our school library had this book and I have borrowed it several times, together with a book on how to make pinhole cameras. I also used to spend hours reading a book called Fun With Radio by Gilbert Davey which Dad used to bring for me from the British Council LIbrary in Trivandrum (I cant recollect how many times he renewed it). These were days before the Photocopier and I recollect copying down the whole book by hand. Here is a copy of this book for old time's sake - https://worldradiohistory.com/BOOKSHELF-ARH/Author-Groups/Gilbert-Davy/Fun-With-Radio-4-Davy.pdf

Later on I repeated the same level of interest when Dad got me the next edition from Gilbert Davey, Fun with Electronics and this was my first introduction to amplifiers - https://worldradiohistory.com/BOOKSHELF-ARH/Author-Groups/Gilbert-Davy/Fun-With-Electronics-Davy.pdf

Then Fun with Transistors by Gilbert Davey - https://worldradiohistory.com/BOOKSHELF-ARH/Author-Groups/Gilbert-Davy/Fun-With-Transistors-Davy.pdf

Followed by Fun with Hi-Fi which introduced me to the famous 3-3 Mullard tube amplifier but my Dad would not let me have anything to do with playing with electricity. So I ended up building my first transistor amplifier with AC187/AC188 outputs in 1981 (I was in 4th Standard then). Some Great memories!

Gilbert Davey's resources - http://www.daveysradios.org.uk/index.html

Here's the link to another book which might be of interest. I have the actual book in my collection:

https://worldradiohistory.com/BOOKSHELF-ARH/W-H-Warrring/Making-Transistor-Radios-A-Beginners-Guide-Warring.pdf

 

[Jolly 7]

Honestly, it brought great joy, just seeing you rebuild this. I could relive the same excitement I experienced in 1980. It was so nice to re-visit those memories and emotions. It was also such a big thrill to go on the air back then. I thought it was something unique to me but many years later with the advent of the internet and google, I got to know that American kids experienced the same thrill building the Knight Kit Broadcaster in the 1950s and 1960s. Electronics is such a universal hobby

PS: I have tried my best to get a hold of EFY's Electronics Projects Vol-1, that original digest which had this circuit but I've been unsucessful. I have Vol-2, 3 and 4. This circuit was original featured under circuit ideas in a 1979 monthly edition and was reprinted in Electronics Projects Vol-1 (I had both books). If anyone comes across this book, I would be interested to buy it. It also featured a 3-band radio circuit using BEL IC 700, provided by BEL Labs. My original Vol-1 was a b-day gift from Dad in 1980, I had these for many years but when I started my travels, they disappeared (probably was given away to the scrap and old newspaper guy).

Thanks. It was a great pleasure for me to work on this circuit too and even more exciting that I got it to work quite well. I have some more modifications in mind that I hope to implement at some stage.

In relation to emulating the Jetking Guru circuit on my 'L Board' and an external board for the oscillator coil and tuning cap, I've had some success too and was able to receive many MW stations at night. It seems to be very sensitive. However, in its current form, the circuit is unstable and sometimes stops working, as it has of late. I need to work a bit more on the circuit to overcome these stability issues.

 

[Subbu68]

These are robust devices great to experiment with that have stood the test of time. I have a few of these, including one that's probably around a 100 years old. The one on the far right of your photo looks like a dual-ganged 500pF+500pF one.

You have the "originals"... Envy you for your preservation of old components.

I was so careless with the ones inherited from my dad - three valve radios and just cannibalized them for parts. I am not sure if if the variable caps, trimmers are still in a box in my father's house. He (now no more) never went to that house for 4 years or so. Not sure if they are there or his servant cleared them.

One in the middle in the picture is a 4 gang type for AM / FM. Need to test it.

The smallest on the left is 20-120pf + 20-320pf but measured 11-116pf + 14-282pf.

The largest on the right is 2 gang 20-500pF (not sure of the lower value). I tested them as 26-512pf

got these to build the one below. Basis is https://earmark.net/gesr/loop/ and Joe Carr formula. Did not work as expected though could see some nulling.






Any experience building tuned AM Loop @reubensm , @Jolly 7

 

[Subbu68]

that four gang is

VC 1 adjustable around 20pf to 200pf
VC 2 adjustable around 20pf to 30pf
VC 3 adjustable around 20pf to 90pf
VC 4 adjustable around 20pf to 30pf

 

[Subbu68]

@Jolly 7 , @reubensm

That AM loop worked

More details and video in another thread.

Still the video is here

 

[reubensm]

@Jolly 7 , @reubensm

That AM loop worked

More details and video in another thread.

Still the video is here

reminds me of the old times, when some of my friends used to approach asking how to connect an aerial to a radio that does not have an external aerial socket, i used to tell them to just wrap the wire around the telescopic aerial without electrical contact or to connect the aerial to a metal plate and place the radio near it or on it. I had also noticed that placing a portable radio on top of a large stainless steel vessel improved reception.

 

[Subbu68]

reminds me of the old times, when some of my friends used to approach asking how to connect an aerial to a radio that does not have an external aerial socket, i used to tell them to just wrap the wire around the telescopic aerial without electrical contact or to connect the aerial to a metal plate and place the radio near it or on it. I had also noticed that placing a portable radio on top of a large stainless steel vessel improved reception.

I used to do it with my SONY 7600GR. Even slip on a MW antenna coil and connect one end to a long-wire. It was better than connecting long-wire to the aerial. The SW reception greatly improved with the wire wrapping. But for MW it was not useful as the aerial does not connect to MW antenna coil.

 

[reubensm]

You have the "originals"... Envy you for your preservation of old components.

I was so careless with the ones inherited from my dad - three valve radios and just cannibalized them for parts. I am not sure if if the variable caps, trimmers are still in a box in my father's house. He (now no more) never went to that house for 4 years or so. Not sure if they are there or his servant cleared them.

One in the middle in the picture is a 4 gang type for AM / FM. Need to test it.

The smallest on the left is 20-120pf + 20-320pf but measured 11-116pf + 14-282pf.

The largest on the right is 2 gang 20-500pF (not sure of the lower value). I tested them as 26-512pf

got these to build the one below. Basis is https://earmark.net/gesr/loop/ and Joe Carr formula. Did not work as expected though could see some nulling.




View attachment 72642View attachment 72643View attachment 72644

Any experience building tuned AM Loop @reubensm , @Jolly 7

Personally, I have only used long wire aerials for shortwave. But in 1994, my brother and I built a 14inch black and white Tv using a HRC kit and with the VHF switchable turret tuner. We had this 2ft square loop wired through a DIY TV signal booster and with this setup, we enjoyed many hours of free analog cable TV. The purpose of this antenna was to receive signals from a cable TV amplifier across the street . We used this set up until 1996 when i was able to buy a colour TV through staff scheme at BPL (my first job was with BPL) and also subscribed to the cable network. That ended our TV experiments.

 

[reubensm]

I used to do it with my SONY 7600GR. Even slip on a MW antenna coil and connect one end to a long-wire. It was better than connecting long-wire to the aerial. The SW reception greatly improved with the wire wrapping. But for MW it was not useful as the aerial does not connect to MW antenna coil.

yes, i have tried it only with shortwave, i never did any work around medium wave unfortunately

 

[Subbu68]

reminds me of the old times, when some of my friends used to approach asking how to connect an aerial to a radio that does not have an external aerial socket, i used to tell them to just wrap the wire around the telescopic aerial without electrical contact or to connect the aerial to a metal plate and place the radio near it or on it. I had also noticed that placing a portable radio on top of a large stainless steel vessel improved reception.

I connected a wire to the window frame (through the lock mechanism for the window pane) and that to a metal table. Wow!!! the SW stations were registering stronger on the S meter of my ATS909 by 4 to 6 times when placed on the table. The whole window was acting as a giant loop.

 

[Subbu68]

I connected a wire to the window frame (through the lock mechanism for the window pane) and that to a metal table. Wow!!! the SW stations were registering stronger on the S meter of my ATS909 by 4 to 6 times when placed on the table. The whole window was acting as a giant loop.

@reubensm
The table is actually becoming a ground plane not an antenna. Folded the antenna in and signal just dropped.