OLD SCHEMATICS
Posted: Mon Oct 12, 2015 11:04 pm
Heres some old paperwork i dug out! A basic Colpitts config, David bowmans band1 receiver and the nrg stereo 1watt exciter!
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Re: OLD SCHEMATICS
Posted: Thu Mar 04, 2021 12:40 am
Sinus I'm just curious to the title of the book showing the FET Colpitts Oscillator. Also the author wouldn't happen to be R.A. Penfold?
Re: OLD SCHEMATICS
Posted: Thu Mar 04, 2021 5:06 am
That first one from EMRFD? Drawing style looks familiar?
Re: OLD SCHEMATICS
Posted: Thu Mar 04, 2021 11:00 am
Wow where did you get the vhf receiver diagram from ? Was he selling kits or something on eBay once ?
I don’t suppose you have a component list do you ?
I don’t suppose you have a component list do you ?
Re: OLD SCHEMATICS
Posted: Thu Mar 04, 2021 10:43 pm
You are on the right track!
Its written by A. Flind Titled Practical Oscillator Circuits, Which i purchased around 1996.Since the internet was not really available in those days, I would spend time in the local libraries also picking up any knowledge i could from older engineers.
It is a great book with excellent examples of all kinds of oscillators including the related theory and mathematics.
I also have books by R.A. Penfold on Audio Power Amplifier design and general Electronics Data.
Re: OLD SCHEMATICS
Posted: Thu Mar 04, 2021 10:59 pm
If i remember correct? Bowman had a website named 'Airwave systems'OldskoolPirate wrote: ↑Thu Mar 04, 2021 11:00 am Wow where did you get the vhf receiver diagram from ? Was he selling kits or something on eBay once ?
I don’t suppose you have a component list do you ?
I Emailed him to order the Receiver and that was the documentation which came with it.
Unfortunately i do not have a parts list, However i do still have the Receiver somewhere?
I may go through it one day? But some of the parts are long obsolete (TDA1062) So may be a pointless exercise?
Re: OLD SCHEMATICS
Posted: Thu Mar 04, 2021 11:20 pm
TDA1062 is still on eBay but it's not very cheap.
Re: OLD SCHEMATICS
Posted: Thu Mar 04, 2021 11:40 pm
Thanks Sinus for the title and author of the book, I'll check out A. Flind and the titles he's published. Penfold is won of my favorite authors. I would pop into Maplin Electronics to pick up those books back in the day, that's when Maplin was good for most bits. RF Transistors, Toroidal Transformers and even the S18 Tokos. Shame they changed there marketing strategy. I think burning their bridge with CPC didn't help either as I was told.sinus trouble wrote: ↑Thu Mar 04, 2021 10:43 pmYou are on the right track!
Since the internet was not really available in those days, I would spend time in the local libraries also picking up any knowledge i could from older engineers.
It is a great book with excellent examples of all kinds of oscillators including the related theory and mathematics.
I also have books by R.A. Penfold on Audio Power Amplifier design and general Electronics Data.
Re: OLD SCHEMATICS
Posted: Thu Mar 04, 2021 11:44 pm
Talking of old schematics. Is this one of the most copied RF Strip designs out there?
Re: OLD SCHEMATICS
Posted: Thu Mar 04, 2021 11:55 pm
Re: OLD SCHEMATICS
Posted: Thu Mar 04, 2021 11:58 pm
I sure there's and APP you can use if you print it out and then use the camera on your phone ?sinus trouble wrote: ↑Thu Mar 04, 2021 11:55 pmHaha! And the only datasheet i can find is in German!
Re: OLD SCHEMATICS
Posted: Fri Mar 05, 2021 12:17 am
Yes I found those books very informative! Most other books seemed to rarely delve into the breakdown of various circuits, Especially when it came to FM.Zozo wrote: ↑Thu Mar 04, 2021 11:40 pm Thanks Sinus for the title and author of the book, I'll check out A. Flind and the titles he's published. Penfold is won of my favorite authors. I would pop into Maplin Electronics to pick up those books back in the day, that's when Maplin was good for most bits. RF Transistors, Toroidal Transformers and even the S18 Tokos. Shame they changed there marketing strategy. I think burning their bridge with CPC didn't help either as I was told.
It is so sad what happened to Maplin and other retailers! There was also a great little shop in Manor Park i used to visit which had every component you needed, Yet no more!
Cricklewood Electronics is the only one i know left! In a world of turnover and profit? I fear their days are numbered too!
Re: OLD SCHEMATICS
Posted: Fri Mar 05, 2021 9:30 am
Yes Cricklewood Electronics, that was the place I bought all my SD1407s back in the final days. There's another place I used, but for the life of me I can't remember their name. I used them to buy 2sc1945's and 2sc1971's. Anyway it's all historical now, and have not need for them these days.sinus trouble wrote: ↑Fri Mar 05, 2021 12:17 am
Yes I found those books very informative! Most other books seemed to rarely delve into the breakdown of various circuits, Especially when it came to FM.
It is so sad what happened to Maplin and other retailers! There was also a great little shop in Manor Park i used to visit which had every component you needed, Yet no more!
Cricklewood Electronics is the only one i know left! In a world of turnover and profit? I fear their days are numbered too!
Re: OLD SCHEMATICS
Posted: Fri Mar 05, 2021 9:35 am
It's an interesting iteration of the schematic, I know the "CA3189E" is the Sub System IC, but isn't technically the TDA1062 sort of a Sub System IC too.? Or one of those Receiver in a chip thingy's? Be handy if there's an English datasheet as Sinus mentioned.
Re: OLD SCHEMATICS
Posted: Sat Mar 06, 2021 11:46 pm
I am not 100% sure what the TDA1062s full function is? But I know it is performing as the mixer and most likely linked to the local oscillator to produce the IF.
The CA3189 is just an IF amplifer/demodulator with a few other added extras.
Re: OLD SCHEMATICS
Posted: Sat Mar 06, 2021 11:54 pm
It'll be interesting to find out more about the TDA. Yeah all understood on the CA3189 and those functions its performing in the one chip, especially in my circles are known as a receiver sub system IC.sinus trouble wrote: ↑Sat Mar 06, 2021 11:46 pmI am not 100% sure what the TDA1062s full function is? But I know it is performing as the mixer and most likely linked to the local oscillator to produce the IF.
The CA3189 is just an IF amplifer/demodulator with a few other added extras.
Re: OLD SCHEMATICS
Posted: Sun Mar 07, 2021 5:33 pm
It is, and as drawn is wrong! For example - if you use type 2 ferrite for the transformer, you'll get huge losses. The output match is a mess as well.
A cleaned-up and fixed version of this could be quite useful!
Re: OLD SCHEMATICS
Posted: Sun Mar 07, 2021 5:40 pm
Yeah I thought that type 2 was a strange one for VHF, but I do have some that do work well, for the life of me I can't remember their type.
The output is as it was copied from a board over 15 years ago?? looks like an HTF and LPF in series.
Re: OLD SCHEMATICS
Posted: Sun Mar 07, 2021 6:19 pm
Albert if you know the correct type toroidal I can amend the schematic. The ones I have are similar size but green coated. Just cant identify them.
Maybe a fixed up filter on the output and possibly a perfectly workable design?
Maybe a fixed up filter on the output and possibly a perfectly workable design?
Re: OLD SCHEMATICS
Posted: Sun Mar 07, 2021 7:23 pm
It is supposed to be a blue and yellow T37-17 core.