Analog AM Radio Receiver Without Chip - UL1111 Replacement with BC847CW Transistors

The first picture confuses this chip.
I made a lot of research about where to find it in the diagram and where all the additional individual transistors come from ...
It would better make sense of something like this


From what I remember, the original headphones had to have a lot of impedance and not all of them were suitable.
How is it in your project?

Mateusz_konstruktor wrote:

The first picture confuses this chip.

I put for a size comparison.

Mateusz_konstruktor wrote:

From what I remember, the original headphones had to have a lot of impedance and not all of them were suitable.
How is it in your project?

Ordinary 2 * 16?.

UL1111 sounded quite quiet from what I remember, although I don't know if it was a matter of headphones or boot errors.

Anyone have a schematic for UL1111 from "Radio Hobby"?

piotr_go wrote:

Anyone have a schematic for UL1111 from "Radio Hobby"?

Perhaps it is the same diagram as in MT, there was even an implementation on the electrode
https://www.elektroda.pl/rtvforum/topic3100861.html

Mateusz_konstruktor wrote:

From what I remember, the original headphones must have had a lot of impedance

It's probably in a detector radio with no power supply.

I've been thinking about this radio for several years now. I remember when a friend made one in the 80's - then it was something!
So, after more than 30 years, I wanted to do it myself. But I wanted to do completely retro - I even bought the UL1111 :-)

As for the radio in a matchbox, the original designs were published in "Młody Technik" and there were two versions:

- On transistors:
https://mlodytechnik.pl/files/mtx/85-nw-04-odbiornik_radiowy.pdf

- On the UL1111 chip:
https://mlodytechnik.pl/files/mwi/84-nw-10-mini_odbiornik.pdf
(On the title page, Mr. Roland Wacławek himself with the iconic "Montana" watch on his hand!)

Nice workmanship, although the smd elements lose the atmosphere a bit.
IMO: The case would be the most suitable for the housing:

Kind of retro - and the modern, beautifully made tile definitely gives it the charm of its second youth
I remember that 30 years ago I tinkered with a little radio from Wojciechowski's book "Modern Toys" based on the MAA115 chip (it's such an archaic 3-stage amplifier - not operational: https://datasheetspdf.com/pdf-file/1120404/Tesla/MAA115 / 1
and I think it even worked, though not without a while of work on it. I had one chip from a friend (and it was a replacement for TAA131 or 113, I don't remember anymore), the second one - knitted by hand from 3 transistors.



Let's enjoy the longwave and AM while we can. Switching off analogue broadcasting in Poland is planned for the years 2026 - 2032 (depending on the sources), and the time is passing very quickly! We only had the "problem of the year 2000" in computers, and here it is 2022. And I am afraid that even PR1 will not last on long wavelengths, although in the case of - oh oh oh! - war or, for example, some cataclysm, such a radio is an important form of communication due to the simplicity of both transmitting and receiving. Well, unless after this time we use a function generator with AM modulation and make a micro illegal radio station at home for our pampered tube junk But it's not the same anymore.

minus3db wrote:

Let's enjoy the longwave and AM while we can. Switching off analogue broadcasting in Poland is planned for the years 2026 - 2032 (depending on the sources)
[..]
in the event - oh oh oh! - war or, for example, some cataclysm, such a radio is an important form of communication due to the simplicity of both transmitting and receiving.

The basic problem is that our country is always run by short-sighted idiots. We used to have one of the strongest radio stations in the world with the world's tallest mast in Konstantynów. You could hear PR 1 in the Middle East, Kazakhstan, North Africa and even the East Coast of the USA. Unfortunately, in 1991 this mast collapsed (it is a symbolic fall - typical for the decade of the 90s, when the achievements of previous years were systematically destroyed). At that time, a disastrous decision was made to build a new supply center in Solec-Kujawski. It was launched in 1998 but its range barely covers the surface of the country. But that's not the problem. Well, by the end of the 90's the entire domestic electronics industry was "finished". Out of the many factories that used to be (ZRK, Diora, Lubartów, Radmor, etc.), none of them produced radio receivers, and the imported ones did not have the long-wave range! So the new transmitter didn't make sense from the start. It was necessary to apply for a frequency change and start transmitting in the MW range. Until recently, this band (marked as FM) had all equipment - from dachshunds and clock radios, through car radios, to home cinema receivers. And it was not necessary to build anything - the PR2 transmitter in Koszęcin was fully operational. But it was sold to the French as part of the privatization of TP SA (BTW: What is the euphemism of "privatization" - the sale of Polish national assets to a French state-owned company - with only Kulczyk getting caught). Anyway, a technically functional transmitter and a mast in Koszęcin was scrapped by Orange in 2014 ...

Probably not the same scheme but a similar idea.

bsw wrote:

It was necessary to apply for a frequency change and start transmitting in the MW range. Until recently, this range (marked as FM) had all the equipment - from dachshunds and

You mean medium waves?
LW and MW transmitters are disappearing because they are uneconomical. AM modulation is very energy inefficient and low quality of the presentation. How many audiences are currently listening to PRI in the LW range? I think it is less than 10,000.
RNC consists of 3 blocks with a power of 400 kW each. And all this energy goes to these several thousand receivers.
The argument about the availability of a radio program during the crisis may not work, because how can you be sure that such power will be available?

Mlody_Zdolny wrote:

bsw wrote:

It was necessary to apply for a frequency change and start transmitting in the MW range.

You mean medium waves?
LW and MW transmitters are disappearing because they are uneconomical. [..]
The argument about the availability of a radio program during the crisis may not work, because how can you be sure that such power will be available?

Yes, but I was talking about the situation 30 years ago. 7 years of building a new broadcasting center, which was completely pointless ...

Initially, it was supposed to be on UL1111, I also combined something with TA7642, I even bought THT capacitors / resistors (SMD is in abundance with us).
In the end, I opted for transistors (I also bought THT). Maybe I will assemble something on the above chips.

piotr_go wrote:

I also combined something with TA7642

Do you have any bad experiences with this scalak? In my opinion, it works like any other radio.
In total, for over 25 years I have made a dozen (AM and FM), from detector, tube and transistor ones, through UL1111 to UL1321 (my favorite), and recently I put together the Chinese wonder CF210SP.

Simon79 wrote:

Do you have any bad experiences with this scalak?

It was waking me up, but it was probably the antenna's fault. I have to check on the new one again.

What can you pick some smaller ferrites from? (5mm * 50mm) Any chokes or something?
I searched various departments of electronic stores but found nothing.

piotr_go wrote:

What can you pick some smaller ferrites from? (5mm * 50mm) Any chokes or something?

Older Dior receivers, turn-of-the-century "dachshunds".
Available in olx or at a flea market at a ridiculous price.
The ferrite rod can be easily shortened by cutting the groove with the dremel and breaking it in your hands.

I was thinking of something cheap and generally available like these DCF modules.
It's a pity to break one radio to make another.

Mlody_Zdolny wrote:

Mateusz_konstruktor wrote:

From what I remember, the original headphones must have had a lot of impedance

It's probably in a detector radio with no power supply.

Not. The point here is that the radios were designed to connect headphones with an impedance of 100-400?, with an impedance of headphones of the "Walkman" type, probably 32?, and people were looking for such.

Mateusz_konstruktor wrote:

Not. The point here is that the radios were designed to connect headphones with an impedance of 100-400?, with an impedance of headphones of the "Walkman" type, probably 32?, and people were especially looking for such.

What were they supposed to design here? The handset is in series in the collector circuit and behind. The lower the resistance, the more power and the stronger the sound.
A resistance of 32 ohms is approximately 46 mA at 1.5 V. The Icmax of the transistor in UL1111 is 50 mA.
In MT 1/1990 the author wrote that "you can use any low impedance headphone with a resistance of 100-400 ohms", which does not mean that you have to, because this is how the system was designed. Maybe Walkman headphones weren't that common back then.

Mlody_Zdolny wrote:

The handset is in series in the collector circuit and behind. The lower the resistance, the more power and the stronger the sound.
A resistance of 32 ohms is about 46 mA at a voltage of 1.5 V.

Ya ... and what is the voltage drop at the CE connector even of a saturated transistor?

Tia, the power on the transistor at 50 mA and Uec = 1.5 V is 75 mW, the catalog Ptot for a single transistor is 300 mW. The voltage Uec contributes to the collector current drop in a directly proportional manner.

When connecting two channels of headphones in parallel, the resultant impedance is 16ohm, but you can connect in series - i.e. connect the jack between R and L without ground - then the situation is bearable.

Krzysztof Kamienski wrote:

Mlody_Zdolny wrote:

The handset is in series in the collector circuit and behind. The lower the resistance, the more power and the stronger the sound.
A resistance of 32 ohms is about 46 mA at a voltage of 1.5 V.

Ya ... and what is the voltage drop at the CE connector even of a saturated transistor?

What connector?

I have wound the antenna on medium and I have a problem with the reception of the local station.
It creaks. It sounds like I have a bad tune or something.
L2 - 1 turn gives enough volume.
Any ideas on how to improve reception?

piotr_go wrote:

I have wound the antenna on medium and I have a problem with the reception of the local station.

What?

100W, distance ~ 1km
It also looks that the signal level from the antenna has no effect on the distortion.
It can also be heard when the sound is low.

Tip: desoldering the R6 improves reception, but the volume drops significantly.

piotr_go wrote:

desoldering R6 improves reception, but the volume drops significantly.

Desoldering R6 causes that the circuit with T3 ceases to function as a voltage amplifier and the current through C6 flows only in one direction.

piotr_go wrote:

100W, distance ~ 1km

I think it's some kind of pirate radio

piotrek0207 wrote:

I think it's some kind of pirate radio

http://www.polskaam.radiopolska.pl/polskaam.htm

Desoldering C7 and R6 probably gives the best results.
Tomorrow I will look for the BC847A and solder the art.

==== update ====
BC847A did not help. Different reinforcement, but the same crackle.

Hello
I look at the diagram of the radio and throw in some theoretical advice.
Peter, if you want to receive local stations, let's start from the beginning of the diagram, throw the coil into a universal tester that everyone probably already has and we read the inductance and choose the capacitance for it. The parameters from the scheme can be felt with long waves, the local transmitter on the medium is rather 60 turns and several dozen pF, as I remember from practice.
R1 should be selected so that there is half Vcc on the collector T1, a similar principle applies to the amplifier on T2, here also half the power supply on the collector.
The detector on T3 is quite strange for me, for my taste, I would use a voltage divider so that the collector has Vcc voltage, then the transistor will only amplify one half of the waveform and the envelope of the carrier wave will appear on C7.
Similarly, I feel an error in the T4, you cannot put a resistor from the base to the power supply in the emitter follower, because this will introduce several dozen percent distortions. Either we give a divider to the base or a DC coupling shorting C6.
Has anyone kicked this diagram? Maybe not, because there were some limitations in that system, some transistor emitters could not have a higher potential than the outputs of other transistors and maybe someone used these relationships. The second thing is beta, in UL1111 it was 40 - 100, in the transistors you use, depending on the group, it can be up to 800, which significantly affects the resistors in the bases of the transistors.
Finally, by freeing from the mutual limitations of voltages at the outputs of the transistors, you can give a slight positive feedback and make a reaction receiver, we gain both gain and selectivity, and a receiver with similar properties can be made on one transistor but in this matter it is worth rummaging around on the Russian or Japanese sites.

PiotrPitucha wrote:

The detector on T3 is quite strange for me, for my taste, I would use a voltage divider so that the collector has Vcc voltage, then the transistor will only amplify one half of the waveform and the envelope of the carrier wave will appear on C7.

Why a divider for a base? The bipolar transistor is controlled by the base current. Here they are nanoamps and the transistor is on the conduction limit.
Same with the duplicate on T4.
The C9 function is interesting, in the original the T4 emitter goes directly to the T5 base.

PiotrPitucha wrote:

The parameters from the scheme can be felt with long waves, the local transmitter on the medium is rather 60 turns and several dozen pF, as I remember from practice.

On medium, I reduced the capacity and the number of turns.

PiotrPitucha wrote:

R1 should be selected so that there is half Vcc on the collector T1, a similar principle applies to the amplifier on T2, here also half the power supply on the collector.

There is 600 ... 700mV on T1 and T2.
I was looking at the T2 oscilloscope, although it adds its noise, you can see the carrier. Doesn't look cropped or anything.

PiotrPitucha wrote:

The second thing is beta, in UL1111 it was 40 - 100, in the transistors you use, depending on the group, it can be up to 800, which significantly affects the resistors in the bases of the transistors.

I checked the BC847C and BC847A. Same distortion.

PiotrPitucha wrote:

The detector on T3 is quite strange for me, for my taste I would use a voltage divider as a base

Resistor to C5, C6, ground or something else? What value?

Mlody_Zdolny wrote:

in the original, the T4 emitter goes directly to the T5 base.

Modification from Fig. 5