Interior of Monika radio from Eltra Audiox, model 410, FM/LW

What use are sponges in coils? Stabilisation of the winding?

Is long wave reception possible or is it drowning in interference?
I wonder how much such a radio can play on battery power.
The lack of a switching power supply may make LW reception easier.

>>21272699 .

Yes, exactly. When the radio was dropped or bumped, for example, the coils were not jittered.

szymon122 wrote:

What is the use of sponges in coils? Stabilisation of the winding?

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The sponges are soaked in something paraffin-like - the idea is to dampen the vibration of the coil.
The voice coil vibrating on impact will detune the circuit and the vibration will be heard in the loudspeaker (so-called coil miking) The effect is most noticeable on the heterodyne coil - the vibrating coil introduces additional frequency modulation in the rhythm of the vibration.

Unfortunately, shoddy receivers have been produced for years in which the tuning knob is attached directly to the rotary capacitor. In addition, you have to buy batteries or have access to mains power.
I already prefer electronically tuned ones with a built-in rechargeable battery and power from a phone charger. Especially as I received such a wda as a free gift with my purchases.

This is exactly what I wanted to point out - no gear between the tuning unit and the dial, thus zero tuning precision, just to save a few pennies on hardware and scale. It would be interesting to know if it holds the station alignment, or if you have to correct it from time to time.

p.kaczmarek2 wrote:

I wonder if it is possible to find a 1:1 receiver from another dealer, without the Polish name and markings...

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Of course you can, after all it is a typically Chinese cheap product, mashed up on behalf of many companies.
Examples:
https://www.mediaexpert.pl/telewizory-i-rtv/d...rtv/radia/radio-nedis-rdfm1340gy-czarno-szary
https://www.sencor.pl/przenosne-radio/srd-210-b

The modern Eltra has nothing in common with the former Eltra from Bydgoszcz, apart from the coincidence of the name. All production outside Poland.

The radio inside is typical Chinese, I've seen and dismantled more than one such radio. Nothing particularly interesting.
I have also seen trafka with double winding in this type of equipment, I wonder what this is due to?

Regards,
A.

James596 wrote:

I wonder if it holds the station alignment, or if you have to correct it from time to time.

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Rather it holds because you can see that there is an ARCz circuit with an additional capacitive diode in the FM oscillator circuit. Thanks to this, you also don't have to precisely tune into the station on the FM range
And on the long-wave range the slight sharpening of the heterodyne over time is not noticeable. In this range, precise tuning is not necessary either, especially since there are so few stations. This is not a short- or medium-wave band where fine tuning is useful, which this radio lacks anyway.

In summary, the tuning knob directly on the axis of the capacitor in this particular radio is not a big problem.
The bigger problem is the extremely poor, lead-free soldering, which will sooner or later become a problem. The author of the topic has already pointed this out.
Chinese electrolytic capacitors will probably also die after a few years.
A product only for a few years and then, unfortunately, for disposal... Unless it gets into the hands of some amateur electronics technician who will patiently correct the faulty soldering points.

Radio very minimalist because the price is also very low.
But no one has paid attention to the very extended manual attached to this radio.
Now such instructions are not included.

p.kaczmarek2 wrote:

there is also a single channel audio amplifier here, TDA2822M

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Error. The TDA 2822M itself is a stereo (two-channel) power amplifier, only with the ability to bridge both channels. This manages to produce more power with the same load and power supply parameters.
Apologies for the OT.

That paraffin must have been spilled by someone after a few deep

@efi222 in older radios it was common to find such paraffin glutes.

I found a very similar one branded Blaupunkt.
I am posting a photo gallery.

Well actually - similar enclosure but different board different scale .... But similar . Even the size is the same (I think?). Only are they VERY similar?

Based on a completely different circuit, the C9616. It appears to be an SDR type chip, the tuning is voltage-based (with a potentiometer), there are no variable capacitances, filters, coils in the circuit. All FM/AM reception is handled by a suitably programmed DSP in this chip, clocked by a 32.7kHz quartz and supervised by an internal microcontroller. Simplified to the limit, however.
In this respect, it can be said to be a very technologically advanced radio compared to the title one.
I am only curious about the quality of reception, immunity to interference, sensitivity, because unfortunately, with this may be different in the case of digital SDR circuits.

As an excuse for my last post....
A long time ago I bought a cassette player (something a'la WALKMAN) at the local bazaar. Contrary to my earlier fears, it had a very good mechanism with auto-reverse, low battery power consumption (enough for about a week of commuting to and from work with quiet listening) and of course - stereo. As my son's name day was approaching, I decided to present him with the same player. A few days after buying the first one, I bought exactly the same (in appearance...) player from the same seller at the same market. To satisfy my conscience, I checked it - it played, but something wasn't quite right. I took it apart and... and in the same casing I found a completely different player! Simplified mechanics (one flywheel - in "mine" there were two), the head as well as the whole signal path MONO, and on top of that a different motor that consumed almost 2x the current....

So a similar , or even IDENTICAL housing does not guarantee exactly the same interior.
As I once wrote in another topic : a Chinese can fake everything - even himself. Most likely, this "my " copy was of those dedicated to a specific recipient (demanding more) and the other copy is a version trimmed to the limit - for the internal market, or for a less demanding network.
Anyway, even in contemporary electronic products available on Ali.... (for example) you can get as nicked as I did back then. Under the same description and even the same photo, a completely different quality of goods can be hidden.
Back then - buying from a marketplace - it was more difficult to recognise "good/not good"; today at least you can read the description under the auction and the comments of customers....