Meaning of some german words on the front of a radio

[Richard9025]

Hi!

What is the meaning of the words next to the ganged switches in the green and red rectangles?
I know that ukw is fm, mw is mediumwave, lw is longwave and kw is shortwave.



The buttons in the red square are very strange, they can be pressed (if you press one, the other one that has been pressed pops out) and also you can rotate the black cover around it and a mini-scale will move. Each scale is marked u1, u2, u3, u4 and u5 (the u afc is a switch that if you rotate clockwise it goes red, counter-clockwise it goes blank).

Another strange thing is that if you're on a station on fm and you press u1 u2 u3 u4 or u5, it changes the frequency (it isn't some kind of memory, in the service manual it is marked "soundboard")
Thanks!

 

[Alec_t]

The push buttons are known as 'radio buttons'. Press in any one and the others should pop out. These are station selectors. Each one presets the tuner to a chosen frequency, which can be adjusted by rotating its black sleeve. So, they are a sort of memory.
'afc' denotes 'automatic frequency control'.

 

[duke37]

U1 to U5 are preset frequencies, probably set by permeability tuning.

 

[Richard9025]

Ok so:
U is the afc (the afc actually works very well)
I calibrated the radio on a station, (the radio button U being pushed), then I pressed U1, it changes the frequency to one near a station. When I rotate the tuning knob or the black sleeve, it does nothing, just stays there, while the red indicator on the scale above U1 moves. Pressing the rest of the Us (U2 to U5) does the same thing, the frequency is still the same, nothing happens if I turn the tuning knob or the black sleeve. Only on U, I can change the frequency using the tuning knob and enabling/disabling afc. Maybe some problem inside this ooollld ('71) radio, will post the schematic on another thread featuring all the problems of this unit.

Now, what are the numbers next to the little scales trying to represent? (2,15,28,41,56) , definitely not the frequency.

 

[kellys_eye]

The numbers seem to correspond to the old VHF TV channels - the receiver may have been used to provide 'hi-fi' sound for TV reception in much the same way surround-sound does these days.

Here's a cap of the radio specifications showing the optional 'UHF' channels:

 

[73's de Edd]

Sir Richard9025 . . . . . . .

I think that back in the 1970s, that it worked like this.
That set of 6 push buttons are just like were being on old car radios .
They are all mechanically latched together such that only one may be pushed in and when another pushbutton is pressed in the former pushbutton disengages , while the new pushbutton then engages .
With the first push button pressed in, you can then tune in stations on the FM dial scale with its manual tuning knob.
You can test the AFC functionality by rotating the rear black skirt knob to the left to turn the AFC off .
If you will then initially tune onto a moderate strength FM radio station and then tune a little to the left, when you start to get a little " off the station " background noise and distortion from being out of tune . If you rotate the AFC knob to its ON position, the radio should auto shift back into tune . Repeat the procedure on the other "edge " of that FM stations frequency . If it passes both tests then that confirms that the units FM alignments " S curve " is being properly set .
NOW . . . . . . for the BIG mystery solution.
You know the good quality of audio that this unit and its speakers can achieve.

( ( ( I now do a check back to this post and see that Sir Kelly has since, put on some relevant info onto this post . . . a la / uf der Radio Museum.) ) )

The idea was to be able to tune into the TV sound of 5 stations via the pretuned pushbuttons, for this unit, instead of having to use the typically quite mediocre sound, produced by a small TV speaker.
You will certainly be more knowledgeable of if its being the 2-56 channels of a VHF or UHF band and it seems like the UHF spectrum would be quite a challenge on this units construction (without AFC).
So . . . . . . .you tell us . . . . . . assuming that it might be the same in your country..
ALSO . . . . I expect all of that spectrum to now be DIGITAL, and with you only picking up a hiss and digital whir r r r r r r at that frequency, instead of audio.


Thasssssittt . . .

73's de Edd

 

[Richard9025]

Here's a cap of the radio specifications showing the optional 'UHF' channels:

On every radio that has FM, on radiomuseum shows "plus FM or UHF"
For example, Gloria, a romanian radioreceiver has an fm band and it shows "plus FM or UHF"
https://www.radiomuseum.org/r/tehnoton_gloria_4_rp_1524.html
Every fm radio shows on radiomuseum "plus FM or UHF" and I reeeaaallly don't think that it can receive uhf bands.
Now I'm looking at the models that look like this one (Imperial HI-FI 2500,2600,2800,3000,4000)

 

[Richard9025]

Ha! Look what the photo above means: (google translate)
Like a computer, the HiFi 2500 system has a "memory." With 6 buttons on the right side of the unit, any FM station can be stored and re-dialed at the touch of a button An automatic decoder takes over the switching of the device to stereo playback when the selected FM station broadcasts stereo broadcasts At the same time, this operating state is indicated by a control lamp connections for turntables with crystal or magnetic pickup, tape recorder and Antennas are easily accessible on the back of the unit Important for recording tape on stereo broadcasts: The pilot tone is suppressed Control unit, turntable and speakers are matched in technology and form - a unit that can be heard and heard.

 

[kellys_eye]

After consulting some more learned friends in the 'antique' radio world it appears that this is a particular 'German thing' of allocating channels 2 - 56 to the VHF Channel II range (87.5 to 108MHz).

The pushbutton unit selects multi-turn presets that set the tuning voltage on a varicap-tuned front-end.

 

[73's de Edd]

So it looks like it was just like television was being handled in the early post VHF days . .with the then onset of additional UHF band ststions.. .
Channels 2-13 were no problem to handle with bandswitch tuning, but the influx of UHF stations in the channel 14-83 created a problem for easily simplified channel tuning.
The result was initially using a variable continuous tuning on UHF, which could be a hassle on retuning to several UHF stations each time.
THEN the utilization of voltage variable varactor tuning along with a final nudge with AFC, led up to the capability of exactly what you see being used there. The use of pushbuttons and the switching in of preset voltages to go to the varactor tuner.
5 preselected station selections in this units case.
Finally digitally synthesized tuning came in and its ease of calling up any channel rapidly.

I guess Sir Harald will have to come in and relate to what were being the older 2-56 band encompassing sector frequencies, probably shifting into no longer being used after the 1970's.

Considering the required frequency spacing between adjacent frequencies, I can thereby see the assignment of those potential 2-56 channel designations.

 

[Harald Kapp]

mono is obviously a stereo/mono selector.
ta krist./magn. is for record plyers with crystal or magnetic pickup respectively (ta = TonAbnehmer).
tb is for a magnetic tape (tb = TonBand).
aus would be off (as in on/off).

Now, what are the numbers next to the little scales trying to represent? (2,15,28,41,56) , definitely not the frequency.

u is probably short for UKW (ultra short wave or FM, although the German term more precisely denotes the frequency range whereas the English term denotes the type of modulation. But for radio broadcasting these terms are equivalent as FM is only used on UKW). The numbers are the "channels" that used to be assigned within the range of broadcast frequencies, starting with channel 2 and having a raster of 300 kHz or so.