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saba: SABA Automatic Station Seeker at 60Hz

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Forum » Radios and other type of sets (Physics) etc. » MODELS DISPLAYED » saba: SABA Automatic Station Seeker at 60Hz
           
Alfred Zeeb
Alfred Zeeb
 
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31.May.04 21:05

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I am contemplating to complement my SABA collection with a model that features the "Automatic Station Seeker" (Automatischer Sendersuchlauf).

The question is whether the automatic works on 60Hz. If not, can it be modified to function and what has to be done? I am looking specifically at a MEERSBURG 7, but I believe the respective electronic / mechanical components are the same as on other Meersburgs and the Freiburg. 

I shall appreciate any advice on this.

Greetings,

Alfred Zeeb

Alfred Zeeb
Alfred Zeeb
 
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25.Jul.04 20:55

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Reply  |  You aren't logged in. (Guest)   2 Hello Major,

thanks for your interest in the problem of adapting my SABA Meersburg 7 to the North American 60 Hz. I'm happy to inform you that the modification has been carried out by a SABA expert in Germany. I understand it involves changing some capacitors  -  details were apparently published in a SABA Service Circular many, many years ago. I am not in possession of that circular.

Basic electronics would indicate that a 20% difference in Hz should have an effect on the speed of an electric motor. Though by comparing the schematics of your Konstanz Automatic 8 with those of my Meersburg 7 it becomes obvious that SABA employed different systems, it is quite conceivable that your radio is affected by the Hz difference as well. Unless, of course, one of the previous owners did something about it.

It's very commendable and should always be part of our collecting experience to attempt to bring these old radios back into their original condition. I see that Hans Kamann has taken up your cause in this matter and you are in good hands with him. Nonetheless, I shall check with my contacts to see if they can rustle up one each of switches S2 and S4. Will keep you posted on this.

Happy collecting
Alfred 
Wolfram Zylka
Wolfram Zylka
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27.Jul.04 08:28

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Dear Colleges.

You mentioned already the existents of frequency converter. May, it is a better idea to restore the old SABA in the origin condition. To use the converter below will solve may be your problem.

I cross the finger and wish you success.

Best regards from the Black Forrest

Wolfram Zylka

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This article was edited 28.Jul.04 11:50 by Wolfram Zylka .

Franz-Josef Haffner
Franz-Josef Haffner
 
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27.Jul.04 08:36

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several documents in rm.org show the changings for 60 Hz, p.e. the model Freiburg 11:

http://www.radiomuseum.org/pages/images/klein/d_saba_1961_freiburg_400_4000_11_108mhz.pdf

This article was edited 27.Jul.04 08:37 by Franz-Josef Haffner .

Georg Schön
 
 
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29.Jul.04 21:07

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Reply  |  You aren't logged in. (Guest)   5 Hello Mr. Sarbell, Hr. Zeeb,
don't have any experience with those fabulous SABAs. (Btw, in German, Saba has the same meaning as Sheeba in English. The company's name, however, is an abbreviation of some kind. The connotation for me will always be that of the wonders of the empire of the Queen of Sheeba - my favourite reading as a boy).

Where I do have some experience is with old recorders from the '50s. The system driving the recorder pen is very similar to the system employed by SABA. I personally own four such recorders. They are among the finest mechanical devices I have ever seen.

At the core of the system is a Ferraris motor with two coils. One coil is connected to an amplifier output; the voltage there is either in phase with mains or it is shifted by 180 degrees, depending on whether the dial is "left" or "right" of a station.

The other coil is fed continuously with voltage shifted by 90 degrees with respect to mains. This is accomplished by a capacitor wired in series with the coil. In my view, the biggest problem when using a 50 Hz device on a 60 Hz circuit stems from that last mentioned coil and capacitor. Because the phase shift is no longer an exact 90 degrees, the system is now asymmetrical.

First thing I would try, is to experiment with bigger or smaller capacitors until the phase shift is approx. 90 degrees. It might be necessary to add some resistance to achieve this.

A general remark on Ferraris motors. The rotational speed (torque) generally depends both on voltage and frequency. When the voltage on one coil drops substantially, (this is the case, when the system approaches equilibrium), the influence of frequency is low. For that reason I am optimistic, that it will be sufficient to change the capacitors.

Best regards,

Georg Schoen

P.S. meanwhile Alfred Zeeb told me, that Franz-Josef Haffner already posted a similar
or identical solution. See the link below. They recommend reduction of capacity
by 25%.

http://www.radiomuseum.org/pages/images/klein/d_saba_1961_freiburg_400_4000_11_108mhz.pdf

Many Thanks to Alfred Zeeb for Help with the text above.

This article was edited 31.Jul.04 13:25 by Georg Schön .

Georg Schön
 
 
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04.Aug.04 19:09

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Reply  |  You aren't logged in. (Guest)   6 Mr. Sarbell,
that type of capacitors were called "MP-Capacitors" in German,
which means "Metall(ized)-Paper".
The important thing is that they heal after small breakthrougs,
allowing a higher voltage than former capacitors.
I have here one of those with a Diameter of 16 mm and a length
of 35 mm. It is rated 220V AC 0.1 mikrofarad. See Img attached.

There are more recent capacitors of that general design,
without paper, but I dont know the Type Names of them,
especially not the American brand names.
This capacitors often do not have the can design.


Respectfully,
Georg Schoen




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This article was edited 04.Aug.04 19:10 by Georg Schön .

  
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