telefunken: 2194; Concertino. AM IF Frequency ?

 

Hello,

I have just overhauled a 1961 Telefunken Concertino 2194 and I have a question about its AM IF frequency.  It's currently set to around 480kHz, some way off the 460kHz stated in the service manual but I don't think the set has been tampered with. Stamped on one of the IF transformers is '485kHz', which may suggest that for the UK and other export markets it was changed. Is it likely that the AM IF frequency on exported versions of this set would be set to 485kHz?  I have overhauled several German built radios of this era and the AM IF frequency has always been the same as the German market sets.

If so I shall align it to 485kHz as it has drifted and the set is lacking a little gain on all AM bands.

Regards ............ Howard

Surrey Hills, England

 

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Hello Howard.

If your radio is made  for the market in Luxembourg or France,  certain the 485Khz realistic.

Why?

The Station  Luxembourg make an interference (*) of  his own  reception frequency = 234 khz,
with the second harmonics in the Mixerstage in the Set.

 e.g. 2x 234Khz  = 468khz - 460 Khz = 8khz. interference, this is audible.

SABA built models for LUX. with 479 Khz as IF. What means an interference = 11Khz.

With your IF of 485 Khz, are the difference = 17Khz.

GRUNDIG an Philips use for BENELUX=  452khz. That makes 468- 452 = 16 Khz

All  this are far or outside of the audio Range from the IF -Channel

mfg  Knoll

 

(*) nonlinearity of the Mixer-Tube

Attachments:

• SABA IF for LUX (13 KB)

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Hello Hans,

Thank you for your reply.

I don't know the history of this Concertino but it does not have a UK dial nor English lettering so may well have been built for the Luxembourg market.

I will therefore align the AM IF to a frequency of 485kHz as it has obviously drifted and hopefully the set  will then work better than it does now.

Regards ...... Howard

 

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Now 472KHz to 480KHz is allowed in many European countries for Amateur 1W EIRP, which could be a 2kW power amplifier. So 485kHz or higher (or 467kHz and lower) is better than 480KHz, assuming a +/- 4.5KHz bandwidth. 

However like the 137kHz Amateur use it's not likely to be too common.

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