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DE8MSH
19-06-2006, 07:43
In german:

http://www.mydarc.de/de8msh/drm/

Disadvantage of radio: no external wire or antenna plug :( So I had to enlarge antenna with wire...

And also: this little project isn't perfect but an experimental thing :) and it works...

fibber
19-06-2006, 20:52
I could read about 60-75% of the article, but would love to read it in English. Is the radio available online? Medion makes low-end PCs for the US market, but I have never seen radios by them over here.

Danke!

dk8cb
19-06-2006, 21:46
Medion makes low-end PCs for the US market, but I have never seen radios by them over here.

And Medion does not make the radios either but just puts its name on them - or rather has it put on them by some chinese manufacturer.
Medion is the main electronics supplier of the ALDI chain, which also has markets in the US now.

As can be seen from looking closer at one of the pictures, the original type number is PLL2628. No idea who really makes it. But there are many similar types of receivers, usually sold in supermarkets of large chains around holiday times, when people go abroad and might want to listen on shortwave. Usually, these are available for a few days only and when you read about their capabilities on the net, they are usually sold out already. No way to re-order them through the shops. Just wait for a year when a perhaps newer model will be available. Models vary in quality and features, PLL or analog tuning, frequency range, FM stereo and the like. Price of a PLL set is usually around 15 to 20 EUR now and selectivity for AM is often poor due to only one ceramic filter and perhaps a single resonant tank in front of the AM demodulator. Being single-conversion receivers with low intermediate frequency, the radios do of course have almost NO image rejection on shortwave, ie they always receive on two frequencies 910 kHz apart at the same time, but so does the widely used (and imho much too expensive) Elektor receiver in its original design.
Sometimes, one may get the same receivers on Ebay here for a comparable price (most likely a bit more expensive).

No idea about the US situation regarding such receivers.

Edit: Using the type number, I have found this:
http://www.hinston.com/Pll-Radio.htm
There you are!

Roland

DE8MSH
20-06-2006, 08:00
Hi Christopher,

as Roland said: this type of receiver is hard to get, I guess. After a week the Medion was sold out. But: I even bought a more cheaper PLL-Radio (Opera PLL 205). Also a chinese thing. This Radio cost 4,99 Euro at Ebay and it works better with my 12kHz converter as the Medion. It even has a plug for external antennas/wires and you can directly type in the frequencies. So it works better for european stations as the Medion MD81157 did. But: this is also very experimental. But it works, too.

At last, I wired the 12kHz converter into my YAESU FRG-100. For me this is the best solution. But to homebrew the cheapest DRM receiver was and is very funny :D

FYI: My english ins't as good as yours. So I can't translate the text by time... But I'll give it a try... :)

DE8MSH
20-06-2006, 08:06
selectivity for AM is often poor due to only one ceramic filter and perhaps a single resonant tank in front of the AM demodulator. Being

But I guess the Medion has also a 10,7mHz filter in it... Never mind.

:) I t ' s   e x p e r i m e n t a l   b u t   f u n :)

dk8cb
20-06-2006, 08:43
But I guess the Medion has also a 10,7mHz filter in it...

... which is only used for FM reception.

Roland

DE8MSH
20-06-2006, 09:03
... which is only used for FM reception.

Roland

Not possible that first the 10.7 MHz and after that the 450kHz filter do work?

dk8cb
20-06-2006, 09:25
Not possible that first the 10.7 MHz and after that the 450kHz filter do work?

Unfortunately not. These cheap receivers are all single conversion sets. Look at the datasheet of the IC and you will find this confirmed.
Or try to receive a station by entering a frequency 910 kHz or 900 kHz (depending on the IF being 455 or 450 kHz) below what you really want to receive. Eg, enter 6410 instead of 7320 kHz and you will receive the BBC DRM signal - with spectrum inverted - nearly as well as on its original frequency.

Roland

DE8MSH
20-06-2006, 10:34
That makes sense. Thank you Roland. I also guessed that this radio is too cheap to have a 10,7mHz to 455kHz superhet... But nevertheless it works somehow...

:confused: :o :) :D And for SWL DRM is a very very cool thing.

dk8cb
22-06-2006, 09:23
I even bought a more cheaper PLL-Radio (Opera PLL 205). Also a chinese thing.

Exactly. It's manufactured by Leetac and its original type number is KA-LT203, look here: http://www.leetac.com/Proview.asp?id=192

Roland

DE8MSH
22-06-2006, 13:39
Exactly. It's manufactured by Leetac and its original type number is KA-LT203, look here: http://www.leetac.com/Proview.asp?id=192

Roland

Hi Roland,

yes, this is the radio, that I've modified, too.

Thank you for info.