PDA

View Full Version : First low budget DRM Radio?


carknue
19-08-2005, 19:53
What about this?
http://www.kchibo.com/drm1.htm

Is it already available?

dk8cb
19-08-2005, 20:58
Hi all,

perhaps, it's only a receiver with a 12 kHz output.
See this (not very good) babelfish translation of the original chinese webpage (http://babelfish.altavista.com/babelfish/trurl_pagecontent?lp=zh_en&url=http%3A%2F%2Fbcl.myetoys.com%2FArticle%2FClass 25%2F200508%2F984.html) on which it says:
This product main characteristic
Digital amplitude modulation/frequency modulation stereo sound/short wave (1-2);
Has the 12KHz signal output jack, uses for the receive numeral broadcast decoding;
Uses the import high quality numeral harmonious (PLL) the processor;
Four ways choices search broadcasting station:
A, direct input broadcasting station frequency;
B, manual search broadcasting station
C, automatic scan broadcasting station;
D, the computer choose in advance the memory 24 broadcasting stations frequencies;
Supposes the (= has a) pressed key locking key, prevents the misoperation; Digital clock and 10-90 minute sleep automatic pass machine control;
Supposes in (= has a) 9K/10K the wave step to enter the frequency selection switch, suits the various countries service pattern;
Supposes (= has a) the local/long-distance sensitivity switch, facilitates under the different environment the receive strong and the weak broadcast signal;
The ad hoc at night illuminates the indicating lamp, facilitates the use;
Uses 3 5th battery power supply, may use the external power supply;
Size: 150 x 88 x 35mm.

Roland

Connor Walsh
20-08-2005, 07:06
Yep, I'm afraid it is just a 12KHz if output.
The line "Has the 12KHz signal output jack, uses for the receive numeral broadcast decoding;" translates more humanely ;) as "has a 12 KHz signal output socket, to supply a digital decoder".

Kchibo generally make quite poor radios, it has to be said.
They say they travelled frequently to the the main broadcasting college in Beijing (now called the Communications University of China, and an associate member of the DRM consortium), and to Changsha (with scheduled MW DRM transmissions) to test the unit out, and eventually, after much hard work, they got it.

Now, for some speculation on my part:
If you look very closely, you can see a slightly twisted DRM logo on the front panel. It's clearer in this pic http://bcl.myetoys.com/Article/UploadFiles/200508/20050811153547527.jpg

My own suspicion about DRM in China is that the government will only allow receivers that cover specific bands: media control is currently being tightened there, and DRM could be a challenge to that. As I understand, a receiver cannot use the official DRM logo if it doesn't cover 150 - 29,999 KHz.

Just how China "enacts" DRM could be very important to the success of DRM jamming could cause a lot of trouble! At the same time, cheap radios coming out of China could help make a "digital changeover" much more feasible.

Edit: Looking at the picture some more, I think it is a computer mock-up, and I can't find any info on weather it's really available.

dk8cb
20-08-2005, 11:27
Originally posted by Connor Walsh
Yep, I'm afraid it is just a 12KHz if output.
...
Just how China "enacts" DRM could be very important to the success of DRM jamming could cause a lot of trouble!

Hmmm..., it might as well have an internal decoder and just feature an auxiliary output for an additional external decoder. Why should they have to travel to Bejing and invest "much hard work" ;-) into just a 12 kHz IF output?

Concerning the jamming issue: it might be "sufficient" for CRI to use a bandwidth of +/- 10 kHz AM on all their shortwave transmissions and to choose the "right" frequencies. I have observed them using such a large bandwidth quite a number of times when I tried to investigate the cause of heavy interference to DRM signals.
The Kashi transmitting centre which has recently been fitted with new 500 kW Thales transmitters and from where DRM test transmissions have already taken place, is quoted on a webpage on broadcast jamming (http://www.radiojamming.puslapiai.lt/photo.htm) as being a jammer site.

Roland

Connor Walsh
20-08-2005, 12:11
Originally posted by dk8cb


Hmmm..., it might as well have an internal decoder and just feature an auxiliary output for an additional external decoder. Why should they have to travel to Bejing and invest "much hard work" ;-) into just a 12 kHz IF output?


That's what I was thinking! But according their website doesn't make any mention of an external decoder they might bundle a complied version of DReaM on CD or something like that! I expect they are just talking up the product and the wonderous work they put in. :rolleyes:

In some ways, if the authorities in China choose to continue with their big wide AM transmissions to jam Mandarin AM broadcasts from BBC, VOA, RFA and so on, then they might affect European DRM transmissions to either side _and since they deny that they are doing it, there would be no recourse. That could screw DRM in Europe. Hopefully there will be some noises from China on how it plans to adopt DRM this year.

dk8cb
20-08-2005, 14:18
Originally posted by Connor Walsh
It's clearer in this pic http://bcl.myetoys.com/Article/UploadFiles/200508/20050811153547527.jpg

One might have a look at it, if the site wouldn't be so awfully sloooooow!
Over here, the browser loads the file at a record-breaking rate of around 17 bytes/s. :o

Roland

DRM-Fan
20-08-2005, 15:54
Links are dead with me. The only true 'proper' DRM radio will be the one from radioscape due out very soon. Let's hope it's very well advertised after the IFA

dk8cb
21-08-2005, 16:17
After yesterday's slow and incomplete data transfer from the site mentioned above, I have managed to download the picture of the KK-DRM01 today, see attachment.

Does anyone have a sufficiently good knowledge of Chinese to be able to explain the functions of the buttons?

Roland

Connor Walsh
21-08-2005, 16:33
Okie Doke!

The column on the left, from the top, reads: "Mode",
"Metre band", and "Time Set/ Save".

The rockers on the right are marked for Minutes and Seconds.

Under the display it says "Digital Tuning/FM Stereo/Short wave (1-2)"

And there is a little LED, the mark of which I can't be sure of, it's either power or tuning. I'll have to check with other people!
CORRECTION: It's a Reset button.


Below the keypad: Under number 5 is "Band Change", and under 8 is "Frequency Entry".

dk8cb
21-08-2005, 16:37
Thanks!

So, there seems to be no switch to choose a DRM mode.

Still no conclusion about the real nature of this receiver ...

Roland

Connor Walsh
21-08-2005, 16:48
I think it is just a Kchibo Clock-radio with a 12KHz if output really. Nothing more!

dk8cb
21-08-2005, 23:18
I wonder, whether they will sell this thing with a software CD and a version of Dream localized into Chinese and perhaps showing a Kchibo Logo.

I for my part, did not have to travel to Bejing to fit my receiver with a 12 kHz IF output. I just went into town and bought a ceramic resonator and an NE612. :p

Roland

HC7AW
26-08-2005, 21:07
Greetings all,

We just wrote to Kchibo. They confirm that the radio is a 12KHz output model and that it requires a computer to decode the audio. However, they say that the unit will sell at the IBC for 47 USD. That is the lowest price I have ever heard of for a 12 KHz output radio. It also seems to mark their entrance into the DRM radio market. That fact is probably more significant than the radio itself.

Doug

DRM-Fan
26-08-2005, 21:19
Originally posted by HC7AW
Greetings all,

We just wrote to Kchibo. They confirm that the radio is a 12KHz output model and that it requires a computer to decode the audio. However, they say that the unit will sell at the IBC for 47 USD. That is the lowest price I have ever heard of for a 12 KHz output radio. It also seems to mark their entrance into the DRM radio market. That fact is probably more significant than the radio itself.

Doug

Yes I totally agree with you. When you think how much the DAB pc radio (forget the name ?) was when it first came out... 47 works out at 26 or 38 Euro, a very cheap price indeed!

dk8cb
26-08-2005, 21:23
Hi Doug,

did they write anything about it being sold with or without software included?

Perhaps not in Europe ...

Roland

HC7AW
26-08-2005, 21:28
Roland,

No, they did not mention if the software came with it or not. I would assume that it does not come with it.

By the way, let me correct myself and say, they plan to be at the IFA in Berlin, not the IBC. Sorry about that small error.

Doug

dk8cb
26-08-2005, 22:12
Originally posted by HC7AW
... they plan to be at the IFA in Berlin, not the IBC.

Thanks for the information, I will be there next week and will pay them a visit. I will try to find out what's behind it and post my findings here.

Roland

DRM-Fan
26-08-2005, 22:18
Originally posted by dk8cb


Thanks for the information, I will be there next week and will pay them a visit. I will try to find out what's behind it and post my findings here.

Roland

Will you take photos of the radioscape module etc ? Do you know if there is any TV 'feed' of the IFA ? I suppose ZDF etc will have news from the show ?

dk8cb
26-08-2005, 22:26
Originally posted by DRM-Fan
Will you take photos of the radioscape module etc ? Do you know if there is any TV 'feed' of the IFA?

Exactly that is my intention. :)
I'm already charging the batteries of my camera.

I don't know about TV feeds but I would wonder if DRM would be featured. But one never knows. Even the german computer magazine c't in its current issue, which includes a special on new trends on IFA, doesn't say a word about DRM.

Roland

DRM-Fan
26-08-2005, 22:34
Originally posted by dk8cb


Exactly that is my intention. :)
I'm already charging the batteries of my camera.
Roland

Great, nice big close ups please :D

carknue
26-08-2005, 22:37
Would be a good chance for Deutsche Welle TV to present DRM.

simone
04-09-2005, 18:54
Originally posted by HC7AW
Greetings all,

We just wrote to Kchibo. They confirm that the radio is a 12KHz output model and that it requires a computer to decode the audio. However, they say that the unit will sell at the IBC for 47 USD. That is the lowest price I have ever heard of for a 12 KHz output radio. It also seems to mark their entrance into the DRM radio market. That fact is probably more significant than the radio itself.

Doug

Hi Doug,
unfortunately I could not find it at IFA :(
73, Simone

DRM-Fan
05-09-2005, 01:18
Originally posted by dk8cb


Exactly that is my intention. :)
I'm already charging the batteries of my camera.

I don't know about TV feeds but I would wonder if DRM would be featured. But one never knows. Even the german computer magazine c't in its current issue, which includes a special on new trends on IFA, doesn't say a word about DRM.

Roland

Did you get some good pictures Roland ?!

dk8cb
05-09-2005, 08:45
Originally posted by DRM-Fan

Did you get some good pictures Roland ?!

Yes I did. I only returned yesterday night from Berlin and will report in more detail later. Watch this space.

In the meantime, just have a look at the attached picture of the new radioscape RS500 module.

Roland

Digger
22-09-2005, 17:16
Hi

The inflation is high in China: I was offered the KK-DRM01 for USD 50.- FOB Hong Kong today. It is a "DRM FM Stereo Two Band SW radio" according to their HK office. They did not mention whether there was a PC included in the FOB price.

A possible application how to use the receiver as a portable unit is enclosed in the attachment.

Cheers,
Terje

PS: My apologies to Practical Wireless Vol. 1 No. 3.

dk8cb
22-09-2005, 18:25
Hi,

if we were to order three or four shipping containers full of this radio, the price might perhaps come down to 10 EUR a piece. :)
I still wonder what kind of software - if any - will be delivered with this receiver. I can only think of one ...


Roland

Digger
10-11-2005, 14:21
Hi,

The little wonder KK-DRM01 arrived this morning, but without the software-CD :D . The radio was shipped in a cute pouch with tassles and came with instructions in English and German, a charger, stereo earphones, a connecting cable with 3,5 mm stereo plugs and an antenna cable.

The frequency bands are:
0.520 - 1.620 MHz in 10 kHz steps, or
0.522 - 1.620 MHz in 9 kHz steps,
2.300 - 7.300 MHz in 5 kHz steps and
9.500 - 26.100 MHz in 5 kHz steps.
87.5 - 108.0 in 100 kHz steps.

That means that BBC on 7.320, 7.465 and 9.470 MHz are not possible to receive.

The first impression was the low S/N ratio. RMC on 6.175 MHz was fairly good, Luxy on 7.295 also, but the result was not impressing. Sines on 15.440 MHz came with a strong signal, but the MSC CRC wouldn't light up.

Any questions?

73

Terje

fibber
10-11-2005, 15:12
How did you get one? Retail or a "sample"?

dk8cb
10-11-2005, 16:53
Originally posted by Digger
Any questions?


Was it really "the container" or just a single box? ;)

The limited frequency range is a problem of many of these small and cheap portable receivers. It results from the particular type of synthesizer chip that is used in the receiver. The manufacturers of these radios don't seem to know that there have been transmissions eg on 9.41 MHz (analogue AM) from the BBC in Europe for decades. I think one can forget any shortwave receiver, on which the BBC can't be received properly in Europe.

Usually, the tuning processors are made by the japanese semiconductor manufacturers (eg Toshiba) in a variety of versions with differing frequency ranges, denoted by differing subtype numbers, eg TC9318FB-060, ...-030 etc.. On some types, it is only a matter of how the diode matrix is wired, a different wiring may result in a different frequency range. But of course, the VCO has to fit the tuning range of the tuning processor. Kchibo should quickly react and bring out a version with a different subtype of the tuning processor (or a suitably wired diode matrix) and change its VCOs a bit such that the frequency range includes frequencies commonly used in Europe, otherwise this is a fairly uninteresting receiver.

Roland

DRM-Fan
10-11-2005, 20:01
Originally posted by Digger
Hi,

The little wonder KK-DRM01 arrived this morning, but without the software-CD :D . The radio was shipped in a cute pouch with tassles and came with instructions in English and German, a charger, stereo earphones, a connecting cable with 3,5 mm stereo plugs and an antenna cable.

Any questions?

Terje

So where did you order from and how much ? Any good on 1440 etc ??

dk8cb
10-11-2005, 20:39
Originally posted by Digger
Any questions?

Still another question which I forgot to ask in my post above:
Is it a single or a double conversion receiver?

Roland

carknue
10-11-2005, 22:43
Has it got an external antenna input?

dk8cb
10-11-2005, 22:53
Originally posted by carknue
Has it got an external antenna input?
Originally posted by Digger
The radio ... came with ... an antenna cable.

So it should have an input to connect this cable to.

Roland

carknue
10-11-2005, 23:03
It could be clipped on the telescopic antenna...:confused:

How wide ist the filter? What is the exact LIF? 12000Hz?

DRM-Fan
11-11-2005, 00:46
Digger has gone quiet, a wind up ?! Unless he brought one in China I can not find a single source to buy online

Digger
11-11-2005, 07:39
Hi all,

Thank you for your questions. Sorry folks, I'm not online 24 hours a day, so I couldn't answer your questions until now.

When I wrote "questions", I should perhaps have written "technical questions".

To Fibber: How I got it? I organised it via my "Tough Guys" in Hong Kong. However, it took some time.

To Roland: Nah, it was one small parcel ;) . I knew about the "SW 1 and SW 2", but I was a bit disappointed to find that the bands were limited. I haven't taken it to pieces yet, but will do so in due course.

To DRM-Fan: Like I mentioned in an earlier post, it was quoted as USD 50.- FOB HKG. The bill has not arrived yet... I haven't posted any reception results yet. Yes, BBC on 1.296 MHz was decoded quite OK, but the receiver is not overly sensitive.

To Roland: Single or double conversion? Don't know yet; there is nothing mentioned in the specification. Have to take the thing to pieces, as there was no Service Manual enclosed in the parcel - hi. The "Single Signal Selectivity" is given as "≤ 16 dB". :confused:

Carsten: External Antenna? No, no Ext. Ant. Jack. I was searching in vain for this input. There is an application example described in the User's Manual (see the enclosed picture). I wonder if the reception is most favourable if the DRM-Transmitter also uses a Curtain Antenna? :)

I haven't measured the selectivity, but the receiver is fairly wideband. I can see that when I compare Waterfall Spectrums with the ones from my FRG7700 (which I pepped up with new, better, ceramic IF filters). When I fed a signal from the Stabilock to the KK-DRM01, I measured 11800 Hz on the 12 kHz output. The output level varies a lot depending of the input signal. Eventually AGC sets in, but at rather high input levels. The 12 kHz output impedance is low, <600 Ohms. One drawback of the receiver is the fairly low S/N ratio. Even though the shifted PSD looks perfect when you look at Dream, the audio won't play, or it plays with dropouts. The performance on MW is better than on SW; RMC on 6.175 was quite OK, but 15.440 with a strong and steady signal would not decode at all. 17 MHz was off the air yesterday.

Need more time to some more tests .

73

Terje

Digger
11-11-2005, 09:28
Hi,

Enclosed is an hour's report using the Kchibo receiver. Quite good, but the signal was quite strong this morning. The log was recorded with the built-in telescopic antenna and the radio placed near a window.


73

Terje

dk8cb
11-11-2005, 09:53
Originally posted by Digger
The "Single Signal Selectivity" is given as "≤ 16 dB". :confused:


Hi Terje,

this sounds pretty much as if it is a single conversion receiver, the image frequency is suppressed by less than 16 dB. But this is really a strange way of specifying image suppression, because normally, one would write "> x dB". The way they specify it could well mean that it is actually zero.

Roland

Digger
11-11-2005, 18:38
Hi all,

As you saw, the radio liked Deutsche Welle. On 6 MHz, I should add. Like Roland suspected, it is a single conversion job. The IF frequency is 450 kHz. The Local Oscillator is f(RX) + IF. The adjacent channel selectivity (10 kHz) is 26-27 dB over the entire Short Wave range, measured with two signal generators.

But after so many trips to the Communications University of China, why did they not make one more trip to discuss double conversion:confused:

The image frequency response is low. Very low. It is 3 dB at 15 MHz. I wonder if there is a ceramic filter at all in the receiver. That explains that DW on 15.440 won't decode. Imagine all the noise 900 kHz up which is added to the DRM channel.

Well... if you want all the data, send me 50 bucks and the PDF is yours :p
That *WAS* a joke!

73s

Terje

dk8cb
11-11-2005, 22:18
Originally posted by Digger
The image frequency response is low. Very low. It is 3 dB at 15 MHz. I wonder if there is a ceramic filter at all in the receiver. That explains that DW on 15.440 won't decode. Imagine all the noise 900 kHz up which is added to the DRM channel.

Hi Terje,

that it is a single conversion receiver does not necessarily mean that many signals are undecodeable. Take eg the Elektor receiver, the concept of which is in no way better, since it is also only a single conversion receiver with about the same IF frequency and no selectivity ahead of the mixer. A lot of people do get good results with this receiver if there are no strong signals on the image frequency.

I have done some tests with a very cheap portable of a similar design than I suspect the Kchibo to be which I have modified for DRM. This cheap receiver had awful AM characteristics due to the low selectivity (two LC filters only) but DRM results were quite good. But I only paid 1,50 EUR + postage (7,50 total) on Ebay for it.

I believe that the synthesizer in the Kchibo is not properly designed and that its phase and amplitude noise increases with frequency, an effect from which my ATS-803A also suffers but to a lesser extent. I suspect the reason being the lower gain of the feedback loop due to a more flat dC/dV response of the varicap diode at a larger tuning voltage (ie a higher frequency) and also because of a larger frequency division ratio at higher frequencies, by which the noise produced by the PLL reference oscillator gets multiplied by a larger factor.

Roland

Digger
11-11-2005, 23:38
Originally posted by dk8cb

I believe that its phase and amplitude noise increases with frequency. .... a larger frequency division ratio at higher frequencies, by which the noise produced by the PLL reference oscillator gets multiplied by a larger factor.


Hi Roland and all,

Could well be, it just won't decode even strong signals in the 19 mb.

Enclosed find a pix from DW on 3.995 MHz from 11.11.05 at 2305 UT. Possible to get to see the same pix received with an Elektor from the same station, just for comparison?

But without taking the thing to pieces I can't get at the VCO. One way to check your theory would be to substitute the LO with a Stabilock or an HP 8640 to see if things improve. But is it worth the effort?

Terje

dk8cb
12-11-2005, 10:06
Hi Terje,

how does Dream's frequency history look like? Is the frequency stable, does it jump around, is it very noisy, especially on higher frequencies?

From the DW 3995 kHz plot, I guess that there is no ceramic filter at all but that only LC bandpass filters are used, which in itself is not necessarily bad. For decades, radios were built with just LC tank bandpass filters with good results and sometimes better performance than you will find in today's cheap receivers which rely on the selectivity of the ceramic filter only. But if only one or two LC tanks are used in the IF amplifier, the result will of course not be an especially outstanding one.
From how it looks like, it could well be that the same IF chip (TA7640) is used as in my own cheap receiver.

AGC filtering may also be insufficient. Amplitude variations and phase variations of the DRM signal (phase variations converted to amplitude variations on the slope of the bandpass skirts) may appear on the AGC line and decrease SNR. This will of course occur regardless of the received frequency, no matter whether it is high or low.

Roland

Digger
12-11-2005, 19:28
Hi Roland and all

I'll let the radio play with batteries and see how long they last from now 1915 UTC. Just for fun. But it has to be a low QRG like 3.995 MHz. To get some audio...

I dumped the Frequency history for you Roland, actually my FRG-7700 is much more nervous, but gives better results anyway.

More 2 come...

Terje

Digger
13-11-2005, 17:19
Hi,

It played all night on batteries last night with approximately the same result as last recording.

I measured the current consumption to 38 mA in "DRM mode" with the batteries used last night. (DRM Mode is turning the volume control to zero ;) ).

Enclosed is the report from 3.995 last night. Looks like the previous one. The dropout in the early morning hours around 5 UT must be because of lack of ionization.


73
Terje

Digger
04-01-2006, 12:33
Hi all,

For those who wonder how much it cost, no bill has arrived for the Kchibo as of today, so I just can't tell.

Neither have I got a reply to my question to Kchibo regarding the limited frequency range.

But the radio is still working. I use it as a clock in the office.


73
Terje

VE3MEO
06-06-2006, 04:49
Discussion of the KK-DRM01 seemed to die rather suddenly last year. How well did it work with Dream in the non-DRM modes? Is it available anywhere? Did the factory respond to questions about the gap in SW coverage or promise any improvements in phase noise? Are there any other lowish cost tuners with 12kHz output?

73, Tom VE3MEO

Digger
28-06-2006, 08:20
Did the factory respond to questions about the gap in SW coverage or .......

Hi,

I wrote to them on the 15th of November 2005 and sent a reminder on the 6th of June 2006, but so far there has been no feedback.

Terje

Digger
28-07-2007, 07:29
The Kchibo defintively does not like antennas. At the beginning of the a logging I had a 4 meter long PVC insulated wire directly connected to the telescopic antenna. Then I wound the wire 4 turns around the telescopic for a while and then continued with 3 turns.

When the wire was directly connected to the telescopic I noticed some carriers inside the DRM signal in the waterfall spectrum. I could also see very narrow band text transmision (it looked like PSK31), probably ham radio related just below the DRM spectrum. These spurii disappeared when the wire was inductively coupled to the Kchibo.

Addendum 30th July:
This receiver is not at all suited for DRM reception. And, it is not worth wasting time to find out why. It is possible to receive your local FM stations with it, that's all.

Digger
14-08-2007, 07:27
After having to put up with the KK-DRM 01 for more than 3 weeks during my "working holidays" in Sweden, I have decided that the BEST thing with this radio is the DIGITAL CLOCK.... (yes Friedrich, it is rather accurate!)