PEAK 102569AGPK Very Poor Performance

[G7Tony]

I'm using the PEAK 102569AGPK (RTL2832U & FC0012) and after several installs have finally got it receiving but the performance is very poor. The dongle worked ok in Tv mode previously. Signals are mostly lost in the noise with only the strongest FM radio stations managing to become readable albeit with fluttering and distorted audio. The fluttering may be related to overload so i am using minimum gain with a small antenna. (Gain is only adjustable in 3 steps Low/Mid/high).

Performance is so bad that i thought the installation wasn't working at all until i transmitted a 1W test carrier locally from a handset tuned to a 2m frequency. This produced a very obvious series of peaks in the display with one main large peak at the centre frequency. At this point i wondered if this idea could be developed into the poor mans Spectrum Analyser ;-)
Using a tuned antenna makes no difference to the reception except to increase signal strength. Resolved audio is still mostly lost in the noise and distorted. I & Q calibration seems to be set ok as any deviation from centre increases the mirror image.
One strange thing is that trying to alter the sample rate produces the error 'Failed to set sample rate'. It changed once and once only then stuck on 1.8msps. Trying to revert back to the original rate still produces the error and another re-install of everything didn't help.
Anyone else using this dongle in Win Xp pls share your results here.
Pics show the setup
If anyone has any ideas that i can try pls let me know
rgds
Tony

[Robert Keizer]

Make sure the antenna is grounded as much as possible. I found a similar problem, and solved it by using a hot water radiator connected to the rest of the pipes in my building. Saw a 10db difference right away.

Rob

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[Miguel A. Vallejo]

I don't know exactly, this is only a theory, but...

When you see this image of a E4000 tuner based device:
http://imgur.com/a/9BNOW#0

You can see the antenna goes directly to the tuner, only a capacitor is
placed between (C33).

This is an image of a FC0012 based device (maybe your unit):
http://i.imgur.com/0T1q1.jpg I can see the protection diodes... and a
lot of smd components under the IR receiver.

Here ( http://img6.imagebanana.com/img/lyltzb0q/pcb.jpg ) I can see in
more detail the circuit.

Is it possible there is a UHF band pass filter in all those smd
components? Most DVB-T signals around the world are placed at UHF
frecuencies, so it is possible there is a bandpass filter at the input
to have better performance as DVB-T receiver. I think this because it is
very strange it works fine with TV signals and at the same time works
really bad with the strong FM broadcast signals.

Most E4000 devices are advertised as DVB-T (470-860 MHz), DAB (230 and
1460 MHz), FM (87.5-108 MHz)... so there is very unlikely they have any
band pass filter at input.

How are advertised FC001x devices? If they are only advertised as DVB-T
receivers there are a lot of chances all those smd components are a band
pass filter. In this case a hardware modification will be needed to have
good performance at other frecuencies.

Just my two cents!

[G7Tony]

Thanks Rob i will try this later on and post any results.
Up to now i only earthed to the groundplane

On Tuesday, May 15, 2012 12:33:34 PM UTC+1, Robert Keizer wrote:

Make sure the antenna is grounded as much as possible. I found a similar problem, and solved it by using a hot water radiator connected to the rest of the pipes in my building. Saw a 10db difference right away.

Rob

On May 15, 2012 1:53 AM, "G7Tony"  wrote:

I'm using the PEAK 102569AGPK (RTL2832U & FC0012) and after several installs have finally got it receiving but the performance is very poor. The dongle worked ok in Tv mode previously. Signals are mostly lost in the noise with only the strongest FM radio stations managing to become readable albeit with fluttering and distorted audio. The fluttering may be related to overload so i am using minimum gain with a small antenna. (Gain is only adjustable in 3 steps Low/Mid/high).

Performance is so bad that i thought the installation wasn't working at all until i transmitted a 1W test carrier locally from a handset tuned to a 2m frequency. This produced a very obvious series of peaks in the display with one main large peak at the centre frequency. At this point i wondered if this idea could be developed into the poor mans Spectrum Analyser ;-)
Using a tuned antenna makes no difference to the reception except to increase signal strength. Resolved audio is still mostly lost in the noise and distorted. I & Q calibration seems to be set ok as any deviation from centre increases the mirror image.
One strange thing is that trying to alter the sample rate produces the error 'Failed to set sample rate'. It changed once and once only then stuck on 1.8msps. Trying to revert back to the original rate still produces the error and another re-install of everything didn't help.
Anyone else using this dongle in Win Xp pls share your results here.
Pics show the setup
If anyone has any ideas that i can try pls let me know
rgds
Tony

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[G7Tony]

This is very interesting and when i am back home later i will view these images and my dongle circuit.
You maybe hit the nail on the head here.. i hope!
Will also look at how this device was advertised and will post back later..
Very good observations..
Thank you
;-)

[Codeine]

Hi Tony

I own the exact same DVB-T Peak device and using Win XP Pro with
HDSDR. I tried this on my 1.6 Ghz  PC but didn't install the drivers for the
DVB-T tuner supplied but just used Zadiag as per the insructions.

It does work (almost) with me being able to listen to the local 2Mtr repeaters but the
output audio stutters continuously. I could find no answer on the forum so I tried my
laptop instead. Slightly improved audio but still it stuttered but more slowly.

I have had some success with changing the read length in the ExitIO were you would type
the RTL hint and that did improve the audio slightly. I would love to know why others have
managed to get it all to work so well on thier meager systems and mine fails to work on
three machines...?

Paul

[2E0SDR]

I am having exactly the same symtons Paul, except i cannot listen to anything, yet i have a good antenna.

Regards

Adrian

[G7Tony]

4th attempt to post his now! I will try it without the attachment.

Hi Paul and thanks for your reply.

I've tried the dongle on 2 Pc's. Specs are:-
3.20GHz & 2.5Gb SP2
2.6GHz & 2Gb SP3
Microsoft Visual C++ Redistributable is present & updated on both.
Got the exact same results. Listen to the attached sound file. It's stuttering & distorted.
CPU loading is down to less than 50% on both my PC's. I see yours is quite high but you do have the waterfall on fast which will use more resources.
I looked into EA4EOZ's theory of a front-end filter causing the problem but after a bit of testing on the board am satisfied this is not the case. The FC0012 (40pin) could have additional circuitry within that is causing the poor performance but with no datasheet available we don't know. (E4000 is 32pin)
My dongles packaging does say it will work for DAB/FM

I ran the application using 'Dependency Walker' and noted from the log that some files were reported missing. However.. they are Windows 7 files so i suspect the software was compiled on a Win7 Pc and that the .manifest has recorded these files being present at the time. So nothing to worry about i think.
Everything else looked correct.

Having spent hours on this i've given up with this dongle for now and await the one i ordered a month ago from China (not yet arrived!) which has the E4000 tuner.

We could do with some input on whether the Peak 102569AGPK  works in Linux because the list of devices does list the FC0012 as 'working'

rgds
Tony

[Miguel A. Vallejo]

G7Tony wrote:

>>> I looked into EA4EOZ's theory of a front-end filter
>>> causing the problem but after a bit of testing on the
>>> board am satisfied this is not the case. The FC0012 (40pin)
>>> could have additional circuitry within that is causing the poor
>>> performance but with no datasheet available we don't know.

>>> My dongles packaging does say it will work for DAB/FM

It is very strange. Have you tride to tune UHF signals? Around 450 or 850-900 MHz? I guess it should work.

Searching I found this:

http://fc0012-sdr.blogspot.com.es/

(for now) the final conclusion is FC0012 should be avoided.

[G7Tony]

Thanks for the input and the link.
My original tests were more simple than in the link as my Rf SigGen only harmonics upto about 450MHz reliably and i don't possess a Spectrum Analyser so i just monitored using HDSDR.
This morning i used an Icom transmitting 1W into a dummy load at varying outputs.
The dongle was connected to an outside vertical antenna.
Results were:-

30MHz - FM    Small indication of a signal / no audio
50MHz - FM    Clearly visible signal / no audio
145MHz - FM  Strong carrier shown / Stuttering.. delayed & distorted audio with a slight echo
450MHz - FM  As 145MHz

I agree the FC0012 should be avoided for now for use in Windows.. but how about Linux..?
Anyone has this dongle working ok in Linux ?

I may order an Ezcap dongle from a uk source today as they promise quick delivery. The China ordered one is apparently still in transit and the supplier says uk customs are holding everything up more than usual because of the Olympic games(!)

[G7Tony]

The line above that says 'This morning i used an Icom transmitting 1W into a dummy load at varying outputs.' should say 'This morning i used an Icom transmitting 1W into a dummy load at varying frequencies.

[Paul]

Hi Tony

 

Sounds like you are getting some results from your Peak DVB-T but not sure why you have no audio....?

I have had some success with an Acer 1.5Ghz laptop and it is quite useable from 28Mhz to 2Ghz using my sig

gen with just a faint flutter on the audio. Untill I changed to 1200 sample rate in HDSDR my audio was just a a distorted

buzz so hope this helps.

 

I have sent you some pics of the settings in ExitIO and the sample rate in HDSDR that work well on the laptop.

I am downloading a copy of Linux and hope to give that a try this weekend and see if it is any better than

windows and want to give GNU Radio a try.

 

 

73

 

Paul

[G7Tony]

Hi Paul..

I have tried those same settings previously without success. I do hear 1 or 2 FM strong local broadcast stations but with a lot of distortion. I only pick up my own 2m & 70cms transmissions and they suffer the same distortion.
I'm surprised yours works down at 28MHz because the brief bit of info which i found on a Chinese website for the tuner gives a lower limit of 40MHz. Do you get audio at 28MHz ?
I didn't expect to get audio because the signal was not strong at those lower frequencies.. It takes a powerful local FM BC station for me to hear anything even with an external antenna.
Any chance you could do a recording and post it..? I did make one but each time i uploaded it here it disappeared. Maybe i'll try Youtube and post the link.

At the moment i'm waiting for my e4000 tuner based dongle to arrive before i go any further.

rgds
Tony

[G7Tony]

As a final note...
My Ezcap DVB-T arrived from China at last after 38 days waiting(!) and once connected to my Pc with all the original settings i used for the Peak dongle.. i was able to tune a local 2m repeater.
For me..  the Peak dongle didn't work and the Ezcap did immediately.
Reception is distortion free with no stuttering

Tony

[Youssef]

Hi,

Can you perform the same test with SDR# ? I've just released a version with ExtIO support and need lots of feedback to stabilize it.
The download location is http://sdrsharp.com/downloads/sdr-nightly.zip

Regards,

Youssef

[Paul]

Hi Tony

 

I have had problems with my C: Master Boot Record so apologies for the delayed replies.

Ok on you giving up with using the Peak stick and having success with the the ezcap with the

e4000 tuner. I already have a Funcube dongle with the elonics tuner but it has gaps in it's tunning

in an but works well from 50Mhz to 2.2Ghz only at 98Khz wide though..!

 

I will persevere with the Peak and make some recordings of it on 10 Mts FM  and wonderd

why the elonics tuner is stutter free and yet the Fitipower  FC0012 tuner has such a problem.

I am wondering why the ezcap DVB-T works so well and yet the  the Fitipower FC0012 tuner

has problemand what the fundemental differences are between the two devices.

 

73

 

Paul

  

[G7Tony]

I will be glad to try it later Youseff
rgds
Tony

[G7Tony]

Hi Paul.. No need for an apology.. ;-)
To be honest i got fed-up trying the Peak device and having no success with it.. but now i have the Ezcap and it works fine i can now go back to trying the Peak again.. and with Youssef's software. (Sorry i spelt your name wrong in my reply to you Youssef!).
A recording of your 'Peak' working would be great Paul.. I did make a recording but found i couldn't post it here. I then made 2 videos with the intention of uploading to Youtube until i heard them and found my narrative was too loud (lol). Will try to do a better one.

I wrote to Realtek asking them for a datasheet or SDK and they said they would supply one once i show them i'm designing a 'large scale' project using their product(!) As i'm not i can't go further.
I also contacted some of my Chinese electronics supplier friends in HK about the FC0012 so they may get back to me in the near future.. It would be great to get a hold of the specs for both tuners..
rgds
Tony

[G7Tony]

As an update.. My Peak device with the FC0012 tuner is working 100% in SDR#..
It doesn't work properly for me in HDSDR
Great program Youssef!
rgds
Tony