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Tuesday 29 January 2013

Climax Digital DTV300 & SDR-Radio

I just purchased a Climax Digital DTV300 dongle. Wow! How on earth can an El Cheapo £15 "DVB-T/Freeview/FM Radio /DAB Receiver" do so much and perform so well?

Well, it can if it is controlled by good software. From comments made so far, I understand these units don't cope too well in strong signal areas, however, here on the east coast I don't have that problem, thankfully, so the DTV300 handles very well, but I discovered its capabilities as a worthy VHF band 2 DX machine are very close to those of my Sony XDR-F1HD.

Don't install the software which comes with this USB dongle if you want to get the best band 2 performance. Instead, try using something like SDR Radio or SDR# as these offer much more control than the bundled software. Both of these are free and each have their own advantages. Personally, I like the SDR Radio software as, although rather complicated at first sight, does a lot, lot more.

My interest in these dongles was aroused a couple of weeks ago when I read that they can be used as SDRs (Software Defined Radios) on the the VHF band 2 FM broadcast spectrum, allowing up to 2 MHz of recording bandwidth. I wasn't convinced, initially, until I read some reports on the Skywaves FM Forum stating just how good they actually were. I was advised to get one to have a play, so I did.

To begin with, the installation of the software isn't exactly straight-forward, though there is a lot of help documented on various websites and forums, such as the SDR Radio Forum and the SDR Radio website. It took me a good few hours to work out how to complete the installation as the appropriate drivers were not initially found by the software, which needs to be told where to find the appropriate drivers.

Once up and running, I was blown away by the DTV300's performance on band 2. It was actually as good as that of my Sony XDR-F1HD and with only subtle differences. The DTV300 probably doesn't quite match up to the XDR-F1HD's superb selectivity - even when using the software's fully variable bandwidth, but it wasn't far behind. I was more impressed by the DTV300's gain. The XDR-F1HD has a slight mute on weak signals, but soon opens up once a very weak signal increases in strength. The DTV300 doesn't have this mute when used with the SDR Radio and SDR# software. Or at least you can disable this annoyance if it has. The results were better access and improved audio clarity on very weak signals which is somewhat reduced on the XDR-F1HD. Once the signal increases, then the XDR-F1HD probably wins - but not by much.

I am primarily looking at the DTV300 from a DX perspective, but the audio quality was also good when used with SDR-Radio and SDR#. The DTV300 also has RDS capability. The sensitivity threshold for RDS data is set too high, in my opinion and I wondered if it might be possible to lower this so RDS forms accurately with lower signal levels. If this can be done then you have quite a beast of a DX receiver.

Recording Demonstration:
Click here for a recording, demonstrating the difference in reception between the SDR Radio/DTV300 setup and the Sony XDR-F1HD. The station I used in this demonstration was RTBF La Premiere, Tournai, on 106.0 MHz. I deliberately beamed slightly south of the direction of Tournai so you can hear the splatter of semi-local Kiss FM from Stoke Holy Cross on 106.1 (wide and splattery). I also had the SDR Radio set to its widest IF bandwidth of 192 kHz. The brighter sounding audio is that of the DTV300 via the SDR Radio software, while the more muffled sounding audio is the Sony XDR-F1HD, which starts off the recording. The antenna in use is a Triax FM5, on the roof of the bungalow, beaming south-south-east.

20 comments:

  1. This comment has been removed by the author.

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    Replies
    1. Hi from south-east France !

      Very interesting post.
      I'm about to purchase this dongle I also intend to use in conjunction with SDR-RADIO v2.

      Could you please explain, step by step, how to install the software / drivers to make it work properly ?

      Thans a lot !
      Regards,
      Patrick

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    2. 2mhz!

      oh man, i really shouldn't be spending more time on the computer, but thats so tempting!
      i can't wait to download one of your fm recordings and tune your band, does it do OIRT?

      this is the first decent review from an fm dxing point of view i've read

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  2. Hello Patrick.

    I was going to write a short explanation about the installation procedure, step by step, but I think the installation difficulties vary between different people, computers, Windows versions, etc.

    I can certainly go through my own installation process. The SDR-Radio software simply needs to know where to look for the drivers, as with any software, but Windows seemed unable to do this, so I used installation software called Zadig, which had its own problems.

    Hopefully I'll have something written here by tomorrow.

    Cheers

    John

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  3. Thanks John !

    BTW, I noticed you can modify the RF value in the 'options' window of the 'Home' menu. How to do this ? Currently I can only modify IF but not RF (the button is not 'active'. I'm using Windows 8.

    This soft is amazing but a bit hard to set up the 1st day you play with ! At least for me ...

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  4. That's odd. I can't hep you there. It's different here - I can modify the RF value but not the IF !!!

    There's a lot to learn here and not everybody will find this straight-forward. I use Windows 7 but I don't know why it couldn't install the drivers.

    Sorry I cannot help, but check the SDR-Radio forum, linked in my post. Maybe somebody has already answered this question.

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  5. I decided to tackle this now Patrick. Check latest post or go to:

    http://skegnessdx.blogspot.co.uk/2013/01/configuring-sdr-radio-v2-with-climax.html

    Good luck!

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  6. Fine John ! I intend to give it a try asap.
    I'm currently playing with a FCD+ and I must admit I'm quite amazed. Last year, I ran some tests with a Perseus FM+ and both seem very close.

    BTW, what is the climax maximum bandwidth ? At least 1.5 MHz I guess ?

    Cheers,
    Patrick

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  7. Good to hear it Patrick. I am looking at other dongles too. Ebay have some at good prices.

    Please let me know how you get on with my instructions and if there are any amendments I need to make.

    Regards

    John

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  8. Hi Tim.

    I haven't tried other bands so far, but I did tune down to MW yesterday and heard nothing. I don't know if the DTV300's circuitry is designed for reception a long way outside the stated bands.

    I am currently recording part of the OIRT to check for meteor scatter. This needs investigating as you can "see" where the DX is on the band - a big help during the Es.

    Cheers

    John

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  9. Excellent John, does really make you wonder what could be designed, if the focus was purely on DX. Who would have thought....on a USB dongle!
    BTW TA MW is starting to improve again!

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  10. I think (hope) this is only the beginning Damien. When you look what can be achieved on MW with SDRs you begin to see the potential of "never missing the DX". But it all depends on how much time you want to put into checking all the files.

    I would like to think that, in the not too distant future, there will be SDRs which cover the FM broadcast band that automatically decode the RDS data on all frequencies simultaneously. Other software could auto-log the data and even report directly to DX clusters or online logbooks.

    For me, this would take some of the fun away as there's nothing to beat live listening, but there's no dispute that the digital age has a lot to offer.

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  11. Hi John ! I'm about to purchase one of these 'Climax' dongle and I'll follow your instruction to install it. What about it max bandwidth please ?
    Thanks !!

    Patrick

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  12. I think it depends on the software you use to control it.

    I had to uninstall all software and drivers because it caused my Perseus SDR to stop working. Once I uninstalled this Perseus came back to life. Once the MW season has finished I will re-install everything.

    I just asked on the Skywaves Skype Chat as it's been a while since I used the DTV300. SDR Radio Console allows up to 192kHz IF bandwidth on the FM band. SDR# allows up to 250kHz. I think SDR Console is probably the better software of the two, but some DXers prefer SDR#. Do try both as performance is slightly different, depending on the software. Also I was told recently that different DTV300 dongles perform differently. I suppose it is to be expected with such cheap hardware.

    Hope this helps Patrick.

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    1. Hi John, it looks like my reply got lost ???

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    2. In case you did not get it : I thought the maximum bandwidth was much more than 192 or 250. Looking at your screenshot above, one can see about 600 kHz on the FM band. That's why I thought BW was about 1 MHz or maybe 2.

      Finally, assuming I already use a FCD+, it's no worth purchasing a Climax or similar dongle if the BW is aboug the same.

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  13. Thanks John ! I thought it was much more than 192 or 250 ... looking at your screenshot above, I can see about 600 kHz of the FM band (from 97.7 to 98.3).

    I read than that some dongles allow up to 2 ou 3 MHz bandwidth. Maybe I misunderstood something.

    Well, since I already own a FCD+ it's not necessary to purchase a Climax dongle if the BW is about the same.

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  14. Hmm. I have your reply via email but it doesn't appear here. Odd.

    If you were asking about the bandwidth as displayed in the UI window then yes it is wider. I had assumed you wanted to know about the IF bandwidth. Apologies.

    Since I don't have the software installed at the moment I am probably not the best person to approach for general questions as I forgotten so much. The SDR Radio forum would be the best place to find out all you need.

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