Monday, November 18, 2013

Just Another DVB-T SDR Upconverter gadget

After we stop to make and distribute the Upconverter gadget UP-100 for the DVB-T SDR dongle we start to receive the e-mails asking to help to improve the performance of the present Upconverters that can be found on the market that are not our products. We decide to design this gadget to help all this guys suffering the weak reception on the HF using various upconverters.
So here it is, LNA for HF. This small gadget can improve your reception by amplifying the HF frequencies in range from 150 kHz - 30 MHz by 19 dB. Up to now we make a couple of such amplifiers (without LP filter) on request but due to increased interest we decide to improve the already good design. The same LNA board accommodate now also the 5 pole low pass 30 MHz cutoff filter at the input together with the active MMIC device, all on the small PCB measuring only 1" square (25x25mm).
The board can be powered from 6-12 VDC but there is possibility to power the board also with the 5 VDC from the already existing 5 V that you have on the upconverter. The consumption is only 19mA which should not create any problems for any regulator you have installed there. SMA connectors on the input and the output became a "standard" with this gadgets so only one extra SMA male/male jumper cable is required or SMA male/male adapter and that's it.


This is just a working prototype made on the LNA4ALL PCB to check the performance of the filter and the amplifier. This is not a finished product. So I need your opinion and according to the interest we can produce a batch of the amplifiers. The target price is 20 Euro for the assembled and tested LNA together with the SMA connectors on board. There is an option to have also the LNA for the HF without the low pass filter at the input for all those who wish to use the same LNA also higher up to 1 GHz. The gain of the LNA without filters is around 18-20dB up to 1GHz and NF up to 2.5dB.

This is how you should connect the LNA4HF together with the existing Upconverter and DVB-T dongle.



I have comments opened for you to see how many interest there will be for a product where you can state your ideas about the price, filters, power supply etc. If we receive the interest for at least 50 LNA4HF we will make a batch of 100-150 pcs. The quality of the product should be the same as the LNA4ALL or UP-100 and up to now we did not have complains on the quality and design of the PCB.
Of course, we plan to offer just a PCB for the guys wish to design their own LNA with the MMIC they like and the filter they want. The same board can accommodate several MMIC types.

If you need the LNA4HF let us know, the comments are open for discussion.
Thanks

34 comments:

  1. I am still using the early type HF LNA you sent me, it has been very good, and survived cat vomit!! (don't ask lol)

    With the LNA connected to my setup (with or without upconverter) I only need to set RTL gain to about 2db, which reduces intermod/ghosting to virtually nothing!

    I wonder if the LPF would help my existing Ham-it-up setup, hmm......

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  2. So the cat does not like my LNA :-)
    I do not have any upconverter left to make some test, the guys took even my last sample. I should make one on the new pcb batch that should be here soon.

    The LPF at the input will most probably result in that you will not have to reduce the gain so much on the RTL. The cut off of the 5 pole filter that I have now in the LNA is 30MHz, reducing WBFM 100 MHz more than 60dB.

    You can always test that just add the LP filter with the following values
    120pf, 390nH, 220pf, 390nH, 120pf (shunt first).

    Adam

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  3. I would most certainly be interested in an HF version! I currently have the LNA4ALL and a Ham-it-Up, this would be perfect with it!

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  4. I have interest.

    Instead of two version, what about to put a switch to turn on/off the LPF?

    ReplyDelete
    Replies
    1. I was thinking about that, but how to implement the switch on the 25x25mm PCB remain the problem.
      Beside that, the switch shoud be good quality, because it will be used a lot :-)
      On the other side, I made some simulations and improvements on S11 and S22 are possible if just HF band will be used.

      Delete
  5. I would most certainly be interested.
    I like the switch idea, but understand the layout problem.
    Could you add some jumper points for the user to turn LPF on/off

    ReplyDelete
    Replies
    1. Jumper points is the possible solution, at the moment the present layout may use direct input through the coupling capacitor and if the filter is required the same coupling capacitor is the just turned for 90 deg. to couple the signal from the filter.
      0 ohm 0805 SMD juper can be a good idea and simple to solder and handle. Will consider this idea for sure in the final layout of the PCB.
      Thanks

      Delete
  6. I WANT ONE AND I WANT IT NOW!!!!!!!

    Seriously though this seems to be a "must have" for my NooElec upconverter so if you decide to "go into production" your can count on me to provide a good home to at least one of these.

    ReplyDelete
    Replies
    1. John you are IN :-)
      By the e-mails received and the posts everything leed to the point where this first bach will be in production very soon.
      Thanks

      Delete
  7. Ill take one for sure. Id love to see some pads to solder in usb power. I bypassed the voltage regulator on my lna4all, but soldering leads to the board was a real pain.

    ReplyDelete
    Replies
    1. Oh, I am sorry to hear that.
      There are two pads for the 0 ohm 0805 SMD bridge for that purpose shorting the Voltage regulator and you continue to use the same power pads.
      Another thing, you can power also the LNA4ALL with the 5V through the 5V regulator, it will work :-)
      The PSA4-5043+ MMIC is working down to 3V power supply without any problem. The IP3 is a bit lower but also the noise figure.
      At the end, you do not to have to modify nothing just plug and play the DC voltage you have.

      Delete
  8. Have you considered crowdfunding your project, as Kickstarter (www.kickstarter.com) ?

    ReplyDelete
    Replies
    1. Well, maybe... but our charging policy is entirely opposite from the Kickstarter one.
      We are not charging until the buyer get what he order :-)
      Maybe I will consider the Kickstarter for another DVB-T dongle gadget project that I have presently on hold.
      I think in couple of days we can have a required interest for the first batch.

      Delete
  9. I would certainly be interested. Let me know when they are available!

    Steve KA9MOT

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  10. I'd definitely be interested as well. The LNA4ALLs and the upconverters I received a couple of weeks ago are working great!

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  11. I'm interested as well.

    -Jonathan
    W5JDP

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  12. Let me know when available for pre-order.

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  13. I am interested in this.
    73 de Arnie W8DU

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  14. I receive it in general post envelope 22.Oct - 16.Nov

    https://fbcdn-sphotos-f-a.akamaihd.net/hphotos-ak-frc1/578544_362231040588847_2109044742_n.jpg

    I'm very happy!!!!

    https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-frc1/1451451_363508717127746_366671815_n.jpg
    https://fbcdn-sphotos-f-a.akamaihd.net/hphotos-ak-frc3/1424375_363508627127755_361084845_n.jpg
    https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-prn2/1455135_363508693794415_801250165_n.jpg
    https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-ash3/1456594_363506717127946_605940310_n.jpg

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  15. I think would like one without the LPF. I may not be aware how LPF would help and would like a broadband design to explore full range. I already ordered the other LNA from you to cover higher bands too.

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  16. I also would like one. I have a Ham it up, and as they say its complement colleagues is essential.
    Let me know when you have it available for sale.
    regards

    juanschuhmacher@gmail.com

    ReplyDelete
  17. i want one white and one white out the filter only when its ready to use.
    i cant solder or stuff like that.

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  18. I am interested...
    73's from India

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  19. I think this might benefit me
    I have a Ham It Up V1 upconverter / RTL2832U R820T for SWL
    But I think strong local vhf signals are causing me trouble

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  20. I am interested too. javi_el_largo at yahoo dot es.

    Greetings from Spain.

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  21. I would be interested in one, if it can be made to work with a dongle in direct sampling mode, without the upconverter.

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  22. Hi Adam 9A4QV,
    I am also interested in this HF LNA for experimenting with the SDR USB dongle. Please keep me updated via vutrongthu at gmail

    Thanks,
    de Thu XV9AA

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  23. I am interested too.
    Let me know when they are ready.
    Thank you.

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  24. I'm interested so put me down for 3. Thanks.

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  25. How and where do I order your LNA4HF?
    Regards,
    Knobs

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  26. Hi Adam. I've been reading your blogs and YouTube videos with real interest. Firstly, let me say the information you have shared is excellent. I am a complete beginner and I needed a cheap way to get back into scanning radio and sdr fits my needs, except for being able to receive the HAM bands. My first SDR dongle will be with me tomorrow and I'm eager to get started. I will be emailing you to order one of the LNA units shortly. I wonder if you could advise where I can obtain the oscillator and mixer boards that you used in your YouTube video to create the complete Upconverter? Thanks.

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  27. Hell Matt,
    Thanks for the nice words, I am glad that you found the informations useful.
    Unfortunately, we are not having the boards you ask for selling, they are made using the X-acto knife and a peace of the double side FR-4 boards. If you want to do something alike, you just buy the components and then you cut the boards according the compoents you need.

    ReplyDelete