Monday, April 15, 2013

LNA for all - Low Noise Amplifier for many applications from 28 MHz to 2500 MHz

Are you looking for the cheap multipurpose preamplifier? HAM radio, DVB-T, ATV, SETI, ADB-S, Air traffic and many more applications all in one PCB, "turn the key" solution.


Low noise and low price amplifier that can find his place in many applications is ready. When I said low noise I mean the noise figure that is lower or equal to 1dB over all range. The LNA is covering all bands starting from HF up to the SHF. Wide band gain coverage starting from 28 MHz and extending up to 2500 MHz. One LNA for all frequencies and more. This small gadget can lower and improve you DVB-T SDR stick noise figure and improve the sensitivity. Adding the LNA in front the front end of your receiver can open another dimension in your reception. Receiving HAM radio satellites should not be a problem even with the small setup and portable antennas.


The amplifier is built around Mini-Circuits PSA4-5043+ E-PHEMT Ultra Low noise MMIC amplifier operating from 50 MHz to 4 GHz. Small SOT-343 package combine low noise and high IP3 performance with internal match to 50 ohms. Manufacturer declare a 0.75dB NF @ 1 GHz and 0.98dB NF @ 2 GHz with IP3 value reaching 33.5dBm. Beside the LNA purpose the same component can be used as a small driver amplifier capable of delivering +21dBm of output signal thanks to high P1dB value. The last but very handy feature is Class 1B ESD protection incorporated on die making this device easy for handling.


Even the price is very popular the performance of the LNA4ALL can be compared with the really expensive LNA in range on the market. We made a several independent lab measurements just to prove the quality of the product and thanks to all this guys we do have some relevant figures. One of the measurements is the TOI (Third-order intercept point) or widely known IP3 done by Thomas, DG1TRF. The TOI/IP3 graph was derived from the automatic measurements sweeping the range from 10 MHz to 3.5 GHz in 10 Mhz steps. The average TOI/IP3 is 34.75 dB over the range.



The above graph was derived from the single measurements like the one bellow on the 1296 Mhz. Following the markers it is easy to calculate the TOI/IP3 but even easier if you have the machine showing all the results for you.


 Thanks to Joost from the Netherlands we do have the latest batch S parameters measurement. As can be noticed, the S1,1 is not good at the lower frequencies but for that we do have the LNA4HF designed for the lower bands.

The LNA is made on professionally made printed circuit board measuring 25x25 mm that can be used also for the other active components using the same SOT-343 package and pin out. There is enough place to combine the input and output matching components on the same board, as well as the bias resistors and various bias configuration. The 500mA 5V voltage regulator is integrated on the board where any voltage from 6 V to 12 V DC can be used for the supply. The consumption is between 50 mA and 60 mA.


Turn the key solution is delivered with the standard female SMA connectors insuring stable operation over all range of frequencies. Experience users and builders may prefer the version without SMA connectors in order to house the LNA into the proper aluminum milled box or other metal housing. We predict also this scenario ensuring the 3 mm dia. holes for tight connection. The ground loops and not a proper grounding is a common mistake among the home brewers all leading to unstable LNA operation and self-oscillations. If you plan to use the LNA this way we prepare also the holes close to the SMA connectors as well to overcome possible problems.


If you already experience the quality of our ideas upconverter up-100 then you know what we are talking about. Enjoy your radio !

The basic setup, what you get when you buy the LNA4ALL is presented on the next slide. The LNA4ALL tested and checked, ready for 6-12 V DC supply. The latest PCBs are "gold" color and the 5V voltage regulator is AMS1117-5V0 instead of the very first version where the 78M05 was used. C10 capacitor is also fitted despite the fact that this is the part required for the optional through the coax power supply.

The most asked modification is a 5 V DC supply possibility. It is very easy to do that just by adding the 0 ohm 0805 SMD size bridge or just a peace of wire on the place marked J3 on the PCB (green colored SMD component on the next slide). Using the same power leads you can power the LNA4ALL now with the 5V DC. We do not supply extra parts for modifications any more.

Next most common modification is possibility to supply the LNA4ALL from the 13.8V DC power supply. The voltage regulator on board should meet this request, but it is much safer to run the LNA through the simple 100 ohms resistor in series with the positive power lead. You should rate the resistor power based on the fact that the LNA consumption is 60 mA. 1/2 watt resistor should do the job as per next slide.

One of the feature requested from the users was the so called "phantom power supply" through the bias-T configuration. To supply the LNA4ALL with the DC power through the coaxial cable from the receiver or bias-T close to the receiver just a simple add-on is required. The 10uH SMD 0805 size inductor should be placed on the place marked L2 close to the OUT  SMA connector. The PCB can accommodate also 0603 and 1006 SMD standard inductor. (Green color on the next slide). The power should be anything from 6-12V DC. We do not supply any more the 10uH inductor nor the bias-T unit.
And what if you have available only 5V DC on the antenna port of your receiver. (I think the FunCube Dongle have this option, or not ??) In that case, the same modification from the previous slide is required (10uH inductor on the place L2) plus the 0 ohm 0805 SMD size resistor or a wire bridge on the place marked J3. Now you can power your LNA4ALL with the 5V through the coaxial cable.


Another very common question is how to protect the LNA from the statics coming from the antenna. We do receive some letters indicating the problem where the MMIC is damaged due to statics or corona discharge effect on the antenna constantly connected to the LNA. So how to protect the LNA? The best way is to disconnect the antenna and before connecting the same back, properly ground and discharge the antenna.
This can not be always possible and handy so the only protection that is used widely is to bridge the input antenna with the BAV99 antiparalel pair of diodes like on the next slide. This may save your LNA but not from the direct thunder hit :-)
The solder mask should be scratched off and the BAV99 diode soldered (green on the next slide) on the antenna input. Using the antiparalel diodes will degrade NF and S11 a bit and there is a treat of the intermodulation products created on the diodes if the strong broadcast signals are present on the antenna. So beware of this facts.



25 comments:

  1. I can't contact you..What is your mail ??
    Michel F5YH Marseille/France

    ReplyDelete
  2. My mail is michel@f5yh.com and your mail adamremove9a4qv@yahoo.com seems to be not valid by yahoo..
    I want to buy a LNA at 20 + 5 euros to france.
    Please, contact me, i can pay Paypal.
    73 Michel F5YH

    ReplyDelete
    Replies
    1. Did you remove the "remove" in the mailadress?
      The correct adress can also be found at http://www.qsl.net/9a4qv/
      73

      Delete
  3. What if I want to power this device from USB?

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  4. If you want to power the device from the USB then you need to connect the +5V DC to the output pin of the onboard 78M05 voltage regulator, or you can use the existing pad but then you need to remove the 78M05 from the PCB and short the in/out regulator pads.

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  5. I believe it could be powered through the coaxial with some minor mods. I would remove all the power parts and replace the AC coupling cap with a 0 ohm resistor, then I would install a biass-tee at the shack.

    The mmic itself seems to have great NF and IP3 values. But it would maybe become overloaded in a big city. I am planning to place a simple BPF before the LNA but I think it would be nice to have the footprints in the board so you could install the filter for you favorite band.

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  6. I gave a look at the datasheet at Minicircuits web site. I think it could be powered with a Li-ion cell for long hours. The 7805 would have to be removed. That would be handy for field day operations. Li-ion cells can be savaged from old laptop battery packs.

    73
    Ricardo EA1APM

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  7. This comment has been removed by the author.

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  8. Does it perform below 28mhz??

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    Replies
    1. Yes it does but not so good as declared on higher frequencies.
      The lower frequency limit is 14MHz with gain of 10dB.
      If you need a HF only amplifier or something like in my upconverter UP-100 write me mail, we can do that.

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    2. I have a Nooelec Ham it upconverter, can you do an LNA for that? Maybe 20dB? maybe under 1.5dB NF?

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    3. This is exactly what we have already implemented in our upconverter:
      http://upconverterup-100.blogspot.com/

      For the moment, we do not have any left and available but in next 30 days we should be out with the new batch of upconverter, and yes, it will be with the 125Mhz LO instead of 100MHz due to user request.

      If you need just the amplifier 20db for HF with the NF up to 1.5dB I can do that on the same PCB as LNA4ALL just another component, same price.

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    4. which is the email address for contact. The account of Yahoo, send mistake

      Delete
  9. Something like this:
    http://youtu.be/VNVRpo8i92s

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  10. So. out of curiosity, what sort of connector is present on this board? Does it plug straight into the Newsky tv228t SDR receiver?

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  11. The LNA4ALL has two SMA (female) connector on board.
    So far i have not seen the USB SDR dongle with the SMA, except modified.

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  12. Does it need Power?
    If Yes i see no Power socket.

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  13. If I am to power this from USB would it be better to bypass the voltage regulator completely and bridge the in/out pins or just attach 5v to the output pin of the regulator? Also, because the power coming in looks to go through an inductor then to the output, will I see a significant drop in performance from powering it from 5v rather than 12v? Thank you!

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  14. You can bridge the in/out pins of the 5V regulator simply by soldering the 0 ohm bridge on the PCB. There is a dedicated place for the 0805 SMD 0 ohm bridge and use the same power pads for the 5V supply.

    Instead you can just connect the positive 5V to the output pin of the regulator.

    The power does not go to the RF output pin. (This is the option for the Bias+T LNA power through the coax). This option is not included on the LNA but there is place on the PCB to add the 10uH inductor and 1nF capacitor.

    You can power the LNA from 3.3V to 5V. If you plan to use 12V then you need a regulator.

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  15. Hello,

    is this still available for purchase. If so, where can I order some?

    Cheers.

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  16. Hello Norbert,

    yes, the LNAis available, just send me e-mail.
    The address is under CONTACTS, top left page side.

    thanks
    Adam

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  17. Hi Adam

    Could you confirm the cost including shipping to the UK and your prefered method of payment as I would like to buy one of your LNA's

    Regards
    Brendan
    G1OHD

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  18. This comment has been removed by the author.

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  19. Hello Brendan,

    can you contact me via e-mail,
    total price for the U.K is 25 Euro

    Adam

    ReplyDelete