Has an electrical engineer dev HF AMP with new mosfet MRFE6VP61K25h?

Discussion in 'Amateur Radio Amplifiers' started by W7EET, Oct 10, 2011.

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  1. W7EET

    W7EET Ham Member QRZ Page

    What I was hoping for is to find a engineer to design a PC board and tell me the parameters of what is suppose to be on the PC board. So, I could put it together and buy the parts to make it work. Your second question about Freescale; No I have not contacted them. I did try once but they did not reply to me.
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    To me, the "problem" is that the best engineer in the world can't verify a design without building it and making measurements. Thus, a "PC board design" has little merit until it's built, tested, de-bugged and likely re-designed. That's just the way things are.

    I've designed and laid out hundred of PC boards for various things, but the "real" working models are always second or third generation, not first. That's why we only make 5 of the first version, since it's never the final version unless it's something very simple. So, to do this, the engineer would need to have the Freescale FETs along with other parts, lay it out, optimize it using a CAD program (easy), have it fabricated, build the design, test it, and then (usually) go back to the drawing board to make changes.

    A VHF or UHF amp is actually easier in almost all respects, to me, since the operating bandwidth can be quite narrow. An HF amp is a bigger challenge, as we're covering at least 3 octaves and maybe four. So the input/output transformers need to be very good, and all decoupling circuits might have to work from 1.8 through 29.7 MHz, which is not so easy.

    Unless a ham does this just to do it (which evidently nobody has, yet), I'd rely on Freescale to do it.
  3. W8JI

    W8JI Ham Member QRZ Page

    I contacted FreeScale months ago and asked for any data on those FET's. I would do a design that would sell thousands of FET's a year if it was the correct FET for the job.

    They never responded.

    Then I asked for an applications engineer to contact or call me about HF linear applications. Nothing happened.

    IMO if they don't respond to a potential or likely market of thousands of devices, they probably do not have a response.

    Another rule for production is there always must be a second independent source for a substitute component, or a way to work in a replacement. Otherwise customers can be stuck with an obsolete product, and all the investment in the design is lost.

    To do a proper RF module, fully tested and proven to be repeatable, takes a few passes. Each pass has to be one or more prototypes (some fail at one and need a redesign). The less time is spent picking through every single detail, of which there are several complex areas, the less likely a layout will work on just two passes.

    As Steve correctly points out, a single band or frequency system is much easier than a 1 through 30 MHz system. With the demand for good RF engineers giving almost unlimited paid work, it is unlikely to find someone that will gift $25-50K worth of work for "spirit" for someone else to give away. :)

    The only option is almost certainly Freescale deciding to fund a public board.

    73 Tom
  4. W7EET

    W7EET Ham Member QRZ Page

    My trade is a electronic technician in the RF field. I wanted to make something for other hams to have fun in making a kit by scratch. Today hams has lost the idea of kit building, by going down to the local store and by the product from the shelf. I really enjoy putting something together and making it work. For an example, The heath kit SB 104 had several problems with it one was the solid state driver. It had lot of distortion in the RF it produce. I did some experimenting and got the problem solved. After that it was a great transceiver. I got in touch with Freescale today by email. They told me that they have a pc for 160 meters thru 10 but not for 6 meters with the new transistor but I will see if they come up with something. I will let everyone know if they do or not within the next couple of days.
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    That's actually really good news (that they have a 160-10m board layout, which hopefully has been built, tested and verified). I hope they also have a good parts list and transformer details to go with that.

    I wouldn't sweat the 6m stuff.
  6. W6RZ

    W6RZ Premium Subscriber QRZ Page

  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Anyone know if they actually produced the kit? The page says, "Our intention is to make a kit..." but doesn't really state if they did it.
  8. W7EET

    W7EET Ham Member QRZ Page

    OK everyone: Here is the scoop from Freescale. They do not have a pc board as of yet but; They may or might produce a test amplifier for HF and sell the boards. I told them that there will be other ham radio operator that will be interested in building a home brew amplifier with this new mosfet. I also told them I was interested in two boards for my home brew amplifier. It probably will help if any of you folks are interested contact Freescale and let them know.
  9. AF6LJ

    AF6LJ Ham Member QRZ Page

    That's really nice looking.
    That would be a nice addition to my shack. :)
  10. W7EET

    W7EET Ham Member QRZ Page

    Thank you WB2WIK,
    That is a really nice HF-6 meter amplifier with the new mosfet. I have already emailed them! We will see how much the amp is in the very near future. It is very well engineered in it's design and they did very good job.
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