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Thread: Yaesu FT-450D RF tap modification for SDR

  1. #1

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    Default Yaesu FT-450D RF tap modification for SDR

    Hello everyone,

    I wasn't too sure where to post this, so any suggestions welcome.

    I have just completed the fabrication and integration of a Low Noise Amplifier (LNA) into my Yaesu FT-450D in order to
    drive the input of a Software Defined Radio (SDRPlay RSP2). This involved designing the LNA PCB, milling the PCB before
    characterisation (spectrum analyser) and integration into the 450D.

    I have created an Instructable to encapsulate the project.

    http://www.instructables.com/id/Yaes...ation-for-SDR/

    Cheers,

    Dave (G7IYK)
    Last edited by dtrewren; Wed 6th Dec 2017 at 08:51.

  2. #2

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    Quote Originally Posted by dtrewren View Post
    Hello everyone,

    I wasn't too sure where to post this, so any suggestions welcome.

    I have just completed the fabrication and integration of a Low Noise Amplifier (LNA) into my Yaesu FT-450D in order to
    drive the input of a Software Defined Radio (SDRPlay RSP2). This involved designing the LNA PCB, milling the PCB before
    characterisation (spectrum analyser) and integration into the 450D.

    I have created an Instructable to encapsulate the project.

    http://www.instructables.com/id/Yaes...ation-for-SDR/

    Cheers,

    Dave (G7IYK)
    Hello Dave,

    While scrolling through the SDRPLAY Specifications for this DC to White Light SDR Receiver (1 KHz to 2 GHz), I was looking for the modes this receiver could handle and I only found AM & FM which seemed strange. I think down at VLF Digital is used but I could be mistaken. The shortwave bands mostly used AM but our ham bands use AM, SSB, CW, FM, SSTV, ATV / DTV & Multiple Digital Formats. I'm not sure where the external SDR receiver is or has an advantage for the casual user and only having the availability of 10 MHz, this SDR receiver would be difficult to use as a Spectrum Analyzer.

    Your interface board turned out very well for the 7.1 MHz Injection Signal and 50 OHM Input Signals and the combination of the FT-450D & SDRPLAY appears as Standard Option. I'm almost thinking that a ham operator could do this modification to most of the present transceivers on the market today. Although many ham operators don't have access to a CNC or Milling Machine available to them so we would need to use our Dremel tools very carefully.

    Dan
    WA9WVX

  3. #3

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    Hello Dan,

    Apologies for not responding - I assumed the forum would email if a post was left but it didn't happen.

    I have attached a screen shot from the SDRPlay software SDRuno which shows the supported modes. The software covers quite a few modes AM, SAM, FM, CW, DSB, LSB, USB and digital. There are a whole bunch of other options for standard filtering or you can define your own filters - there is a lot under the hood. Since completing the mod I usually have the SDR monitoring a section of the band. If I am just receiving for fun it is very easy to see where and when QSOs are popping up and very simply to hop about with the mouse chasing conversations. Also it is handy just to pop up the band and at a glace you can see how much is going on - an active band is very easy to spot.

    At the moment I am really into PSK31 and JT65 especially the latter. Routing audio from the SDR into the JT65 decoder gives similar results compared with routing audio from the Yaesu into the decoder. With the CAT interface connected and automatic PTT apart from switching on/off the FT-450D I essentially never touch it - how things have moved on !

    True, not everyone has a CNC machine but if a few guys threw together some pocket change boards would a only cost a few $/£ to get made commercially. Usually the cost of ten boards is only a little more than the cost of one board.

    I am planning on putting together some little videos on digital modes like JT65 - maybe someone might be interested and it is fun to do.

    Cheers and 73s,

    Dave

    SDRuno screen.JPG
    Last edited by dtrewren; Wed 13th Dec 2017 at 15:12.

  4. #4

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    Hi Dave,

    Well I had forgotten the fact about doing a quantity of ten boards as a first run prototype build. It's good to know that this SDRPlay Receiver will do multiple receiving modes because when I read through the information it listed AM & FM which isn't much good in the ham bands. As I read your reply this indicated to me that the SDRPlay Receiver was much like having a separate receiver to tune different bands / frequencies besides whatever you had your FT-450D listening on at the same time. I made note that the SDRPlay Receiver is manufactured in the United Kingdom (because of the VAT Tax) but I could order one (I'm not sure which one I would order) and modify my Elecraft tapping a similar location within the receive section. It might be some what more difficult to do as Elecraft doesn't supply any overlays or parts list for their equipment. Had I known this fact, I probably wouldn't have bought one on the new or used market.

    I discovered this fact when my Elecraft K3 took a Lightning hit so I'm forced to send my transceiver into their factory in California for the repairs. I'm very disappointed since I worked on surface mounted components while I was employed by Motorola, Inc. in Schaumburg, Illinois. I still remember the tricks of the trade while performing repairs on customer modules.

    Perhaps I interpreted the 10 MHz bandwidth incorrectly since you can narrow the filters down to what you need versus the modes and then you could use the SDRPlay Receiver as a Spectrum Analyzer although I would prefer a separate 7.1 MHz Injection Oscillator for this function.

    Operating PSK-31 is okay but I'm not that good at typing. Over on this side of the big pond most of hams are using FT-8 because of the shorter time to establish a contact. I certainly understand the JT65 mode while using it for Moon Bounce Operations and weak signals used with that mode. The Digital modes really took over since the bands are suffering from propaganda problems or the lack of Sunspots. I still believe that Digital is the future of Amateur Radio.

    73,

    Dan
    WA9WVX

  5. #5

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    Hi Dan,

    The SDrPlay unit I went for was the RSP2 which has the additional HiZ antenna input and also more control over the front end gain. However, since my purchase they have introduced the RSP1A which has many of the aforementioned features but with only one standard antenna input - which is all you need for a tap input.

    When I use PSK31 most of my responses are macro based. After a very short time you build up some quite sophisticated macros negating the need to do much lengthy typing but just inserting the odd bit here and there. I am going to have a crack at FT-8 as my decoder of choice can handle this even newer mode. There is a lot of activity on JT65, getting lots of contacts deep into Russia as well as over the pond into the East coast of the US. So far my most distant decode from the UK was Tasmania on JT65.

    I have attached another couple of images showing the SDR narrow band selectivity. The first image shows the spectrum zoomed right in with a 250Hz CW filter applied. The second image results in exactly the same output in that the 250Hz CW selectivity filter is still applied at the same point in the spectrum but now the entire 40m band is displayed from 7MHz to 7.3MHz. With the 250Hz filter applied you can hop about at the click of the mouse with a 10Hz step resolution. The Aux SP window (top right) shows the demodulated portion of the spectrum after the 250Hz selectivity filter has been applied.

    Of course with every click of the waterfall the Yaesu FT-450D is following in frequency, mode and all other features as SDRUno is controlling the rig via omnirig over the CAT interface

    Cheers & 73s,

    Dave

    SDRplay 1.jpg

    SDRplay 2.jpg
    Last edited by dtrewren; Thu 14th Dec 2017 at 10:21.

  6. #6

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    Hi Dave,

    I read your reply and then opened each JPEG separately. I had to reread the reply referring to the filters which I understand now. It's never to late to put on my Christmas list. I'll need to compare the RSP1A and the RSP2 for pricing as you've stated they practically do the same options which is a good thing. I was also thinking that I would need another computer for my ham radio software and a separate display on the operating desk and leave the main computer for other things such as this forum & e-mailing friends.

    I wonder if you have played with the Digital Voice on the HF Bands? I have a neighboring ham who lives 1/2 mile northeast of my home and he gets on the air at 7 AM local time with many other operators and they go to each band to check the propagation around the U.S. Here's the Digital Voice website: https://freedv.org/ There's already HF Frequencies set up for the operators around the world. I want to explore the use of this mode as it uses half the bandwidth of a normal SSB Channel or Bandwidth. It seems to have some advantages and I can't see why it couldn't be used on VHF & UHF. Just a thought.

    Whoa, Tasmania is half way around the world! My XYL Karen WB9YCW was down there this past spring as she has met a woman, Carol who lives in Australia and Carol took two weeks off from work to show Karen every worth while place to visit in Australia. Karen took an extra week to visit New Zealand although she ran into a problem while being in New Zealand, she had forgotten about Easter. Every worth while place to visit were closed for four days on Easter Weekend, I'm grateful that I didn't plan her vacation, otherwise I would have never heard the end of that problem even being six feet under. Women don't forget mistakes!

    Karen's been over to Scotland and England three times as she has cousins living in both countries. She has seen the Tatttoo where the Best of the worldwide Military compete ... I've watched the Tattoo on YouTube and it's very interesting seeing the Servicemen perform at Edinburgh Castle https://www.youtube.com/watch?v=aetZLFg5t1k Rain or Good weather ... nothing overhead to shield the rain if it happens. You English are a tough bunch of people!!! I never get to go because of my health problems ... Oh Well.

    73,

    Dan
    WA9WVX

  7. #7

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    Hi Dan,

    On the SDRPlay web-site there are very useful single page spec sheets associated with each of the available units so it is quite easy to compare the functionality. In the UK the RSP1A is £99 ($133) and the RSP2 is £130 ($175) which I think is an excellent price considering what functionality you get for your money.

    Thanks for the digital speech link I will definitely check that out and am going to have a crack at FT-8 this evening if the band is behaving.

    I have been to the Tattoo in Edinburgh, my wife is Scottish. We found a very nice old Scottish whisky bar afterwards and I don't remember much after that It was raining that day to - rains a lot up in that neck of the woods. The weather is always unpredictable in the UK especially where I am over in the west. It can be lovely in the morning, raining at lunchtime and snowing by tea time. Just get used to it really - I was on a business trip to California earlier in the year and it just seems to be sunny all the time which was weird.

    Think it's time to leave work and switch on the radio !

    73s,

    Dave

  8. #8

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    Quote Originally Posted by dtrewren View Post
    Hello everyone,

    I wasn't too sure where to post this, so any suggestions welcome.

    I have just completed the fabrication and integration of a Low Noise Amplifier (LNA) into my Yaesu FT-450D in order to
    drive the input of a Software Defined Radio (SDRPlay RSP2). This involved designing the LNA PCB, milling the PCB before
    characterisation (spectrum analyser) and integration into the 450D.

    I have created an Instructable to encapsulate the project.

    http://www.instructables.com/id/Yaes...ation-for-SDR/

    Cheers,

    Dave (G7IYK)

    Hi Dave,

    Thank you for sharing this which I found it very interesting, Iíve been looking for an alternative solution since the passing of G4HUP.

    Is this something you would consider manufacturing your version of Yaesu FT-450D IF tap?

    Because this is something I would consider purchasing.

    Thanks anyway.

    73ís David.

  9. #9

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    Hello David,

    I think there are boards available commercially already :
    https://www.sdrplay.com/panadapter-i...ble-from-kd2c/

    These are being produced by KD2C and are supplied built. The boards are shipped out of the US and so for me including postage they are more expensive compared to making one as I already had the parts and tools. As KD2C is selling these I would not start selling myself but might make one up for someone if they are really stuck and can't buy one.

    Cheers & 73s,

    Dave

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