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    The new version solved the problem. I have it...

    The new version solved the problem. I have it running now. Thank you Frank! Now I have to learn how to use Tisho's menu!

    I am embarrassed to say that I figured out the problem with the LO birdies...
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    Interesting. Perhaps it is because I am using the...

    Interesting. Perhaps it is because I am using the 8mA setting on the Si5351 or have a termination problem. I am also running the LO through a length of coax - I may have an impedance mismatch. I will...
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    For the new software, I get this error compiling...

    For the new software, I get this error compiling because the define is only called with HARDWARE_DO7JBH_T41 enabled.
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    73,
    Bill WH7U
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    Oh nice. Preselectors are great. I think a good...

    Oh nice. Preselectors are great. I think a good set of filters plus a preselector might be a good idea. The only people who don't like preselectors are very lazy people :-)

    Thank you for updating...
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    I think this is probably the best way to go. The...

    I think this is probably the best way to go. The narrow IF could have smaller integrating capacitors so a naturally narrower bandwidth.

    I know that this project was not meant to compete with the...
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    Thank you Karlchen. I did not know wideband...

    Thank you Karlchen. I did not know wideband transformers were available.
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    Frank, you are a genius! I found that my Si5351...

    Frank, you are a genius! I found that my Si5351 drive strength was set very low. I turned it up to 8mA and added a 50 Ohm resistor to my receiver and it came alive! It is working much better now and...
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    On another subject, I wanted to see if I could...

    On another subject, I wanted to see if I could make a transformer that covered from 100 kHz to 200 MHz for the input to a wide-band QSD. This is a very large bandwidth for one transformer.

    A...
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    Hi Frank, Si5351 I think you are right. Thank...

    Hi Frank,

    Si5351
    I think you are right. Thank you for the link - I reviewed it and also re-read the data sheet. When I get back to the radio, I will check to see that I have the setting at 8 mA....
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    @DD4WH and everyone. I am not having great...

    @DD4WH and everyone.
    I am not having great performance from my modified QRP Labs QSD receiver and Teensy setup. I finally bought myself an oscilloscope, an RF generator, a large pile of filters, a...
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    Mirror rejection is the same as image rejection....

    Mirror rejection is the same as image rejection. I think it is more of a DSP term than a radio term, but it means the same thing.
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    I didn't measure it yet. I need to get some more...

    I didn't measure it yet. I need to get some more attenuators. I used to have a whole bunch of them but now I only have a few.
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    Nice work Tisho! Sounds like your radio is...

    Nice work Tisho! Sounds like your radio is working well. I like the menu - it looks great.
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    Ok Frank. I figured out how to make complex...

    Ok Frank. I figured out how to make complex bandpass filters. After fruitless research and less-fruitless experimentation, it is actually embarrassingly trivial. I don't know why this information is...
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    I recreated the filter kernel in...

    I recreated the filter kernel in calc_cplx_FIR_coeffs in MATLAB and plotted the response. I see now how it is a Hilbert filter and Bandpass filter both.
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    This is for 96 kHz sampling rate,...
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    @DD4WH Hi Frank, I read the chapter in my DSP...

    @DD4WH
    Hi Frank,
    I read the chapter in my DSP book on FFT convolution. I don't have the Lyons book but I do have "Digital Signal Processing" by Steven W. Smith. I also have the standard...
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    Hey Frank. No problem on all the time it took....

    Hey Frank. No problem on all the time it took. I'm learning and having fun with this stuff.
    I am planning to dig into this filtering business a bit more. It may take time because I have to juggle...
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    hi Karlchen, I was trying to get the Potato...

    hi Karlchen,
    I was trying to get the Potato chips from the Potato distributor listed on their website and the distributor told me they didn't have stock. I didn't know there was an online shop. I am...
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    Hi Frank B, I checked again a little more...

    Hi Frank B,
    I checked again a little more carefully. At 256kHz sample rate, my S meter is almost at max with noise, so I didn't think it was working. But you are right. I can hear signals. I don't...
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    Here is a link to MATLABs ARM code generator if...

    Here is a link to MATLABs ARM code generator if you want to see what it is all about:
    https://www.mathworks.com/help/releases/R2018a/supportpkg/armcortexmdst/examples.html
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    21058 @DD4WH Hi Frank, I spent way too much...

    21058
    @DD4WH
    Hi Frank,

    I spent way too much time fooling with MATLAB today. Making FIR filters is easy. Making linear phase FIR filters is a bit trickier but still easy. Making minimum phase FIR...
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    Frank B. Thanks for checking on that. I'm going...

    Frank B. Thanks for checking on that. I'm going to experiment some more with my setup to see if I just have a lazy chip or I'm doing something wrong. I still need to replace the caps in my receiver...
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    Hi Frank, I see what you mean about the AD8333....

    Hi Frank,
    I see what you mean about the AD8333. That is not as great as it first appeared. I have spent a great deal of time trying to find a quadrature detector chip that is a little faster than...
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    This almost looks like it is designed to work...

    This almost looks like it is designed to work with the Si5351.
    https://www.analog.com/media/en/technical-documentation/data-sheets/AD8333.pdf
    Could have different transformers for LF and HF to have...
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    Hi Frank. Thanks for the explanation! I...

    Hi Frank.

    Thanks for the explanation!

    I don't know why there should be a linear calibration factor. If the reference frequency is corrected, everything "should" fall into place. But some of...
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    Hey Les Happy to accidentally help. :-) I was...

    Hey Les
    Happy to accidentally help. :-) I was playing with the different bandwidths and noticed that the 256k didnít work but the 192k works fine. Trying to figure that out. The chip is only rated...
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    I am working my way through the code and figuring...

    I am working my way through the code and figuring it out bit by bit. There is a lot of stuff in there!
    One thing that I am confused about is that the sampling rate can be set up to 256kHz. But the...
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    Thanks Frank B. It is within a few Hz at 1 MHz...

    Thanks Frank B.
    It is within a few Hz at 1 MHz and 30 MHz both. I'm happy with that. I've thought about hooking up one of my little GPS boards to give it a precise 1 Hz clock. Then I can run a fixed...
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    Never mind Frank. I figured it out. I was tuning...

    Never mind Frank. I figured it out. I was tuning into one of the harmonics near my signal generator.
    After reading through the text doc in the Si5351 library... the calibration is in parts per...
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    Hi Frank, Thanks! I'm excited to start...

    Hi Frank,

    Thanks! I'm excited to start experimenting.
    I have the latest code and the correct Si5351 library. I think you have the calibration_constant and calibration_factor reversed. The...
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    My newly build receiver is off in frequency. I...

    My newly build receiver is off in frequency. I have the calibration constant set to 0. My crystal is 27 MHz and I'm using the DD4WH hardware setup.
    I set a test oscillator up at 1 MHz and my...
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    Here are some pictures of my finished Convolution...

    Here are some pictures of my finished Convolution SDR.
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    Now I need to put some filters in there.
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    That makes sense. So long as there is a divide by...

    That makes sense. So long as there is a divide by 2 in the output register of the Si5351, the 2xfo should work fine. I also saw somewhere that two outputs of the Si5351 can be set to the same...
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    @DD4WH The reason for using the 4xfo is this:...

    @DD4WH
    The reason for using the 4xfo is this: Crystal oscillators begin with a sine wave. A crystal is a very narrow filter - in frequency terms, an FFT with one bin turned on and the rest off -- so...
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    Have you made any progress on the variable gain...

    Have you made any progress on the variable gain op-amp idea Frank? I have been thinking about it. As you say, keeping the level into the ADC high but not overloading is important for the dynamic...
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    Those are impressive measurements Tisho. If you...

    Those are impressive measurements Tisho. If you want to double check that you are getting good numbers, you can add more attenuation and see if the NF changes (it should not). But with more...
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    Hi Tisho, Your plan to measure noise figure...

    Hi Tisho,
    Your plan to measure noise figure sounds excellent. It is a great way to quantify your improvements as you refine your receiver. The tricky part of NF measurements is the bandwidth. Noise...
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    I bought my terminators from this place:...

    I bought my terminators from this place:
    https://www.w5swl.com
    And this is the model:
    https://www.w5swl.com/Mini-Circuits-SMA-Male-14-Watt-Termination-Load-DC-2GHz_p_6170.html
    Measured with my...
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    I need to fix my example above. I forgot to...

    I need to fix my example above. I forgot to include the gain of the audio amps. But the principle is still correct.
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    Hi Tisho, I always choose TI parts if I have the...

    Hi Tisho,
    I always choose TI parts if I have the option. My only reason for this is that their data sheets are very good and almost always have the necessary info for a designer. If they don't tell...
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    QEX requires a subscription. But all the software...

    QEX requires a subscription. But all the software and PCB files etc. are available here:
    http://www.arrl.org/qexfiles
    Look for the January/February article by James Koehler. I am almost positive...
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    WH7U - only be careful when buying these switches...

    WH7U - only be careful when buying these switches with Aliexpress - defective non-functional pieces have been reported at some retailers. I can confirm that.[/QUOTE]

    Thanks for the warning radek....
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    20729 Here is a picture of my nanoVNA. This is...

    20729
    Here is a picture of my nanoVNA. This is the authentic version. The two 50 Ohm terminators that are not in the box I purchased separately (the ones that come with the nanoVNA are not very...
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    If you decide to get a nanoVNA, make sure you...

    If you decide to get a nanoVNA, make sure you donít get one of the cheap clones. Go to nanovna dot com and get that one. I donít know why people are making cheap clones of something already so cheap...
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    I have a nanoVNA. It works well for an...

    I have a nanoVNA. It works well for an inexpensive VNA and you canít beat the price. But I also built a VNA from an article in the Jan 2020 issue of QEX that I prefer. Either one will work well for...
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    Thanks Tisho. Those are nice little switches if...

    Thanks Tisho. Those are nice little switches if they work well at low frequencies. The manufacturer designed them for GSM and WCDMA so they likely work fine but maybe they didn't bother to test them...
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    Hi Tisho, Nice work in the receiver. I have a...

    Hi Tisho,
    Nice work in the receiver. I have a question.
    The data sheet for the PE4259 says that the bandwidth is 10 MHz - 3.0 GHz and the PE42641 states 100 MHz - 3.0 GHz. Have you tried these...
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    I'm in a meeting at work while I'm typing this,...

    I'm in a meeting at work while I'm typing this, so I hope it makes sense. It might clear up some things in the discussions I have been catching up on.

    As far as the noise discussions for different...
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    Here is the schematic. I had trouble attaching...

    Here is the schematic. I had trouble attaching it.
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    Hi Frank, You could do that? Interesting idea....

    Hi Frank,
    You could do that? Interesting idea. Normally, at low voltage, FET switches are better at pulling signals to ground. They may struggle if floating if the audio gets near Vdd.
    I have used...
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