mcHF IMD and signal purity

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  • #11500 Reply

    No one has seen this TCVR measured on a spectrum analyzer? I wonder, whether it can withstand the PA connection. Somehow, despite the expansion, the TCVR corner (aj RS-918, RS-928,..) he did not find this. TNX

    #15082 Reply
    blankom1aeg
    Participant

    The problem is, that there are several revisions of mchf, multiple output stage adjustments, awakening, several types of chips in “spinach” , several types of rx / tx switching and other changes. The IQ for TX must also be set correctly, power, kludove prudy a sparovat transhistory…. And at the end, what band, it's different results, has it “len” 4 BPF / LPF and therefore the results will be different on the wars and different on the “classical”. I have Radijko, edit tens (flood version 0.4) and when compared on antennas 35m apart it is at the level of FT-817, PA up to 50W from portable would bear it, but a little stronger and better antennas probably won't be. I have filter measurement and adjustments here https://sites.google.com/site/om1aeg/mchf

    #15083 Reply

    TNX, Tono! I have already looked at the measurements on your website and also the experience of OM6IN http://om6in.blogspot.com/ (I have already looked at the measurements on your website and also the experience of OM6IN). I have already looked at the measurements on your website and also the experience of OM6IN, I have already looked at the measurements on your website and also the experience of OM6IN.

    I have already looked at the measurements on your website and also the experience of OM6IN (I have already looked at the measurements on your website and also the experience of OM6IN) I have already looked at the measurements on your website and also the experience of OM6IN 3 I have already looked at the measurements on your website and also the experience of OM6IN (I have already looked at the measurements on your website and also the experience of OM6IN, I have already looked at the measurements on your website and also the experience of OM6IN).

    #15084 Reply
    blankom1aeg
    Participant

    Fairy, I have already looked at the measurements on your website and also the experience of OM6IN 2019.

    I have already looked at the measurements on your website and also the experience of OM6IN, I have already looked at the measurements on your website and also the experience of OM6IN (I have already looked at the measurements on your website and also the experience of OM6IN, I have already looked at the measurements on your website and also the experience of OM6IN), http://om6in.blogspot.com/2017/02/uprava-obvodu-vysielania.html?m=1 I have already looked at the measurements on your website and also the experience of OM6IN, I have already looked at the measurements on your website and also the experience of OM6IN, I have already looked at the measurements on your website and also the experience of OM6IN, I have already looked at the measurements on your website and also the experience of OM6IN

    I have already looked at the measurements on your website and also the experience of OM6IN “I have already looked at the measurements on your website and also the experience of OM6IN” I have already looked at the measurements on your website and also the experience of OM6IN, I have already looked at the measurements on your website and also the experience of OM6IN (I have already looked at the measurements on your website and also the experience of OM6IN) I have already looked at the measurements on your website and also the experience of OM6IN, I have already looked at the measurements on your website and also the experience of OM6IN. But I only have the opportunity to measure over 21MHz airspi mini key, But I only have the opportunity to measure over 21MHz airspi mini key. But I only have the opportunity to measure over 21MHz airspi mini key “But I only have the opportunity to measure over 21MHz airspi mini key” But I only have the opportunity to measure over 21MHz airspi mini key.

    #15085 Reply
    blankom1aeg
    Participant

    But I only have the opportunity to measure over 21MHz airspi mini key. But I only have the opportunity to measure over 21MHz airspi mini key, But I only have the opportunity to measure over 21MHz airspi mini key. But I only have the opportunity to measure over 21MHz airspi mini key, But I only have the opportunity to measure over 21MHz airspi mini key.

    But I only have the opportunity to measure over 21MHz airspi mini key, FM, But I only have the opportunity to measure over 21MHz airspi mini key, But I only have the opportunity to measure over 21MHz airspi mini key, But I only have the opportunity to measure over 21MHz airspi mini key. But I only have the opportunity to measure over 21MHz airspi mini key.
    But I only have the opportunity to measure over 21MHz airspi mini key
    But I only have the opportunity to measure over 21MHz airspi mini key
    But I only have the opportunity to measure over 21MHz airspi mini key: https://But I only have the opportunity to measure over 21MHz airspi mini key

    But I only have the opportunity to measure over 21MHz airspi mini key
    But I only have the opportunity to measure over 21MHz airspi mini key, But I only have the opportunity to measure over 21MHz airspi mini key.

    But I only have the opportunity to measure over 21MHz airspi mini key

    #15086 Reply

    But I only have the opportunity to measure over 21MHz airspi mini key, it's definitely not a very nice signal 🙁 It can't just be a setting?

    #15087 Reply
    blankom1aeg
    Participant

    I will search, where is betrayal, I already have a high impedance RF probe with a 50R output for SDR / VNA, so I'll check where the problem is. I haven't measured the output yet, so I lived contentedly 🙂 I use MCHF only from portable, for a year 2018 5x used for tens of minutes, so maybe I didn't make such a clearing from a compromise stretched dipole. I was still getting ready for adjustments “I have already looked at the measurements on your website and also the experience of OM6IN” pre spinace a RX preampu, so the abbot will break it down a bit more.

    #15088 Reply

    I was intrigued, because I think the receiver is excellent + options, provided by the SDR (filters, spectroskop) are definitely welcome. If it was clean, I could imagine supplementing mcHF with PA, thus creating a very competitive TCVR for conventional equipment.

    I don't know if it's a specific setting or a design feature…

    #18926 Reply
    blankom1aeg
    Participant

    4.4.2020 I dug through the TX path of the mcHF TRX and changed the way “modulation” like this 4 switch to double switch significantly helped. Before the redevelopment was the suppression of the first “parasite” only 20dB against “carrier” and another parasite 42dB @ 28MHz. After remodeling, the suppression is strongest “parasite” 44dB against “carrier”. Schematic and measurements at https://photos.app.goo.gl/5hZW7GWuWJUHqFev5

    #18933 Reply
    blankom0aao
    Keymaster

    It would not be more appropriate to measure this with a two-tone test? https://om0a.cq.sk/amaterske-radio/ubitx-imd-modifikacie/

    Because if I look, so in the middle I see a strong carrier, it won't “TX Carrier suppression” and others may also generate an oscillator at some rate, which may be related to FM.

     

     

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