Home › Forums › CQ HAM forum › Projects, Mods, Fixes and Add-on's › mcHF IMD and signal purity
- This topic has 9 replies, 3 voices, and was last updated 2 years, 3 Search ago by
om0aao.
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OM0AAO (OM0A)
MemberNo 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
om1aeg
ParticipantThe 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
OM0AAO (OM0A)
MemberTNX, 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).
om1aeg
ParticipantFairy, 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.
om1aeg
ParticipantBut 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 keyBut 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
OM0AAO (OM0A)
MemberBut 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?
om1aeg
ParticipantI 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.
OM0AAO (OM0A)
MemberI 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…
om1aeg
Participant4.4.2020 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
om0aao
KeymasterIt 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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