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MMIC-based bidirectional amplifier (would love to hear from ajparent)!
#homebrew
#rf
Farhan, For that reason I added Schottky diodes as switches (PIN diodes would have been better). That way the TX amplifier is completely disconnected from the circuit during RX. My main concern is wit
Farhan, For that reason I added Schottky diodes as switches (PIN diodes would have been better). That way the TX amplifier is completely disconnected from the circuit during RX. My main concern is wit
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Rafael Pinto [PU1OWL]
· #90026
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MMIC-based bidirectional amplifier (would love to hear from ajparent)!
#homebrew
#rf
Hi folks Following our discussion on integrated circuits on the uBitx design, I decided to try and design a bidirectional amplifier based on MMIC circuits. I chose the MAR-6SM+ because of the reasonab
Hi folks Following our discussion on integrated circuits on the uBitx design, I decided to try and design a bidirectional amplifier based on MMIC circuits. I chose the MAR-6SM+ because of the reasonab
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Rafael Pinto [PU1OWL]
· #90023
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Integrated
Farhan, I have considered exploring the RP2040 PIO as second IF and BFO oscillator, or in a image cancellation design. The RP2040 PIO can operate in very fast clocks and is reasonably configurable. No
Farhan, I have considered exploring the RP2040 PIO as second IF and BFO oscillator, or in a image cancellation design. The RP2040 PIO can operate in very fast clocks and is reasonably configurable. No
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Rafael Pinto [PU1OWL]
· #89944
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Integrated
Hi I agree with Bill that replacing with integrated parts might not be very interesting for the regular ham tinkerer. On the other hand, the engineer in me keeps me asking why not taking some MMIC amp
Hi I agree with Bill that replacing with integrated parts might not be very interesting for the regular ham tinkerer. On the other hand, the engineer in me keeps me asking why not taking some MMIC amp
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Rafael Pinto [PU1OWL]
· #89936
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Mini PA für my uBITX
#ubitx
Mark, I am in the same path you are: I am building a "minipa70" which can output almost 40W at 13.8V, and using the XF-HF-LPF filter. I really liked the display and Arduino. Did you use any attenuator
Mark, I am in the same path you are: I am building a "minipa70" which can output almost 40W at 13.8V, and using the XF-HF-LPF filter. I really liked the display and Arduino. Did you use any attenuator
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Rafael Pinto [PU1OWL]
· #89745
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Need color format help
#ubitxv6
You are absolutely right! Actually I program both on a day-to-day basis, and my tired mind didn't notice the extra '>'! But replacing >>> with >> would work immediately.
You are absolutely right! Actually I program both on a day-to-day basis, and my tired mind didn't notice the extra '>'! But replacing >>> with >> would work immediately.
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Rafael Pinto [PU1OWL]
· #89733
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Need color format help
#ubitxv6
Will, there you have it! A function to do the conversion: int RGB888ToRGB565(int rgb888) { int red = (rgb888 >> 16) & 0xFF; int green = (rgb888 >> 8) & 0xFF; int blue = (rgb888) & 0xFF; int B = (blue
Will, there you have it! A function to do the conversion: int RGB888ToRGB565(int rgb888) { int red = (rgb888 >> 16) & 0xFF; int green = (rgb888 >> 8) & 0xFF; int blue = (rgb888) & 0xFF; int B = (blue
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Rafael Pinto [PU1OWL]
· #89714
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Need color format help
#ubitxv6
Will, The "standard RGB" tria you refer is a RGB888, which uses 8-bits for each color (hence 8-8-8). The value 0xf8afec, for instance means 0xf8 value for red, 0xaf for green and 0xec for blue (0x mea
Will, The "standard RGB" tria you refer is a RGB888, which uses 8-bits for each color (hence 8-8-8). The value 0xf8afec, for instance means 0xf8 value for red, 0xaf for green and 0xec for blue (0x mea
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Rafael Pinto [PU1OWL]
· #89713
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Ordered Another V6
#ubitxv6
Justin I was considering ordering a basic kit, just to mess with it. That way I would have a "good unit" and a "messed unit". If import taxes were not that high in Brazil, the devil would have me do t
Justin I was considering ordering a basic kit, just to mess with it. That way I would have a "good unit" and a "messed unit". If import taxes were not that high in Brazil, the devil would have me do t
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Rafael Pinto [PU1OWL]
· #89546
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Specan Yet Again
Hi David I am very interested in your progress, though I have very little experience on building RF circuits. May I ask: with no input, is the input conector terminated somehow? Those spurs seem like,
Hi David I am very interested in your progress, though I have very little experience on building RF circuits. May I ask: with no input, is the input conector terminated somehow? Those spurs seem like,
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Rafael Pinto [PU1OWL]
· #89529
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Chinese LPF
Hi Farhan As Jerry pointed out, this is the thread about the low-pass filter kit for the amplifier. It comes assembled, but consistently with a lot of errors, like the wrong capacitor on the 80m filte
Hi Farhan As Jerry pointed out, this is the thread about the low-pass filter kit for the amplifier. It comes assembled, but consistently with a lot of errors, like the wrong capacitor on the 80m filte
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Rafael Pinto [PU1OWL]
· #89219
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Chinese LPF
Hi Jerry! At least I can tell you the Chinese LPF is consistent!! Mine just got here and, lo and behold, there is a 150pF cap on the 80m filter! Just ordered a replacement 1.5nF. Also, 40m is waaaay l
Hi Jerry! At least I can tell you the Chinese LPF is consistent!! Mine just got here and, lo and behold, there is a 150pF cap on the 80m filter! Just ordered a replacement 1.5nF. Also, 40m is waaaay l
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Rafael Pinto [PU1OWL]
· #89212
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uBITX Output
Jerry, Those used to be 100nF in v3, but since v4 they are not fitted, if I remember it correctly, to improve the gain in the top bands. Rafael
Jerry, Those used to be 100nF in v3, but since v4 they are not fitted, if I remember it correctly, to improve the gain in the top bands. Rafael
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Rafael Pinto [PU1OWL]
· #89099
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uBITX Output
Jerry, Can this be some form of self-oscillation? It is so bad, this looks like single-tone FM!! Rafael Pinto
Jerry, Can this be some form of self-oscillation? It is so bad, this looks like single-tone FM!! Rafael Pinto
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Rafael Pinto [PU1OWL]
· #89084
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Chinese Linear R.I.P.
Rafael, How much input power are you using to drive your chinese amp? Jerry had a problem with his uBitx overloading his amp, and I am kind of worrying about it. I'll probably reduce the drive on my o
Rafael, How much input power are you using to drive your chinese amp? Jerry had a problem with his uBitx overloading his amp, and I am kind of worrying about it. I'll probably reduce the drive on my o
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Rafael Pinto [PU1OWL]
· #89082
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uBITX Loop
Hi Gerald I have built a somewhat similar loop with 2.6m of half inch heliax and a very small capacitor (5pf to 40pf), aiming the top bands. The problem is that tuning is very, very sensitive in that
Hi Gerald I have built a somewhat similar loop with 2.6m of half inch heliax and a very small capacitor (5pf to 40pf), aiming the top bands. The problem is that tuning is very, very sensitive in that
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Rafael Pinto [PU1OWL]
· #88971
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Cheap Chinese Linear LPF
Jerry You are right. The inductors are the most likely culprits, as the core permeability varies a lot... I usually use this website as reference for my filters (https://rf-tools.com/lc-filter/). Its
Jerry You are right. The inductors are the most likely culprits, as the core permeability varies a lot... I usually use this website as reference for my filters (https://rf-tools.com/lc-filter/). Its
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Rafael Pinto [PU1OWL]
· #88735
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Cheap Chinese Linear LPF
Jerry, I wrongly wrote a message about your SWR, but thinking on the SWR of the amplifier input and not the LPF. Usually high SWR in the pass band of a filter means wrong adjusted impedances. How were
Jerry, I wrongly wrote a message about your SWR, but thinking on the SWR of the amplifier input and not the LPF. Usually high SWR in the pass band of a filter means wrong adjusted impedances. How were
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Rafael Pinto [PU1OWL]
· #88732
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Farhan to give sBITX talk at FDIM
hi, Does anyone have a recording of this talk? I've been crazy busy lately and just found about it today. Regards Rafael, PU1OWL
hi, Does anyone have a recording of this talk? I've been crazy busy lately and just found about it today. Regards Rafael, PU1OWL
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Rafael Pinto [PU1OWL]
· #88677
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Suggestions for a switching regulator
Farhan, Ultimately I'd go to some of the big HF rigs service manuals and check how they internally regulate the voltages. The IC7300, for example, uses a TPS62110 from Texas Instruments, but that is a
Farhan, Ultimately I'd go to some of the big HF rigs service manuals and check how they internally regulate the voltages. The IC7300, for example, uses a TPS62110 from Texas Instruments, but that is a
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By
Rafael Pinto [PU1OWL]
· #88674
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