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Re: calibrate v4 ubitx
No, adjusting the BFO frequency is a bad idea.
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That will change the audio characteristics on both transmit and receive. And it will only "calibrate" the rig when operating at the frequency of the reference oscillator you happen to be using. The si5351's reference oscillator is nominally 25mhz, but might be off by several ppm. When using the si5351bx routines, the vco inside the si5351 is operating at a nominal frequency of 35*25mhz = 875 mhz. The value of the variable si5351bx_vcoa has a nominal value of 875000000, what we want to do is adjust that value until it is exactly equal to the true vco frequency. So one way to do this is to measure the 25mhz oscillator of the si5351 reference, perhaps using a separate well calibrated receiver instead of a frequency counter to avoid loading that crystal. Let's call that value fxtal25mhz. Then force si5351bx_vcoa to be equal to? 35*fxtal25mhz. Now the si5351bx routines use this new si5351bx_vcoa value when computing the output divider values used to create clk0, clk1, and clk2.? All three should be dead on. We need to calibrate all three clocks simultaneously, not just the BFO. ? Was more complicated on the Bitx40, where we had a separate crystal oscillator for the BFO. On the uBitx, we only have one reference oscillator. An easy way to calibrate using a 50mhz reference might be to divide it by two using a flip-flop, and calibrate using the resultant 25mhz signal using whatever calibration software is in the firmware you are using.? ?I have not looked over the various firmware releases, but? given some of the forum posts my impression is that is is not being done right. Jerry, KE7ER On Fri, Jul 20, 2018 at 07:11 AM, Joel Caulkins wrote:
I agree that calibration is a 'exercise', why does it need to be this hard. I'm no coder, but Don ND6T's calibration routine worked really good for me when I was calibrating my Bitx 60, ? All we need to know is what our actual 25Mhz crystal frequency is and change that line in the sketch, then all we need to adjust is the BFO frequency which is easy when the rig is on frequency. I don't know how to code so I'm not sure what is involved in adding something like this to the existing sketch but it sure beats zero beating. |
Re: I think this will work for the Ubitx...microphone
Kevin Rea
My screws were all Phillips on the one that I have. On Fri, Jul 20, 2018, 7:45 AM <george.woods@...> wrote: Hi Kevin, |
Re: uBitX CAT problem on 40m
#ubitx
#ubitx-help
#ft8
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On Jul 20, 2018, at 9:49 AM, bill richardson <ng1p.bill@...> wrote:
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Re: uBitX CAT problem on 40m
#ubitx
#ubitx-help
#ft8
¿ªÔÆÌåÓýI have the same issue with both of my uBitx¡¯s only on 40 meters. Last weekend I was at Lobstercon and Dave kd1na on his bitx40 also suffered from RF getting into his but again just on 40 meters. The two I have and Dave¡¯s are v3 boards. Also I will add that both mine are shielded and Dave¡¯s has his in a metal case. I have found using a different antenna helps.. ie using a end-fed it will always suffer from RF getting into the mic audio, using a dipole normally no issues as long as it¡¯s at least 50 feet away. My 80 meter loop also works well. Using my 160m doublet will cause the issue. 40 meters again is the only band this happens on.?On Jul 20, 2018, at 9:27 AM, R. E. Klaus via Groups.Io <reklaus@...> wrote:
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Re: uBITX adjustable power supply?
Look at fig 2 of that wikipedia page for the boost converter:
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? ??? ?? If the inductor is large enough, the inductor current will be constant. When the switch is on, all of that inductor current gets shunted to ground,? and energy gets stored in the inductor's magnetic field as the current rises slightly. When the switch is off, that inductor current must go somewhere, so the voltage rises and it pushes it's way through the diode. The switch inside the chip can handle a max of 4 Amps, that sets the maximum inductor current we can allow. So we have up to 4 amps through the switch when the switch is on, and those same 4 amps going out to the load when the switch is off. As the wikipedia page explains, the duty cycle of the switch is equal to the output voltage over the input voltage, As the output voltage rises, the amount of time that the 4 Amps is going through the diode is reduced. So max current out is 4 Amps if Vout = Vin, and max current is reduced as Vout rises. Specifically, max current out is 4Amps*Vin/Vout. So if boosting from 12v to 24v, max current is 2 Amps. If boosting from 5v to 25v, max current is 4*5/25 = 0.8 Amps. That assumes all parts are perfect, which they are not, actual max output current will be somewhat less. And the output will get plenty noisy as Vout rises, since the duty cycle of inductor current through the output diode is reduced, and the inductor and output cap will be less than ideal. Jerry On Fri, Jul 20, 2018 at 07:16 AM, Jerry Gaffke wrote:
Here's a tutorial on boost converters: |
Re: calibrate v4 ubitx
I believe most of them use TORX (also known as Star or Spline ) screwheads. ?Probably T-8 or T-10 size if I remember right. Jim - W0EB
------ Original Message ------
From: "Joel Caulkins" <caulktel@...>
Sent: 7/20/2018 9:11:56 AM
Subject: Re: [BITX20] calibrate v4 ubitx Jerry, |
Re: uBitX CAT problem on 40m
#ubitx
#ubitx-help
#ft8
Gordon Gibby
¿ªÔÆÌåÓýThe USB input to the raduino is particularly vulnerable. ?Ferrites there are a good idea, and also use a one to one current balance on your antenna cable. ?The cause is unbalanced feedline currents looking for an RF connection. ??
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Re: uBitX CAT problem on 40m
#ubitx
#ubitx-help
#ft8
R. E. Klaus
I had the same issue with my Yeasu when I first started using Fldigi. I put snap on Ferrites on the audio leads and wound the control cable about 6 turns around a ferrite toroid and that solved the issue for me.
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Re: uBITX adjustable power supply?
Maximum available output current will fall drastically as the output to input voltage ratio rises.
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You might get 4A out if the input voltage were about equal to the output voltage, it falls off from there as you ask for higher output voltages. Also, as that voltage ratio rises, the output current gets much choppier and noisier, demanding more from the inductor and diode and output filter cap for acceptable results. These things can work, but as you have found the spec's they give are "optimistic" at best. Here's a tutorial on boost converters: ? ?? And a datasheet for the chip used: ? ?? Note that pin 2 of the chip is an ENABLE pin, could pull that low during receive. Most of these modules don't give you an explicit connection on the board to shut it down, but if you study the data sheet of the part used it is often possible. Using two modules, one for each FET as you suggest, should work on the uBitx. Though that means two spots to adjust output voltage, and twice the number of places it can fail. A single large boost switcher might be better. Jerry, KE7ER On Fri, Jul 20, 2018 at 01:28 AM, Tom, wb6b wrote: My apologies for the stream of consciousness nature of these last few posts. But, if it turns out one of the power converters can't handle the load, I realized the uBITX does not use a center tapped output transformer. I might try supplying each half of the push-pull finals with a separate boost converter. |
Re: calibrate v4 ubitx
Jerry,
I agree that calibration is a 'exercise', why does it need to be this hard. I'm no coder, but Don ND6T's calibration routine worked really good for me when I was calibrating my Bitx 60, ? All we need to know is what our actual 25Mhz crystal frequency is and change that line in the sketch, then all we need to adjust is the BFO frequency which is easy when the rig is on frequency. I don't know how to code so I'm not sure what is involved in adding something like this to the existing sketch but it sure beats zero beating. Joel N6ALT |
Re: uBitX CAT problem on 40m
#ubitx
#ubitx-help
#ft8
Hi John,
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I assume that you are using a computer connected to the radio since you are running WSJT-X AND CAT. It may be the computer that is being tickled by stray RF. How is your RF ground configured? The shrortest cable possible to a good earth ground is desirable but may have a length that presents a high impedance to ground for RF at one or more bands. Before you put a lot of effort into that (assuming you already have some sort of grounded cable) try to connect your computer 'common' to the same RF ground you use for your radio. At least bond the radio chasis ground and computer ground. If I don't have that RF ground included on the computer frame I have some nasties that show up too. The suggestions in the other replies this far are good too. 73, Bill KU8H On 07/20/2018 08:24 AM, John wrote:
Hello all, --
bark less - wag more |
I have noticed this as well. For example when you set the step size to 50 Hz if you tune quite quickly it seems that the step-size
increases.? Are you sure that this isn't intentional ? ?I see to recall Ian making a passing comment about variable rate tuning at some point. Michael VE3WMB P.S. I am really enjoying the ability to select the step size via touch screen in V2 of Ian's "Nextion" display code. This was a great addition. I may have found another bug though. More on this later when I have had more of a chance to test it out.? |
Re: uBitX CAT problem on 40m
#ubitx
#ubitx-help
#ft8
Gordon Gibby
¿ªÔÆÌåÓýRadio interference! Happens on whatever bands you get currents through sensitive junctions.?Experiment try to fix it, add grounds, single point ground, try ferrites lots of different places, eventually you will stop the current that is locking up the rig.
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Re: uBitX CAT problem on 40m
#ubitx
#ubitx-help
#ft8
M Garza
I would suggest putting a clip on ferrite core on the USB cable, right at the Raduino connector and one on the wires from the Raduino connector going to the encoder. Others have brought this issue up and this was the easiest and quickest solution. 73s, Marco - KG5PRT? On Fri, Jul 20, 2018, 8:04 AM Marc Jones via Groups.Io <gw0wvl=[email protected]> wrote:
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Re: uBitX CAT problem on 40m
#ubitx
#ubitx-help
#ft8
Sounds like a Bit of RF is getting in there ... Gw0wvl
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uBitX CAT problem on 40m
#ubitx
#ubitx-help
#ft8
Hello all, Running CEC firmware v1.095 with Nextion 2.4 display. I don't have any chokes on my audio cables and have been working on the higher bands without any problems. Any clues? |
I had an issue with encoders several years ago, in a PIC application.? I looked at the A/B outputs and noticed spikes on the square waves.? Adding two .001uF caps across the outputs to ground, cured the issue.? Maybe that will help?? Most likely you encoder is easy to get to...
Your mileage may vary, Jim W0CHL |
Re: surprising CW sidetone value in uBITX Manager 0.11
#ubitx
Jack Purdum
Virgin EEPROM on the Arduino family is set to 0xFF. My guess is that some value the software needs from EEPROM has not been set. Jack, W8TEE
On Thursday, July 19, 2018, 11:52:48 PM EDT, Mike KK7ER <groupio@...> wrote:
Alas, having the correct version of uBITX Manager did not solve the problem.? Now the CW Side Tone and CW Speed both show as 65535 (0xFFFF).? They are still just as meaningless as before and do not correspond to the values shown on the LCD display. FYI. 73 Mike KK7ER |