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Re: BITX QSO Afternoon/Night, Sunday, February 4, 3PM/7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere
Get well soon John. Listening to the top end of 40M right now and it's chock full of AM Rally stations all over the place from 7.250 to 300. I'm QRV on 7.240 for traffic and a possible substitute frequency. Open to suggestions.
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Re: #ubitx-help Strong Audio Tones in and outside audio receive passband
#ubitx-help
Joe Puma
¿ªÔÆÌåÓýI¡¯ve been following this post. What does this all mean for a beginner who is waiting on a uBitx? Is there a problem with original design? Are these strong audio tones noticeable or interfering with when using the ubitx straight away??Joe KD2NFC? On Feb 4, 2018, at 11:58 AM, Arv Evans <arvid.evans@...> wrote:
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Re: ubitx receive audio troubleshooting
Gordon Gibby
¿ªÔÆÌåÓýSo in order to have an oscillation, you have to have a closed loop with a gain greater than one at the oscillation frequencySince your squeal begins when you turn the vine control up, and then input of the loop that Apparently exists is earlier in the system. ?
My guess would be via the power supply lines. ?That would suggest adding additional filtering in Decoupling capacitance in parallel with the lowest inductance (short leads ) as possible as near to the chips involved as possible. ? Probably the audio Amp
chip & its preamp should have additional filtering on the power supply lines. ?You can test this by ?merely touching capacitance to the proper places temporarily.
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whistles in receive
I am sitting here reading some of this information and studying the new technology.? When I was young (at leas 50 years ago), solid state technologies were either in their infancy or still a dream.? Our rigs were two pieces of equipment, a receiver and a transmitter with a variety of accessories.
Most of our receivers for those of us who were not well heeld in the financial area were of the single conversion genre with an if frequency of 455 kHz.? With little preselection capability, this relegated the ham bands 20 mtrs and above useless with hetrodyne images from frequencies 910 kHz either above or below the desired reception point. There, in that day, were three remedies to fix this. The first two were: ??? 1.)? add a really selective high gain preselector to tune the offending images out ??? 2.)? raise the if to something on the order of 1600 kHz which left bandpass selectivity at a substantial disadvantage. The third option, and the most expensive in its day was double (or, even triple) conversion.? If? you were able to pay the 1958 price of over $300, you were in and there were few difficulties thereafter until the receiver aged and developed some bad shield grounds or worse.? The second or third conversion local oscillator would provide a cornu copia of birdies of one type or another. These included signals that were always there, I know the newer designs with balanced mixers and the like have few of these problems, but, it is worth considering. An aging ham from way back. Lee, WA9AOE --- This email has been checked for viruses by AVG. |
Re: Second batch of uBITX shipping?
#ubitx
Where did mine December 15th and got it about a week ago
Andy KM4TRT |
Re: ubitx receive audio troubleshooting
Gordon Gibby
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Re: #ubitx-help Strong Audio Tones in and outside audio receive passband
#ubitx-help
Bingo!
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See this ceramic resonator on Mouser:? pnum??81-CSTCE16M0VH3L99R0 Same physical size as what's on the Nano, I didn't see any quartz crystals that small. Tolerance of those Murata parts is 0.07%, so could be off by as much as plus or minus 16mhz*0.0007=11.2khz? Whatever they stuff on a $2 Nano is probably not Murata, unless they are Murata rejects. This internal oscillator capacitance thing, is though only in the interest of accuracy? Or is it a matter of the oscillator not working at all? Regardless, anybody with tones, I suggest you pack some capacitance across pins 7 and 8? of the ATMega328P chip (hard to get at those signals on the very small ceramic resonator). I have no idea how much, perhaps hundreds of pF, if the Raduino display no longer works then that's too much. This might be something best done at hfsignals on new units, as those 328P pins are pretty small And if that doesn't help, try shorting out one end of the 12mhz resonator to ground. Found on the back?of the Nano, unfortunately. On Sun, Feb 4, 2018 at 09:15 am, Arv Evans wrote:
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Re: #ubitx-help Strong Audio Tones in and outside audio receive passband
#ubitx-help
So, moving the Nano 8" away did away with tones in the crystal filter passband,?
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which would be the ones of most concern to folks here in the forum But you still see tones coming through the demodulator, up around 13khz.? Can you give some idea of how strong these 13khz tones are? I assume they are relatively weak. You said that a finger on the 16mhz crystal does not affect these tones. Did a finger on the 16mhz crystal affect the the tones you heard within the passband back before the 8" move? There's all sorts of weird things that can happen around mixers. Always have some unwanted products that come out the IF port. We have a filter there (45mhz or 12mhz) to only select the signal of interest, those other signals are not getting terminated and so reflect back into the mixer to mix again, creating all sorts of unexpected havoc. Could be this 13khz stuff has nothing to do with the Nano. Jerry On Sun, Feb 4, 2018 at 09:19 am, Jerry Gaffke wrote:
Ah, very nice that you were able to do all of this, and document it so well. |
Re: #ubitx-help Strong Audio Tones in and outside audio receive passband
#ubitx-help
Ah, very nice that you were able to do all of this, and document it so well.
See my comments inline with your original text below ?
On Sat, Feb 3, 2018 at 09:50 pm, John wrote:The exact frequencies you report seem reasonable, others may find their rig to? be using 12mhz crystals that are a khz or two off from what you report. Crystals are sorted by frequency at hfsignals, different rigs get slightly different freq crystals. So by moving the Raduino 8 inches away from the uBitx, the radio no longer hears these interfering signals on either low or high side BFO settings.? Suggests we could deal with it using shielding.? Our assumption has been that it is the 4x harmonic of the BFO (4*12=48mhz) beating with the 3x harmonic of the Nano (3*16=48mhz). Any chance the tones shift by 400hz per 100hz of BFO, not 550hz?? ?550hz would be difficult to explain, that's a very funny number. Typical of a crystal ladder filter that one side is less steep, the skirts are not symmetrical. Indeed, this is unexpected. Perhaps the 12mhz and 16mhz crystals are insensitive enough to not vary much when interfered with. (But wasn't there a previous report of tones changing when a finger was near the 16mhz crystal?) And perhaps the 12mhz and 16mhz crystals are somehow beating against each other? Or there is some totally different source for these tones, apparently coming from the Raduino? Once you tune the radio and can observe these tones, see if you can disable the 12mhz and 16mhz crystals by shorting one end to ground.? See if shutting down one or the other somehow gets rid of the tones. The 12mhz crystal is only needed when downloading new firmware. The 16mhz crystal is needed to tune the rig, but once the si5351 is programmed the 16mhz can go to sleep. You may need to reset the Nano to get it back on the rails after re-enabling the 16mhz crystal. I'm not sure I totally understand all of this. Some change in signal strength is expected if as you use different parts of the 45mhz crystal, the passband isn't all that flat. The four to one ratio (4000 to 1000) here is consistent with our assumption that it is the 4'th harmonic of the 12mhz BFO involved, at 48mhz. But I would think the BFO is not moving when you hear these tones move, is that the case? If the BFO is not moving, this is quite puzzling, and perhaps the tones are due to some fourth harmonic of either the first or second oscillator. I assume that as you move one, you also move the other by an equal amount, you might try only moving one of the two local oscillators, see which one causes the tones to vary.? I haven't totally grok'd your new code yet. Jerry, KE7ER? |
Re: #ubitx-help Strong Audio Tones in and outside audio receive passband
#ubitx-help
¿ªÔÆÌåÓýNot 100% sure but popular thinking indicates the "crystals" on smaller Arduino boards are actually ceramic resonators.? If this is true then it should be possible to use capacitence to pull them further than would be possible with a real crystal.? This also lends credibility to the caution about possibile need to change AVR internal oscilator capacitence if changing resonator or crystal device. Recently i purchased some Arduino Pro-mini units that have a standard crystal for the CPU clock.? These are for a frequency counter project where the stability of a crystal is needed.? Search Ebay for "arduino pro mini crystal" for these units.?? The Pro-minii Arduino are also interesting because they do not include built-in USB and thus there is no 12 MHz crystal to interfere with the BITX 12 MHz IF. Arv. K7HKL _-_ Sent from my Verizon, Samsung Galaxy smartphone -------- Original message -------- From: James Lawrie <lawriejk@...> Date: 2/3/18 11:15 PM (GMT-07:00) Subject: Re: [BITX20] #ubitx-help Strong Audio Tones in and outside audio receive passband I know I'm late to this party but you cannot swap crystals on nano board without first using a atmel programmer to burn the fuse bits that tell what freq it will be using or you will brick your nano.... also if the ftdi or whatever usb chip is using 12mhz, you could get the sparkfunPro 16mhz/8mhz board that does not use usb but instead uses usb to serial cable to upload. Be warned 16mhz board is 5 volt and 8 mhz is 3.3 volt. I only use the Sparkfun Pro 16 for my projects. Another note if you go with the ATMega32U4 boards they have built in usb.... Maybe this will help someone or maybe not.... James Lawrie Sent from my Galaxy Tab A -------- Original message -------- From: Arv Evans <arvid.evans@...> Date: 2/3/18 09:38 (GMT-06:00) Subject: Re: [BITX20] #ubitx-help Strong Audio Tones in and outside audio receive passband Jerry Interesting observation that the 12 MHz USB clock oscillator is on nearly the same frequency as the uBITX IF and BFO.? If the BFO is offset to the high side of the IF passband it could well be within audio range of the USB clock frequency.? If this is the problem then it might be possible to pull the USB clock crystal down with a small parallel capacitor.? That should not make a significant change in USB clock timing but could take it out of range of the receiver IF and BFO frequencies.? Some experimenting is probably necessary to tell how far to pull the crystal.? It would not be good to accidentally put it within the IF filter passband. Arv? K7HKL _._ On Sat, Feb 3, 2018 at 1:47 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote: I assume you mean changing the Arduino crystal, not cap. |
Re: uBITX drive level..
#ubitx
Rod Self
¿ªÔÆÌåÓýTilman and all, Per, I think, Raj's suggestion, I change R63 to 11 ohms, and that seems to work well. 0805 parts fit on 1206 pads, and power dissipation is not an
issue with an 0805 11ohm. YMMV Rod KM6SN On 02/04/2018 08:18 AM, Tilman D
Thulesius wrote:
Jerry |
Re: uBITX Firmware (CEC) 0.30 released (Test version).
#ubitx
¿ªÔÆÌåÓýThanks for fast ansver, it is working.
In next days try to conect to pc. if it working with n1mm.
And with mmvari. This program using for digital and for contest.
Use this interface
In contest working only 2 or 3 times.
I am too old for contest.
Best regards and 73 from Slovenia
Matjaz
? From: Ian Lee
Sent: Sunday, February 04, 2018 2:48 PM
Subject: Re: [BITX20] uBITX Firmware (CEC) 0.30 released (Test
version). #ubitx ?
Matjaz
?
Thanks for interresting.
?
I saw the schematic you attached. It seems to have only an encoder and a
function key.
I do not test it, but I guess. so My guess might be wrong.
My guess is that the CW key is malfunctioning. The CW key (A6?)?
must with pullup resistor.
If you connect any resistor around A6 and VCC, it will work
normally.
(This is similar to the original source.)
?
And I released 0.34. The latest version adds more fun features.
?
Ian KD8CEC ?
2018-02-04 20:05 GMT+09:00 matjaz via Groups.Io <matjaz_zejn@...>:
? -- Best 73 KD8CEC / Ph.D ian lee kd8cec@... (my blog) |
Re: #ubitx-help Strong Audio Tones in and outside audio receive passband
#ubitx-help
Not familiar with the ATMega328P, but table 9.3 on p300 of the datasheet says the Low Power Crystal Oscillator
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can take a crystal anywhere from 0.4mhz to 16mhz, and that we must load bits CLKSEL[3-1] to inform the chip what the crystal frequency is.? The top range with CLKSEL=111 is for 8 to 16mhz, so I assume we could have a crystal anywhere in there without having to burn fuse bits. My datasheet has the unfortunate name of:?? ? ??Atmel-8271-8-bit-AVR-Microcontroller-ATmega48A-48PA-88A-88PA-168A-168PA-328-328P_datasheet_Complete.pdf The primary reason not to swap out the 16mhz crystal is that the one they have is so blasted small. Take a look, it's visible on your Raduino's Nano, just above the Nano pin labeled "D5". Not all of us would want to deal with it. If we disable or remove the USB-to-UART chip from the Nano (and make sure we have some sort of 3.3v regulator), we can still program the Nano via the TX/RX Uart lines at D0,D1 of the Nano board edge using an external FTDI USB-to-UART cable or similar.? Unfortunately this probably means separating the Nano from the Raduino to work on the bottom of the Nano, so probably not an option.? Thus far, it seems the 12mhz USB crystal is not an issue though, since reports of tones come with the news that the tones change when a finger is placed on the 16mhz crystal.? Could be the 12mhz crystal is involved here too though. Jerry, KE7ER On Sat, Feb 3, 2018 at 10:15 pm, James Lawrie wrote:
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Re: uBITX Firmware (CEC) 0.30 released (Test version).
#ubitx
Please keep in mind that some of us don¡¯t want a disk image and prefer a simple package to install. This way, i can just add it to a disk that is already set up the way I want my Pi to be.
Thanks for the work you are doing!? -- Karl Heinz - K5KHK |
Re: uBITX drive level..
#ubitx
Jerry
My uBITX has proper 10W output on 80 and 40 meters keydown CW. So I assume the BIAS is set ok. When trying to get some serious output power (10W) running phone I have to wistle in my mike a lot. I have put RV1 all the way up.? So Im considering moving up the micgain in the mic-amp. How much would be a good starting point on R63. 100ohm ? / Tilman SM0JZT |
ubitx receive audio troubleshooting
I am still trying to identify the cause of an audio "squeal" which makes receiver unusable.
Audio is ok at lowest volume setting. As I turn up volume, a "squeal" begins and gets louder obliterating any other signals. The TPA2016 chip gets extremely hot if left in this state for any length of time. I suspect that something is causing the audio stage to oscillate at higher volume levels. I have tried "cleaner" power supplies, created a ground plane for my front panel, and substituted shielded cable for the volume control leads, all without any improvement. Any suggestions as to getting to the bottom of this problem? Btw, the radio is able to receive strong signals at the lowest setting. Craig KC2LFI |
Bitx40
Michael Davis
Are T1 and T2 identical in the Bitx40? Any others? I have a spare board and my original board has a mechanically intermittent T2. I am practicing desoldering and removing these devices and will replace the intermittent one, if my recent re-soldering efforts proved unsuccessful.?
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Re: uBITX Firmware (CEC) 0.30 released (Test version).
#ubitx
joe i saw your posted message on my blog. and Thank you very much for youer suggestion. Most of the wsjt-x portable work is done.?It was a little late because i had to work with uBITX firmware. Working on this, I found some things that make wsjt-x even more usable for uBITX. i will propose to the wsjt-x team after the work is done.? Now i develop a launcher program to control raspberry pi simply with wsjtx portable. This would be possible without a keyboard or mouse, assuming a 3.5-inch LCD is attached to uBITX. I want to create an disk image of raspberry pi 2 and 3, respectively.?With this image, users will not need complex RPI setups, libraries and wsjtx installations, wsjt-x portable settings. Just copy the image file to the sdcard with a utility like win32diskimager. Your suggestion will help people who want to use wsjt-x in raspberry pi. Thanks again. Ian KD8CEC 2018-02-02 9:17 GMT+09:00 Joe <joeman2116@...>:
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