Re: V5 and the poor carrier suppression.
Raj, ok mni tnx for your reply :-)
Farhan, also mni tnx for your reply :-) Okay, that'll be the first thing I'll check. But I didn't made any changes before - the drive pot is untouched so far;-)
73, Frank
?
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I guess it could have been worse, I
could have types 50MV :-)
This is a v3 that I finally got around to playing with a couple of
months ago.
It had been in the project stack for quite a while.? For now it's
just built into
the shipping container until I decide what it's going to be when
it grows up.
I have a JackAl board about ready if it goes that way.
I've attached spectrum captures for 20m and 40m.? Didn't take them
of other
bands.? The chart below does show the general trend higher
frequency -> worse
spurs.? I tried to cherry pick numbers for 12m but still couldn't
quite get there :-)
Thanks for the feedback.? As always, more learning to do.
John
W1JDS
|
Iz
with these numbers I would speak softer into the microphone and be just fine.? important to see if they correspond to 'full' output power, if so I think most of us would be thrilled with them.? (but do check the harmonics also!)
a typical v4 uBITX has SSB spurs on 15, 12 and 10 meters that are too high for a tuner to confidently address.?
I am very curious about this data as I am not getting useful results with a added 45 MHz xtal filter stage.? If I figure out who is selling those shielded inductors in NA, I would be interested in them given this data.?
Curt
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Indeed, they seem almost good results, especially on the 15m band, which was the most critical for spurs. Which version of ubitx do you have? If you use an ordinary (high - pass) tuner, you should be fine on 10m and possibly on 12m too. Thumbs up!
Il 08/apr/2019 10:33, "John Sutter" < jds@...> ha scritto:
I set up to do some SSB testing getting putting about 50Vpp in.
I don't know if I read the right peaks or not, but I looked for
the strongest signal that wasn't a harmonic.
Don't know how I skipped 17m, but that's life.? I'll do it next
time.
I've replaced the relays and L5/L7.
Does this look about right or am I looking at the wrong thing?
It looks like no 12m or 10m based on spars or 80m due to harmonics
for me at this point.
John
W1JDS
|
John
info appreciated.? I don't think you are likely using 50 volts audio -- maybe 50 mV ?? There may be more variation in the audio gain than RF perhaps.? I suggest you watch the output power as you adjust the audio, as producing an expected RF output tells us you are measuring spurs while simultaneously getting several watts of RF output.?
You didn't happen to say if this is v5 or a previous version?
I recognize that 12m spur being 5 MHz away -- mine has similar spurs almost equally below and above the carrier (one is a mixer spur, the other seems to be a signal passing through the mixer a second time (RF from PA leaking back into mixer input).? What you label as separation looks like you have subtracted the spur level from the main carrier?? By convention these are given as a negative value.? If you are outputting say 3 or more watts at 10m -- I really like your numbers -- they are 8 dB better than my v4.? Note your worst spurs are up there also, but yours are close to compliance - indeed if your rig is simultaneously outputting desired transmit power.?
The SSB spurs you are measuring tend to be a worse problem at the highest frequencies - I have non-compliant spurs on SSB only at 15, 12 and 10 meters.?
Also you need to seprately measure the worst harmonic.? Note these mostly impact bands at 20m and below, since the PA doesn't transmit as efficiently up above 10m where these spurs would land if they start at 18 MHz or higher.?
Be patient and you should get some good measurements.?
Curt
|
I set up to do some SSB testing getting putting about 50Vpp in.
I don't know if I read the right peaks or not, but I looked for
the strongest signal that wasn't a harmonic.
Don't know how I skipped 17m, but that's life.? I'll do it next
time.
I've replaced the relays and L5/L7.
Does this look about right or am I looking at the wrong thing?
It looks like no 12m or 10m based on spars or 80m due to harmonics
for me at this point.
John
W1JDS
|
Re: How to connect ubitx microphone jack to soundcard output; now unsuppressed carrier in SSB or digital modes.
For those trying to follow the conversation, it started in this other thread: ? ?? /g/BITX20/topic/30204401Karl's adio had been working well as an SSB transmitter, but after trying to adapt it to a PC soundcard for use on digital modes, it now has a strong residual carrier. My understanding is that this undesired carrier is roughly as strong as the desired sideband. Karl tried replacing the BAT54S diode pair in the modulator, that apparently did not help. This fault may have nothing to do with the attempts at a soundcard interface,? could just be from jostling and banging around the board. Curious that the carrier is not getting at least somewhat suppressed by the 12mhz crystal filter. I'd try shorting across R114 to disable the output from the modulator, then see if the carrier is still there when the mike is keyed.? Could be that CLK0 is somehow getting coupled in after the filter. Karl reports "At the C50/C63 node, I am getting?1.4 mV without the microphone being keyed and 1.2 to 1.5 mV when the microphone is keyed". That node is going into the modulator from the mike amp. Not clear if that is a DC level, or some sort of audio or RF AC. If it's AC, that might just be local noise (perhaps from CLK0) getting picked up by a scope ground lead. If it's DC, I would not expect that, but then I would not expect a mV or so to cause a very strong carrier. Might be worth removing C50 and C63 from the board using two soldering irons, clean the board in that area with alcohol in case some flux is providing a conductive path, then power up and see if there is still a significant carrier when the mike is keyed.? Check those caps with an ohmmeter to verify they are not leaking. Perhaps windings on T7 have shorted out? Might be worth rewinding T7 with new magnet wire, see if that helps. Could replace that modulator with a commercially available diode ring mixer such as an SBL1 or ADE1. One of the cheap AD8307 RF sniffers on ebay would be useful for looking at these?low level RF signals.? Solder coax into the uBitx keeping signal and ground?as short as possible, run that coax into the sniffer. ? ?? Hacking at boards to investigate problems like this must be done carefully. Would be very easy to create a second reason for this strong residual carrier. Jerry, KE7ER
On Sun, Apr 7, 2019 at 02:47 PM, Karl Heimbach wrote:
Jerry,
I have the v3 board as do you.? I bought 10 diodes from Mouser and installed a replacement (twice) this afternoon.? No improvement and still have the unsuprressed carrier.? I also heated up the pins on T7 to check for a cold solder joint, looked over the entire board with a magnifying glass to see if I missed something.? Loaded version CEC version 1.1 software, recalibrated, etc., without any success.
At the C50/C63 node, I am getting 1.4 mV without the microphone being keyed and 1.2 to 1.5 mV when the microphone is keyed.? I looked very closely at the microphone jack for bent pins and can't see any.
As before the radio works fine on CW and receives well.
Any other thoughts?
Karl - W5QJ
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Re: V5 and the poor carrier suppression.
On v5, the drive pot should be set to half-way. This prevents overloading of the PA chain. If you overload the PA, it clips the top end of audio while amplifying the carrier. This results in low signal to carrier ratio. A good suppression value is about -30 dbc. Beyond that, the IMD producta dominate. - f
You could play with different values of C217 to C221 inclusive.
Try 56pf or even 47pf you should get better tone with IF at 11.0555
Raj
At 07/04/2019, you wrote:
>Hi folks,
>
>like others my v5 has got a very poor carrier suppression.
>
>To fix this, I followed the solution from former topics to vary the? BFO-Frequency.
>
>I think 11055500 is a good compromise for me.
>
>Depending on the band, the carrier suppression is between -32 an - 40 dB.
>
>But the audio is incredible? sharp: - /
>
>So, I figured out when the IFS is set to higher levels, the audio is clean and nice for my ears.
>
>Maybe that`s not the best solution, but it helps for the moment.
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Re: Broke it like only a newbie can - Calibration problems
....and he fare (sic) prefers Linux.? ?
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Re: How to connect ubitx microphone jack to soundcard output; now unsuppressed carrier in SSB or digital modes.
Jerry,
I have the v3 board as do you.? I bought 10 diodes from Mouser and installed a replacement (twice) this afternoon.? No improvement and still have the unsuprressed carrier.? I also heated up the pins on T7 to check for a cold solder joint, looked over the entire board with a magnifying glass to see if I missed something.? Loaded version CEC version 1.1 software, recalibrated, etc., without any success.
At the C50/C63 node, I am getting 1.4 mV without the microphone being keyed and 1.2 to 1.5 mV when the microphone is keyed.? I looked very closely at the microphone jack for bent pins and can't see any.
As before the radio works fine on CW and receives well.
Any other thoughts?
Karl - W5QJ
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Re: Raduino reinforcement, 3d printed
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Re: New Arrivals Universal Case for uBitx- Nextion
thats a great idea as regards just a front panel wonder if youd care to let us know ashar. regards Dave G0AYD Bitx owner? 2 X V 3 and 1 x V4..
...would be cool to have just the Nextion front panels available, so those of us that already own cases can upgrade.. :)
also: i think the 'sold out' status can be misleading, in that new items created in the vending section of the website START showing SOLD OUT, and when they go on sale they show as available - so don't think You have missed out on a new release, it's probably just not been actually put on sale yet is all. maybe.
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Re: 3,5" Firmware did not fit the whole screen
One other thing:
The MAX232 is just a logic level converter, between RS232 voltages and TTL/CMOS logic levels
The underlying UART protocol remains the same.
The UART protocol could be described in a paragraph.
USB is a different protocol all together, and ridiculously complex:
? ??
There's much more than logic level conversion going on inside the USB-to-UART devices.
USB is fine, so long as somebody else makes it work for me.
UART's are far simpler, easily debugged using?something like a $20 scope from JYETech.
? ??
Jerry
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Re: Raduino reinforcement, 3d printed
Yes it is printed. Never tried putting anything into the files section.
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Arduino current requirement
Found this on-line.? It looks interesting for those who want maximum battery life
with a BITX transceiver or Arduino powered test equipment.
Arv? K7HKL _._
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Re: Raduino reinforcement, 3d printed
Did you print that bracket? If so you might consider sharing that in the files section...
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of d balfour Sent: Sunday, April 7, 2019 8:55 AM To: [email protected]Subject: [BITX20] Raduino reinforcement, 3d printed I have noticed particularly on my ubitx radios that the raduino board is just hanging on the 16 pin connector. Very bad engineering to not have a mechanical mount. The other day while putting together another radio I decided to make a mechanical mount for the raduino. I used 12 mm long 3mm screws and nuts to hold it together. It is using stock front mounts with the original screws replaced by 12mm screws. I think it is a worthwhile modification. The part could be made from metal but was easy to make from plastic. I am going to make another one for my bitx40. I imagine that the length will be different. --- This email has been checked for viruses by AVG. -- ¡_. _._
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Re: 3,5" Firmware did not fit the whole screen
Indeed Of late have only had to worry about converting between 3.3 and 5v. But I do remember replacing driver chips max232 on Unix servers when the RS232c interfaces failed.
Takes me back to 1982?
On Sun, Apr 7, 2019, 1:21 PM Jerry Gaffke via Groups.Io <jgaffke= [email protected]> wrote: Hmm, looks like an excellent opportunity for a rant.? ?;-)
Safely ignored if you already know about RS2332 signal levels, 5v vs 3.3v? logic levels,
and going from USB to UART signalling.
>? First, it is very important to have a level converter (e.g. DeLock Converter USB 2.0 male > Serial TTL)
>? because the ?Cs serial Port on the Raduino-Board will be toasted if you connect it directly to the computers serial port.
>??Yep, ttl<->cmos level conversion always very important with Serial comms.
A serial port from an old PC uses RS232 signal levels, typically logic levels of -12v for a mark, +12v for a space.
Those RS232 signal levels are from a 60 year old standard, now more than a little bit archaic.
So that old 9 pin PC serial port is RS232 signal levels, not compatible with TTL or CMOS logic levels.
A MAX232 chip will take RS232 to 5v logic levels of +5v for a mark, 0v for a space (it inverts the signal).
??
There are similar parts to take it to 3.3v logic levels, if that's what you need.
The ATMega328P chip on our Nano's uses the same UART protocol as the old RS232 standard,
but at voltage levels of +5v for a mark, and 0v for a space.? So compatible with the logic side of the MAX232 chip.
A chip on our Nano clone (the CH340) allows a modern computer's USB port to talk to
the ATMega328P's 5v UART lines, no RS232 signal levels involved at all.
Generally, if operating from the same supply, TTL and CMOS logic can be directly connected.
If you have 5v TTL and 3v CMOS, it will mostly work except you need some way to protect
the 3.3v CMOS receiver from the 5v TTL high levels, perhaps just a resistive divider.
The threshold between logic 0 and logic 1 of a TTL receiver is typically down around 1v,
so transmitting from CMOS 3.3v into a 5v TTL receiver works just fine.
Transmitting from 3.3v CMOS into 5v CMOS can be unreliable, that depends on what the
threshold of the 5v CMOS receiver is, might be around 5v/2 = 2.5v? (read the datasheet).
Some combination of voltage loss through the 3.3v driver, a high 5v CMOS receiver threshold
(often around 2.5v), a volt or so of hysteresis at the 5v receiver, a bit of noise in grounding
(or RF getting injected into the cables) is a recipe for trouble.
Some sort of 5v buffer device that has a lower receive threshold inserted between the two would solve this.
For long cables, a differential signaling scheme such as RS422/RS485 or LVDS
can go much faster than RS232.? If ground currents might be an issue, optocouplers can be used
at the receiving end.? But RS232 still works as well as it did 60 yrs ago if you don't need the speed.
??
On modern computers we don't have RS232 serial ports, we have USB ports.
There are several devices out there like the CH340 on the Nano clones
to convert from USB to UART at 3.3v or 5v logic levels.
Here a USB to UART module that works with either 5v or 3.3v logic:
? ??
The USB connection provides 5v power, the module has a voltage regulator to supply 3.3v
to the CP2102 chip from SiLabs.? Logic levels on the TX UART line from the CP2102 is 0v/3.3v,
but 3.3v is usually high enugh to be seen as a high on a 5v processor such as the ATMega328P.
The RX UART line going into the CP2102 is tolerant of up to 5.8v, the threshold between
low and high is somewhere between 0.8v and 2.0v, so works fine with the 5v signal from the ATMega328P.
That module has user pins labeled GND, RXD (in), TXD (out), 3.3V (out), 5V (out), RST (in).
The 3.3v and 5v pins are there to power your logic, but don't draw more than 100ma or so from 3.3v.
The RST pin can be used to reset the USB interface, but I'd just leave it unconnected.
The CP2102 may require a special driver installed on some operating systems (such as MsWin),
my Ubuntu install came with the required software driver.
The FTDI chips (and cable assemblies) are also very popular for this sort of thing:
? ??
Jerry, KE7ER
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Re: 3,5" Firmware did not fit the whole screen
Hmm, looks like an excellent opportunity for a rant.? ?;-)
Safely ignored if you already know about RS2332 signal levels, 5v vs 3.3v? logic levels,
and going from USB to UART signalling.
>? First, it is very important to have a level converter (e.g. DeLock Converter USB 2.0 male > Serial TTL)
>? because the ?Cs serial Port on the Raduino-Board will be toasted if you connect it directly to the computers serial port.
>??Yep, ttl<->cmos level conversion always very important with Serial comms.
A serial port from an old PC uses RS232 signal levels, typically logic levels of -12v for a mark, +12v for a space.
Those RS232 signal levels are from a 60 year old standard, now more than a little bit archaic.
So that old 9 pin PC serial port is RS232 signal levels, not compatible with TTL or CMOS logic levels.
A MAX232 chip will take RS232 to 5v logic levels of +5v for a mark, 0v for a space (it inverts the signal).
??
There are similar parts to take it to 3.3v logic levels, if that's what you need.
The ATMega328P chip on our Nano's uses the same UART protocol as the old RS232 standard,
but at voltage levels of +5v for a mark, and 0v for a space.? So compatible with the logic side of the MAX232 chip.
A chip on our Nano clone (the CH340) allows a modern computer's USB port to talk to
the ATMega328P's 5v UART lines, no RS232 signal levels involved at all.
Generally, if operating from the same supply, TTL and CMOS logic can be directly connected.
If you have 5v TTL and 3v CMOS, it will mostly work except you need some way to protect
the 3.3v CMOS receiver from the 5v TTL high levels, perhaps just a resistive divider.
The threshold between logic 0 and logic 1 of a TTL receiver is typically down around 1v,
so transmitting from CMOS 3.3v into a 5v TTL receiver works just fine.
Transmitting from 3.3v CMOS into 5v CMOS can be unreliable, that depends on what the
threshold of the 5v CMOS receiver is, might be around 5v/2 = 2.5v? (read the datasheet).
Some combination of voltage loss through the 3.3v driver, a high 5v CMOS receiver threshold
(often around 2.5v), a volt or so of hysteresis at the 5v receiver, a bit of noise in grounding
(or RF getting injected into the cables) is a recipe for trouble.
Some sort of 5v buffer device that has a lower receive threshold inserted between the two would solve this.
For long cables, a differential signaling scheme such as RS422/RS485 or LVDS
can go much faster than RS232.? If ground currents might be an issue, optocouplers can be used
at the receiving end.? But RS232 still works as well as it did 60 yrs ago if you don't need the speed.
??
On modern computers we don't have RS232 serial ports, we have USB ports.
There are several devices out there like the CH340 on the Nano clones
to convert from USB to UART at 3.3v or 5v logic levels.
Here a USB to UART module that works with either 5v or 3.3v logic:
? ??
The USB connection provides 5v power, the module has a voltage regulator to supply 3.3v
to the CP2102 chip from SiLabs.? Logic levels on the TX UART line from the CP2102 is 0v/3.3v,
but 3.3v is usually high enugh to be seen as a high on a 5v processor such as the ATMega328P.
The RX UART line going into the CP2102 is tolerant of up to 5.8v, the threshold between
low and high is somewhere between 0.8v and 2.0v, so works fine with the 5v signal from the ATMega328P.
That module has user pins labeled GND, RXD (in), TXD (out), 3.3V (out), 5V (out), RST (in).
The 3.3v and 5v pins are there to power your logic, but don't draw more than 100ma or so from 3.3v.
The RST pin can be used to reset the USB interface, but I'd just leave it unconnected.
The CP2102 may require a special driver installed on some operating systems (such as MsWin),
my Ubuntu install came with the required software driver.
The FTDI chips (and cable assemblies) are also very popular for this sort of thing:
? ??
Jerry, KE7ER
|
Re: Broke it like only a newbie can - Calibration problems
Way off-topic.? This is the BITX discussion group. _._
?Heads up on a word used. ?tinier means more tiny ?tinnier means more tinny
?Makes it easier for others to know what you meant. ?I know that English, of bout UK and USA are not always understood, and words get confused.
?Regarding OS, I fare prefer Linux, with Linux Mint being tops in my opinion, and Ubuntu second. ?Windows I dislike, especially when they NEVER get all of the bugs cured. ?My newest laptop came with windblows 8.1 installed. I had already used a version of 8.0 for a while, and found that i disliked it more than 7.1, that I have tried. Of Previous versions, I like 2000 Pro, AKA NT 5.0 to be the best. Win 95 lacked USB support, till late, and I did not know about the support being added till recently, when I acquired a bunch of? CD's with 95 with USB support. ?Win 98 was only marginaly better, and I wound up using 2000 till they messed it up on my, by making it mandatory to change password, hence locked me out because I spent 3 1/2 months in hospitals, and came home to being unable to access my computer due to this.
?I do plan to set up one smaller drive I have with windows 7, so I can run some programs that I cannot find or install with linux. ?Sorry about being long winded. ?Wayne WA2YNE
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Re: Broke it like only a newbie can - Calibration problems
?Heads up on a word used. ?tinier means more tiny ?tinnier means more tinny
?Makes it easier for others to know what you meant. ?I know that English, of bout UK and USA are not always understood, and words get confused.
?Regarding OS, I fare prefer Linux, with Linux Mint being tops in my opinion, and Ubuntu second. ?Windows I dislike, especially when they NEVER get all of the bugs cured. ?My newest laptop came with windblows 8.1 installed. I had already used a version of 8.0 for a while, and found that i disliked it more than 7.1, that I have tried. Of Previous versions, I like 2000 Pro, AKA NT 5.0 to be the best. Win 95 lacked USB support, till late, and I did not know about the support being added till recently, when I acquired a bunch of? CD's with 95 with USB support. ?Win 98 was only marginaly better, and I wound up using 2000 till they messed it up on my, by making it mandatory to change password, hence locked me out because I spent 3 1/2 months in hospitals, and came home to being unable to access my computer due to this.
?I do plan to set up one smaller drive I have with windows 7, so I can run some programs that I cannot find or install with linux. ?Sorry about being long winded. ?Wayne WA2YNE
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Ted
_Dave_ AD0B
MadRadioModder