Date   
Re: #ubitx-help Strong Audio Tones in and outside audio receive passband #ubitx-help

Ashhar Farhan
 

The best solution is to move the IF to 11 MHz. The caps will remain the same, the crystals will have to change.

-- f

On Sat, Feb 3, 2018 at 1:25 PM, Ashhar Farhan <farhanbox@...> wrote:
changing the arudino cap is going to be a challenge as the arduino is soldered and you need to access it from the underside to desolder it. we had to resort to solder it in as keep it on a socket was leading to bulge and an additional failure point on the board.

- f

On Sat, Feb 3, 2018 at 1:18 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
Kind of murky, but I think the ATMega328P on the Nano has a max crystal freq of 16mhz.
My datasheet in section 9-3 says 16mhz max when using the "Low Power Crystal Oscillator",
in section 9-4 says 20mhz max when using the "Full Swing Crystal Oscillator".
My guess is that the Arduino set-up routines use the Low Power Crystal Oscillator.
And this document says the Full Swing Crystal Oscillator is going away:
    http://img.digikey.com/Retractions/WC154601%20-%20PCN-12-23-2015.pdf

Significant changes to the crystal frequency will affect timing, things like keyer speed
and delays in closing relays.  Easily fixed, but will require a new sketch.

The 328P on the Nano does operate from a 5v rail. 
(Even when executing Arduino code.)

Adjusting the BFO freq may help the tones, but is not a good solution
because this also affects the range of audio frequencies on receive or transmit
as mentioned in my previous post.
 
Curious that the Bitx40v3 never had this problem, it had the same 16mhz Nano clock and 12mhz BFO
And the BFO was commonly placed both above and below the crystal filter passband.
Perhaps lack of trouble was due to the physical separation the Nano had from the modulator.
On the uBitx, the modulator is right next to the Nano and si5351, which is good because
it ensures clean consistent clocks from the si5351 get to the mixers, but bad if the Nano's 16mhz
throws a monkey wrench into the works.  

If physical separation works on the Bitx40v3, then some simple shielding may work on the uBitx.
Perhaps just a piece of tinfoil or copper sheet taped over the modulator, grounded but otherwise insulated. 

Additional power supply filtering on the Nano may be help, as John suggested.
And caps to ground on the control signals from Nano to uBitx main board.

Would be interesting to move the uBitx BFO to the high side of the crystal filter, closer to 12mhz.
The tones will likely show up on most any uBitx, allowing countermeasures to be tested.

Currently the uBitx BFO is always below the crystal filter to avoid the tones, second LO always at 45-12mhz
Would be nice to  be able to switch sidebands by flipping the BFO to high or low side.
Could then have the second LO at either 45+12 or 45-12mhz, whichever gives fewer birdies
and other such artifacts. 

Jerry



On Fri, Feb 2, 2018 at 07:43 pm, John Backo wrote:
Actually, one could substitute any crystal from 8 MHz
to probably 20 MHz. Theoretically, running the arduino
changes the voltages to about 3.3v, but I and others have
noticed it works fine on 8 MHz and 5v. I would avoid anything
around 12 MHz as that is the USB frequency range and might
interfere. Easily had is a 10 MHz crystal which would probably work
fine. Even a HC49S type would work with just one jumper wire for
one lead (or maybe soldered direct), and the other pin soldered directly.
The old crystal would. of course, need to be removed.

A simple solution is to do what Jerry suggests, and change the BFO
frequency slightly. That may or may not cure the "symptoms"; it certainly
will not cure the problem.

It is likely that uPC crystal radiation is the problem, however. But it may be coming
from inside the radiuno itself. Sometimes (often) this because of Rf leakage back
through the power supply; make sure that is well filtered. Farhan's suggestion
of crystal aging is also very apropos.

Probably the next simplest solution is to replace the nano...



Re: #ubitx-help Strong Audio Tones in and outside audio receive passband #ubitx-help

Ashhar Farhan
 

changing the arudino cap is going to be a challenge as the arduino is soldered and you need to access it from the underside to desolder it. we had to resort to solder it in as keep it on a socket was leading to bulge and an additional failure point on the board.

- f

On Sat, Feb 3, 2018 at 1:18 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
Kind of murky, but I think the ATMega328P on the Nano has a max crystal freq of 16mhz.
My datasheet in section 9-3 says 16mhz max when using the "Low Power Crystal Oscillator",
in section 9-4 says 20mhz max when using the "Full Swing Crystal Oscillator".
My guess is that the Arduino set-up routines use the Low Power Crystal Oscillator.
And this document says the Full Swing Crystal Oscillator is going away:
    http://img.digikey.com/Retractions/WC154601%20-%20PCN-12-23-2015.pdf

Significant changes to the crystal frequency will affect timing, things like keyer speed
and delays in closing relays.  Easily fixed, but will require a new sketch.

The 328P on the Nano does operate from a 5v rail. 
(Even when executing Arduino code.)

Adjusting the BFO freq may help the tones, but is not a good solution
because this also affects the range of audio frequencies on receive or transmit
as mentioned in my previous post.
 
Curious that the Bitx40v3 never had this problem, it had the same 16mhz Nano clock and 12mhz BFO
And the BFO was commonly placed both above and below the crystal filter passband.
Perhaps lack of trouble was due to the physical separation the Nano had from the modulator.
On the uBitx, the modulator is right next to the Nano and si5351, which is good because
it ensures clean consistent clocks from the si5351 get to the mixers, but bad if the Nano's 16mhz
throws a monkey wrench into the works.  

If physical separation works on the Bitx40v3, then some simple shielding may work on the uBitx.
Perhaps just a piece of tinfoil or copper sheet taped over the modulator, grounded but otherwise insulated. 

Additional power supply filtering on the Nano may be help, as John suggested.
And caps to ground on the control signals from Nano to uBitx main board.

Would be interesting to move the uBitx BFO to the high side of the crystal filter, closer to 12mhz.
The tones will likely show up on most any uBitx, allowing countermeasures to be tested.

Currently the uBitx BFO is always below the crystal filter to avoid the tones, second LO always at 45-12mhz
Would be nice to  be able to switch sidebands by flipping the BFO to high or low side.
Could then have the second LO at either 45+12 or 45-12mhz, whichever gives fewer birdies
and other such artifacts. 

Jerry



On Fri, Feb 2, 2018 at 07:43 pm, John Backo wrote:
Actually, one could substitute any crystal from 8 MHz
to probably 20 MHz. Theoretically, running the arduino
changes the voltages to about 3.3v, but I and others have
noticed it works fine on 8 MHz and 5v. I would avoid anything
around 12 MHz as that is the USB frequency range and might
interfere. Easily had is a 10 MHz crystal which would probably work
fine. Even a HC49S type would work with just one jumper wire for
one lead (or maybe soldered direct), and the other pin soldered directly.
The old crystal would. of course, need to be removed.

A simple solution is to do what Jerry suggests, and change the BFO
frequency slightly. That may or may not cure the "symptoms"; it certainly
will not cure the problem.

It is likely that uPC crystal radiation is the problem, however. But it may be coming
from inside the radiuno itself. Sometimes (often) this because of Rf leakage back
through the power supply; make sure that is well filtered. Farhan's suggestion
of crystal aging is also very apropos.

Probably the next simplest solution is to replace the nano...


Re: #ubitx-help Strong Audio Tones in and outside audio receive passband #ubitx-help

Jerry Gaffke
 

Kind of murky, but I think the ATMega328P on the Nano has a max crystal freq of 16mhz.
My datasheet in section 9-3 says 16mhz max when using the "Low Power Crystal Oscillator",
in section 9-4 says 20mhz max when using the "Full Swing Crystal Oscillator".
My guess is that the Arduino set-up routines use the Low Power Crystal Oscillator.
And this document says the Full Swing Crystal Oscillator is going away:
    http://img.digikey.com/Retractions/WC154601%20-%20PCN-12-23-2015.pdf

Significant changes to the crystal frequency will affect timing, things like keyer speed
and delays in closing relays.  Easily fixed, but will require a new sketch.

The 328P on the Nano does operate from a 5v rail. 
(Even when executing Arduino code.)

Adjusting the BFO freq may help the tones, but is not a good solution
because this also affects the range of audio frequencies on receive or transmit
as mentioned in my previous post.
 
Curious that the Bitx40v3 never had this problem, it had the same 16mhz Nano clock and 12mhz BFO
And the BFO was commonly placed both above and below the crystal filter passband.
Perhaps lack of trouble was due to the physical separation the Nano had from the modulator.
On the uBitx, the modulator is right next to the Nano and si5351, which is good because
it ensures clean consistent clocks from the si5351 get to the mixers, but bad if the Nano's 16mhz
throws a monkey wrench into the works.  

If physical separation works on the Bitx40v3, then some simple shielding may work on the uBitx.
Perhaps just a piece of tinfoil or copper sheet taped over the modulator, grounded but otherwise insulated. 

Additional power supply filtering on the Nano may be help, as John suggested.
And caps to ground on the control signals from Nano to uBitx main board.

Would be interesting to move the uBitx BFO to the high side of the crystal filter, closer to 12mhz.
The tones will likely show up on most any uBitx, allowing countermeasures to be tested.

Currently the uBitx BFO is always below the crystal filter to avoid the tones, second LO always at 45-12mhz
Would be nice to  be able to switch sidebands by flipping the BFO to high or low side.
Could then have the second LO at either 45+12 or 45-12mhz, whichever gives fewer birdies
and other such artifacts. 

Jerry



On Fri, Feb 2, 2018 at 07:43 pm, John Backo wrote:
Actually, one could substitute any crystal from 8 MHz
to probably 20 MHz. Theoretically, running the arduino
changes the voltages to about 3.3v, but I and others have
noticed it works fine on 8 MHz and 5v. I would avoid anything
around 12 MHz as that is the USB frequency range and might
interfere. Easily had is a 10 MHz crystal which would probably work
fine. Even a HC49S type would work with just one jumper wire for
one lead (or maybe soldered direct), and the other pin soldered directly.
The old crystal would. of course, need to be removed.

A simple solution is to do what Jerry suggests, and change the BFO
frequency slightly. That may or may not cure the "symptoms"; it certainly
will not cure the problem.

It is likely that uPC crystal radiation is the problem, however. But it may be coming
from inside the radiuno itself. Sometimes (often) this because of Rf leakage back
through the power supply; make sure that is well filtered. Farhan's suggestion
of crystal aging is also very apropos.

Probably the next simplest solution is to replace the nano...

Re: AE7EU Top mod update

Diver Martin <diver.martin@...>
 

Well, damn if I didn't check the schematic like 15 times.  Apparently I ordered MCP601T's instead of MCP601RT's.  The difference?  VDD and VSS are swapped.

Explains why at 3V the current use went to 1A+.  Removing the two MCP601T's brought everything up.  So, no smoke at 12V now...  Baby steps!  The AGC mod will have to wait until I get parts in next week, but I can start debugging and programming other features in the meantime...


On Fri, Feb 2, 2018 at 11:11 AM, N8DAH <Dherron@...> wrote:
Looks great!
--
David

 N8DAH
Kit-Projects.com




--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

Re: uBITX AM BCI Filter #ubitx

Mike Woods
 

Nick

Looks good!   Have you cut tracks or removed parts?  Can you describe exactly where this has been inserted as I want to feature this on the ubitx.net website to help others insert a BCI filter in the RX input line.

73 Mike ZL1AXG

On 3/02/18 3:19 PM, Nick VK4PLN wrote:
My filerf implementation:


--
Mike Woods
mhwoods@...

Re: #ubitx-help Strong Audio Tones in and outside audio receive passband #ubitx-help

John Backo
 

Actually, one could substitute any crystal from 8 MHz
to probably 20 MHz. Theoretically, running the arduino
changes the voltages to about 3.3v, but I and others have
noticed it works fine on 8 MHz and 5v. I would avoid anything
around 12 MHz as that is the USB frequency range and might
interfere. Easily had is a 10 MHz crystal which would probably work
fine. Even a HC49S type would work with just one jumper wire for
one lead (or maybe soldered direct), and the other pin soldered directly.
The old crystal would. of course, need to be removed.

A simple solution is to do what Jerry suggests, and change the BFO
frequency slightly. That may or may not cure the "symptoms"; it certainly
will not cure the problem.

It is likely that uPC crystal radiation is the problem, however. But it may be coming
from inside the radiuno itself. Sometimes (often) this because of Rf leakage back
through the power supply; make sure that is well filtered. Farhan's suggestion
of crystal aging is also very apropos.

Probably the next simplest solution is to replace the nano...

john
AD5YE

Re: #ubitx-help Strong Audio Tones in and outside audio receive passband #ubitx-help

Jerry Gaffke
 

 Adding a cap across the 25mhz crystal (or adjusting the loading capacitance in the si5352 initialization code)
and going into calibration and adjusting the bfo setting both do the same thing.
They move the BFO frequency a bit down, further away from the 12mhz crystal filter passband.
(I'm assuming this 16mhz harmonic is above the 12mhz harmonic, as most raduinos have it)

I'd recommend trying the latter, as it is simpler. 
But however you do it, transmit and receive audio will change, becoming higher pitched.

I think the ideal solution would be to move the 16mhz Nano oscillator by a few khz.
If we're lucky, we can add capacitance in parallel with it and move it well below 16mhz.
Unfortunately it will have to move pretty far, as that 3'rd harmonic is going from above
the 4'th harmonic of the bfo (at 48mhz) to below the bfo harmonic. 
Pushing the 16mhz crystal up in frequency is more difficult to do, perhaps a series inductor.

Replacing the 16mhz crystal entirely might be best.
The max spec for the ATMega328P is 16mhz, so if it's a significantly different freq it should be lower.
Hard to get in the dinky form factor used on the Nano, but other crystal package sizes would be fine
if you hot glue it to the board and use short wires, being careful to keep the crystal case insulated.

Mouser has their 449-LFXTAL002057BULK which is 15.625mhz in stock, quite cheap and relatively small.
Also 449-LFXTAL003555BULK which is 15.81mhz, somewhat bigger.
Mouser 449-LFXTAL012514BULK is at 16.02355, I doubt the ATMega328P would notice it being out of spec.
That last one looks best to me.

The ones I show above are all pretty big physically, you might shop for smaller

Another possibility is to shield the Nano as best you can, try to keep that 16mhz from getting to the radio.
Perhaps grounding the 16mhz crystal case is all that is needed.
I doubt there is much 16mhz floating around there except the at the crystal and the two ATMega328P pins
that go to the crystal.

Jerry


On Fri, Feb 2, 2018 at 06:10 pm, Ashhar Farhan wrote:
I suspect the 16 mhz crystal must have aged. There are two things you can try. First is go into the bfo settings and move it slightly so the spurs go away. Second is to add some capacitance to the 25 mhz crystal, about 10 pf. There is a third way too, which is to program the si5352 initialization code to enable a different load capacitance on oscillator. I havent tried the third method myself.
 

Re: #ubitx-help Strong Audio Tones in and outside audio receive passband #ubitx-help

Gordon Gibby <ggibby@...>
 

I have programmed the initialization for various capacitances on the 25MHz Crystal, and it works, but if I remember correctly it didn’t move the frequency a whole lot.  However, since you’re looking at harmonics it might be enough.


On Feb 2, 2018, at 21:10, Ashhar Farhan <farhanbox@...> wrote:

Since we noticed these problems, we do check for the presence of these tones. Our pass test includes viewing the audio spectrum at 5v/db, 625 hz per division setting of FFT on rigol. We set the carrier so that the audio passband is inside two cursors at 300 hz and 3000 hz. Then we check for any spurs upto 15 khz that are above the noise floor. If these tests pass, we move to the next test of transmit outputs on 3.5, 7, 14 and 28 mhz. These tests are a part of the firmware being shipped.

I suspect the 16 mhz crystal must have aged. There are two things you can try. First is go into the bfo settings and move it slightly so the spurs go away. Second is to add some capacitance to the 25 mhz crystal, about 10 pf. There is a third way too, which is to program the si5352 initialization code to enable a different load capacitance on oscillator. I havent tried the third method myself.

Very often, closed commercial designs tend to ignore or bury design faults. Open source proceeds with acknowledgment and fixing these to make the system better. As the saying goes, given enough eyeballs, all bugs are shallow.

- f

On 3 Feb 2018 4:19 am, "Jerry Gaffke via Groups.Io" <jgaffke=yahoo.com@groups.io> wrote:
HFO's being off suggests the 25mhz crystal at the si5351 might be the problem on this one.
Regardless, it is probably a matter of 3'rd harmonic of the 16mhz nano oscillator
beating with the fourth harmonic 1.9985mhz bfo.
Tone should change when you bring your finger close to the very very dinky crystal near the nano's processor.
Will likely change when you bring your finger near the 25mhz ref crystal near the si5351 also.

I'd take a calibrated SW receiver, listen for the 16 and 25mhz oscillators, see if one is off frequency
then maybe try swapping out just that crystal.    Especially if that signal seems somewhat unstable.
A crystal in an entirely different package will probably work  if you keep the wires short.

If the 25mhz reference oscillator were unstable, that would make the ubitx receiver unstable also,
which I assume is not the case.  So best guess is John's 16mhz crystal near the Nano.

What exactly do you mean by "HFOs were off far enough to effect the signal by 8dB."
So, perhaps your BFO as shipped from HFSignals was far enough from the 12mhz crystal ladder filter
that signals were down by 8dB?  Or perhaps you updated your firmware, and lost the HFSignals calibration?

Jerry

On Fri, Feb 2, 2018 at 02:04 pm, Dave Bottom wrote:
John,
 
Thanks for your hard work.  My uBITX has the same exact issue with the "squeal".  Mine did not originally have this issue until a couple of weeks ago (received Dec 22) and now it has gotten worse over that time.
 
It is interesting that the HFOs were off far enough to effect the signal by 8dB. Something to check and maybe this should be part of alignment for each radio?  At least with a spectrum analyzer this won't be too hard.
Yes interested in your code for this test.  
 
So now when I have time I know what to try, although it doesn't sound like much fun changing the Nano.
 
Dave WI6R
 

Re: uBITX AM BCI Filter #ubitx

Nick VK4PP
 

My filerf implementation:

Re: uBITX AGC - Adafruit TPA2016, A Success! #ubitx

Nick VK4PP
 

Hi john, both boards from eBay...
I am really happy with the setup, AGC is performing very well in my opinion...

Re: #ubitx-help Strong Audio Tones in and outside audio receive passband #ubitx-help

Ashhar Farhan
 

Since we noticed these problems, we do check for the presence of these tones. Our pass test includes viewing the audio spectrum at 5v/db, 625 hz per division setting of FFT on rigol. We set the carrier so that the audio passband is inside two cursors at 300 hz and 3000 hz. Then we check for any spurs upto 15 khz that are above the noise floor. If these tests pass, we move to the next test of transmit outputs on 3.5, 7, 14 and 28 mhz. These tests are a part of the firmware being shipped.

I suspect the 16 mhz crystal must have aged. There are two things you can try. First is go into the bfo settings and move it slightly so the spurs go away. Second is to add some capacitance to the 25 mhz crystal, about 10 pf. There is a third way too, which is to program the si5352 initialization code to enable a different load capacitance on oscillator. I havent tried the third method myself.

Very often, closed commercial designs tend to ignore or bury design faults. Open source proceeds with acknowledgment and fixing these to make the system better. As the saying goes, given enough eyeballs, all bugs are shallow.

- f

On 3 Feb 2018 4:19 am, "Jerry Gaffke via Groups.Io" <jgaffke=yahoo.com@groups.io> wrote:
HFO's being off suggests the 25mhz crystal at the si5351 might be the problem on this one.
Regardless, it is probably a matter of 3'rd harmonic of the 16mhz nano oscillator
beating with the fourth harmonic 1.9985mhz bfo.
Tone should change when you bring your finger close to the very very dinky crystal near the nano's processor.
Will likely change when you bring your finger near the 25mhz ref crystal near the si5351 also.

I'd take a calibrated SW receiver, listen for the 16 and 25mhz oscillators, see if one is off frequency
then maybe try swapping out just that crystal.    Especially if that signal seems somewhat unstable.
A crystal in an entirely different package will probably work  if you keep the wires short.

If the 25mhz reference oscillator were unstable, that would make the ubitx receiver unstable also,
which I assume is not the case.  So best guess is John's 16mhz crystal near the Nano.

What exactly do you mean by "HFOs were off far enough to effect the signal by 8dB."
So, perhaps your BFO as shipped from HFSignals was far enough from the 12mhz crystal ladder filter
that signals were down by 8dB?  Or perhaps you updated your firmware, and lost the HFSignals calibration?

Jerry

On Fri, Feb 2, 2018 at 02:04 pm, Dave Bottom wrote:
John,
 
Thanks for your hard work.  My uBITX has the same exact issue with the "squeal".  Mine did not originally have this issue until a couple of weeks ago (received Dec 22) and now it has gotten worse over that time.
 
It is interesting that the HFOs were off far enough to effect the signal by 8dB. Something to check and maybe this should be part of alignment for each radio?  At least with a spectrum analyzer this won't be too hard.
Yes interested in your code for this test.  
 
So now when I have time I know what to try, although it doesn't sound like much fun changing the Nano.
 
Dave WI6R
 

Re: #ubitx Current draw when transmitting? #ubitx

Ghericoan
 

When just receiving, the current drawis only 0.16A. When I go to transmit it runs around 1.4-1.8 amps depending on the SWR. I have a 2A fuse inline with the power feeding both the radio and final amplifier. I was just wondering if that current draw on transmit sounds about right, cause it also varies by band, with a significant drop on 30 meters to only 1.01 amps transmit. 

On the other hand, skipping my antenna tuner brings the current draw up to nearly 2.2 amps, but thats most likely from the resulting SWR cause the finals run toasty in that condition. 
--
----------
N5WLF, Greggory (or my nickname, Ghericoan)
General Class, Digital Radio Hobbyist

Re: Diy oscilloscope #parts

Jerry Gaffke
 

My cloud of dots would be a silly way to try and see an RF signal's envelope.
Instead, spend $0.10 on a diode, resistor and a cap or two for an RF probe (or AM detector).
The RC low pass filter should have a corner freq of 100khz instead of 1Hz,
as we will be watching the output with a DSO138 instead of a DVM.

That's probably more what Dexter had in mind when he suggested
watching RF envelopes with the DSO138.

Jerry



On Thu, Feb 1, 2018 at 07:30 pm, Jerry Gaffke wrote:
Could see Dexter's modulation envelope on sub 1mhz RF as a cloud of dots,
accumulating that cloud over many trigger events. 

Re: #ubitx Current draw when transmitting? #ubitx

jsullivan10512016@...
 

In all the  writing  on ubitx website, I read that the power supply should supply  up to 3 amps, but elsewhere, on same site, I read that  the 12 volt regulated line should be fused, at  2 to 2.5 amps.    Do you get  same range, of 1.4 to 1.8 amps, when transmitting, as I suspect transmit mode will probably draw more current than in receive mode?    I tend to think that 2 amp fast blow fuse; perhaps 2.5 A at the most, is appropriate.

#ubitx Current draw when transmitting? #ubitx

Ghericoan
 

Been using the ubitx to transmit digital modes such as WSPR and PSK31, however the current draw
has me wondering. I've searched around but haven't found a clear answer on what the ubitx should
pulling for amperage on 12 volts. I get in the range of 1.4-1.8 amps, SWR depending; is this correct?
--
----------
N5WLF, Greggory (or my nickname, Ghericoan)
General Class, Digital Radio Hobbyist

Re: [uBITX] How to adjust CW sidetone volume? #ubitx

Rod Davis
 

Hi Dean,

Just yesterday I changed R250 (the input of the low-pass network for the sidetone) from 1k to 220k, and my sidetone is comfortably low at full volume.

100k probably would have been better, as the sidetone is a bit weak.

I only had 0805 parts, but they fit just fine on 1206 pads. No worries.

Good Luck,

Rod KM6SN




On 02/02/2018 03:23 PM, K5DH wrote:
Is it possible to adjust the CW sidetone volume in the uBITX?  I'm finding that if I have the volume turned up to hear a weak station and I hit the key to respond, my sidetone will be ear-splitting.  Any easy way to fix this? 

73/72,
Dean K5DH
uBITX msn 279

[uBITX] How to adjust CW sidetone volume? #ubitx

K5DH
 

Is it possible to adjust the CW sidetone volume in the uBITX?  I'm finding that if I have the volume turned up to hear a weak station and I hit the key to respond, my sidetone will be ear-splitting.  Any easy way to fix this? 

73/72,
Dean K5DH
uBITX msn 279

Re: #ubitx-help Strong Audio Tones in and outside audio receive passband #ubitx-help

Jerry Gaffke
 

HFO's being off suggests the 25mhz crystal at the si5351 might be the problem on this one.
Regardless, it is probably a matter of 3'rd harmonic of the 16mhz nano oscillator
beating with the fourth harmonic 1.9985mhz bfo.
Tone should change when you bring your finger close to the very very dinky crystal near the nano's processor.
Will likely change when you bring your finger near the 25mhz ref crystal near the si5351 also.

I'd take a calibrated SW receiver, listen for the 16 and 25mhz oscillators, see if one is off frequency
then maybe try swapping out just that crystal.    Especially if that signal seems somewhat unstable.
A crystal in an entirely different package will probably work  if you keep the wires short.

If the 25mhz reference oscillator were unstable, that would make the ubitx receiver unstable also,
which I assume is not the case.  So best guess is John's 16mhz crystal near the Nano.

What exactly do you mean by "HFOs were off far enough to effect the signal by 8dB."
So, perhaps your BFO as shipped from HFSignals was far enough from the 12mhz crystal ladder filter
that signals were down by 8dB?  Or perhaps you updated your firmware, and lost the HFSignals calibration?

Jerry


On Fri, Feb 2, 2018 at 02:04 pm, Dave Bottom wrote:
John,
 
Thanks for your hard work.  My uBITX has the same exact issue with the "squeal".  Mine did not originally have this issue until a couple of weeks ago (received Dec 22) and now it has gotten worse over that time.
 
It is interesting that the HFOs were off far enough to effect the signal by 8dB. Something to check and maybe this should be part of alignment for each radio?  At least with a spectrum analyzer this won't be too hard.
Yes interested in your code for this test.  
 
So now when I have time I know what to try, although it doesn't sound like much fun changing the Nano.
 
Dave WI6R
 

Re: uBITX Firmware (CEC) 0.30 released (Test version). #ubitx

Philip
 

I am going to try disconnecting the 5 Volts on the USB, as it is power up the display via the USB lead.

Ian thanks for the great firmware

Re: Accident, Did I damage my Raduino

AA7GW
 

The old carpenter’s rule!

AA7GW

On Feb 2, 2018, at 9:44 AM, David Nelson <kc2ipx@...> wrote:

The 8 pin and the 5 pin both have an orange wire. Easy to get confused.  Dave


On Fri, Feb 2, 2018 at 11:40 AM, Michael Hagen <motdog@...> wrote:

I would recommend in building these radios that you change All ground wires to Black and All Power (5 or 12V) to Red.

Reserve these colors for just 2 purposes.

You can use the wires you remove for additions.  Leave the molex pin on them.  I had a lot of spare Brown ones.

I can't stand an Orange wire being B+ (the term for us old Valve guys)!  26 Ga. stranded works great.   I got a bunch of colors at All Electronics.  Molex pins are at Tayda and Mouser.

You don't have to be in such a hurry and blow things up.  Check your wiring several times.  You could even make a connector chart with J numbers and pin numbers with wire color.   Match it up to what is on hfsignals.   It may mean you catch a mistake and save a lot of trouble shooting?

73'3

Mike,  WA6ISP


On 2/2/2018 8:03 AM, Richard Sanders wrote:
You are not alone! I had my bitx40 in pieces on my benchtop and wired the raduino using the orange I/O wire instead of the orange +12v wire...powered on....got nothing on my LCD...turned off...checked wiring...turned on a second time...still nothing...turned off...THEN I saw what I did wrong....it wasn't until I had reflashed the v2 software the I finally figured out why my unit keeps going to the Settings menu....it thinks that I am holding the function button down upon power up! With the button uninstalled I check the power of the orange A3 wire and am getting 0v!! :-( So I'm going to try and remap a different pin for the Function button...if that does not work or if I find that I actually damaged more than the I/O pin...then I'll go the "New Arduino Nano" route! Best of luck to all who are experimenting with the bitx's out there!!

73
Ric
KN4FTT

-- 
Mike Hagen, WA6ISP
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