Date   

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

Jerry Gaffke
 

Wrong.     This part that  reads
    <<   second LO always at 45-12mhz
should say
   second LO is at 45-12=33mhz for LSB  and  45+12=57mhz for USB

Leaving the second LO parked at 57mhz will likely give fewer birdies.

Jerry



On Fri, Feb 2, 2018 at 11:48 pm, Jerry Gaffke wrote:
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. 


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

Arv Evans
 

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.

The 16mhz ATMega328P crystal is about 3mm x 1.5mm, goes to  ATMega328p pins 7 and 8.
It is on the top of the Nano, just above the silk for edge pin D5.
Seeing the actual crystal now, and not just looking at datasheets and schematics, I see that it is
extremely small.   I doubt most of those with uBitx in hand will want to mess with it.

I bought some spare Nano clones, I believe they're identical to what's on the Raduino.
Mine have a CH340G chip on the back of the Nano for the USB interface.
This chip has another 3mm x 1.5mm crystal nearby, this one happens to be 12mhz.
    http://www.datasheet5.com/pdf-local-2195953

Quite possibly it is the 12mhz oscillator for the USB interface that is causing the trouble in at least some cases.
Though in post 40432 it was reported that a finger on the Nano's crystal caused the tones to vary,
which suggests that case was due to the 16mhz crystal since the 12mhz crystal is not usually accessible.

None of this was ever a problem on the Bitx40v3, far as I know.
I'd like to think there will be a simple fix, perhaps soldering in a bit of copper tape somewhere for shielding,
or adding a few caps.    Moving the IF would be pretty disruptive.

Jerry



On Fri, Feb 2, 2018 at 11:55 pm, Ashhar Farhan 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.
 



Re: BitX40 v1.27.7 SPOT mode

Allard PE1NWL
 

Vic,

There's nothing wrong, it's just a matter of rounding.
In SPOT/Fine tune mode, the display shows the actual frequency at 1 Hz
precision. In normal mode the precision is 100 Hz, so we need to round the
number to the nearest 100 Hz.
So if the real frequency (as shown in fine tune mode) is for example
7.254.955 Hz, it will be rounded to 7.255.0 on the display in normal mode.

Rounding is performed as follows:
f(display) = int ( f(actual) + 50 )

73 Allard PE1NWL

On Sat, February 3, 2018 12:33, Vic WA4THR via Groups.Io wrote:
I am using Allard's wonderful v1.27.7 sketch in my BitX40, and because of
an trip planned this weekend was rushing to package it so it could be
used. I have added the PTT sense line, a FCN switch, and a SPOT switch,
and have significantly shortened leads in this final package. Everything
seems to be working well and I was able to use the rig mobile. When I
press SPOT I am able to fine tune in LSB mode very easily, but the
frequency displayed in SPOT mode differs from what the normal display
shows. For example, if I am on 7.255.00 and press SPOT, the display reads
7.254.955, so if I tune that to 7.255.00 and release SPOT I get 7.255.05
on the normal display. Am I doing something wrong? Is there some sort of
offset in LSB SPOT that needs to be adjusted?

 

73, =Vic=

WA4THR


New file uploaded to BITX20@groups.io

BITX20@groups.io Notification <BITX20+notification@...>
 

Hello,

This email message is a notification to let you know that a file has been uploaded to the Files area of the BITX20@groups.io group.

File: I designed this case for the uBITX all Band Transceiver.pdf

Uploaded By: Carl Beck

Description:
Case designed for uBITX

You can access this file at the URL:
https://groups.io/g/BITX20/files/I%20designed%20this%20case%20for%20the%20uBITX%20all%20Band%20Transceiver.pdf

Cheers,
The Groups.io Team


Re: Nextion display

馬玉麟
 

Thanks for your suggestion.

2018-02-03 19:12 GMT+08:00 Dr Fred Hambrecht <w4jle@...>:

For those that may be considering the Nextion display, let me suggest you start out by going to their website Https://nextion.itead.cc On the home page select download and select the Nextion editor.
This will give you a chance to play without spending any money on buying the actual display but allows you simulate the display and see if it meets your needs.

V/R
Fred W4JLE



BitX40 v1.27.7 SPOT mode

Vic WA4THR
 

I am using Allard's wonderful v1.27.7 sketch in my BitX40, and because of an trip planned this weekend was rushing to package it so it could be used. I have added the PTT sense line, a FCN switch, and a SPOT switch, and have significantly shortened leads in this final package. Everything seems to be working well and I was able to use the rig mobile. When I press SPOT I am able to fine tune in LSB mode very easily, but the frequency displayed in SPOT mode differs from what the normal display shows. For example, if I am on 7.255.00 and press SPOT, the display reads 7.254.955, so if I tune that to 7.255.00 and release SPOT I get 7.255.05 on the normal display. Am I doing something wrong? Is there some sort of offset in LSB SPOT that needs to be adjusted?

 

73, =Vic=

WA4THR


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

John <passionfruit88@...>
 

Thanks Nick.

73, John


Nextion display

Dr Fred Hambrecht
 

For those that may be considering the Nextion display, let me suggest you start out by going to their website Https://nextion.itead.cc On the home page select download and select the Nextion editor.
This will give you a chance to play without spending any money on buying the actual display but allows you simulate the display and see if it meets your needs.

V/R
Fred W4JLE


Re: uBITX AM BCI Filter #ubitx

Nick VK4PP
 

HI Mike and the group.

Yes I cut the trace either side of the new HPF board, exposed a bit of the trace and jumperd onto that.
You need to cut the second trace from the PA side. They are in order:
1: TX pwr to the PA circuits via R89
2: RX path (between K1 and K3 relays. (CUT AND INSERT HERE)
3: TX pwr to the LPF bank.
4: RX pwr to the receive circuit (R18,R38...)

I picked up GND from the 2 unused caps C216 and C210
Filter Details: https://groups.io/g/BITX20/wiki/uBITX-AM-BCI-Filter

73, Nick. VK4PLN


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

MVS Sarma
 

sorry for my typing sir. I meant 9MHz crystal ladder filter.


Regards
MVS Sarma
 

On Sat, Feb 3, 2018 at 1:35 PM, Ashhar Farhan <farhanbox@...> wrote:
yes, sarma-ji.
- f

On Sat, Feb 3, 2018 at 1:30 PM, Mvs Sarma <mvssarma@...> wrote:
Farhan jee
You mean 11.0592....MHz
 Can one use (MHz as most rigs had ssb filters around that? Of course with needed changes in Raduino.
regards
 sarma
 vu3zmv

Regards
MVS Sarma
 

On Sat, Feb 3, 2018 at 1:27 PM, Ashhar Farhan <farhanbox@...> wrote:
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

Jerry Gaffke
 

I assume you mean changing the Arduino crystal, not cap.

The 16mhz ATMega328P crystal is about 3mm x 1.5mm, goes to  ATMega328p pins 7 and 8.
It is on the top of the Nano, just above the silk for edge pin D5.
Seeing the actual crystal now, and not just looking at datasheets and schematics, I see that it is
extremely small.   I doubt most of those with uBitx in hand will want to mess with it.

I bought some spare Nano clones, I believe they're identical to what's on the Raduino.
Mine have a CH340G chip on the back of the Nano for the USB interface.
This chip has another 3mm x 1.5mm crystal nearby, this one happens to be 12mhz.
    http://www.datasheet5.com/pdf-local-2195953

Quite possibly it is the 12mhz oscillator for the USB interface that is causing the trouble in at least some cases.
Though in post 40432 it was reported that a finger on the Nano's crystal caused the tones to vary,
which suggests that case was due to the 16mhz crystal since the 12mhz crystal is not usually accessible.

None of this was ever a problem on the Bitx40v3, far as I know.
I'd like to think there will be a simple fix, perhaps soldering in a bit of copper tape somewhere for shielding,
or adding a few caps.    Moving the IF would be pretty disruptive.

Jerry



On Fri, Feb 2, 2018 at 11:55 pm, Ashhar Farhan 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.
 


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

John Backo
 

I substituted 11.092 MHz for 10 MHz in a build of the BITX v.3.

It decoded both 40m and 20m very well, just by changing the
BFO from LO to HI. And the VFO had to be spread out a bit.
Of course, 40m tuned in reverse, but it works..

I figured out that the best IF would be ~10.5 MHz as this gives nearly
a symmetric VFO/BFO mirror (in the spirit of the 9 MHz 20/80m classic rig).
But such crystals are unobtanium. Hi.

john
AD5YE


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

Ashhar Farhan
 

yes, sarma-ji.
- f

On Sat, Feb 3, 2018 at 1:30 PM, Mvs Sarma <mvssarma@...> wrote:
Farhan jee
You mean 11.0592....MHz
 Can one use (MHz as most rigs had ssb filters around that? Of course with needed changes in Raduino.
regards
 sarma
 vu3zmv

Regards
MVS Sarma
 

On Sat, Feb 3, 2018 at 1:27 PM, Ashhar Farhan <farhanbox@...> wrote:
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

MVS Sarma
 

Farhan jee
You mean 11.0592....MHz
 Can one use (MHz as most rigs had ssb filters around that? Of course with needed changes in Raduino.
regards
 sarma
 vu3zmv

Regards
MVS Sarma
 

On Sat, Feb 3, 2018 at 1:27 PM, Ashhar Farhan <farhanbox@...> wrote:
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
 

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