Date   
Re: Audio squealing

Jerry Gaffke
 

If the squeal on your lm386 only happens when the volume pot is at low settings,
you may need Raj's resistor between pot wiper and LM386 pin 3:
    https://groups.io/g/BITX20/message/32372

The LM386 can behave badly when pin 3 is nailed to ground. 

Re: Removing nano from radiuno #nano #radiuno #ubitx

Jason Schlager
 

Not pretty but I took some diagonal cutters to the nano and removed it from the radiuno board.  Then removed the pins one by one with soldering iron.  Thanks for the tips though.
--
Jason Schlager
KM6AUS

Re: Audio squealing

Jerry Gaffke
 

A more concise post from Raj:
  https://groups.io/g/BITX20/message/32154


On Mon, Apr 9, 2018 at 01:07 pm, Jerry Gaffke wrote:
If the squeal on your lm386 only happens when the volume pot is at low settings,
you may need Raj's resistor between pot wiper and LM386 pin 3:
    https://groups.io/g/BITX20/message/32372

The LM386 can behave badly when pin 3 is nailed to ground. 

How to wire up the PTT push button supplied with my uBitx kit

Frank PA7F
 

Hallo group,

My uBitx kit was supplied with a tiny push button, I suppose its purpose is to make uBitx go into transmit (PTT). I' m not sure how I should wire it up. Do I put it in the blue wire going from the mic ground lug to GND on the audio connector? Or in the orange wire going from PTT on the digital connector to the mic socket leftmost tab? 

Frank PA7F

Re: TDA2822 Audio problem #ubitx #tda2822

Jason Schlager
 

Removed and replaced nano.  Unfortunately that was rather destructive for the nano.  Now the noise peak moved from 9khz to 11khz.  So next change may need to be a filter. 
--
Jason Schlager
KM6AUS

Re: Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch. #ubitx

qrper72@...
 

Good Morning dear John,
Thanks a lot for your information.
Well I modified your suggested code as below;

//int sMeterLevels[] = {0, 5, 17, 41, 74, 140, 255, 365, 470}; original
int sMeterLevels[] = {0, 3, 10, 25, 54, 100, 195, 291, 403}; modified

To be a little bit more sensitive setting. It's fairly good!
But my uBITX has a strong internal spurious around 6.994MHz so the s-meter indicate "S8" from 7.000 to 7.050MHz, this is independent issue from firmware. hi...

And about the IAMBIC keyer I tested the original Ian's version and it was "bad". Not correct iambic operation I think. I'm also using the latest Ian's firmware 1.06 or 1.07 and it works well about the iambic keyer so please confirm.

Thanks Hidehiko, ja9mat

Re: Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch. #ubitx

qrper72@...
 

Sorry John,
I confirm Ian's 1.06 and 1.07. And I found that both code does not work iambic mode correctly. It maybe an original issue...

Hidehiko ja9mat

Re: Micro bitx in the spectrum analyzer #ubitx

Tim Gorman
 

Mine too runs at about -40db for the 3rd harmonic of 3920khz. Good but
not quite good enough. On a two-tone test My carrier suppression is
only about 20db and the 3rd harmonic on a two-tone test is not the best
either at about 34db.

For a 10 watt peanut whistle I'm not worrying a great deal. Using an
outboard filter is an option.

tim ab0wr

On Mon, 09 Apr 2018 07:17:19 -0700
"Don, ND6T via Groups.Io" <nd6t_6=yahoo.com@groups.io> wrote:

Yes, FCC requires -43dBc for these frequencies. My preliminary
measurements (back in December) revealed that, although close, my
unit didn't meet those specifications. Close, but not quite.
Therefore I use an outboard filter until I can find time for an easy
solution. Admittedly, I have not revisited the problem yet and have
made several changes in my case and so should do that shortly. Screen
shots are attached. Worst case was 30m with just less than -36 dBc. I
don't like to bring up a problem without having a solution prepared
but there it is. Sorry. 73, Don

Re: Raduino no longer recognized by PC

KB2HSH
 

Yep. Multiple USB ports and different laptops. Same outcome. The display lights and powers the rig, but, no luck communicating with it. If it IS deaf and unable to sync with the laptop, at least the software is updated and the rig is operational. 

Re: Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch. #ubitx

John <passionfruit88@...>
 

Hello Hidehiko-san,

No, I am sure Ian's code is working. So we have to look at the hardware side.

It may be quite possible that the value read when you press both side of the paddle is not within the default limits in the software.

To calibrate the values, use the "ADC Line Monitor" and record the values you have when you press the dot side of the paddle, the dash side and then both together.

Record only the values of the analogue input where you have your paddle connected to (A6 by default, A3 if you have moved the paddle to PTT  to free the A6 input).

Then using the uBitx Memory manager program, you can enter the ranges for the detection of the three values, making sure they don't overlap. Then upload to the uBitx.

Here are the default ranges:

Both From = 51, To = 300;
Dot From = 301, To = 600
Dash From = 601, To = 800

uBitx manager is at http://www.hamskey.com/2018/03/cat-support-ubitx-firmware-cec-version_24.html

All the best,

73, John (VK2ETA)

Re: AGC circuit to try?

Tim Gorman
 

On Mon, 09 Apr 2018 09:46:58 -0700
"ajparent1" <kb1gmx@...> wrote:

The mixer is a 200 ohm design. T1 is a 2:1 turns ratio or a 4:1
impedance conversion, i.e. 200/4 = 50 ohm. The 6db pad consisting of
R101, R102, and R103 is a 50ohm pad left-to-right and right-to-left so
it helps isolate the mixer and the amplifier but the input resistance
of the amplifier will impact the effectiveness of the pad at impedance
matching.<<<<

No. It is a bog stock 50 ohms DBM assuming reasonable LO drive.
All ports are expected to be loaded to 50 ohms give or take.  Further
the 6db pad is there because the si5351 output impedance is not 50
ohms and its level needs to be reduced.
I think we are talking two different things. I mentioned T1 and 200ohms
but t2 is the exact same thing. It converts the 50ohm RF into 200ohms
for the mixer. Thus all ports are working at the same impedance which
provides maximum isolation.

But since there is no 50pad isolation from T2 to Q10 then Q10 is most
likely to work the best with a 200ohm base impedance.



What your 50 or 66 ohm comments miss is the transistors reflected
impedances are already loaded against the 200+ ohms of external
circuit components.  So in all cases your do not get 50 ohms based
solely on gain and emitter resistance.   Nor is it that critical.
You are correct for the receive side. The impedance seen is 200ohm, not
50 ohm. But changing the emitter resistor will affect that 200ohm
impedance which means the mixer port will be be at something other than
200ohm.


The TIA is a fair amplifier but like all resistive feedback amps its
gain bandwidth are very dependent on the devices used.  Because of
the resistive feedback the device noise figure is is contributory but
less so as the resistors themselves are noise contributors.   The
choice of bias and feed back not only controls the operating input
impedance the output circuit however is not controlled by that. The
output impedance is limited only be the emitter resistor and the
current thought the output device. At best the output impedance is
lower than desired for 50 ohm systems (why the 47 ohm resistor is
there).  It does however limit the effect of output load change due
to the current gain of the stacked pair and makes the 330 ohm
collector resistor of the first device the effective load.  This
stabilizes the output load and allows the feedback to determine the
input impedance along with the parallel effect of the bias
resistors.  Varying the gain by altering the emitter degeneration
then has a reduced effect on impedances as the negative feed back is
dominant.  
The 3rd harmonic of the carrier and the 3rd harmonic in a two-tone test
for this transmitter barely meet acceptable standards. I wonder how
much of this is from not being consistent with mixer port terminations?



EMRFD does not give the full equation for this but if you assume a
constant load of 330 ohms you can test this in any spread sheet.  

In actual practice I've tested it with a variation of that amp at
20db gain and the measured input never was 50 ohms despite math
predicting that.  Over the range of 3 to 50 mhz it underwent a near
1.7:1 change starting at 54 ohms (swr of 1.08 or return loss of
better than 24db) down to 35 ohms (swr 1.45:1 return loss of 17db )
using 2n5019 (ft 1200mhz) as the device.  Part of the change was the
unmodeled board level parasitics making the input a complex value.
 Changing to 2n3904 caused degradation starting at 25mhz and becoming
notable at 30mhz  which is fair for a device of 300mhz ft.  If the
device cannot make the gain the impedance drifts from predicted
point. Also the commonly used models generally do not include
parasitics, Genesys with the correct spice models for devices and
board modeling gets very close but its expensive and like most
modeling software gigo (guesses in garbage out) prevails. 

The measurements for a project were done using a Aligilent 8357A
programmable network analyser as it was handy.  Those types of
measurements could easily be done with a return loss bridge, signal
source, and a spectrum analyser.  The Rigol 815T is very suitable.

In that circuit varying the gain had an effect but was limited.
There was no significant change at the output (determined by bias to
the devices) and input change limited by the gain of the device and
feed back.  For my case it was a 20db amp.  The uBtx design center of
about 17db it is expected to show less variation due to higher
feedback.   For the 20DB case and higher values of resistor values
for bias and feedback I did see variation for near 3:1 at the higher
frequencies.  But those changes if loaded with the reverse direction
amp resistors and the 1K at the CW injection point (R25, 26, 27, a
nodal value of 340ohms)  as appears in the ubitx would result in that
case to under 2:1.  This is within the accept range for most DBMs
excepting those in more critical designs.   This is not a critical
design and tolerates it well.  Further the discrete DBMs are in
general better than commercial an example where an amateur can do
better in specific cases.
R25, R26, and R27 are also in parallel with R105, R10, and R11 on
transmit. The nodal impedance on transmit will be about the same as for
receive.

The output of this transmitter is not the cleanest. It is acceptable to
me but I wouldn't brag about it being better than with commercial DBM's.

For this I'm not guessing.  I'm not running on speculation, I have
knowledge from modeling, constructing, testing, and practical
experience of verifying in commercial and hobby spaces. That and I've
built enough radios to know and measure what does and does work and
what can be problematic.  

Allison
I'm sure you have. But I have done quite a bit on my own as well. I
know from experience that not being careful with mixer port
terminations can result in all kinds of problems. I've always worked on
80m and 40m stuff useful for local work on nets and such. So I've never
worried much about the high freq gain of the IF and RF transistors
causing problems. Even the lowly 3904 and 2222 work pretty well at 3mhz
and 7mhz.

tim ab0wr

Re: How to wire up the PTT push button supplied with my uBitx kit

Jerry Gaffke
 

Yes, the tiny button goes between the orange PTT wire and ground.

The microphone element supplied works well, be careful to get polarity right.
Many here mount that microphone element in a large felt tip pen barrel
or some plastic plumbing pipe.  
The switch works, but is small as you note.  Perhaps cover it with a piece of hard plastic
so you have a larger area to press with your fingers, hinge that plastic with a piece
of adhesive tape to your microphone barrel.

Others buy a Baofeng  mike (may wind up being a Baofeng clone) on the web somewhere.
Some of those mikes require a hole drilled over the microphone cover to let some sound in.

Jerry


On Mon, Apr 9, 2018 at 01:14 pm, Frank PA7F wrote:
My uBitx kit was supplied with a tiny push button, I suppose its purpose is to make uBitx go into transmit (PTT). I' m not sure how I should wire it up. Do I put it in the blue wire going from the mic ground lug to GND on the audio connector? Or in the orange wire going from PTT on the digital connector to the mic socket leftmost tab? 

Frank PA7F

Re: How to wire up the PTT push button supplied with my uBitx kit

Randy
 

mic

Re: TDA2822 Audio problem #ubitx #tda2822

John <passionfruit88@...>
 

Hello Jason,

On mine, I noticed that the tone frequency would change the most when I adjusted the BFO frequency.

If you re-calibrate the BFO to a slightly different frequency, does you tone move as well?

A more complete test would be to try Ian Lee's software version 1.61 and use the IF Shift function to see if that moves your tone.

If it does, you could try to shift the IF so that the lower frequencies are emphasised and continue in the same direction until you have reversed the sideband. If in that position, after swapping the sideband in the menu you can receive signal properly without an audible tone, then we can look at swapping them in software.

If this does not work, you could try to move the first IF instead.  You could load the test version I uploaded in the files section in the  "Software based IF attenuation" folder and through the menu change the first IF and see if your tone moves in frequency.

Then we can it from there.

Good luck. This issue drove me nuts...lol.

73, John (VK2ETA)

Re: Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch. #ubitx

qrper72@...
 

Hello,
Well Ian's firmware is OK when I disconnect the PTT to Keyer connection as you said. Sorry John and Ian for my mistake. I will try to set the parameter with uBitx manage.
73,ja9mat Hidehiko.

Re: Raduino no longer recognized by PC

Ross - VA1KAY
 

Same cable?


On Mon, Apr 9, 2018 at 6:16 PM KB2HSH <john.marranca@...> wrote:
Yep. Multiple USB ports and different laptops. Same outcome. The display lights and powers the rig, but, no luck communicating with it. If it IS deaf and unable to sync with the laptop, at least the software is updated and the rig is operational. 

Re: Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch. #ubitx

Tim Gorman
 

Thanks for confirming what I found. I have pitched two controller
backpacks that didn't work. The third one is the one I have now and it
appears to be working.

I'm not sure where one can buy quality, tested backpacks. I am now
leery of the ones from China.

tim ab0wr

On Mon, 9 Apr 2018 13:27:32 -0500
"K9HZ" <@Doc_Bill> wrote:

After your last reply yesterday i went through my entire stash of
1602 displays with I2C converter boards on the back of them. Sure
enough two of them didn't work right and now i have the task to
figure out why. Maybe bad I2C to paint parallel chips, bit at least
now I have them marked as failures.


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ
Owner - Operator
Big Signal Ranch – K9ZC
Staunton, Illinois

Owner – Operator
Villa Grand Piton - J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com

email: @Doc_Bill


On Apr 9, 2018, at 9:10 AM, Tim Gorman <tgorman2@...> wrote:

I changed out the nano and the lcd interface board.

Now the display works but the software has a problem. It
initializes in CW mode at 7250khz. The encoder will not change the
frequency. The function switch does put the unit into menu mode and
you can change the mode to LSB, USB, etc but when you turn the
encoder it jumps back to CW at 7250khz. Other menu choices can be
accessed, e.g. band, channel to vfo, etc. Changing band to 80 still
leaves the unit in CW at 7250khz.

This is the 1.07 software.

Still works fine with the w0eb el al. software.

I'm going to try John's software to see if elminating some options
might change things.

More troubleshooting ahead I guess.

tim ab0wr

On Sun, 8 Apr 2018 11:53:11 -0500
"K9HZ" <@Doc_Bill> wrote:

Ok then it must be a difference in the controllers we are using.
Mine works with both Ian's software and the W0EB release. I can't
explain why that would be...


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ

Owner - Operator
Big Signal Ranch – K9ZC
Staunton, Illinois

Owner – Operator
Villa Grand Piton – J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com
Like us on Facebook!

Moderator – North American QRO Yahoo Group.

email: @Doc_Bill




Re: Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch. #ubitx

Tim Gorman
 

In my case two of three of my controllers worked with w0eb software but
not with CEC software. The third one seems to be working with both.

So I don't think it is the i2c address that is the problem.

I got all three of my backpacks from the same supplier in China. I
haven't had a chance to check all three for any differences.

tim ab0wr

On Mon, 09 Apr 2018 11:42:34 -0700
"Jerry Gaffke via Groups.Io" <jgaffke=yahoo.com@groups.io> wrote:

Do all those i2c displays have the same serial-to-parallel chip?
Have you scanned them all to ensure they are have same i2c device
address? Even displays from the same vendor can arrived configured
for different addresses.

I find it curious that some liquidcrystal_i2c libraries have you
specify the parallel pins out of that serial-to-parallel chip, and
some don't. Perhaps some i2c backpack boards have the parallel pins
wired up to the display differently.

Jerry, KE7ER

On Mon, Apr 9, 2018 at 11:27 am, K9HZ wrote:


After your last reply yesterday i went through my entire stash of
1602 displays with I2C converter boards on the back of them. Sure
enough two of them didn't work right and now i have the task to
figure out why. Maybe bad I2C to paint parallel chips, bit at least
now I have them marked as failures.  

 

Transformer pins 1&6: floating, grounded or "whatever"?

Michael LeBlanc
 

I'm hand-assembling the uBITX: the schematic for some toroid trifilar transformers shows apparently unused coils, indicated by an 'x' at the coil ends. Does this indicate that the wire ends are floating, should they be grounded, or does it not matter?

-Michael VE1LEB

Re: Transformer pins 1&6: floating, grounded or "whatever"?

M Garza <mgarza896@...>
 

Hi Michael,
These are floating.  You could also just make the transformer with a bifilar winding.

Hope this helps.

Marco - KG5PRT

On Mon, Apr 9, 2018 at 7:22 PM, Michael LeBlanc <michaelleblanc1@...> wrote:
I'm hand-assembling the uBITX: the schematic for some toroid trifilar transformers shows apparently unused coils, indicated by an 'x' at the coil ends. Does this indicate that the wire ends are floating, should they be grounded, or does it not matter?

-Michael VE1LEB