Date   
Re: Homebrew from scratch #ubitx

Peter Carr
 

Here is the finished board with the on board Arduino and Si5351 alongside an original uBITX.

Re: Bitx40 75KHz Spurious, How to solve it. #bitx40

jj1epe@...
 

Hi!

Thank you for your comment and advice.

My friend have found the cause of spurious of 75 KHz.
He said the cause of spurious was the noise of VCC around 19 MHz of 0.15V.
As the result of the modifications of Bitx40 to reduce the noise, such as adding the big condenser and choke coil etc , the spurious level went down below of the criteria.

By this modification, my Bitx40 meets the criteria of the spurious of Japanese regulation.
So I am going to submit the application for obtaining the certification of Bitx40 from the relevant authority.

There are two criteria for the spurious.
   1)  Baseband area :  under -40db of power of fundamental frequency
            This frequency range is the 2.5 x  occupied band of frequency of TX mode.
   2) Spurious area :  under -50db of power of fundamental frequency.
           This frequency range is the out of Baseband area for super harmonic spurious.

The attached files are
  1) The picture of noise of VCC
 2) The picture of Spurious of 50KHz/div after the modification.
 3) The picture how the modification were added.

73!
Akira
JJ1EPE






Re: KD8CEC Firmware

Glenn
 

What about the Nextion code Ian?


On Sun, Jul 1, 2018 at 06:10 pm, Ian Lee wrote:
Thanks for your interresting.
You can get it from the link below
 
See the Release section for more convenience.
 
Ian KD8CEC
 

2018-07-02 10:07 GMT+09:00 MadRadioModder <madradiomodder@...>:
Where did you find it?

 

 


--
Best 73
KD8CEC / Ph.D ian lee
kd8cec@...
www.hamskey.com (my blog)

Re: Bitx40 75KHz Spurious, How to solve it. #bitx40

Allard PE1NWL
 

Hi Akira san,

thanks for your update:

He said the cause of spurious was the noise of VCC around 19 MHz of 0.15V.
As the result of the modifications of Bitx40 to reduce the noise, such as adding the big condenser and choke coil etc , the spurious level went down below of the criteria.
That's good news, congratulations!
This issue may also be related to the strong "birdie" that can be heard at 7199 kHz when the radio is in LSB mode (almost no birdie in USB mode).
It was found that the strength of the birdie greatly depends on the VFO drive level. Default drive level is 4 mA. In the SETTINGS menu, you can try different drive levels (2,4,6,8 mA). The optimum level may be different for each BitX40 radio.
The VFO drive level setting may also have an effect on the spurious signals you observed. Perhaps it is possible to fix this issue just by adjusting the drive level setting (in that case, extra hardware modification such as adding capacitor or choke could be avoided).

Could you try it out?

73 Allard PE1NWL

Re: RFI from uBitx TX after AGC and other mods installed

John KC9OJV
 

Rick,
I have a Kees kit and the symptoms are almost exactly as you describe. I don't know that I've heard squeals but otherwise muffled RFI is how I would describe it. Unless Don weighs in with a better variant of this mod I'll probably try Mark's version this morning as that's very simple for others to effect and easier to modify Kees's kit to reflect that change relative to bridging the base/emitter on Q1 with a capacitor. Thanks for the good troubleshooting and persistence- this was a tough bug to swat.

John
KC9OJV

Re: Bitx40 75KHz Spurious, How to solve it. #bitx40

Jer Tres
 

Dear Akira,
Please share with us the specific details about modifications you used that successfully solved the spurious output problems.
Thank you very much and
73
Jerry aa1of

Re: Easy, Inexpensive Cooling Fan, Excelway Case

Arvo W0VRA
 

On Sat, Jun 30, 2018 at 04:32 pm, n4eev wrote:
Arv, you are one smart dude! I love your idea.
Haha, well, there are always unforeseen complications.

On mine, when I open PTT the fan coasts down and I'm guessing acts like a little magnetic generator and puts quite the whir into the AF signal for a second or two.  I'm thinking the DC pulses produced by the freewheeling fan are of opposite polarity from the PS, so I could snub them with a diode, right?

Does sound kinda cool, though.  Maybe not as cool as a "Roger beep" and nobody else (I hope) can hear it.

That's what I get for testing the idea on WSPR with the volume all the way down.

Re: BITX QSO Afternoon/Evening, Sunday, July 1, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

William Cullison
 

I really don't have myself setup for portable and I'm on vacation visiting with family in South Carolina so I'm off net for 7 days.
73 Bill WA8VIH/4

On Jul 1, 2018 23:15, "Daniel Conklin" <danconklin2@...> wrote:
I didn't try tonight because I have the uBiTX in pieces waiting to get stuffed into a new box  
Dan, W2DLC 


Re: Easy, Inexpensive Cooling Fan, Excelway Case

Jim Sheldon
 

Hey Arv,
If you try the "snubber" diode, you might put a .1uf or maybe even higher value cap across the diode to help take down the little overshoots that will occur even with the diode in most cases.  

Jim, W0EB

------ Original Message ------
From: "Arvo KD9HLC via Groups.Io" <arvopl@...>
Sent: 7/2/2018 8:48:36 AM
Subject: Re: [BITX20] Easy, Inexpensive Cooling Fan, Excelway Case

On Sat, Jun 30, 2018 at 04:32 pm, n4eev wrote:
Arv, you are one smart dude! I love your idea.
Haha, well, there are always unforeseen complications.

On mine, when I open PTT the fan coasts down and I'm guessing acts like a little magnetic generator and puts quite the whir into the AF signal for a second or two.  I'm thinking the DC pulses produced by the freewheeling fan are of opposite polarity from the PS, so I could snub them with a diode, right?

Does sound kinda cool, though.  Maybe not as cool as a "Roger beep" and nobody else (I hope) can hear it.

That's what I get for testing the idea on WSPR with the volume all the way down.

Re: Bitx40 75KHz Spurious, How to solve it. #bitx40

Jerry Gaffke
 

Recommendation:  Use Allard's v2 firmware and associated hardware mods:
    https://github.com/amunters/bitx40-raduino-v2
Moving to a high side vfo using Allard's firmware should fix this spur.

When operating at 7.2 mhz with a low side vfo,
that vfo is at 12-7.2 = 4.8 mhz.
The fifth harmonic of the vfo mixes with the second harmonic
of the 12mhz bfo:    4.8*5 = 24  = 2*12
PA4Q (Cor) figured this one out:  https://groups.io/g/BITX20/message/21996

The bfo and vfo have no reason to mix, except that this rig is not shielded.
Also, both are being generated inside the si5351, there may be crosstalk there.

Going to a high side VFO should work, the vfo is now at 12+7.2 = 19.2
To operate lower sideband as is customary on 40m,
the bfo must now be moved down a few khz to the other side of the 12mhz crystal filter.
The easiest way to do all of this is to use Allard's v2 code for the Bitx40,
he uses the si5351's clk0 to drive the bfo instead of the 12mhz crystal oscillator.

Curiously enough, 19.2*5 = 96 = 12*8
So their might still be a slight birdie when operating at 7.2 mhz with a high side vfo
but much reduced from the stock low side vfo.

Jerry, KE7ER


On Sun, Jul 1, 2018 at 10:53 pm, Raj vu2zap wrote:
OK! connected up the bitx40 with Raduino.

Yes, there are spurious as reported. The spurious distance from carrier varies with frequency.

All the spurs all come together and disappear at near 7.2 Mhz. This is mixing of harmonics but
cant remember the maths.. Jerry and others had worked it out.

I will try out a filter that I had wired on some board but donno where I kept it!

Re: Compiler warnings

ajparent1/KB1GMX
 

I wondered on that too.

Some of C++ features are bulky but for Arduino you don't use them. But it makes building reusable code far easier.
Encapsulation is a useful one and I don't see any cost for it in the code size.

OF course if your that concerned about space....  A good macro assembler for the target machine works.

Allison

Re: Compiler warnings

AA9GG
 

Google "oop and microcontrollers" or "C++ and microcontrollers" .  The main reason is the code bloat OOP generates

On Mon, Jul 2, 2018 at 10:16 AM, ajparent1/KB1GMX <kb1gmx@...> wrote:
I wondered on that too.

Some of C++ features are bulky but for Arduino you don't use them. But it makes building reusable code far easier.
Encapsulation is a useful one and I don't see any cost for it in the code size.

OF course if your that concerned about space....  A good macro assembler for the target machine works.

Allison




--
Paul Mateer, AA9GG
Elan Engineering Corp.
www.elanengr.com
NAQCC 3123, SKCC 4628

Re: Compiler warnings

ajparent1/KB1GMX
 

As someone that cut their teeth is the '70s with K&R C the biggest thing I see is poor programming
not poor programming languages.  I also grew up in systems where resources are scarce and 
adding them was expensive.  So pardon me if I think 32K of code space, 1k of eeprom and 2K
of ram is a lot of space.  Sure beats 8749 with 2K of program Eprom, 128byts of ram and a timer.

OOP is not a bad word but it may be very stupid in a machine with maybe 2K of ram, code
accordingly.  The problem is coders (not programmers) that figure if it doesn't fit use a bigger
chip.  Then again if the objects are small it can be useful.  For example a Arduino Mega2650
running a two axis (elevation and azimuth) antenna control that serves out position and
tracking as a web page.  No it isn't full and it even gets the TLEs for the Sat to track via
the web page.  One of these days I need GPS and a electronic compass so it knows
where it is and what way is north so I can move it with out calibrating it afterwards.
Writing that in plain ansi C is just more error prone work than it needs to be.


Allison

Re: RFI from uBitx TX after AGC and other mods installed

Kees T
 

If the problem is feedback from the RF portion of the AGC board back to the AF input, wouldn't a ferrite bead on the Audio input at the AGC board accomplish the same thing without attenuating the audio any with another capacitor to ground ?  On the first pass of the AGC board (none were shipped out), I had a 470pF capacitor to ground but it caused oscillations .....apparently a 10nF capacitor does not, based on the work you guys did.(and thank you for the input) . 

73 Kees K5BCQ

Re: Anyone seen an SSB xmit causing the menu to pop up?

KE0GYC
 

I have this happen, but typically with poor SWR.  That would make sense if it is an EMI issue, wouldn't it?

Re: RFI from uBitx TX after AGC and other mods installed

John KC9OJV
 

Kees, I tried the clip on beads and if anything it made matters worse- applied to the audio cable. Perhaps multiple turns on a more perfect mixture may help but in reality adding that additional capacitor has very little effect on audio quality as best I can tell.

John
KC9OJV

Re: RFI from uBitx TX after AGC and other mods installed

Kees T
 

Did you add the ferrite bead on only the Audio line (not the ground) and was it #43 material ? That's what I would try.

But if adding 10nF-15nF to ground which is about 7K at audio frequencies is OK, it's easy to add a 805 size capacitor across the Audio connector pins. 

73 Kees K5BCQ

Re: Compiler warnings

Jack Purdum
 

Writing that in plain ansi C is just more error prone work than it needs to be.

What is your suggestion to fix that?

There are elements of C++ that I don't like and tend to be misused (e.g., multiple inheritance). However, one can practice the OOP concept of encapsulation even within the confines of ANSI C, and that's a very good thing. Perhaps the two biggest mistakes I see made by beginning programmers are 1) the reliance on globally-scoped variables and 2) trying to write functions that do too much (i.e., they are not "cohesive"). A globally defined variable means that every single statement in the program has the ability to change that variable. It's like placing a hooker at the top of the program and giving every statement in the program a $50 bill and, after something goes wrong, trying to find out who the father of the error is. Encapsulation at least lessens the scope of the error search.

If you can't tell someone what a function does in two sentences or less, it is not cohesive. Another tip off is a function that has a bunch of variables passed to it, especially variables that are little more than flag variables. Writing Swiss Army knife functions may seem like a good idea, but they are almost always too complex for the task at hand and, because they try to do too much, they are rarely reusable.

Just paying attention to those two things as you write code will make the code less error-prone. Personally, I've used a lot of different languages over the years and I still think C is the best. There must be some agreement, otherwise it wouldn't be the first language most companies resurrect on a new processor and it wouldn't have lasted over 40 years.

Jack, W8TEE

On Monday, July 2, 2018, 12:08:58 PM EDT, ajparent1/KB1GMX <kb1gmx@...> wrote:


As someone that cut their teeth is the '70s with K&R C the biggest thing I see is poor programming
not poor programming languages.  I also grew up in systems where resources are scarce and 
adding them was expensive.  So pardon me if I think 32K of code space, 1k of eeprom and 2K
of ram is a lot of space.  Sure beats 8749 with 2K of program Eprom, 128byts of ram and a timer.

OOP is not a bad word but it may be very stupid in a machine with maybe 2K of ram, code
accordingly.  The problem is coders (not programmers) that figure if it doesn't fit use a bigger
chip.  Then again if the objects are small it can be useful.  For example a Arduino Mega2650
running a two axis (elevation and azimuth) antenna control that serves out position and
tracking as a web page.  No it isn't full and it even gets the TLEs for the Sat to track via
the web page.  One of these days I need GPS and a electronic compass so it knows
where it is and what way is north so I can move it with out calibrating it afterwards.
Writing that in plain ansi C is just more error prone work than it needs to be.


Allison

Elmer in Atlanta GA with working BITx40 RFSignals Kit working

Hugo Boots
 

Howdy,

I am seeking someone close to Atlanta, GA that has a working Bitx-40
"Kit" the one that you just do the final wiring and put the "kit" in a enclosure.

My "kit" receives great but does not transmit.

Thanks in advance.

Hugo

Re: RFI from uBitx TX after AGC and other mods installed

Kees T
 

Forgot to ask. Did you connect the capacitor across the connector end to ground of C1 or the 2N3904 Base end of C1 to ground ?

73 Kees K5BCQ