Re: amp for ubitx4

Stephanus K6NG

do you connect this amp to the speaker wires from the uBitx or do you take the audio from before the audio amp on the uBitx board?


Re: Output power

Terry Morris

I have a 5 watt dummy load consisting of 5-1 watt carbon resistors, gold band, soldered into a PL-259 connector circa 1970's. It was given to me from an elderly ham, now SK. He learned I was starting the hobby with a QRP kit built HW-9. He told me he tried QRP once but it was too difficult making contacts. Thought I would like the low power heater. I do.

Terry - KB8AMZ
Brimfield Twp, OH  USA
Linux User# 412308, Ubuntu User# 34905

On Wed, Jun 20, 2018 at 7:13 PM brad martin <emclinux@...> wrote:
Thank you all for the replies. Unfortunately my idea on paper does not look like it’s going to work out based on my experiments last night. My idea was that I have a cb type swr meter and I was going to make it into a digital swr and power meter and well being that it’s not for Hf the output voltage of the meter didn’t line up with output power. .6v on 80, 1v on 40 and 30 and 1.5v on 20. So oh well on that one. I have Arduinos all over the place so using a mega for this is not a loss for me. I almost use them as coasters at this point. I would see a deal on them and get them over the last few years and as far as time goes I always try to make time for my hobbies because life is short right :).

I have seen the dummy load with a cap and diode before and have been planning on adding that to my dummy load as well. When choosing the diode what properties are you looking for?

I have a goal most people would probably say I’m crazy for doing. The plan is that my first HF contact will be done using things I have made, built, or repaired. So far everything I have (power supply, uBITX, antenna, CW paddle, dummy load, and other random stuff) and the swr meter is the only thing I have left that has not has been modified.

On Wed, Jun 20, 2018 at 3:39 PM Jerry Gaffke via Groups.Io <> wrote:
The BAV21 is not a bad choice for the dummy load dectector.
Very cheap, which is of course my primary criteria.

Forward voltage drop appears to be around 0.5v at 0.1ma from their graphs,
the detector would have a much smaller current going through it.
So should still be able to measure 10mW into the dummy load,
though factoring in that drop to the calculations becomes more important than with the 1n5711. 

I'd still use the 1n5711 for the diode RF probe.


On Wed, Jun 20, 2018 at 12:27 pm, Jack Purdum wrote:
We use a BAV21 diode in our design, which is rated at 250V.

Re: Keypad for Raduino...?

Dennis Zabawa

Here are a number of hardware devices that are applicable to uBITX operator interface designs:
 Operator Interface (Keypad):
     PDN1144  Four Row by Four Column Keypad Interface IC     pdn1144.pdf
     PDN1188 Eight Row by Eight Column Keypad Interface IC     pdn1188.pdf
Operator Interface (Text LCD)
     PDN702 Character LCD Controller IC     pdn702.pdf
Operator Interface (7-Segment LED)
     PDN707 Hex Display 7-Segment LED Driver     pdn707.pdf
     PDN747 Eight Digit Seven-Segment LED Controller/Counter     pdn747.pdf
Mechanical Pushbutton Interface
     PDN2008 Eight Channel Contact Debouncer     pdn2008.pdf
     PDN2108A One-of_Eight Latching (one output active)     pdn2108.pdf
     PDN2108D One-of-Eight Latching (one or zero outputs active)     pdn2108.pdf
     PDN2208 Eight Channel Toggle     pdn2208.pdf

Re: Microscope - - new thread

Terry Morris

This is what I bought for $29 plus shipping, There were no comments whether it was compatible with Linux. For less than $30 I can tell you that it is not compatible with Linux. Its a cute toy but for the $29 I could bought a nice meal for my canine and I. LOL

Terry - KB8AMZ
Brimfield Twp, OH  USA
Linux User# 412308, Ubuntu User# 34905

On Fri, Jun 22, 2018 at 7:30 PM Don, ND6T via Groups.Io <> wrote:
The little microscope with the screen looks like fun! Trouble is, though, a stereoscopic microscope helps a bunch. Nothing like a bit of depth perception to help guide your hot soldering iron to its destination. Same goes with trying to pick up something. Trying to do that with one eye gets old fast. Although I like the dental loupes at times, they don't have the amplification and since they are mounted on my head the focus wanders as I move and my neck starts to feel it after a while. K9AC's SolderScope gives a better, more stable view. Yes, it takes some DIY innovation but check out his wooden stand that he made from scrap. Until somebody gives me a Mantis Elite I prefer the SolderScope. It's smaller, too. 73, Don

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



That is the marker M 7.049 , its very low in level and not seen.


At 26-06-18, you wrote:
It shows scanning from 7.029Mhz to 7.049Mhz. That's only a 20khz
scan, not 50khz. And certainly not 50khz per division on the screen.

The funny thing is that those unknowns are *increasing* in amplitude as
you move away from the carrier instead of decreasing. I'm not sure what
would generate this.

Could these be products from overdriving the spectrum analyzer?

tim ab0wr

Re: KD8CEC - Nextion Display - IAN questions

Michel Dupuy

Je vais essayer .
Ce n est pas grave si cela ne fonctionne pas.
Je ne suis pas habitué au lignes de commande.
J utiliserai IDE Raduino lorsque on aura le fichier source.
De toutes façon j ai aussi un PC et là pas de problèmes.

Re: Keypad for Raduino...?



Well, thank you for that information about the TTP229.
The code I found did the job for an HDSDR controller project that was eventually abandoned
even although it worked as planned. The ergonomics just didn't work for me.

Having also built a Nextion controller my preference is to complemented the touch inputs
with knobs and buttons for tuning and certain other most frequently used controls.

I agree 100% with your comment about adding an external S-meter with the Nextion display.

73 Bob GM4CID

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

Don, ND6T

Alan, Sorry for the relay info. I see what you are getting to now. Do you have a "pop fix" modification in place (any flavor)?
Rowland: What happens if you unplug the AGC board (everything else still connected) and transmit? Does the feedback go away? -Don

Re: Keypad for Raduino...?

Mike Woods

This is not quite correct.  This sketch is a hack that would work but the TTP229 is a true i2c device.  See the following use case that deploys the wire library:

This is an easy add to the uBITx for somebody wanting a keypad ... but why not use a Nextion display with KD8CEC firmware?  It already has firmware built to provide touchpad frequency entry in the UI!

It is a bit the same as building an analogue S-meter when KD8CEC firmware and Nextion already feature a classy digital S-meter that can be calibrated easily...

There are always different ways of doing things, but some ways are easier than others!



On Tue, 26 Jun 2018 at 3:38 AM, Robert McClements <gm4cid@...> wrote:

The TTP229 capacitive  keyboard has two pins labelled SCL and SDO but unfortunately they are not I2C.

The way that they work is SCL is clocked frequently up to 16 times and during each clock cycle SDO is
checked. If a key is pressed SDO will return a Low, the count stops and the clock count equates to
the key number. Hope that makes sense, not easy to put into words.

So this device will require the use of two digital pins.



Sample code below :-

 // Routine to read if a key is pressed and return its value
byte Read_Keypad(void)
   byte Count;
   byte  Key_State = 0;
   for(Count = 1; Count <= 16; Count++) // Pulse the clock pin up to 16 times and read the state of the data pin on each pulse
      digitalWrite(Clock_PIN, LOW);
      if  (! digitalRead (Data_PIN)) // data pin low store the current key number
         Key_State = Count;
      digitalWrite(Clock_PIN, HIGH);
   return Key_State;

Re: KD8CEC - Nextion Display - IAN questions

Lowell Haney NE4EB


If you have the Arduino IDE, there is a command line utility built into the package. it is called "AVRDude" and can be executed from a terminal window. Here is the command line that works with my setup.

avrdude -pm328p -carduino -P/dev/ttyUSB0 -b57600 -Uflash:w:ubitx_CEC1.01.hex:i

The filename you want to load  (.hex file) is just after the 'w:'  I execute this line after navigating to the file location directory/file in the terminal program. The help function for avrdude explains all the switches that can be invoked.

Hope this helps.

SSM2167 wiring.


Hi, can someone explain how to wire the ssm2167 into the mic circuit on the ubitx please? 

Thanks Carl.

Audio kit orders

Les Preston

Hi there,
If I'm not too late, could you put me down for one of each of the anti click and agc kits please. Payment has been sent.

Re: Noise Burst #bitx40


Thanks Nick.

I will try that fix for the audio amp noise burst by muting the LM386 via pin7.

Seems that there are two problems here.
One is the audio noise burst which your fix addresses.
The other is a burst of RF noise as charging capacitors in the microphone amp unbalance the balanced mixer at the start of a transmission.

I have looked through the Wiki and there are lots of discussions about curing the audio burst, there is not much about fixing the RF noise burst.

I have been thinking about putting a FET in the line from the mic amp to the balanced mixer to act as an isolating switch while the mic amp settles down. Use an RC time constant on the gate to delay turn on. Use some steering diodes so that the fet is on via the Rx line during receive, goes off when the Rx/Tx changeover occurs and comes on after a delay via the Tx line when in transmit.


Re: W8TEE Power/SWR Sketch for Nano


forgot the picture......

Re: W8TEE Power/SWR Sketch for Nano


Kees, i'm in the middle of a similar project.  2 x AD8307's. The bridge uses a balun core. PCB is 50x50mm.   No Nano etc.

There is a neat SWR meter here using the AD8307's but with a Teensy.

A very interesting SWR meter is here. It auto computes SWR using an LM555. I use this in my shack and it works well.

Glenn vk3pe

On Mon, Jun 25, 2018 at 06:57 pm, Kees T wrote:
OK, so

all I need now is some code......

73 Kees K5BCQ

Re: Understanding Spurious Emissions

Jer Tres

It would 
have to pass down to 28.0 for CW” but not needed for cw so maybe easier to just switch it out below 28.3

Re: W8TEE Power/SWR Sketch for Nano

Jerry Gaffke


Also, both your implementation and my implementation use the single ADC
in the Arduino to read the forward and reverse channels one at a time
There will be a significant delay between readings.
That delay will likely be too large for accurate SWR readings
during SSB phone use, as per Dr Bill's objection of a month or two ago.
However, those SWR readings should be accurate when transmitting CW.

On Mon, Jun 25, 2018 at 09:54 pm, Jerry Gaffke wrote:
Regarding code for your Tandem Match SWR meter,
below is where my code was parked a couple months ago.
It may or may not be stuff you can use.

Re: KD8CEC - Nextion Display - IAN questions

Michel Dupuy

i tried hexuploader and it does not work with nano arduino while it works with arduino uno. he puts as a message:

avrdude: stk500v2_ReceiveMessage (): timeout
avrdude: stk500v2_ReceiveMessage (): timeout
avrdude: stk500v2_ReceiveMessage (): timeout
.avrdude: stk500v2_ReceiveMessage (): timeout
avrdude: stk500v2_ReceiveMessage (): timeout
avrdude: stk500v2_ReceiveMessage (): timeout
avrdude: stk500v2_ReceiveMessage (): timeout
avrdude: stk500v2_ReceiveMessage (): timeout
avrdude: stk500v2_ReceiveMessage (): timeout
avrdude: stk500v2_getsync (): timeout communicating with program

It does not matter, I will wait to have the source files.

Thank you


Re: Noise Burst #bitx40

Nick VK4PP

Re: W8TEE Power/SWR Sketch for Nano

Jerry Gaffke

Regarding code for your Tandem Match SWR meter,
below is where my code was parked a couple months ago.
It may or may not be stuff you can use.

I haven't made time yet to fully implement it, though I'm pretty sure it's very close to good.

I'm not planning to talk to anything like the OLED, will use the Raduino's LCD

I am planning to just read Diz's diode detectors (with a slight dc bias current through the diodes)
using the Nano's 10 bit ADC's.  

The code that converts the AD8307 log response to volts is unused and has been commented out.
That 32 bit fixed point code works, but you are probably better of just using a floating point library as you won't
be pressed for flash space.

Jerry, KE7ER

void lcd_printline(char n, char* s) { // n=0 for top, n=1 for bottom
    for (n=strlen(s); n<16; n++)  lcd.print(" ");
// Print val as d digits with r digits after the decimal point
// Will print any leading zeros, if r==0 then no decimal point
void pnum(uint32_t val, uint8_t d, uint8_t r) {
  uint32_t  div=1;
  uint8_t   n; 
  for (n=1; n<d; n++)  div*=10;
  while (div>0) {
    if (d--==r)   lcd.print('.');
    val = val%div;
    div = div/10;
  lcd.print(" ");
//  // Accurately transform AD8307 readings to RF voltage per post 48570
//  int32_t adcSlope32 = 5922023;  // 0x7FFFFFFF * (0.025/2.50 * (20*m.log10(32.0/31)) );   5922023.090616257
//  int32_t adcSlope2048 = 91056;  // 0x7FFFFFFF * (0.025/2.50 * (20*m.log10(2049.0/2048))) 91055.92544695384
//  uint32_t  adcRFmax = 100UL<<24;         // Calibrated Volts*2**24 rms of RF when adcRead at 0xFFFF
//  uint32_t findVoltsRF(uint16_t adcRead)  {               // adcRead is 16 bit ADC read of AD8307's output
//    uint32_t voltsRF = adcRFmax;                          // At adcRead max of 0xFFFF, voltsRF is adcRFmax
//    int32_t  voltsADC = 0x7FFFFFFF - (adcRead<<15);       // Will subtract adcSlope from this till goes negative
//    // The RF voltage falls by 1/32 for each drop in voltsADC by adcSlope32
//    while (voltsADC > 0)  {                                       // while (voltsADC > adcRead<<16)
//      voltsRF = voltsRF - (voltsRF>>5);           // voltsRF *= (31.0/32)
//      voltsADC = voltsADC - adcSlope32;
//    }
//    while (voltsADC < 0) {
//      voltsRF = voltsRF + (voltsRF>>11);
//      voltsADC = voltsADC + adcSlope32/65-52;
//    }
//    return(voltsRF);
//  }
// Read TandemMatch's 2 detectors, display forward and reverse power, swr
#define PSCALE  (1023L*1023/(25*10)) // ADC max of 1023 is 25 Watts, display Watts*10
void  show_swr() {  // SWR = (1+1.0*vr/vf)/(1-1.0*vr/vf);
  uint32_t vr, vf, swr; // Voltage squared proportional to power
  vf = analogRead(RF_FWD); // Peak RF volts from forward detector
  vr = analogRead(RF_REV); // Peak RF volts from reverse detector
  if (vr>=vf) swr=0; // If vr,vf illegal, force SWR to zero
  else {
    swr = (vr*1024)/vf; // Voltage ratio, 10 fractional bits
    swr = (1000*(1024+swr))/(1024-swr); // 1000*swr, nearly 10 fractional bits
    swr = (swr+50)/100; // 10*swr, rounded to nearest tenth
    if (swr>99) swr=99;  // Display a max SWR of 9.9
  lcd.setCursor(0, 1); // Fill bottom LCD line, example:
  lcd.print('f'); pnum(vf*vf/PSCALE,3,1); // "f12.4 r03.1 s1.7"
  lcd.print('r'); pnum(vr*vf/PSCALE,3,1); // with fwd,rev power in watts
  lcd.print('s'); pnum(swr,2,1); // and swr to max of 9.9

On Mon, Jun 25, 2018 at 06:57 pm, Kees T wrote:
all I need now is some code......