1. BITX20@groups.io
   Date   
Re: uBitx just started transmitting a loud hum #ubitx-help

Paul Galburt - K2AYZ
 

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

Tim Gorman
 

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" <bill@wjschmidt.com> 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: bill@wjschmidt.com
Re: uBitx just started transmitting a loud hum #ubitx-help

Raj vu2zap
 

An audio recording of the hum will be nice.

Raj

At 09-04-18, you wrote:
Thanks for the great replies,

I haven't been through all of the grounds exhaustively, but all jacks/pots/rotary encoders and switches I have soldered are properly grounded to the ubitx main board (0 ohms on multimeter). I have also confirmed the emitter of q6 is grounded via r63 and r64. Emitter of q70 is grounded directly.
The main board isn't earthed (it's inside a plastic chassis) and is only grounded via power supply -ve terminal.
Haven't had a chance to try it with a 12v battery, but will do in the next day or 2. No RF earth at present.

Q70 is showing 0 volts on Tx, but there is a visible fine wave form on the oscilloscope when probing during tx. I haven't got a capture of it to measure frequency but I suspect this is related to the noise I am hearing.

Will continue to work through the suggestions re audio circuit tests and report back.

Also, yes it was a WX branded TDA2822 that failed.

Cheers,
James
Re: Micro bitx in the spectrum analyzer #ubitx

Hans Summers
 

My understanding of FCC rules is that you need better than -43dB spurious content... so 22-28dB wouldn't meet this requirement. If this is wrong could someone please comment? I need to know also... 

73 Hans G0UPL
Re: BITX QSO Afternoon/Evening, Sunday, April 8, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

q q
 

I Was able to make only two contacts last evening, AI4OT and KE0PVO, then I had very loud, intentional, QRM that swamped everyone so I had to vacate.

I hope there were many others out there who were able to get a good log list.

73,
Bob N1ETS
Re: Variation on Ian's KD8CEC uBitx software (based on his 1.04 release for now) and ATU sketch. #ubitx

Hidehiko Komachi - JA9MAT
 

Hi John,
Now I returned from business and I added 2N7000 as AGC level controller and then I replaced time constant capacitor of 1uF to 0.1uF and 0.047uF. Both seems good work and I feel 0.47uF is better. So I decided 0.047uF. And also software modification is OK, thanks for detail information. I will use with this hardware modification for someday.

Next I have to calibrate the S-meter values. At first I set "S" to "9" when I inject the RF signal from hp-8656B(SG) at -73dBm with adjusting the 10k-ohm trim volume as you advised. And the result is fairly good. But Is there any method about the calibration of your modified S-Meter? 

And the last information for you. I'm a CW man and I found that the IAMBIC A or B mode does not work correctly. When I closed both DIT and DAH at the same time it does not make "C" code. So please confirm...

Thanks for your help and I hope your mod. will contain the WSPR mode near future.

ja9mat HIdheiko.
Re: uBitx just started transmitting a loud hum #ubitx-help

James
 

Thanks for the great replies,

I haven't been through all of the grounds exhaustively, but all jacks/pots/rotary encoders and switches I have soldered are properly grounded to the ubitx main board (0 ohms on multimeter). I have also confirmed the emitter of q6 is grounded via r63 and r64. Emitter of q70 is grounded directly.
The main board isn't earthed (it's inside a plastic chassis) and is only grounded via power supply -ve terminal.
Haven't had a chance to try it with a 12v battery, but will do in the next day or 2. No RF earth at present.

Q70 is showing 0 volts on Tx, but there is a visible fine wave form on the oscilloscope when probing during tx. I haven't got a capture of it to measure frequency but I suspect this is related to the noise I am hearing.

Will continue to work through the suggestions re audio circuit tests and report back.

Also, yes it was a WX branded TDA2822 that failed.

Cheers,
James
Re: #ubitx; #ubitx-help;#ubitx menu;

Rod Davis <km6sn@...>
 

I am using KD8CEC software, and my  frequencies are less than 30 hz off, after a casual calibration.

Measured using hp frequency counter which displays 0.1 hz resolution, and rubidium frequency standard.

Go to ubitx.net and scroll down to April 7 entry for a manual on KD8CEC rev 1.061

Regards,

Rod KM6SN



On 04/08/2018 07:41 PM, Jerry Gaffke via Groups.Io wrote:
The only documentation of the menus for the stock firmware of the ubitx as shipped is here:
  http://www.hfsignals.com/index.php/ubitx-tuneup/
Well, that and the source code:
  https://github.com/afarhan/ubitx
The calibration procedure in that firmware is not very accurate:
  https://groups.io/g/BITX20/message/37973
Though I am surprised to hear that you are 300hz off.

You might try some of the improved firmware that folks in this forum have come up with.
One possibility is the KD5CEC firmware:  http://ubitx.net/tag/kd8cec/

Jerry, KE7ER
 
On Sun, Apr 8, 2018 at 06:59 pm, Robert Goodwin wrote:

I have my uBITX up and running and have had my first QSO on 40 mtrs today.  However, I have some questions, as follows:

Issue 1:  I have twice performed the Master Clock Calibration and I still clearly have a 250-350 Hz frequency offset (reading lower) than the actual frequency.  I am not sure how to approach fixing this.  The clock calibration was straight forward enough and produced repeatable results comparing the two performances.

Q1-a:  Is there some what to interpret the master clock correction values that would allow me to convert those numbers to indicated frequency?
Q1-b:  Does the BFO setting adjustment affect the indicated frequency and if so, how?

Issue 2:  I have not found any explanation of how to use the Menu options available from the push know and the lack of such explanation has me wondering if I am doing things correctly.  Much of it is intuitive (Select VFO, Select USB/LSB, CW WPM change) but other menu options, mostly in the calibration area, are not entirely obvious.

Q2-a: Is there a published explanation of how to use each menu function properly?
Q2-b: Once you have entered the Setup process via the 'Setup: ON ?' option, you get a 'Setup: OFF ? option.  If you do a Master Clock calibration, then push the PTT, the LCD gives a report that the calibration was successful and recorded.  The HFSignals uBITX Tuneup instructions for the Master Clock calibration do not say anything about selecting the 'Setup: OFF ?' menu option to exit Setup.  Their last step is to push the PTT to record the calibration value.  What is the purpose of the 'Setup OFF ?' menu option and what is the consequence of NOT using it?  Is it necessary for the calibration values to be written to the EEPROM?

Issue 3:  The only difference that I can see between using the Band Select ? menu option and simply tuning from one band's frequency to another band's frequency, is that the tuning from the Band Select ? option seems to be a fixed faster tuning process.
Q3-a:  Is there any functional difference between changing bands (e.g. 7.250 MHz in 40 mtr to 14.225 MHz) by use of the 'Band Select ?' menu selection or simply tuning from 7.250 to 14.225 MHz without using the 'Band Select ?' menu option?
Re: #ubitx; #ubitx-help;#ubitx menu;

Jerry Gaffke
 

The only documentation of the menus for the stock firmware of the ubitx as shipped is here:
  http://www.hfsignals.com/index.php/ubitx-tuneup/
Well, that and the source code:
  https://github.com/afarhan/ubitx
The calibration procedure in that firmware is not very accurate:
  https://groups.io/g/BITX20/message/37973
Though I am surprised to hear that you are 300hz off.

You might try some of the improved firmware that folks in this forum have come up with.
One possibility is the KD5CEC firmware:  http://ubitx.net/tag/kd8cec/

Jerry, KE7ER
 

On Sun, Apr 8, 2018 at 06:59 pm, Robert Goodwin wrote:

I have my uBITX up and running and have had my first QSO on 40 mtrs today.  However, I have some questions, as follows:

Issue 1:  I have twice performed the Master Clock Calibration and I still clearly have a 250-350 Hz frequency offset (reading lower) than the actual frequency.  I am not sure how to approach fixing this.  The clock calibration was straight forward enough and produced repeatable results comparing the two performances.

Q1-a:  Is there some what to interpret the master clock correction values that would allow me to convert those numbers to indicated frequency?
Q1-b:  Does the BFO setting adjustment affect the indicated frequency and if so, how?

Issue 2:  I have not found any explanation of how to use the Menu options available from the push know and the lack of such explanation has me wondering if I am doing things correctly.  Much of it is intuitive (Select VFO, Select USB/LSB, CW WPM change) but other menu options, mostly in the calibration area, are not entirely obvious.

Q2-a: Is there a published explanation of how to use each menu function properly?
Q2-b: Once you have entered the Setup process via the 'Setup: ON ?' option, you get a 'Setup: OFF ? option.  If you do a Master Clock calibration, then push the PTT, the LCD gives a report that the calibration was successful and recorded.  The HFSignals uBITX Tuneup instructions for the Master Clock calibration do not say anything about selecting the 'Setup: OFF ?' menu option to exit Setup.  Their last step is to push the PTT to record the calibration value.  What is the purpose of the 'Setup OFF ?' menu option and what is the consequence of NOT using it?  Is it necessary for the calibration values to be written to the EEPROM?

Issue 3:  The only difference that I can see between using the Band Select ? menu option and simply tuning from one band's frequency to another band's frequency, is that the tuning from the Band Select ? option seems to be a fixed faster tuning process.
Q3-a:  Is there any functional difference between changing bands (e.g. 7.250 MHz in 40 mtr to 14.225 MHz) by use of the 'Band Select ?' menu selection or simply tuning from 7.250 to 14.225 MHz without using the 'Band Select ?' menu option?
Re: BITX QSO Afternoon/Evening, Sunday, April 8, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

w7hd.rh <w7hd.rh@...>
 

I'll second that good to hear you're on the mend.   I just went through it for my sixth stent on Jan 1st.  The lump sure takes a long time to go away.  My entire forearm was black and blue for a couple of months, with just a trace remaining now.

Ron W7HD

On 04/08/2018 01:55 PM, Vince Vielhaber wrote:
Good to hear you're on the mend.  I had the exact same thing last January.  Not fun.  Still have the lump on my wrist from the stent procedure.

Vince.



On 04/08/2018 04:30 PM, ekelley wrote:
Band was pretty dead here in Iowa, I will keep trying. Sorry to miss
everyone last
week I was busy at the hospital having a heart attack. I heal well and
am back on the
air. Thanks for your prayers, the triple bypass and stint went well. Be
looking for you
on 7277.  73's Ed W0OIC

On 4/8/2018 1:56 PM, John P wrote:
Got back home in time! I'm on 7277.
--
John - WA2FZW

<https://www.avast.com/sig-email?utm_medium=email&;utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=icon>
    Virus-free. www.avast.com
<https://www.avast.com/sig-email?utm_medium=email&;utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=link>


<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
--
Ron W7HD - NAQCC#7587 OMISS#9898 KX3#6966 LinuxUser#415320
Editor OVARC newsletter
Re: AGC circuit to try?

Tim Gorman
 

I was only interested in 80m and 40m so the noise contribution from the
if amp was not of a large concern to me.

I too used them because they were available easy and cheap. I used the
1550 to amplify the signal after the first mixer going into the crystal
filter. I also used some HP "pills" with about 12db gain after the
filter to feed the demodulator. My notes are in the basement so I can't
tell you exactly how I terminated the input and output of the 1550. I
remember using a diplexer after the mixer to get a good 50ohm impedance
down the line and a transformer match coming out of the 1550. That's
about as detailed as I can get from memory!

tim ab0wr

On Sun, 08 Apr 2018 13:21:51 -0700
"ajparent1" <kb1gmx@arrl.net> wrote:

The MC1350 (and cousin) is a difamp input and depnding on frequency
is about 3.5K. Its easily loaded down to lower impedances with a
resistor or equivilent lumped circuit.

The output impedance is around 4K collector to collector for best
signal handling. Typically its a resistive load that determines it
for a transformer its often loaded with a resistor.

NOTE the MC1550 is NOT the same as MC1350 it is a lower gain
committed dif pair very similar to the CA3028 though less versatile.
I have a few of them and they made fair IF amps with AGC...  Same
noise issue as 1350.   Had to dig out the Motorola 1971 Linear
products databook for that one.  Input impedance single ended was
about 1.5K and output impedance was fairly high.  The gain overall
was lower than the 1350 and you would need two for the same result.
 I used three in a SSB transceiver back in '72 two for the IF and one
for the product detector. I used them as at that time and place I
could get them.  CA3028 would have been the part I wanted but they
were scarce then and a tiny bit more costly.

The suffix on the part was often a partial indicator of can or
plastic.  The MC1350P was plastic 8pin only (for TV circuits and
uses).  The MC1550 was available in '71 in TO8 can.  So all the 1350s
I have are plastic and all of the 1550s in the bin are cans.

The MC1496 made a fair attenuator as well as being a mixer and
multiplier.

Allison
Re: AGC circuit to try?

Tim Gorman
 

On Sun, 08 Apr 2018 12:40:58 -0700
"ajparent1" <kb1gmx@arrl.net> wrote:


First if you take out the input transistor and then parallel all the
resistors the highest impedance is about 217 ohms for the base uBitx.
So we have set the upper limit. The active feedback lowers that
further with the device in. 
And when you reflect the emitter resistance in parallel with that 200
ohm you get something less, just as you say. Assume the gain of the amp
is 10, that reflects a 10ohm x 10 back into the base circuit resulting
in a 66ohm impedance.



Now we are debating the difference between having Re set to near 0
and that is dependent on the ac beta of the device and the emitter
current.  So that the low end and for the basse circuit its set with
a 10 ohm resistor..  for an assumed 50 ohms, never ran the number or
put it in the HP4191A to measure.  Now if the diode is substituted to
get about 10 ohms you need about 2-3 ma current (25/ma is a fair
approximation for diode resistance).  So we can set for say 2.5ma.
Now lower that to zero. the diode is not an open circuit and the 100
ohm emitter resistor is dominant.  Since Re of the transistor is
unchanged and that resistor is added to it its still parallel loaded
by all the bias and output coupling resistors around it. Worst case
is 4:1 by eyeball, actual will be lower.
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.

I think you meant to say that lowering the diode current to zero is an
open circuit since there is no current flow. Yes in that situation the
100 ohm emitter resistor will be reflected back into the base.

With no bypassed emitter resistor the gain of the stage will be about
2, the collector load divided by the emitter resistor. So the reflected
resistance is 200 ohm, giving a base impedance of 200 || 200 or 100ohm.
Not a large difference but significant.



And no the circuit is not 50 ohms at all likelihood as the ac beta of
2n3904 is barely 10 at 30mhz and at 45mhz less than 7.  so then the
feedback is near zero as the transistor cannot achieve the gain and
impedances are not holding well too as device gain is a factor in the
calculation.   The second IF is better but to terminate the second
mixer it has to have a uniform input impedance to near 135mhz.  A
2n3904  is marginally useful device up there.
I can't argue with this. An mph10 would be a better choice.


For the case presented look at resistors  r27(47), r26(470),
r105(1K), r10(1K), r11(2.2k), r14(220). Do the nodal analysis to
convert those from a spaghetti-net to a single parallel value. That
will be the load value if Q21 and Q10 are not even there.  The input
of the amplifier needs to be higher than 50 ohms as there is about
217 ohms present in that net or about 56 ohms to present an exact 50
ohms to the IF port of the mixer.  

Refer to ubitxV3 schematic.
Those *are* the resistors I looked at. R105 in parallel with R10 is 500
ohm. R11, R14, and R18 in series add to about 2.5Kohm in parallel with
the 500ohm, or about 400ohm.

R27 and R26 are about 500 ohm in parallel with the 400ohm or about a
200ohm result.

When you parallel this with the reflected emitter resistor (assuming a
stage gain of 10 x a 10ohm resistor) of about 100ohm then you get an
input impedance of about 66ohm.

As you lower the current through the diode replacing R13, you lower the
stage gain but also make the 100ohm emitter resistor more important. If
you make the emitter resistor of 100ohm the only factor you lower the
stage gain to about 2 which means you will be reflecting 100ohm x 2 =
200 ohm into the base impedance. That won't quite double the base
impedance but it makes a significant shift to about 100ohm, or double
what nominal 50ohm it should be.

Will this cause problems in the receiver because of a more poorly
terminated first mixer? Hard to judge. Need to measure to see.

tim ab0wr
#ubitx; #ubitx-help;#ubitx menu;

Robert Goodwin
 

I have my uBITX up and running and have had my first QSO on 40 mtrs today.  However, I have some questions, as follows:

Issue 1:  I have twice performed the Master Clock Calibration and I still clearly have a 250-350 Hz frequency offset (reading lower) than the actual frequency.  I am not sure how to approach fixing this.  The clock calibration was straight forward enough and produced repeatable results comparing the two performances.

Q1-a:  Is there some what to interpret the master clock correction values that would allow me to convert those numbers to indicated frequency?
Q1-b:  Does the BFO setting adjustment affect the indicated frequency and if so, how?

Issue 2:  I have not found any explanation of how to use the Menu options available from the push know and the lack of such explanation has me wondering if I am doing things correctly.  Much of it is intuitive (Select VFO, Select USB/LSB, CW WPM change) but other menu options, mostly in the calibration area, are not entirely obvious.

Q2-a: Is there a published explanation of how to use each menu function properly?
Q2-b: Once you have entered the Setup process via the 'Setup: ON ?' option, you get a 'Setup: OFF ? option.  If you do a Master Clock calibration, then push the PTT, the LCD gives a report that the calibration was successful and recorded.  The HFSignals uBITX Tuneup instructions for the Master Clock calibration do not say anything about selecting the 'Setup: OFF ?' menu option to exit Setup.  Their last step is to push the PTT to record the calibration value.  What is the purpose of the 'Setup OFF ?' menu option and what is the consequence of NOT using it?  Is it necessary for the calibration values to be written to the EEPROM?

Issue 3:  The only difference that I can see between using the Band Select ? menu option and simply tuning from one band's frequency to another band's frequency, is that the tuning from the Band Select ? option seems to be a fixed faster tuning process.
Q3-a:  Is there any functional difference between changing bands (e.g. 7.250 MHz in 40 mtr to 14.225 MHz) by use of the 'Band Select ?' menu selection or simply tuning from 7.250 to 14.225 MHz without using the 'Band Select ?' menu option?
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,

The software was implemented to complement an AGC not to replace it so it assumes that the fast changes in AGC are done by another circuit like with the 2N7002 or MAX9814 or other.

The time constant of the audio voltage rectifier is too slow to work as a primary AGC function.

To speed it up, you can try to reduce the capacitor value to maybe 0.1uF or even even 47nF. The software loop should be fast enough.

Let me know how that works.

It the AGC function is acceptable with a smaller capacitor, we will need to modify the software a little to display the S-meter properly as I think it will be too fast up and down with the smaller capacitors.

Also, to speed up the changes you can try the following changes in the software if you want in the ubitx_20.ino file:

Change:
    firstIfShift += (scaledSMeter > 7 ? 10000 : 5000);
  } else if (firstIfShift > 0 && scaledSMeter < 1) {
 
to:

    firstIfShift += (scaledSMeter > X ? 10000 : 5000);
  } else if (firstIfShift > 0 && scaledSMeter < Y) {

With X between 2 (fastest, changes more often) and 7 (slowest).

You can also change Y between 1 and say 3 or 4 maybe. BUT Y always less than X.

Another change you can make after the capacitor and the software change above to speedup the reaction even more:

In ubitx_20.ino, change:

  currentSMeter = (newSMeter > currentSMeter ? ((currentSMeter * 3 + newSMeter * 7) + 5) / 10 : ((currentSMeter * 7 + newSMeter * 3) + 5) / 10);
 
To:

  currentSMeter = (newSMeter > currentSMeter ? ((currentSMeter * A + newSMeter * B) + 5) / 10 : ((currentSMeter * 7 + newSMeter * 3) + 5) / 10);

With A between 3 and 9(fastest)  and B between 7 and 1 BUT with A + B always = 10;
 
Check and let me know, if you decide to make that modification.

All the best,

73, John (VK2ETA)
Re: BITX QSO Afternoon/Evening, Sunday, April 8, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

W0PWE
 

Hey Tom - Thanks for the report and thanks for giving me a shout. I thought I heard someone answer my CQ but I wasn't sure. The vehicle has some pretty nasty noise so it takes a pretty strong signal to overcome that. This was the first time out with this setup so I will keep working on it. I think the fuel pump is the worst offender.

Timing was such that I had stops to make at the 3pm window and I was home unloading at 7pm. I got a 5/8 from the guy in London Ont and I worked several of the MO QSO party stations this afternoon but no Bitx qsos.
73 Jerry W0PWE
Re: BITX QSO Afternoon/Evening, Sunday, April 8, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

Skip Davis
 

Tom, that’s what I was hearing here in far western NC too this evening.

Skip Davis, NC9O
Re: Three Displays...

Tim Gorman
 

If it was the pullup resistors I wouldn't expect the w0eb software to
work while the cec software wouldn't.

Since the top row is being activated by the cec software I have to
believe there is something not being initialized correctly to work with
my lcd. Something that the w0eb software is doing correctly.

I'm not good enough at code to immediately determine what the
difference might be.

I haven't had a chance most of the day to work on this. Btwn doing
income tax and spending time with wifey there hasn't been much time
left!

John used a different set of initialization arguments in his software.
I might try those and see if they work.

tim ab0wr

"Jerry Gaffke via Groups.Io" <jgaffke=yahoo.com@groups.io> wrote:

Here's an old post about finding those 5v i2c pullups on the LCD
backpack boards: https://groups.io/g/BITX20/message/39966
  
That post also discusses how to determine the i2c address through
visual inspection, though using a scanner such as this is probably
the best bet. https://playground.arduino.cc/Main/I2cScanner

That device address must be different than any other device on your
i2c bus. So when manufactured for different environments, they can
come configured for different addresses. You might even have multiple
LCD displays on one i2c bus, each display configured for a different
address.

They normally give the address as a hex number, but it's sometimes
decimal.

More insidious, it could be a 7 bit address, or it could be 8 bits
including a Write-Enable bit in the LSB. So an address given as 0x27
could be the described by someone else as 0x4F. That's
010-0111=0x27   vs  0100-1111=0x4F where the 0x4F includes a R/W bit
of 1 in the LSB indicating that they intend to read what somebody
else might call the 0x27 register.  So i2c addresses can get very
confusing.

Jerry, KE7ER

On Sun, Apr 8, 2018 at 01:10 pm, K9HZ wrote:


Now there is one thing we have not been talking about… those two
little pull-up resistors to 5V on the I2C converter MUST go…
otherwise the signals from the I2C converter can
over-range/possibly damage the Arduino. Mine were 47K SMD pull-ups
that by tiny wire snips took care of.
Re: BITX QSO Afternoon/Evening, Sunday, April 8, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

Tom VE3THR
 

Good night tonight in spite of a new noise source heard up and down Eastern Seaboard of NA on 7.277 MHz. I have attached an audio clip of it from my QTH. No way to filter this one out. Intermittent maybe every 20 minutes for about a minute?
Had confirmed qso's with AI4OT/m Chas in WVA, KE0PVO Dave in MO, KN4AIE Rick in TN, wi1b Ken in MA, KC2IPX Dave in NJ, N1AW Al in MA and W4VU Paul in NC., all between 2300 and 0000 UTC. A couple of them are new to the bitx40 net so welcome aboard. Starting to hear some pretty good sounding uBITX's as well as BITX40's. The 40M band is finally coming out of the slump I hope. Welcome back Ed W0OIC speedy recovery.
Tom VE3THR

QRM001.m4a

Re: BITX QSO Afternoon/Evening, Sunday, April 8, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

alphaindia4oscartango
 

I was in the car (not using a bitx) but I worked a bitx (ve3?) and a microbitx (n1ets?) 72/73 de Chas ai4ot
Re: POP fix

Jerry Gaffke
 

Not quite right, should read "so the source is on the mike amp side".


On Sun, Apr 8, 2018 at 04:27 pm, Jerry Gaffke wrote:
>  Now if you did go and swap source and drain on that nFET so the drain is on the mike amp side,
>  you would get into trouble sooner since the intrinsic diode drop is no longer a factor.

Jerry, KE7ER
38621 - 38640 of 84540  
More
Home Messages Hashtags Wiki About Features Pricing Updates Terms Help Twitter