Date   
Re: Known issues on uBITX r4 #ubitx

hirosmb JAZZ <hirosmb@...>
 

Wow!, my uBITX has been shipped!!

Many, many thanks for all who advised to me.

BR,

// hiro, JJ1FXF



2018/06/30 10:38、hirosmb JAZZ <hirosmb@...>のメール:

Bo,

Heathkit was my great aspiration when I was a junior high school student, I remember.

I feel the same heated atmosphere with uBITX this time.

Thanks for your message, Bo.

ARIGATO!

// hiro, JJ1FXF



2018/06/30 6:02、Bo Barry <bobarr@...>のメール:

I have a v3 & v4 and am "tickled to death" (American slang expression) with both of them.
NO mods (except KD8CEC mods to one) so far except for a tiny 5v fan.
As a retired engineer having done design, programming, & construction, I continually think about the excellent efforts that went into bringing this unique hardware and software to the market for "pennies'" or free.
I reserve any comments that may be considered criticism by the creators.
I'm sure they appreciate constructive comments about improvements to consider when they have time from their schedules.
So much more fun than the Heathkit days!
73, Bo W4GHV since '54   (at 78, just glad to be alive!)

Re: Neat power supply!

 

Ordered it and will try. I needed a variable PS for some other purpose.
For bitx I use one of the many bench power supplies in my collection.

Earlier I modded a laptop charger to make it variable but without display.
for 12 bucks this looked like a steal with display!

Raj

At 30-06-18, you wrote:
Looks good, but switch mode supplies can cause a lot of RF interference.
Have you tried it?
Cheers
--
John VK6JAH

Re: Known issues on uBITX r4 #ubitx

hirosmb JAZZ <hirosmb@...>
 

I got a 12V 5A regulated power supply with ferrite core for noise filter, plus I got 10 pieces of extra ferrite core, just in case.

I also got some knobs for VFO and volume which shafts are 6mm. Is it OK?

I will make a front panel tomorrow.

// hiro, JJ1FXF



2018/06/30 16:38、hirosmb JAZZ <hirosmb@...>のメール:

Wow!, my uBITX has been shipped!!

Many, many thanks for all who advised to me.

BR,

// hiro, JJ1FXF



2018/06/30 10:38、hirosmb JAZZ <hirosmb@...>のメール:

Bo,

Heathkit was my great aspiration when I was a junior high school student, I remember.

I feel the same heated atmosphere with uBITX this time.

Thanks for your message, Bo.

ARIGATO!

// hiro, JJ1FXF



2018/06/30 6:02、Bo Barry <bobarr@...>のメール:

I have a v3 & v4 and am "tickled to death" (American slang expression) with both of them.
NO mods (except KD8CEC mods to one) so far except for a tiny 5v fan.
As a retired engineer having done design, programming, & construction, I continually think about the excellent efforts that went into bringing this unique hardware and software to the market for "pennies'" or free.
I reserve any comments that may be considered criticism by the creators.
I'm sure they appreciate constructive comments about improvements to consider when they have time from their schedules.
So much more fun than the Heathkit days!
73, Bo W4GHV since '54   (at 78, just glad to be alive!)

Re: Noise Burst #bitx40

Allard PE1NWL
 

If you set semiQSK to ON (in the SETTINGS menu, CW params), then the radio
will automatically switch to CW mode as soon as the CW key (or tune
button) is pressed.
To return to SSB mode, just press the PTT switch on the mic.

73 Allard PE1NWL

On Sat, June 30, 2018 09:30, jah12@... wrote:
Sorry Allard.
Figured it out now.
I did not have the BitX in CW mode via the Function push button.
All works now!
Cheers
--
John VK6JAH



Re: Known issues on uBITX r4 #ubitx

 

Hiro,

The Volume control is 4mm with switch. So if you are at Akhiabara tomorrow pick up
a 10KA pot with switch (if required) of 6mm type.

Raj

At 30-06-18, you wrote:
I got a 12V 5A regulated power supply with ferrite core for noise filter, plus I got 10 pieces of extra ferrite core, just in case.

I also got some knobs for VFO and volume which shafts are 6mm. Is it OK?

I will make a front panel tomorrow.

// hiro, JJ1FXF

Re: Known issues on uBITX r4 #ubitx

hirosmb JAZZ <hirosmb@...>
 

Raj,

Thanks for ur reply.

I understand that VFO shaft is 6mm but the volume shaft is 4mm.

I will try to find again a knob for 4mm shaft and also the 6mm pot and switch, just in case.

Thank you for ur advice.

// hiro, JJ1FXF



2018/06/30 20:17、Raj vu2zap <@Raj>のメール:

Hiro,

The Volume control is 4mm with switch. So if you are at Akhiabara tomorrow pick up
a 10KA pot with switch (if required) of 6mm type.

Raj

At 30-06-18, you wrote:
I got a 12V 5A regulated power supply with ferrite core for noise filter, plus I got 10 pieces of extra ferrite core, just in case.

I also got some knobs for VFO and volume which shafts are 6mm. Is it OK?

I will make a front panel tomorrow.

// hiro, JJ1FXF


Re: uBitxr4 audio distortion fix

Tim Gorman
 

Allison,

This circuit does the same thing I mention, just in a different manner.
This circuit uses feedback to drive the collector of TR1 to the proper
voltage.

My method eliminates the need for the feedback.

Both will work to enhance the fidelity from the amplifier. I have used
my method in several audio amps and had no problem.

tim ab0wr

On Fri, 29 Jun 2018 19:02:34 -0700
"ajparent1/KB1GMX" <kb1gmx@...> wrote:

Tim no.

The problem is if the first transistor Q71 is not biased to the half
power supply point the output are both unbalanced and the bias is
wrong.  IF Q71 collector is not at about 6V (for 12V supply) full
stop.  Adjust R72 until it is.  Then adjust the bias if needed to the
complementary pair.  

The most common variation is to derive the bias from the common point
of both emitters as then it tries to self center at 6V or half the
supply.  The cost of of doing that is lower gain but higher fidelity.

See the design from this site (attached) and explanation.
http://www.deeptronic.com/electronic-circuit-design/small-audio-power-amplifier-using-3-transistors/

Do not let their published 3V power scare you it works well at 12V
too. The key is how Q1 is biased and the resulting bias to the output
string (3904 and 3906).

Allison

It should be possible to change the V4 circuit to that.


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

alans77@...
 

Hi Pat: I have tried to duplicate your clever fix of picking off receive-only 12v from R52 without success. On my radio with the pop fix kit installed 12V is active on RX and TX.
73,
Alan

Re: Neat power supply!

iz oos
 

I heard that some switching power supply when they fail they may make extensive damage because of leaks of AC, at least this what I was told. In some appliances that had noisy switching power supplies, I wrapped them into aluminum foil and added a ferrite to the vdc cable (wound many times). In the worst cases I connected the foil to ground. I solved completely the issue.


Il 30/giu/2018 10:01, "Raj vu2zap" <rajendrakumargg@...> ha scritto:
Ordered it and will try. I needed a variable PS for some other purpose.
For bitx I use one of the many bench power supplies in my collection.

Earlier I modded a laptop charger to make it variable but without display.
for 12 bucks this looked like a steal with display!

Raj

At 30-06-18, you wrote:
>Looks good, but switch mode supplies can cause a lot of RF interference.
>Have you tried it?
>Cheers
>--
>John VK6JAH




Re: uBitxr4 audio distortion fix

Tim Gorman
 

You can also fix this by adding a bias resistor from the base of the
PNP transistor to ground and feeding the audio into the midpoint of the
diodes with an isolating capacitor.

Using Q71 as a current source for Q72 and Q73 will require either
negative feedback or an adjustable resistor in the Q71 base bias or
even both, otherwise differences in the transistors used can cause
problems. You may even need to add a balance resistor between the bases
of Q72 and Q73 to eliminate cross-over distortion.

With my solution these adjustments aren't needed as much.

tim ab0wr

On Fri, 29 Jun 2018 19:02:34 -0700
"ajparent1/KB1GMX" <kb1gmx@...> wrote:

Tim no.

The problem is if the first transistor Q71 is not biased to the half
power supply point the output are both unbalanced and the bias is
wrong.  IF Q71 collector is not at about 6V (for 12V supply) full
stop.  Adjust R72 until it is.  Then adjust the bias if needed to the
complementary pair.  

The most common variation is to derive the bias from the common point
of both emitters as then it tries to self center at 6V or half the
supply.  The cost of of doing that is lower gain but higher fidelity.

See the design from this site (attached) and explanation.
http://www.deeptronic.com/electronic-circuit-design/small-audio-power-amplifier-using-3-transistors/

Do not let their published 3V power scare you it works well at 12V
too. The key is how Q1 is biased and the resulting bias to the output
string (3904 and 3906).

Allison

It should be possible to change the V4 circuit to that.


Re: Neat power supply!

Arv Evans
 

Most AT and ATX style computer power supplies are shielded by the metal case.  They do lack
shielding in the form of bypass capacitors on the DC leads leaving the case.  This can be fixed
by installing 0.1 mfd capacitors on the DC leads as close as possible to where these leads pass
through the metal chassis. 

Laptop type computer power supplies are a little different because they are designed to charge
batteries and not for directly running devices that have rapidly varying loads.  It is usually possible
to remove some of the RF interference from these units by adding 0.1 mfd on each DC lead, but
the plastic case is the real problem.  Some luck has been had by removing the plastic case and
installing the PCB inside a metal case, with appropriate input and exit RF bypass arrangements. 

Switching power supplies that are designed for constant load can sometimes be made to work
with varying loads by adding 2200 or 4700 mfd capacitors across the DC outputs.  These
capacitors can usually be found and salvaged from dead or unneeded AT or ATX style PC power
supplies.  This might be a good tactic for laptop type power supplies that don't quite have enough
current on peaks to handle the varying load of an SSB or CW transceiver. 

Arv  K7HKL
_._


On Sat, Jun 30, 2018 at 10:56 AM iz oos <and2oosiz2@...> wrote:

I heard that some switching power supply when they fail they may make extensive damage because of leaks of AC, at least this what I was told. In some appliances that had noisy switching power supplies, I wrapped them into aluminum foil and added a ferrite to the vdc cable (wound many times). In the worst cases I connected the foil to ground. I solved completely the issue.


Il 30/giu/2018 10:01, "Raj vu2zap" <rajendrakumargg@...> ha scritto:
Ordered it and will try. I needed a variable PS for some other purpose.
For bitx I use one of the many bench power supplies in my collection.

Earlier I modded a laptop charger to make it variable but without display.
for 12 bucks this looked like a steal with display!

Raj

At 30-06-18, you wrote:
>Looks good, but switch mode supplies can cause a lot of RF interference.
>Have you tried it?
>Cheers
>--
>John VK6JAH




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

alans77@...
 

Hi all: I remembered that the pop fix split TX/RX power so I moved the lead from R52 to the pop fix board RX pad. This eliminated the loud and clear audio on transmit leaving only a much lower muffled response that can probably be addressed with ferrite beads on the volume control to AGC twisted pair.

73,
Alan

Re: JackAl board pricing

PeteWK8S
 

On Fri, Jun 29, 2018 at 01:45 pm, Jack Purdum wrote:
the 5" touch screen
It might be fun to play ahead of the JackAL board's arrival.  PJRC has the Teensy and Audio Bd. but for compatibility where is suggested to find/buy the 5" TFT touch screen?

Pete WK8S

Nextion Display programming, extension cable

rohn blake
 

As I was "parts shopping" online I came across a micro SD card extension cable that could be used, I think, to extend the micro sd card slot of the Nextion display out to the exterior of the case - for those that are doing experimentation with that display. A link to the amazon page is: https://www.amazon.com/Extension-Extender-Flexible-Monoprice-Raspberry/dp/B072X27V58/ref=pd_sim_147_14

Maybe this helps someone
73 de Rohn, kr0hn

Re: uBitxr4 audio distortion fix

ajparent1/KB1GMX
 

Yes it does but insufficient and is very sensitive to the DC beta(HFE) of the particular device.

The two posted do not exhibit this.  I can list a small high of gear that use
similar rather than an IC without issues. 

Allison

Re: Compiler warnings

ajparent1/KB1GMX
 

I take them seriously as it impacts future upgrades of the compiler which may
not accept it at all.  That and its a basic fix.

I'm an old Pascal user and wild type changes were not permitted.  

Also old assembler writer where you can do terrible things and
maybe survive.... ouch!


Allison

Many thanks to many great hams

Dennis Yancey <bigbluedry@...>
 

at the risk of leaving someone out, I won’t mention anyone specific, but rather speak to the several as a group. 

I want to say a special thanks to you... those that provide great kits at a more than reasonable price, those that supply software, articles and tutorials, but also, the wonderful folks that are willing to dig in with you on a problem and help resolve it. This entire group is owed a vast debt of gratitude by those of us that are able to holler CQ, CQ on 8 watts....

Thank each and every one of you.
72 and God bless you.

Re: JackAl board pricing

Jack, W8TEE
 

There are two display options for the JackAl board: 5" or 7". These are purchased from BuyDisplay.com. Their order numbers are:

ER-TFTM050-3        (5")
ER-TFTM070-5        (7")

both displays use the following options:

4-wire SPI interface
3.3V
Resistive touch
No font (we use the library)

Both are 800x480 displays using the RA8875 chip. If you run the samples using a touch screen, make sure you run the Calibration sample program first.

Jack, W8TEE


On Saturday, June 30, 2018, 1:49:48 PM EDT, PeteWK8S <pmeier@...> wrote:


On Fri, Jun 29, 2018 at 01:45 pm, Jack Purdum wrote:
the 5" touch screen
It might be fun to play ahead of the JackAL board's arrival.  PJRC has the Teensy and Audio Bd. but for compatibility where is suggested to find/buy the 5" TFT touch screen?

Pete WK8S

Re: Running on a Jump Box

Tim Gorman
 

You can't regulate output "power" by regulating the amount of current
the power supply provides. You can regulate the voltage you apply but
the current drawn is a function of the input power to the amplifier
chain and the amplification of the amplifier chain. The amplifier chain
needs to be operated where the amplifier is linear.

If you operate so that the power supply *never* has to provide 1.5amps
then you would be ok. But if you are depending on the power supply to
regulate the current to 1.5amps regardless of the drive level then you
are likely operating the amplifier chain in a non-linear manner thus
causing IMD products.

At 12v to the mainboard and 15v to the final amplifiers my unit pulls
about 2.2 amps on CW. Of course it pulls about 300ma on receive because
I am using an enhanced Radi2cino with a teensy adapter and a teensy 3.6
cpu.

A 3amp supply wasn't cutting it initially, the output voltage from the
suppy would drop on voice peaks. I went to a 10amp supply and had no
more problems.

try this site: en.wikipedia.org/wiki/Intermodulation
to begin with.

tim ab0wr

On Fri, 29 Jun 2018 20:48:55 -0700
"Gwen Patton" <@NG3P> wrote:

Thank you, Tim.

That's certainly a better answer than assuming I want to overdrive
it, or telling me what I already knew, that I needed to regulate it.
I'll check RV1.

I'm still a bit confused about what kind of power to put INTO the
thing, though. 12v at how many amps? My bench supply can put out 3a
easily, but I've been running it at 1.5. I got one suggestion to
regulate the input power...isn't that what I was doing, with the
bench supply? Maybe I need a link to a reference or something,
because the docs aren't very explicit and so far I've gotten 3 wildly
different opinions on it.


Re: uBITX Version 4 first attempt #ubitx-help #ubitx

Richard
 

Good Afternoon,

It appears all the opinions have faded - I have an update.  I purchased an Amazon LM386 mini amplifier, and  isolated it with a 100mF Electrolytic with the positive side towards the Transistor that is feed off the wiper of the volume pot-   And Voila-  the speaker is now loud enough to hear across the room, and it sounds nice,  I have now been able to hear SSB QSO's - however I still need assitance in the calibration technique for a V4 with factory Firmware-  Any tips on how to do it?    The little amp is pulling some stray RF and I can hear myself a little through the speaker - but I will work on that in a while...

Please understand the V3 Calibration process is different.
--
Richard
KC7DDW