Date   
Re: KD8CEC Firmware

Glenn
 

sorry for bw..... finally found it.


On Fri, Jun 29, 2018 at 05:46 pm, Glenn wrote:
ian or anybody, I am trying to locate the actual source of Ian's files for the NEXTION displays to download.

I have looked over Ian's web pages but just cannot find  a link to the files. Any ideas?

glenn
vk3pe

Re: Running on a Jump Box

Tim Gorman
 

Gwen,

Anytime you control the amperage to a linear amplifier, such as with a
current limiter, you make it non-linear. This will cause all kinds of
inter-modulation products. It is similar to "flat-topping" a linear
amplifier where you no longer have a linear relationship between the
input and the output.

The only way to control the maximum output of a linear amplifier is to
control the maximum input levels to it. That keeps the amplifier
linear.

The method for doing this in the ubitx is the RV1 control. If you want
less output then turn RV1 down.

tim ab0wr

On Fri, 29 Jun 2018 10:50:40 -0700
"Gwen Patton" <@NG3P> wrote:

You misunderstand me, Ralph. I don't WANT it to act the same. If I
wanted that, I'd just run it directly from the jump box. But I don't
want it to run away in RF, as at that level it can damage my tuner. I
want it to run at 5-10 watts, not 18-20! I can control it with the
amperage, and since the fuse is a 2A inline, I don't want it to run
more than that. So I'm certainly not going to set it to 3A unless I
want to toast marshmallows on my tuner.


Re: RF in 12v Supply

Tim Gorman
 

This sure sounds like a good arrangement.

tim ab0wr

On Fri, 29 Jun 2018 14:41:50 -0400
"Bill Cromwell" <wrcromwell@...> wrote:

Hi Mark,

I laid out and folded a case of steel for my ubitx. Looking from the
front, my antenna connector is at the far right rear corner and the
internal connector wire is less than two inches long to reach from
the board with just a little slack. The DC power connector is over at
the far left back. The volume control is way over on the lower right
corner of the front panel along with the on-off switch. I routed the
power wires under the ubitx board to take advantage of the mostly
ground plane board to help shield it from RF at the finals, output
filters, and antenna connector. The power line runs much closer to
the front of the radio until it gets to the left side and then back.
It only comes out from under the circuit board *AT* the back corner.
There is no problem with RF. I hope this is helpful to you and others
when they layout and assemble theirs.

On 06/29/2018 01:17 PM, Mark M wrote:
The issue discussed in the 'RFI from uBitx TX after AGC and other
mods installed' thread appears to be caused by RF getting into the
12v supply and from there into the 5v supply that feeds the AGC
board (the ND6T/K5BCQ kit). At least that appears to be the issue
on mine. I thought I'd start another thread to talk about that.

I have the ubitx in a case from amateurradiokits.in. The power
comes in thru a plug in the rear panel at the right of the panel
(looking at it from the front), thru a fuse and then thru three
wires twisted together along the rear panel to the connector on the
board at the far left. There's also a polarity protect diode across
the supply. The power connector is right next to the antenna
connector and the supply wires run past the final transistors and .

I'm running the ubitx on 13.8v from an Astron 20A power supply, The
testing was done feeding a Heathkit Cantenna dummy load.

So, any suggestions on how to fix this would be appreciated. Don
mentioned heavier supply wires and capacitor at the input. I
thought I'd try re-routing the supply wires inside case to get them
away from the RF section. Moving the power connector to the other
end of the rear panel would make the run much shorter. Other than
that, I don't know. RF hardware is not my forte (I'm mostly a
software guy).

Thanks.... Mark AA7TA

Re: Known issues on uBITX r4 #ubitx

hirosmb JAZZ <hirosmb@...>
 

Thanks, Iz.

I will try to find a silent 3-5A power supply, or maybe I can buy a standalone AC noise filer.

// hiro, JJ1FXF



2018/06/30 5:57、iz oos <and2oosiz2@...>のメール:

I confirm my 2A was not enough and shut down. Use at least a real 3A, linear is better to avoid any issue you might not even a clue.


Il 29/giu/2018 22:48, "Daniel Conklin" <danconklin2@...> ha scritto:
The other thing you can do if you don't have a 5A or better supply is turn back the drive to your finals.
Dan, W2DLC

Re: Known issues on uBITX r4 #ubitx

hirosmb JAZZ <hirosmb@...>
 

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: Shipping issues

AC0AX
 

As did I, David. Thanks for the reply. The popularity of the uBitX continues I see.

Hal
AC0AX

Re: RF power chain mods and improvements..

ajparent1/KB1GMX
 

Understanding the circuit...

Both the pre-driver and driver the pairs have their own (per transistor emitter resistors) and 
the idea is to have the device operating at a reasonable point that being 20ma per device.
If there are two its still 20 ma per deives and you get that by measuring across the emitter
resistor and applying ohms law V/R=I  so .22V arcoss a 11ohm resistor is .02A (20mA).

If too high changing the various bias resistors is called for.

Running too high a current is a waste of power and does not enhance performance.

Allison

Re: RF in 12v Supply

ajparent1/KB1GMX
 

I've build SS amps for radios up to 350W and never had RF get into a power supply.

I could understand if the antenna was poor and you had high shield currents but 
a dummy load?  No.

I'd suspect the wiring of the antenna connection from the board to the load
has the ground and RF hot reversed.  If you did that you would have RF all
over the place and possible ill effects.

I have two Astrons and they are not particularly RF sensitive.

Allison

Re: Microscope - - new thread

Terry Morris
 

It's possible this might work on Linux with the Cheese application. I need to find out if this is so before I drop $200 for it though.

Terry - KB8AMZ
Brimfield Twp, OH USA EN91hd
Linux User# 412308, Ubuntu User# 34905, PCARS#78, NAQCC#6668, QRP-ARCI#8855, SKCC#14195

Re: uBitxr4 audio distortion fix

ajparent1/KB1GMX
 

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: uBitxr4 audio distortion fix

ajparent1/KB1GMX
 

Another that more closely resembles the V4 circuit with improvements.

The two NPN can be 2n3904 and the pnp is 2n3906.

I've used this flavor from 5V though 20V.  At 12V it will put 250mW in to a 8ohm speaker.

Allison

Re: uBitxr4 audio distortion fix

Jack, W8TEE
 

Thanks, Allison...looks interesting.

Jack, W8TEE

On Friday, June 29, 2018, 10:09:15 PM EDT, ajparent1/KB1GMX <kb1gmx@...> wrote:


Another that more closely resembles the V4 circuit with improvements.

The two NPN can be 2n3904 and the pnp is 2n3906.

I've used this flavor from 5V though 20V.  At 12V it will put 250mW in to a 8ohm speaker.

Allison

Re: Running on a Jump Box

Gwen Patton
 

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: uBitxr4 audio distortion fix

 

I tried a mod like this and the gain dropped so I split the feedback resistor by 2
and bypassed to ground with a 10uF at the center. Sounds great now.

At 30-06-18, you wrote:
Another that more closely resembles the V4 circuit with improvements.

The two NPN can be 2n3904 and the pnp is 2n3906.

I've used this flavor from 5V though 20V. At 12V it will put 250mW in to a 8ohm speaker.

Allison

Re: Running on a Jump Box

Ralph Mowery
 

Trying to make it simple.  You regulate the voltage.  Let the device draw how ever many amps it needs or wants.  In the case of the ubitx it will be around 2 to 3 amps depending on the power it is putting out and how efficient it is.   If you do want to run less power to the antenna , use the RV1 pot to cut back the output power.

You may think of this like your house wiring.  If in the US, most outlets are 120 volts and have 15 to 20 amp breakers.  If you plug in a 100 watt lightbulb, it will draw just under 1 amp.  If you plug in one of the newer LED bulbs it will draw around a tenth of an amp.  If you plug in a toaster, it will draw probably 10 or so amps.  If all devices are working correctly, they will only draw what they need to operate correctly.

As I mentioned in the first post, if you set the current to 1.5 amps and it is wanting to draw 2 amps, your voltage will drop.  This can cause all kind of operating problems.  As another mentioned, the amplifying stages will become non linear and can cause the transmitter to generate undesired signals.

If you do have a current regulating supply, set it to about 4 amps.  This is high enough to power the transmitter but low enough not to burn out too much stuff if there is a problem.  You should have a 3 to 5 amp fuse in the power line anyway to take care of major problems.

KU4PT

On Fri, Jun 29, 2018 at 11:48 PM, Gwen Patton <ardrhi@...> 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: Running on a Jump Box

Christopher Miller
 

I had suggested regulating the voltage, but didn't consider that pot. I agree with the above. 

Neat power supply!

 

Re: Noise Burst #bitx40

John
 

Hi Allard
Went to add a Tune button to my BitX40  Raduino but cannot get it to work.
As suggested, added a push button in series with a 1K resistor between pin A1 on connector P1 to ground, as well as a 4K7 resistor between the hot side of C107 at the balance mixer to pin D6 on connector P3, but no carrier output for tuning when button pressed while in transmit.
Rig works fine transmitting ssb.
Looking at my BitX40v3 board (dated 2016) I see that there are no diodes D15 and D16 in place and no balance pot R105 in place. I wonder if I have an upgraded board that has had changes made, and the Tune wire from D6 to C107 needs to attached to another point on the BitX board?
Also D6 remains Low (0v) at all times. Is there some lines in software that needs to be 'Uncommented" or altered to get D6 to toggle between Rx andTx?
Regards
--
John VK6JAH

Re: Noise Burst #bitx40

John
 

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: Neat power supply!

John
 

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