Re: Known issues on uBITX r4
#ubitx
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@...&²µ³Ù;¤Î¥á©`¥ë:
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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@...&²µ³Ù;¤Î¥á©`¥ë: 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@...&²µ³Ù;¤Î¥á©`¥ë: 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!)
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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
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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
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Re: Known issues on uBITX r4
#ubitx
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@...&²µ³Ù;¤Î¥á©`¥ë:
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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@...&²µ³Ù;¤Î¥á©`¥ë: 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!)
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Looks good, but switch mode supplies can cause a lot of RF interference.
Have you tried it?
Cheers
--
John VK6JAH
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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
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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
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or
Cheers
--
Raj, vu2zap
Bengaluru, South India.
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Re: Running on a Jump Box
I had suggested regulating the voltage, but didn't consider that pot. I agree with the above.?
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Re: Running on a Jump Box
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.
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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.
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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
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Re: Running on a Jump Box
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.
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Re: uBitxr4 audio distortion fix
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
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Re: uBitxr4 audio distortion fix
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
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Re: uBitxr4 audio distortion fix
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.
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.
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Re: Microscope - - new thread
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
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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
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Re: RF power chain mods and improvements..
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
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As did I, David. Thanks for the reply. The popularity of the uBitX continues I see.
Hal
AC0AX
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Re: Known issues on uBITX r4
#ubitx
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@...&²µ³Ù;¤Î¥á©`¥ë:
toggle quoted message
Show quoted text
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: Known issues on uBITX r4
#ubitx
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
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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.
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Raj vu2zap
Gwen Patton
Terry Morris