Alison :
Doesn't it kill the CW Sidetone with your mute connected to VOL-H ?
Ashar has his V4 pop circuit connected at M2(R70) with the value of R70 increased to 1K ohms. ?I think that this option still allows you to
hear CW sidetone.
Skip (NC9O), ?M1/M2 is connected via relay (RX voltage) so I would think that you would want to mute at M2 rather than M1/C51 to isolate the
input of the audio amp from the relay opening and closing.?
Michael VE3WMB?
P.S. Alison ... thanks for this it is very timely as I was just about to build a pop fix for my V3 board !?
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Re: BITX40 and uBITX Kits missing encoders for VFO!
#ubitx
#bitx40
I just received a uBITX yesterday and I'm a total noob at this. I have a small cylinder about 1 cm in diameter and 1 cm high. Is that the electret mic? If not what is it? I do have a small rectangular piece with a knob on top and pins on the bottom, which I assume is the tuning encoder.
-Bill? KG5RMJ
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Re: Exciting times in the uBITx world
It is exciting!??
It would be great if Sunil of?amateurradiokits.in could create a "deluxe" case with a cutout for the Nextion and either room or cutouts for additional switches and pots, e.g. an RF gain pot and a bunch of push buttons.? A couple of inches of internal room for add-ons would be nice too.
Yes, I could drill my own but with my skills and tools, it won't look nearly as nice.? And Sunil's including a bag of parts with the case is awesome - pretty much everything you need to finish the txcvr.
How about it? :-)?
73,
Rowland K4XD
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Re: Exciting times in the uBITx world
I ordered a 3.2 enhanced from ITEAD on their website. Then I looked around AliExpress and Ebay just to see the knock-offs. Funny, no particularly compelling savings (most actually more expensive) and none of the extensive support available from ITEAD (granted some for a price). Saving grace are the indications that these display are available in depth.
Looking forward to trying Ian's excellent software with this super nice display. Also, learning more about it's capability by personal experimentation.
73,
Paul - K2AYZ
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Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels
#ubitx
#ubitx-help
Good Mike,
To make it ultra neat: solder back the diode and cut the track inbetween
the diodes. Solder a fixed resistor
between the cut track (you need to scrape it but a resistor may fit
between the two diodes pads!).
Not forgetting to measure the value you have currently adjusted the
preset!
Just for information please check the DC voltages on the finals CBE
points.
I guess the diode voltage drop is less than that of the transistor Vbe!
I hope Farhan is listening!
This issue would not have been there if there was one more transistor
and DC feedback from output
to input like an opamp!
Raj
At 17/06/2018, you wrote:
toggle quoted message
Show quoted text
Did the biasing mod. That solved
the crossover distortion issue. I took a 500 ohm pot and paralleled that
with a 125ohm resistor. The mod doesn't look so good? (LOL) but it
works. One of the transistors became warm if the voltage difference due
to the pot became too large. I adjusted this while feeling the temp and
listening to? a cw carrier: low distortion AND low temperatire,
became the setting point.
(Disregard the screened cable in the lower left of the pic. That was the
tap to my external amp, before biasing the original amp more
properly).
![[]](/g/BITX20/attachment/52186/)
?
|
Hello,
This email message is a notification to let you know that a file has been uploaded to the Files area of the [email protected]
group.
File: UBITX CASE MANUAL PCB FRONT PANEL.pdf
Uploaded By:
Sunil Lakhani
Description:
A short manual of explaining how to build up the front panel board for stereo sockets For case sold by amateurradiokits.in for micro bitx.
You can access this file at the URL:
/g/BITX20/files/UBITX%20CASE%20MANUAL%20%20PCB%20FRONT%20PANEL.pdf
Cheers,
The Groups.io Team
|
Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels
#ubitx
#ubitx-help
Did the biasing mod. That solved the crossover distortion issue. I took a 500 ohm pot and paralleled that with a 125ohm resistor. The mod doesn't look so good? (LOL) but it works. One of the transistors became warm if the voltage difference due to the pot became too large. I adjusted this while feeling the temp and listening to? a cw carrier: low distortion AND low temperatire, became the setting point. (Disregard the screened cable in the lower left of the pic. That was the tap to my external amp, before biasing the original amp more properly). 
|
Re: MAX 9814 AGC for the uBitx help required
John
The general rule of thumb is to connect the negative end of the
capacitor to the circuit that goes to earth (perhaps via a
resistor).
In the circuit here:??
C2 is positive going through the resistor to the +5v line and
negative to ground
C6 is positive going to the Output of the MAX9814 module, and
negative to the top of the potentiometer via R2 (and then to
ground through the lower connection of the pot.
Mike ZL1AXG ubitx.net
On 17/06/18 7:16 PM, johnelvy via Groups.Io wrote:
Hello,?
I have downloaded the MAX 9814 AGC circuit courtesy of the uBitx
site but? note that no polarities are shown for the?
10uF Capacitors C4, & C6. Can anyone help here please?
Thank you.
John?
ZL2BH
|
MAX 9814 AGC for the uBitx help required
Hello,?
I have downloaded the MAX 9814 AGC circuit courtesy of the uBitx site but? note that no polarities are shown for the?
10uF Capacitors C4, & C6. Can anyone help here please?
Thank you.
John?
ZL2BH
|
Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels
#ubitx
#ubitx-help
Mike,
Try this: Lift up D15 or 16 diconnecting one end from the board. Solder
the
center and one end of a 47 ot 100 Ohm preset between the two diodes.
Make sure the preset is at minimum. Power up and slowly increase the
preset till distortion goes away.See that the Q72/73 don't get hot
while
the volume is low.
You are increasing the quiescent current in the final transistor to
overcome
cross over distortion.
Raj
At 16/06/2018, you wrote:
toggle quoted message
Show quoted text
Raj, VU2ZAP: here are the
voltages you asked for.
![[]](/g/BITX20/attachment/52181/)
?
|
Re: The BITeensio board is here.
#ubitx
To my dear XYL's chagrin, I have just purchased a stereo AmScope SE400-X microscope with fixed 5x or 10x magnifications (depending upon the eyepice selected).? This has a 9 inch distance to the work object and a wide field of view, so very little chance of burning one's nose with the soldering iron. But USD200! + freight down here to Oz.? However it provides a stereo view of the pcb with great clarity.? I understand that freight to CONUS is free. Usual disclaimers.
73 all,
Kevin VK3DAP? / ZL2DAP
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Re: Progress is being made
Just have fun with it.
It's not a $1000 investment (although I wish my Yaesu could receive this well)
Here's a pic of my 1st build.
As you can see . . . no metal . . just a cardboard box.
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Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels
#ubitx
#ubitx-help
The voltages seem fine to me. I dont have my board with me here at the
farm, I will
have to get back after a week to check my boards!
Raj
At 16/06/2018, you wrote:
toggle quoted message
Show quoted text
Raj, VU2ZAP: here are the
voltages you asked for.
![[]](/g/BITX20/attachment/52178/)
|
Re: The BITeensio board is here.
#ubitx
I bought a pair similar to those.? Could only use one eye at a time and my nose was about 2 inches from the board.? After trying several things, I finally spent $ 200 for a good stereo microscope.? I had spent about 1/3 of that trying several cheep things.
de ku4pt
On Sat, Jun 16, 2018 at 7:51 PM, Roy Appleton <twelveoclockhigh@...> wrote: No way I could use those "goggles" with a focus length of 2" (50mm)!
Roy WA0YMH
On Sat, Jun 16, 2018, 5:40 PM Lawrence Macionski via Groups.Io <am_fm_radio= yahoo.com@groups.io> wrote: Jim-
Thank you for showing me the BITeensio Board at the swap-n-shop today!!..
Guys-
??????? I had the board in my hands and I have 40 years in IT/Heavy Military and NASA. It is Total 1st class quality.. Yes, I know there is a hundred ways to go to make your uBITX your's .. But seriously consider Jim's value added features and such to see if they are right for you.? Especially the 4 line display ability offers so much more than just 2.
Not that is is a negative but both Jim and I agree- Assembly requires patience, a very good soldering station, and soldering tools.. Plus if you are like us..You need? Geezer goggles!!!? ()
|
Excellent!? ?Thank you Allison!? And thanks for the diagram too!
|
What's not seen and didn't make a difference to pop/thump was I removed k3 from the audio path
(K3 contacts 1,3,5) so I could use them to ground the RX path during TX and use K1 to switch
the antenna and Q90 to the output/input of the 30mhz low pass filter.? This relieves the filter
and receiver of Q90 base resistor (100 ohms) from the path on RX and helps improve sensitivity.
There are many mods most will not do or feel are not needed for them.? Most of what I am doing
are to suit my wishes eclectic as they may be.
Allison
|
Yes it is the timing Allison I set mine to about 1.5 ms (I¡¯d have to check my notes) and that solved both thump and pop. I played with the values too before settling on what I ended up with, using parts on hand.?
toggle quoted message
Show quoted text
On Jun 16, 2018, at 19:25, ajparent1/KB1GMX < kb1gmx@...> wrote: Hi Skip,
Also just having the Resistor and diode on the Radiuno was less effective
as you get the return to RX thump when DC is applied to Q70.? It only got the POP.
I wanted the TX release thump to go away.
This approach using the Raduino kills the RX audio before the relay actually moves so the key
down pop when power is applied to Q6 disappears completely.? The TX power resistor and diode
hold the audio off until after Q70 has power by a few milliseconds (1k*.1uf=about 1ms) and that
kills the return to RX thump.? FYI the cap needs about 3-4 RC time to release the mosfet as
the gate threshold us under 4V and we charge the cap to 12V.
Its a timing issue.? Relays are slow and there are enough capacitors in the switched lines
that nothing stops working immediately so we get RX/TX overlap.??
Muting this way is very clean and the audio comes back smoothly.? That and its well tested.
I finally got to writing it up.
Allison
|
Re: The BITeensio board is here.
#ubitx
I tried those 2 inch focal length goggles but I kept burning my nose on the soldering iron.? 8-)
_._
No way I could use those "goggles" with a focus length of 2" (50mm)!
Roy WA0YMH
On Sat, Jun 16, 2018, 5:40 PM Lawrence Macionski via Groups.Io <am_fm_radio= [email protected]> wrote: Jim-
Thank you for showing me the BITeensio Board at the swap-n-shop today!!..
Guys-
??????? I had the board in my hands and I have 40 years in IT/Heavy Military and NASA. It is Total 1st class quality.. Yes, I know there is a hundred ways to go to make your uBITX your's .. But seriously consider Jim's value added features and such to see if they are right for you.? Especially the 4 line display ability offers so much more than just 2.
Not that is is a negative but both Jim and I agree- Assembly requires patience, a very good soldering station, and soldering tools.. Plus if you are like us..You need? Geezer goggles!!!? ()
de Larry W8LM
ARRL Life Member - Licensed? 368 DOG Years..
|
Re: The BITeensio board is here.
#ubitx
No way I could use those "goggles" with a focus length of 2" (50mm)!
Roy WA0YMH
On Sat, Jun 16, 2018, 5:40 PM Lawrence Macionski via Groups.Io <am_fm_radio= [email protected]> wrote: Jim-
Thank you for showing me the BITeensio Board at the swap-n-shop today!!..
Guys-
??????? I had the board in my hands and I have 40 years in IT/Heavy Military and NASA. It is Total 1st class quality.. Yes, I know there is a hundred ways to go to make your uBITX your's .. But seriously consider Jim's value added features and such to see if they are right for you.? Especially the 4 line display ability offers so much more than just 2.
Not that is is a negative but both Jim and I agree- Assembly requires patience, a very good soldering station, and soldering tools.. Plus if you are like us..You need? Geezer goggles!!!? ()
de Larry W8LM
ARRL Life Member - Licensed? 368 DOG Years..
|
On Sat, Jun 16, 2018 at 02:19 pm, Joel Caulkins wrote:
MTP3055V
Will work fine for the lower bands.? I've used them for 40M and they work ok, shame they are obsolete.? Some one got them thinking they were 2n3055 by error bought them and could not find a use for them.? They found their way to me. Input C is 410PF (nominal) and only 50V.? At 12V it should be OK but power on 20 and up will be lower as the drivers have to work harder.?? It would be like using IRF520. Allison
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Paul Galburt - K2AYZ
Raj vu2zap
Skip Davis