Date   

Re: The BITeensio board is here. #ubitx

Jack, W8TEE
 

Has anyone tried this type of scope:

Inline image
(eBay 352344602558)? For $60, I'd be very interested if it works.

Jack, W8TEE

On Sunday, June 17, 2018, 1:16:28 AM EDT, Kevin Luxford <kbgluxford@...> wrote:


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






Re: Alternate pop fix...

 

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 ! 


Re: BITX40 and uBITX Kits missing encoders for VFO! #ubitx #bitx40

Bill Maier <ciric50@...>
 

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


Re: Exciting times in the uBITx world

RowlandA
 

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


Re: Exciting times in the uBITx world

Paul Galburt - K2AYZ
 

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


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:
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).
[]  


New file uploaded to BITX20@groups.io

BITX20@groups.io Notification <BITX20+notification@...>
 

Hello,

This email message is a notification to let you know that a file has been uploaded to the Files area of the BITX20@groups.io 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:
https://groups.io/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

Mike
 

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

Mike Woods
 

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:   http://ubitx.net/new-feature-agc/

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


--
Mike Woods
mhwoods@...


MAX 9814 AGC for the uBitx help required

johnelvy@...
 

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.
https://en.wikipedia.org/wiki/Crossover_distortion


Raj


At 16/06/2018, you wrote:
Raj, VU2ZAP: here are the voltages you asked for.
[]  


Re: The BITeensio board is here. #ubitx

Kevin Luxford
 

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


Re: Progress is being made

Russ KG0BK
 

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.


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:
Raj, VU2ZAP: here are the voltages you asked for.
[]



Re: The BITeensio board is here. #ubitx

Ralph Mowery
 

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!!!  (https://www.banggood.com/DANIU-White-10X-15X-20X-25X-Spectacles-Glasses-LED-Lamp-Magnifier-Loupe-Maintain-Tool-p-1067682.html?rmmds=detail-top-buytogether-auto__2&stayold=1&cur_warehouse=CN)


Re: Alternate pop fix...

davedt1e@...
 

Excellent!   Thank you Allison!  And thanks for the diagram too!


Re: Alternate pop fix...

ajparent1/KB1GMX <kb1gmx@...>
 

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


Re: Alternate pop fix...

Skip Davis
 

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. 

Skip Davis, NC9O

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

Arv Evans
 

I tried those 2 inch focal length goggles but I kept burning my nose on the soldering iron.  8-)

_._


On Sat, Jun 16, 2018 at 5:52 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!!!  (https://www.banggood.com/DANIU-White-10X-15X-20X-25X-Spectacles-Glasses-LED-Lamp-Magnifier-Loupe-Maintain-Tool-p-1067682.html?rmmds=detail-top-buytogether-auto__2&stayold=1&cur_warehouse=CN)

de Larry W8LM
ARRL Life Member - Licensed  368 DOG Years..


Re: The BITeensio board is here. #ubitx

Roy Appleton
 

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!!!  (https://www.banggood.com/DANIU-White-10X-15X-20X-25X-Spectacles-Glasses-LED-Lamp-Magnifier-Loupe-Maintain-Tool-p-1067682.html?rmmds=detail-top-buytogether-auto__2&stayold=1&cur_warehouse=CN)

de Larry W8LM
ARRL Life Member - Licensed  368 DOG Years..