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Yes, My homebrew µBitx now work!!


Gerard
 

Hello Evan, Hello all
I’ve finished turning up the amplifier. I’m going to test the amp and smeter to morrow.
I also ordered BFR transistors to replace the 3904
I took both CMS and TO50 box components.
I will see how I can install all this. I thought to drill a hole from the diameter of the TO 50 at the level of the base and weld the legs. Better see the correspondence of the CMS and weld it on the back side of the circuit. I’ll put some pictures for you.
Good weekend


Gerard
 

Hello Evan,
I tested the amplifier. It’s working fine. I need to put shielded cables on the potentiometer because we’re picking up the 50Htz and it’s picking up a little bit. For Smeter, it works, but doesn’t move much.
2 cases, see settings with the manager, either connect behind the 1st amp to recover more signal.
cdt


Vic WA4THR
 

Nice that it is working, Gerard, although I couldn't see the Nextion screen well enough to see the S-meter in your video. Here are the settings I used on my V4 uBitX when I was using the same amplifier to drive the S-meter. This agreed well with a commercial rig and with the logic of what the S-meter readings are supposed to represent (6dB per unit):

I think you are modeled on a V4, right? The audio levels is pretty poor on that rig, but all the adjustments to improve are typically after the high side of the volume pot so they won't affect the readings. I added a AGC-controlled audio amp between the high-side of the pot and the wiper and it has fixed all the audio levels nicely.

=Vic=


Gerard
 

Hello Vic, 
Thank you for your comments
Yes, I will improve all that.
I will change the potentiometer cables and put shielded. Then I will test the Smeter with the manager Ubitx.
On the diagram, as M0THY says, we can improve the sound by modifying the cabling of the potentiometer.
See what it says in the pdf. I put you the plan of its construction which I inspired.
This should make the AGC work a little better.

I also made a modification on the mosfet for the famous "pop"
Add diode+ resistor and capacitor
It is true that in this amplification story, we could use a pc amplifier  directly as we had on the sound card.
See you soon for news
cdt