¿ªÔÆÌåÓý

  1. BITX20
  2. Topics

Homebrew SBITX - first phone contact #homebrew #sBitx

 

Hi all....

Quick progress report. Happy to report my first phone contacts were made today. I only have a low pass filter for 40 m. so far so only one band.?

if you want to listen.

I built a mic today with one of the sensitive electret capsules that have been discussed in the other threads.? I put it in a 3D printed case using a micro switch for the PTT.? First contact reported distorted audio but then I realized I had the mic gain at 100... Back it off to 50 and then to 35 and started making contacts with good audio reports.

I still have a few kinks to work out. I'm not sure the codec board is functioning well. It seems to go into oscillation when using the built-in CW sender. And I get some crackling and noise in the side tone audio. I also still have an issue where the displayed frequency counter track with the tuned frequency.

Curious if anyone else is using the codec board from Mikroeelectronica?? I noticed that it has different values for the serious capacitor and termination resistors on the headphone audio-out channels then is used in the SBITX version.

Below is what the rig looks like as of today.

73,
Dean
 

Dean,

NICE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

73
David
ac9xh
Paul
 

Brilliant, just noticed on your screen in the video that it looks like you have two instances of the sbitx application running as shown on the top menu bar. This can cause some strange issues so, may be worth you making sure there is only a single instance of the sbitx app running to prevent chasing issues that might be caused by running the 2 instances.

Regards
Paul G0KAO
 

Paul, you don't have two running because one is the tray icon and the other is the running program.
--
Gyula HA3HZ
Paul
 

Ok, I don¡¯t have the tray icon hence the comment
 

Congratulations! Did you do Manhattan construction on the boards??

73 John N4HNO
 

On Tue, Feb 27, 2024 at 06:39 AM, Tech Guy wrote:
Congratulations! Did you do Manhattan construction on the boards??
Hi John,

Yes. The analog portion is all Manhattan style.? The digital circuit is on a through hole prototype PCB.

73,
Dean
Jack, W8TEE
 

This is so cool...I envy your talents!

Jack, W8TEE

On Tuesday, February 27, 2024 at 08:06:57 AM EST, Dean Souleles <dsouleles@...> wrote:


On Tue, Feb 27, 2024 at 06:39 AM, Tech Guy wrote:
Congratulations! Did you do Manhattan construction on the boards??
Hi John,

Yes. The analog portion is all Manhattan style.? The digital circuit is on a through hole prototype PCB.

73,
Dean


--
Jack, W8TEE
 

¿ªÔÆÌåÓý

Hi Dean,
? Very very nice work! I have a Mikroe WM8732 board. The Mikroe schematic has the series R33 of 330 ohms and the coupling cap C23 as 1nF. ? But from the sbitx V2 schematics looks like sbitx does not use the WM8732¡¯s mic input but uses the RLINEIN pin as the mic input. The?WM8732¡¯s input and bias pins are not used.
Hope this helps.
Jerry KN6BJK

On Feb 26, 2024, at 8:47 PM, Dean Souleles <dsouleles@...> wrote:

Hi all....

Quick progress report. Happy to report my first phone contacts were made today. I only have a low pass filter for 40 m. so far so only one band.?

if you want to listen.

I built a mic today with one of the sensitive electret capsules that have been discussed in the other threads.? I put it in a 3D printed case using a micro switch for the PTT.? First contact reported distorted audio but then I realized I had the mic gain at 100... Back it off to 50 and then to 35 and started making contacts with good audio reports.

I still have a few kinks to work out. I'm not sure the codec board is functioning well. It seems to go into oscillation when using the built-in CW sender. And I get some crackling and noise in the side tone audio. I also still have an issue where the displayed frequency counter track with the tuned frequency.

Curious if anyone else is using the codec board from Mikroeelectronica?? I noticed that it has different values for the serious capacitor and termination resistors on the headphone audio-out channels then is used in the SBITX version.

Below is what the rig looks like as of today.

73,
Dean

<PXL_20240227_002544463.jpg>

 

On Tue, Feb 27, 2024 at 03:37 PM, jerry okeefe wrote:
Very very nice work! I have a Mikroe WM8732 board. The Mikroe schematic has the series R33 of 330 ohms and the coupling cap C23 as 1nF. ? But from the sbitx V2 schematics looks like sbitx does not use the WM8732¡¯s mic input but uses the RLINEIN pin as the mic input. The?WM8732¡¯s input and bias pins are not used.
Hi Jerry - thanks for the note.? its not the mic input I am referring to, it is the left and right phone outputs LHPOUT and RHPOUT that are used in the SBITX to send audio to the speaker and to the analog transmitter? The Mikroe board uses 330uF series capacitors and 47K terminating resisors.? The SBITX board uses 47uF caps and 10K resistors.? Just wondering if that makes a difference.

73,
Dean
KK4DAS

1 - 10 of 10