开云体育

ctrl + shift + ? for shortcuts
© 2025 开云体育

Re: Bitx 40 Problem


Jeff Glass
 

开云体育

Do you have a nice strong power source? Like all high-gain LM386 circuits, the audio amp is prone to becoming an oscillator when starved of sufficient power.

Best,
Jeff
KK9JEF

Sent from my iPhone

On Nov 28, 2016, at 4:20 PM, Ken Chase chase8043@... [BITX20] <BITX20@...> wrote:

?

You may also be able to drape it over the antenna connector. Try that first without the antenna connected.

73 Ken

On Mon, Nov 28, 2016 at 5:19 PM, Bill Robbins wrobbins@... [BITX20] <BITX20@...> wrote:
?

Yes I have one.?

Sent from my iPhone

On Nov 28, 2016, at 5:05 PM, Ken Chase chase8043@... [BITX20] <BITX20@...> wrote:

?

Let's rule out the antenna. Do you have a signal source to fed to the antenna input? It has to be very low strenghth around 50 uvolts (S9). If you feed too strong a signal, you may overload the front end.

73 Ken

On Mon, Nov 28, 2016 at 5:02 PM, Bill Robbins wrobbins@... [BITX20] <BITX20@...> wrote:
?

Ken:

Thanks. That's the first thing I did having followed this group. I did spread a few out a little but no help.?

Bill?

Sent from my iPhone

On Nov 28, 2016, at 5:00 PM, Ken Chase chase8043@... [BITX20] <BITX20@...> wrote:

?

Hi Bill

Start by checking that the toroid leads are not shorting together. You can use a toothpick to gentle spread them apart.

73

Ken VA3ABN

On Mon, Nov 28, 2016 at 4:25 PM, billrobbins946@... [BITX20] <BITX20@...> wrote:
?

I decided that you guys are having so much fun that I took out #67 to give it a whirl.?


When powering up I get a very loud buzzing in the ear phones.? So, I power down, remove all external pigtails and then add them one at a time.? It seems to happened when adding the antenna to the circuit board.


Forgive me for asking here but I have little experience with the very small components.


Where to start looking??


Bill




Join [email protected] to automatically receive all group messages.