Order Tray | Contact Us | Home | SIG Lists

[wxsig] Tx problem fixed

John Koster w9ddd at tapr.org
Tue May 12 22:05:20 UTC 2009

Please refer to my message of 4-28 where I suggested changing it to     
0.1 mF.

On Tue, 12 May 2009, pedro.motilla at ono.com wrote:

> Hi, today I isolated the problem, it was the capacitor 111, I do not know why, but it does not permit the signal to reach pin8 on P100.
> The procedure was to follow the signal with the scope. Finally it was clear that this cap was causing the problem, so I jumped the cap, and, voilá¡¡¡¡¡ the signal was on the air.
> Now I have one question, what is the function of this capacitor?, should I change the value of the cap? or can I leave it without the cap?
> On my last comunication I made some mistakes with the measurements of the scope. Today it has been my second time on using a scope, I am not still used to work with the oscilloscope. The pin 7 on U100, has a sine wave signal with 500 Hz, not 50 Khz, as I said. I used a loudspeaker from an old toy. So, I could assure that from pin 7 were going out signal. Also on pins 1 and 2 voltage is not 30 mv and 20 mv, but 3 and 2 mv.
> So I put the signal on the air, but a little bit worried because I do not know if the absence of the cap 111 could affect to the modem's performance or the transceiver.
> Cable is good, the wiring works ok.
> I do sorry if I confused some of you with my measurements.
> Thanks to everyone, hope anybody can tell me something about the c111.
> Best Regards.
> EA5BFT, Pedrolo._______________________________________________wxsig mailing listwxsig at tapr.orghttps://www.tapr.org/cgi-bin/mailman/listinfo/wxsig

John, W9DDD

More information about the wxsig mailing list