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[wxsig] Problem with modem2 tx

pedro.motilla at ono.com pedro.motilla at ono.com
Sun May 10 21:44:20 UTC 2009

News from my modem2:

This weekend and next week, i have an oscilloscope at home.

This is what I found:

1- u100, pin1, there is a signal about 30 mv. at 3,57 MHz, so the oscillator, does his job.
2- u100, pin2, there is a signal about 20 mv at 3,57 MHz, ¿it is normal that pin 2 has lower p-p voltage than pin 1?

anyway  seems that it is out of doubt,  the u100 has a clock signal (sine wave form).

3- u100, pin7, there is a clock at 50 KHz, running on all the time.
4- u100, pin7, when tx, the signal changes, but I can't read it because the scope is analog, so it does not like digital outputs.

so, it looks like it would work, doesn't it?

to eliminate cable issues, I soldered a new one, the problem is still there, but I still keep packet socket from Icom 706mk2g

Some questions:

1- it is normal that u100, pin 7 has continously a 50 KHz signal?, if yes, how should this signal arrive to P100, pin 8?, I mean that on P100 pin 8 I think that should be continously a signal. is it right?

2- looks like it would be a wiring issue?, did any of you had a look to the scheme i sent? it is ok?

3- if I try to use a pc loudspeaker with input from P100 pin 8, should I hear anything?

Maybe next step I am going to take is to make a cable for acc socket...

Thanks in advance.

EA5BFT "Pedrolo"

NOTE: I am a newcomer on using an oscilloscope, so i am not used to work with it, if I say something wrong, let me know, I like to learn.

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