I've got this cheap http://akizukidenshi.com/download/ds/jye/UserManual_138_new_s.pdf oscilloscope, and I'm on a budget. For most measurements I need more than one channel (at least two channels, to calculate phase shift V-I across reactive loads for example), so I was wondering, if I bought a second oscilloscope just like the one above, and I connected together the grounds of both of them, could I sort of simulate a two channel oscilloscope?

Thank you,

 

Possible. You will have to hack the second board at R15 to receive TP4 from the first board.

 

TP4 from the first board to point A or B in the second board? Besides connecting both grounds, I imagine.

Do you think it's sensible?
Are there any oscilloscopes with these kind of specs

with two channels for 30 €?
What about the auto diagnostics oscilloscopes? Hantek 1008C? That's eight channels for 60€ They only go as far as 250kHz, that is not much, but probably more than enough for me.

 

TP4 from board #1 to point-B of board #2
This will cause the second board to trigger from the same input signal applied to board #1.

You will have to lift one leg of R15 on board #2 and inject the trigger signal from board #1 into the lifted leg.