I'm having problems using 1200 bps (A)FSK modulation with an ICOM 910H.
The hardware setup that I have is an ICOM 910H and a TNC which outputs are connected to the MAIN data socket in the rear panel of the rig.
I'm using two symbols for modulation (so, it is 2-FSK or AFSK with two levels) and I used a signal of 1's and 0's (A square pulse with 600 Hz) to test the RF output.
With an spectrum analyzer I saw the RF signal from the ICOM. What I expected to see was two peaks in +/- freq_sep/2, something like thishttp://i48.tinypic.com/14brf5u.jpg
(This is an image taken using the max hold feature of the analyzer)
but what I saw was thishttps://vimeo.com/53870405
As you can see, the output is kind of "noisy"
I checked all the cables and everything was fine. I used a signal generator (to discard problems with TNC and a noisy output) to simulate the FSK signal and the RF output was the same and I also checked ICOM's configuration (9600 mode off).
Well, my first question is: Is this behavior normal?
I think that is NOT normal because with the same analyzer I've checked the FSK signal transmitted by a small transceiver (which I want to communicate with the ICOM as my final objective) and the signal received was "clean" as in the picture, so, what can be wrong? the TNC, the ICOM? I've read about frequency stability problems of some ICOM 910H, Can be this the reason fo the problem?
Hope that you can help with the possible solution or ideas to test my equipment.