Most oscilloscopes will display signals well beyond their rated BW. The
problem is that what they display is not necessarily what is there. They
are not displaying the leading edges of the waveforms with any accuracy at
all, and that is typically why you look at an RF waveform with a scope.
Aside from buying a new scope, the simplest way to display higher frequency
signals on a scope is to mix them down to a useable frequency. Since you
are not cutting the mixer on and off (with your keying) the edge of the
waveform is not necessarily altered via the mixing process. I would check
the accuracy of the presented waveform after construction of such a mixer
on a scope that WOULD display all the frequencies to be certain the circuit
parameters are not changing things besides frequency. Use either an NE-602
or just try a doubly-balanced mixer diode set and a simple oscillator and
see what you get. Don't forget impedance matching/etc.
72/73
Ed Tanton N4XY EMAIL: n4xy@avana.net TEL: (770)579-3933 V/MBX/FAX
189 Pioneer Trail
Marietta, GA 30068-3466
QRP-ARCI#7663 G-QRP#6779 OK-QRP#172 QRP-L#758 AdvRC#140
NORCAL#1779 NCDXF SEDXC
Life Member: ARRL AMSAT IDRA INDEXA QCWA
URL: Coming Sooner or Later
"Think you can, think you can't: either way you're right!" Henry Ford
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