As FvM says, you have to consider how your measurement device affects the circuit being measured. In addition at 30MHz, your construction technique and components might be changing the performance.
A "normal" way of achieving your measurement would be to keep the signal 50ohms all the way to the scope, but to insert a 50ohm 10dB or 20dB attenuator in the signal path. Such things widely available, but make sure it is rated dissipate the transmitter's power.
Alternatively you could consider making your own "low impedance Z0" probe, which should be OK to GHz and avoids many of the problems of conventional 10:1 probes. See
https://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/ for more information.