Comparing forward voltage (barrier potential) of diodes for N5ESE RF Probe

I had used 1N4148 diode instead of the 1N34A germanium diode when I homebrewed N5ESE Classic RF Probe a few days back as the latter was not available in the local shops. Now I have a received a pack of four 1N34A diodes online. I was quite surprised to see the variation in forward voltage (barrier potential) of these diodes, which varied from 0.25 to 0.4 V and one was defective. 1N4148 and 1N4007 had forward voltage of around 0.55V which would mean that the RF probe will be less sensitive if they are used instead of a good 1N34A germanium diode.