Several contributers have taken the view that it is impossible to receive Amplitude Modulation transmissions on 121.5 MHz on an ADF receiving on a few hundred Kilohertz and I have the same opinion. The frequencies are separated by a huge margin which is most definitely outside the frequency range of receivers designed for ADF.
That said, Amplitude Mod as a transmit-receive system is susceptible to being able to detect signals outside the normal operating range provided that they are in close physical proximity, such that the first stages of signal filtering in the receiver are “overpowered” as has been described by the reception of strong local signals from Police stations (and local taxis etc).
Another factor is how pure the transmitted signal is – a “dirty”, mal-adjusted one will radiate on several frequencies simultaneously. Indeed, it may be that historically, 243.0 MHz came into use to be able to capture the second harmonic of 121.5 MHz.
So, using a cheap transistor radio on the “AM” waveband in close range on the ramp would probably work and tuning across the range wouldn’t have much effect on how well the ELT is received. The VA offering to use ADF to locate the ELT is very commendable but completely misguided for not appreciating how frequency is measured, equipment capability and for my reasons above.