Why all the others need dishes ?
I did not try this yet (will try later today) but I was kind of expecting it because of the very strong signal via the dish.
However, I guess for optimal receive performance you need a small dish, maybe 30cm, at least.
Also remember that the usage is now quite low. When the entire transponder is populated like a HF band the power available to a single QSO decreases.
(even worse when the transponder goes into AGC due to that)