For direction finding at 460Mhz (ish), a loop antenna sounds a poor idea, a loop antenna inside a "bucket" sounds even worse.
I would be inclined to use a yagi antenna, which could be quite compact but have useful gain and directivity.
However, an FM receiver is a really bad idea. As Mike suggested, an AM receiver with a meter on the AGC would be ideal, but where you would get one for that frequency, other than make it yourself, I dont know.
Consider the possibilities of using a low frequency, 1Mhz (ish).
AM receivers are plentifull, the internal ferrite rod (loopstick in the USA?) antenna has very good directional properties and a signal strength meter is easy to add to the AGC line.
A simple transmitter is very easy to build.
The problems:
The ferrite rod antenna has two nulls* which is ambiguous for direction finding, but adding a short rod antenna will make the response into a cardiod with one null* for unambiguous direction finding.
The antenna on the transmitter will need to be quite long in order to radiate a strong enough signal. (How long is "quite long" I would not like to postulate without doing a test.
* It is usual to take DF bearings using the null in the antenna response, rather than the peak. The reason being that the null is much sharper and gives a more precise reading.
JimB