Although some of them may seem a little large for walks through the forest, many hunters go afield with their 2 or 3 element VHF yagi or quad antennas. Among the projects on his great web site Joe Leggio, WB2HOL, describes a very inexpensive Portable 2 meter yagi beam with flexible elements that are not easily damaged by charging through the brush. This is just the ticket for hunting on foot, and a great way to get started.
If you're looking for an even smaller directional antenna scheme, and if the receiver you're using can also tune the range of 435-450 MHz, you might want to try using a small yagi or quad designed for the third harmonic of the hidden transmitter's frequency*. The third harmonic of a hidden transmitter in the 2 meter band falls within the 70 cm. band, and antennas for that band are about 1/3 the size of their 2 meter counterparts. This can give the advantage of a small, lightweight and highly directional antenna system for your on-foot quest. One note of caution is in order here, however. The third harmonic signal is MUCH weaker the fundamental frequency, so you may need to be fairly close before your antenna starts picking it up. Some users say that this is not really much of a drawback, since they can build a high gain, highly directional 6, 7 or 8 element third-harmonic beam that is still smaller than one designed for the fundamental frequency. This extra gain makes up for the disadvantage of looking for the weaker third-harmonic signal, they say, and the accompanying sharper antenna pattern allows them to point more precisely toward the target.
There is a lot of information available
on building small 70 cm. beams, including some in our own
to Build section.
Whichever directional antenna approach you take, hunting the fundamental frequency or the third-harmonic, you'll also need an attenuator or Active attenuator to keep the signal strength within a manageable range as you approach your target and its signal gets stronger, as we discussed in our sections about hunting from your car.
If you are not satisfied with what directional antennas can do for you, there are also portable devices that indicate, by means of varying tones, lights or a meter, when the device is pointed in the direction of the signal. Such devices include various incarnations of the simple "Handy-Finder", the more sophisticated K6BMG "Super DF", and others, that can be built or bought commercially.
Foxhunting on foot is very popular throughout the world, where it's known as "Amateur Radio Direction Finding", or just "A.R.D.F." There are even World Championship competitions held each year. For a very comprehensive summary of equipment (and techniques) for Foxhunting on foot, check out this section of Joe Moell's "Homing In" web site.
Continue to Hunting On Foot - Basic Techniques
Hudson Valley Direction Finding Association