Quote:
Originally Posted by J_Player
If you were use a small transmitter at your hunting site, then the signal coming from this transmitter will be broadcasting RF in the near field, whose propagation properties are not the same as transmitters far in the distance.
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Yes, but huge changing in propagation (like changing wave polarization etc) are in first line characteristic of very high frequency band as UHF not in VLF/ULF band. By local small transmitter we find some others aspect of problem. We are searching for weak source of reflected signal and at the same time we have in vicinity relative strong source of transmitted signal at the same frequency which cover weak target signal and disturb successive search . This is why I repeated that 0.3W is far enough and even too much for successive search. This is why we need as much as possible directive RX antenna to suppress direct TX signal in combination with some tricks and searching skill.
If we compare UHF and ULF frequency band from reflectivity view UHF are better to detect especially small target in air because of its directivity and worse to detect something underground because of his weak penetration ability, on other side ULF are weak on directivity and so worse to detect something in air but way better to detect something underground because of his excellent penetration ability in soil. Theoretically ULF radar can detect invisible objects (objects behind of hills or behinds of horizon) which UHF radar cannot. This is why ULF can reach targets on unusual way and why we speak about importance of RX sensitivity and Rx antenna directivity.