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Hi there, I'm trying to perform a spectrum survey from about 50 Mhz to 3 GHz. I have access to a spectrum analyser, but no antenna (for this application anyway). The survey is intended to be indicative - we're just interested in learning roughly how noisy bits of the spectrum are in this frequency range.

It's been suggested I try out a series of electrically small, loop antennas, tuned to various frequencies in this range, and then overlay the results. My thinking was to use something like a spiral antenna to maximise the bandwidth (would need a few to cover the whole range).

Anyone have any thoughts on what would be best for this application? For the avoidance of doubt, I'm looking to do this quickly and (fairly) cheaply, so a commercially tuned very-wideband antenna is not an option.

Any advice is much appreciated!

[admin]

Loop antennas are typically used for near field sensing. So no, don't use that.

Use some sort of dipole (which can be just a coaxial cable with the exposed inner conductor). The larger the better. You can somewhat manually correct your received power by assuming the antenna is 100% efficient when the inner lead is a quarter wavelength, and falls off below that frequency.