15 Jan 2021

E-field probes

There is a common myth that VLF, LF and MF antennas have to be big. Whilst this is true for radiated TX antennas, this is absolutely not true on RX. 

In the past I have used E-field probes very successfully on 136kHz RX and good ones can be quite as good (or better) than large antennas and can work from VLF to 30MHz despite being very tiny. Typical ones are just a few cms long.

One of mine, used taped to the window, is shown in the photo. Normally they are placed outdoors away from noise sources. They work because as antennas get smaller the signal level falls, but so does the noise. At low frequencies external noise usually dominates.

See https://sites.google.com/site/g3xbmqrp3/antennas/efp.

1 comment:

Anonymous said...

Is this the same as a Voltage Probe Antenna?

A number of kiwisdr sites use this and I think they are quite good.

Wouldn't this type of antenna be called an Active Antenna?