1m sized antenna for radio transmitter at 3.5 - 4 Mhz frequency

Hello all,

I'm trying to design a radio transmitter at frequency 3.5 to 4 Mhz.

The bigest problem is the Antenna design. At 4Mhz the half-wavelenght antenna will be 37.5 m, which is not acceptable at all due to space limits, even quarter-wavelenght is not acceptable.

what is the recommended antenna that has small size like 1m lenght or diameter that can be used.

Thanx in advance for any help.

You probably should go ask on a ham radio board. But if it were me, I would use a base loaded short whip antenna. The base loading would be a big airwound inductive coil.

hi,

i was told a long back that we can try monopole antenna (with a big Ground plate) with resonator loading to reduce the length of antenna around 30MHz.

hi,
may i know that u design for main antenna for the radio right?

Ya cant break the laws of physics mate ;) if you want a working transmitting antenna for ~ 4MHz its gonna be big
even a base loaded whip is going to be several metres long ! its just the way it is live with it

You are never likely to get any antenna that is only 1m long to resonate at 4MHz, its going to be extremely inefficient

Dave
VK2TDN