An EH Antenna for 27 MHz Packet Radio.
First test in the garden.

Test of the EH L+L Antenna on a pole in the garden

The EH Antenna in front of the house The second prototype tested on the air

I placed the second prototype of the EH Antenna on a 2,5 meter long wooden pole on the lawn. Especially with the EH Antenna critics in mind I laid the first carefully cut 1/2 wave length of coaxial cable through the wall from my shack and then through an air duct under the house to the outside of the house. At this point I inserted the SWR meter and connected the EH Antenna with another multiple of a 1/2 wavelength of coaxial cable. It became necessary to make a slight re-adjustment of the trimmer capacitors. Again, C1 was tuned on a CB channel in the middle of the band to maximum radiation on a field strength meter placed in the direction away from the cable, in the garden. Then C2 was tuned for a minimum reflected power. The coaxial cable was taped to the pole and run 4 meter on the lawn to the SWR Meter. Very small changes on the SWR meter were noticed when touching the coaxial cable in different locations from the pole up to the SWR Meter. Touching the transceiver case also had no effect on the SWR readings. I took note of the SWR readings over the CB channels and the results are even better than the bench test!

NB: I did only adjusted the capacitors once. They were tuned on a center channel.

Close-up of the 2nd prototype

A note several years after: After many many tests and frustrations, I gave up this type of the EH Antenna. It was too unstable and too dependent on how the coaxial cable was placed. If an EHA, then go for the EH Star with the "3:rd Element".

Revised 21st November 2021