16 Jun 2020

Ferrite rods as TX antennas

Something similar has been on before, but I make no apologies for this gentle reminder!

Ferrite rods will work on TX as long as the ferrite does not saturate and the material is fine for the intended frequency.

Low power usually means millwatts or low watts. Some years ago I gave it a try with a random ferrite rod (characteristics unknown) on WSPR with great success. To be honest, it was far better than I expected. I think of ferrites as distorting space with the effective size being proportional to the effective permeability of the ferrite.

I wonder what would happen on 7MHz FT8?

See https://sites.google.com/site/g3xbmqrp3/antennas/ferrite_tx
See https://en.wikipedia.org/wiki/Ferrite_core

UPDATE 1344z: Well I had to try 40m FT8 with the ferrite rod on TX!! With no earths connected and no HF antennas here apart from the highly tuned 10m indoor loop, I have 8 spots already using the FT817ND at 2.5W. Best DX spot was  -7dB S/N from F5NK (936km). Highly impressed! This is the first time at this QTH with this antenna.

UPDATE 2003z:  12 spots of me today so far on 40m FT8 with just the tiny ferrite antenna. I guess the biggest problem is being buried by bigger stations on the same frequency without realising.

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