Miniature HF antenna design - help needed

[MSH]

miniature hf antenna

I want to design a miniature HF antenna as a receiver in the 4-15MHz with 1.5metter length limit. If anybody has a idea, please help me :roll:

Regards

 

[VSWR]

actant antenna

See these links:

http://www.hard-core-dx.com/nordicdx/antenna/special/swactive.html
**broken link removed**
http://www.marsius.com/sci/electr/ACTANT/actant.htm

 

[flatulent]

Re: Miniature HF antenna

For receiving you do not have to have any particular terminal impedance. Use a JFET source follower if connecting the 1.5 m length of wire to your receiver does not bring the bakground atmospheric noise high enough to notice in the receiver. Do this test at the low frequency end of the range.

The basis for this is that at this frequency range, the atmospheric noise is higher than the receiver noise figure noise. The SNR is already set in the E&M field before it gets to your electronics. Doing impedance matching to get the sum of the atmospheric noise and your signal into the receiver at a higher power level does no good in the output SNR.