There is an extensive discussion of ferrite rod antennas in Chapter 4 of:

        Gibson, David (2004) Channel Characterisation and System Design for 
Sub-Surface Communications PhD thesis, Leeds University 2004.

John 
F5VLF

On 15 Aug 2011, at 09:46CEST, Roger Lapthorn wrote:

> Although I've little experience of ferrite rods on LF receive I did wind my 
> 600uH 500kHz ATU loading coil for my 5w transverter on one.  With just a 5m 
> top loaded vertical it worked well without saturation problems when  sitting 
> on the bedroom table. At QRP it is less lossy as less wire is needed. 
> 
> People have successfully engineered (single turn I think) ferrite rods as TX 
> antennas for 10MHz QRPp WSPR. Somewhere I have some information on this. As 
> long as saturation is avoided there is some mileage for HF TX applications in 
> very compact QRP stations. 
> 
> Worth some experiments on LF receive Stefan. 
> 
> 73s
> Roger G3XBM
> 
> Via my iPod Touch 4g 2.4GHz handheld. 
>