No you won't, I have posted a later version of the mathcad file to
http://www.vk1od.net/bpl/loop02.mcd .

Yes, got it ok, thanks.

The file you downloaded is an image (.gif) called loop.mcd.gif, and it
looks like your download process dropped the extension, or you hide the
extension on your machine. (Some software thinks that the first dot begins
the file extension, whereas it is the last dot that does so.)

Guessed it was something like that.

Might be interesting to replicate your results with NEC2.

I have modeled the loop in EZNEC and get very similar inductance and
resistances.

Now this is where it gets interesting, and hope I can learn something from
it, as I am sure I have made a mistake someplace. I have not directly
attempted to verify your math, so don't know if you developed it from first
principals or got it from a book. I have a number of references including
Kraus' "Antennas", and also a text by Stutzman and Thiel, etc., so may try
to replicate your methods later.

Using NEC2 I set up a 40 m dipole in free space, and fed it with 1 kW (for
nice large current values in the loop). I placed a square loop, 0.5 m per
side and 40 m distance. with the plane of the loop parallel to the axis of
the dipole, also two sides parallel to the dipole. The dipole uses perfect
conductors, and copper for the loop, with 0.7 mm radius conductors. The
segmentation of the loop is significantly different than the dipole, but
thought it not important because of the large separation of the two
antennas. In the loop I am very close to the minimum segmentation allowed
in NEC at 0.001 wavelengths per segment -- i.e. 11 segments per side. One
segment, near a corner, has a 50 ohm load.

As is easily verified, the field strength from the dipole, at 40 m, is
5.5V/m (RMS). According to NEC the current in the loop varies from segment
to segment, ranging from 0.1 mA (peak), to 0.3 mA (peak). I took the
average (0.191 mA peak), and computed the RMS average current in the loop.
Multiplying by 50 ohms, gives me an output voltage 6.76 mV RMS.

The antenna factor is therefore 58 dB. Wonder if anybody has any idea where
the error lies. I have copied the code below.

Regards,

Frank

NEC Code:

CM Dipole antenna
CE
GW 1 41 0 0 0 20.25 0 0 0.0026706
GW 2 11 10 40 0.25 10.5 40 0.25 0.0007
GW 3 11 10.5 40 0.25 10.5 40 -0.25 0.0007
GW 4 11 10.5 40 -0.25 10 40 -0.25 0.0007
GW 5 11 10 40 -0.25 10 40 0.25 0.0007
GS 0 0 1
GE 0
EX 0 1 21 0 379.63 0.00000
LD 4 5 1 1 50 0
LD 5 2 1 11 5.8001E7
LD 5 3 1 11 5.8001E7
LD 5 4 1 11 5.8001E7
LD 5 5 1 11 5.8001E7
FR 0 12 0 0 7.15 0.0025
RP 0 181 1 1000 -90 90 1 1
EN