On Fri, 12 Mar 2010 18:24:01 +0100, "JC" wrote:

but what is wrong in this test ?

The loss of such cable is rated in dB per 100 feet. Your 30cm
(roughly a foot) is a substantial fraction. If we were to perform a
first order estimation from that alone; then by consulting the charts
for RG58 at 2450 MHz, Times-Microwave doesn't even go that high.
Instead, taking their 1GHz figure of 15.3dB and abstracting that to
20dB and then taking its fraction for your length, then we get
something on the order of 0.2dB.

This would be roughly a 5% load to your 900 W IF that power were
confined to the cross-section of polyethelyne in TEM mode. It is not.

If it were, that would have 45W spread across 30cm. Think of that
length as a series of 30 half-watt resistors. That would have each
resistor over-taxed, trying to dissipate 1.5W each. Now, take one of
those resistors between your forefinger and thumb. How hot is that?

73's
Richard Clark, KB7QHC