Antenna - The never ending story
#1
We don't need big antennas for the range 30-300km

I have made lots of antennas and they all work well.
Important - Self-resonance must be high.

First I made a "reference antenna" 160mm Ø, 1mm, 14turn

Then one for a 75mm standard plastic tube
A piece of brake pipe and a 48-turn transformer on a toroid

The top antenna is isolated from toroid and is also used as an E-Field antenna - Perhaps the third channel in the H-Field antenna could be for E-Field  Idea Wink Rolleyes 

/Richo


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#2
That's very neat and compact, could be tempted to play. Don't have any "scrap" brake pipe but do have some 2 mm dia solid copper wire, probably equal copper cross sectional area, which is the more important factor over dia? Presumably each loop is a single shorted turn, ie no gap?

Trying to think of a readly available source for 75 mm pipe and fittings. Pretty sure that UK waste water only comes in 32 40 and 50 mm before jumping to 110 mm. Roofing down pipe is 78 mm but doesn't have fittings with seals, stop ends etc.

Are additional H-field preamp boards available (bare or SM populated)? I'd not want to mess with the one on the main, installed, loops, just swapping Cat5(s) would be far easier and quicker.
Cheers
Dave.

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