LF Aerials etc.]

[Andre' Kesteloot]

LAWRENCE MAYHEAD wrote:

>  Hi Alan and all contributers to this discussion.I am glad we sorted
> out the misunderstanding.I dont know haw much modelling will help,but
> who knows! The facts that appear clear to me are:-1) Those with long
> top wires achive low loss redistance.2) Those with good ground need
> less top wire to achieve low resistanceMy experimens indicate that the
> top wire dosnt need to be in a straight line,but it must cover "new"
> ground.3 )It is nearly impossible to improve the ground with buried
> wires, ground rods etc.a singe good connection to water ,electricity
> etc gets you most of the way.4) What is the spray angle (cone as you
> suggest) this would gice clue toto best spacing of wire in meandered
> configs.Un-answered questions are:-1) Relationship between capacitance
> and loss resistance?2) How effective are multiple paralled top wires
> compared to extended top wires of the same total length.( I only did
> the one experiment,perhaps it need s repeating).3) Is the relationship
> between the length of top wire and ground loss linear,or does it
> decrease with length(Law of diminishing return)To answer your
> questions:- My 3 wire top was about 28m long. the wires were spaced
> 0.75m and it drooped,about 14m high at the ends and 13m in centre.I
> tried both parallel and meandered configs,there was a small
> improvement with one meander config.Which I belived due to some of the
> wire acting as an inductance feeding the rest.But the effect was
> minimal.2) I measure the loss two ways  a)current to the Ant at known
> power level,not very accurate. b)Impedance bridge, home made,usual
> config with ferrite torroid x former and resistive/capacitive balance
> arm.I feed this bridge from the exciter and use an SPM3 level meter as
> detector. Many thanks to all who have contributed to this discussion
> and to Andy who started it. Cheers Laurie..