Laurie said:
I dont know how to calculate the voltage at the end of a top loading =
wire,but I use two ribbed ceramic insulators with a peice of terelene =
rope (5mm) between.The rope has burnt through!!!
Ceramic insulators should not be a problem. However my Admiralty
Handbook of Wireless Telegraphy (1925) has this to say:
"Loss by Leakage over Insulators
..........................It is, therefore, the duty of the wireless
staff to keep these (insulators) scrupulously clean, especially after
high speed steaming, heavy rain or bad weather, since under these
conditions the insulators will probably be covered with a
semi-conducting layer of 'stokers dirt' and dried salt".
I don't know about 'high speed steaming' but the lake around my shack
is now large enough for me to sign Maritime Mobile.
I find that ribbed insulators are worse for collecting dirt, which
gets down in between the ridges. The long PA0SE ceramic insulators
are best although the tooth brush handles should be OK. I think that
a method of lowering the antenna for maintenance is a necessary
design feature, especially in coastal areas.
--
Regards, Peter, G3LDO
<[email protected]>
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