On 11/20/11 9:16 AM, Michael Poteet wrote:
> I've a question that, perhaps, someone on this group can answer:
>
> I have a couple of sloping wire antennas.
>
> Typically a static bleed resistor is placed at the feed line entrance to the
> house.
>
> I plan to switch my antennas with a relay at the top of the tower and would
> like to protect the relay.
>
> Would placing the static bleed resistor at the low end of each antenna where
> it is close to the ground suffice to protect the relay? Or are there "time
> constant" effects that would leave the relay contacts exposed to high
> voltages?
>
> And would I still need a bleed resistor at the point where the feedline
> enters the house (the feed is ladder line down to a balun at the house)?
>
Static bleed can be anywhere.. the idea is just to put some high Z
between metal in the air to ground, and it carries a very small current..
Obviously, it does absolutely nothing in terms of lightning protection, etc.
The trick is finding a high resistance that doesn't have low impedance
(e.g. capacitive parasitics).
At the end of a sloper, if it's resonant, the voltages can get pretty
high, right?.. so breakdown voltage might be an issue.
Something like black automotive vacuum hose sometimes work as a high
value resistor (because of the carbon black pigment) and is pretty
tough. However, it's very, very brand/lot dependent (like using flat
black spray paint as a resistive conductor)
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