[TowerTalk] static bleed question

[Jim Lux]

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)