Ladder Line Surge Suppressor

I usually get static build up on my HF doublet due to sand particles (I live above the beach) in the air so have been thinking about a way to bleed off the static and provide some protection to my TS-590SG. After a little research, I came up with this, a lightning arrestor/static bleed device that provides a permanent path to earth for DC whilst allowing RF to pass and providing protection from nearby lightning strikes.

Here’s the parts list:

150 x 110 x 80 box
2 x 100mm M6 304 stainless bolts
3 x 45mm M6 304 stainless bolts
5 x M6 304 stainless locknuts
20 x M6 304 stainless nuts
15 x M6 304 stainless washers
5 x 6.4mm ring terminal
2 x 0.01uF 6KV Capacitor (Mouser PN 75-564R60GAS10)
2 x 2W 1MOhm Resistor (Mouser PN 660-HPC2C105K)
2 x 2700V GAs Discharge Tube (Mouser PN 652-2095-270-BLF)

I spaced the connections to match my 3″ ladder line feeder.

Assembled the bolts ready to install.

The bolts are installed with 2 at the top foe the feed to the antenna, 2 at the bottom for the feed to the ATU (protected side) and one in the middle at the bottom for the connection to earth. I put a little silicone around the bolts to help with weatherproofing.

The resistors installed. These allow DC to pass and bleed any static buildup to earth.

The Gas Discharge Tubes went in next. These are basically spark gaps inside a gas filled tube so they spark at 2700v. The theory is that any nearby lightning strike that generates enough voltage on the antenna will be able to short to earth and bypass the resistors.

Last to go in are the capacitors. These allow RF to pass but block DC from flowing down to the ATU and onto the radio.

I selected an enclosure with a clear lid so I could easily check on the components to see any signs of damage after a storm. Note the small white bag inside the unit. This is a descant pack made from a home “moisture trap” refill and a coffee filter to help help the air inside the enclosure dry.

The next job will be to cut down the bolts (they were the only lengths I could get) and then to install in into my antenna system.

12 Replies to “Ladder Line Surge Suppressor”

  1. Hi Rick.

    Apologies for the late reply. I’ve run 400W continuous through mine with no problems. That’s the UK legal power so I can’t test any higher bit my guess is around 1KW should be OK. You can always increase the component ratings if you want to go higher. I hope that helps.

  2. you list the capacitor as 0.1uF 6KV but the Mouser PN 75-564R60GAS10 is a .01uf. ?

  3. I used 1.5 kW RMS (that’s is legal here for my Class)
    And no apparent troubles (yet in a very heavy rain !)

    73 PP5VX

  4. Nice job! I had a problem with the silica packs leaking and damaging the connections so I removed them from mine and drilled a small breathing hole in the bottom of the unit. May be worth considering for yours to prevent any damage.

  5. Hi dude ! you are a master !!! that’s was exactly what im looking for !
    Thank’s for sharing !
    best 73s
    de Mario IK1LBL

  6. Mouser is still out of the 6kv ceramic disc capacitors and if they had them they would be $6 usd each. They have been listing them as on order for a very long time now. Can something else be substituted? Is there a range to the capacity or does it need to be more than .01uf so .1uf is used? I think I might have some .001uf at 3KV but nothing at 6kv.

  7. Hi and thanks for your comment. I’ve never used anything but 0.01uf so personally I would stick with that value. A lower voltage rating should work, 6KV may be a little overkill! Also, think about the RF power going the other way. Make sure the caps can handle the power if you’re pushing 1KW of RF through them. Let us know how it works out for you.

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