After a strike killed most of our gear, we're rebuilding our systems with lightning protection that will hopefully allow for multiple strikes with no damage / downtime. As I've never done lightning protection before (I'm more of a software guy), I just want to pick the brains of this forum. So far, here's my plan:

1/4 wavelength arrestor between antenna and radio for tower top
PoE surge filter at the bottom of the tower just before the PoE inserter
Install single point ground in the equipment room to connect all the PoE surge filters to

A few questions though. Is the tower itself considered a ground or would/should we run a separate ground to the tower top equipment? If yes, is there any disadvantage of using the tower as a ground? Would I also need a PoE surge filter at the tower top just before power hits the routerboard? My theory is that induction in the ethernet caused by a strike or nearby could travel both directions, or will it just head straight for ground? With the antenna lightning arrestor, can I simply attach it to the N-female bulkhead on the outdoor case for the APs, or does it have to 'hang' in between two runs of coax? Any good brands or recommendations for arrestors/filters, if that's allowed here? And finally, I'd also like to protect the radio from static discharge from the antenna picked up by wind, would the 1/4 wavelength arrestor accomplish that too?

Thanks in advance for any advice!

Interesting topic.

With several AP's I would also suggest to look at the cost - risk level.
To protect 100% against direct hits on a tower is very difficult and costly. It costs almost the same as the AP unit itself. If one has several towers to protect you might consider the following; The risk lightning strikes in several towers in short time is very little. I have 5 and later probably more then 10 towers. To protect them all as good as possible would cost me lots more than to have just one or two spare units available.
I'd gamble on the low risk compared with the availability of spare units. Unit gone,.... replace it with a new one.... (depends also on accessability of the tower off course..)

If you would decide to protect anyway I have some second thoughts myself.
The router boards inside the outdoor boxes are grounded with a screw to the outside of the box. This should then in return be connected to the mast/tower which is in return connected to the real earth with a proper earth pin. This all to get rid of static electricity.
What happens now if a lightning strikes the tower, or just nearbye? The induction itself travels everywhere and thus also up into the tower and through its ground connection into the board! Even if the coax and UTP are well protected!
So, we replace one possible issue with another.

My conclusion is that I don't connect my AP's in the towers to the tower with the ground screw. I have so far never seen any issues with static electricity building up on the antenna's that might ruin the radiocards. But by not connecting the board to the tower it protects it at least a bit against nearbye strikes (induction).
It comes more down to risk assesment. Discharge static electricity probability against lighting strikes probability.

I live in a area where thunderstorms are not frequent but dry winds are. But so far never had any problems with both.

I think you can connect the antenna lightning arrestor direct on the n-female connection of the box. That's what the manual of the manufacturer showed me anyway.

I also see your point in having two ehternet surge protetors. That looks a good idea if the utp cable runs outside the tower and can thus have an induction current created if a high current runs through the tower. But in a direct hit on the tower the current will probably jump onto the cable itself anyway so induction is not your problem then...

These are my thoughts, but I would also like to see more input in the subject. Who's next!

You definitely want the tower grounded (unless it's an AM radio tower). It should be grounded to the earth at the base and guy points. It should also be connected to the electrical utility ground just like your equipment grounding. We gained a great deal of additional protection by adding a spike atop and a 4/0 ground wire to the top of the tower. It will carry the lightning instead of the tower structure or coax.

You definitely want the tower grounded (unless it's an AM radio tower). It should be grounded to the earth at the base and guy points. It should also be connected to the electrical utility ground just like your equipment grounding.

Why ¨definitely¨? Not all my towers are grounded and from what I know lots of towers from others aren't neither. In the four years some of these are used never experianced any problems. Grounding of some of these would be complicated so left it without.
Why does it seems to be so important while towers not grounded properly still work fine?
And why should it be different for AM? The frequencie has nothing to do with it?