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Roof mounting solutions

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KG6H
Roof mounting solutions

Rather relatively new ham here.  My current QTH antenna is a 2M copper slimjim mounting on my chimney with a corner-mounting system like this:

The actual use is this:


In high wind it can sway a bit, but not too worried about it.  I could put up another of these on the other side of the chimney, but I think I'd need two straps and move up to 1.5" pipe for Ubiquiti gear.  However, the top of the chimney doesn't clear the top of the neighbors' houses on either side, so I'd need at least 8 feet or more to get over them.

Suggestions for how to mount sectors (or anything) at on the top of "Spanish" concrete tile roof peak? We have two story homes all around (as is ours, but the neighbors on either sides are slightly more elevated peaks as they have walk-up front doors vs. our front door is level with the ground) and palm trees to our west and we probably need all the altitude we can get, so it probably needs to be at the peak of the roof and mounted on a pole. I do have a satellite dish mount near the peak at the rear of the house with an unused dish I could take off and use for a mount point, but I'd think I'd want guying wires somehow, except that I could only get them going to the sides and behind, but not beyond the roof.

There are tripods such as this, but I don't know how I would put them on the tile beyond just mounting them on wood and having them sitting there and not anchored: https://www.amazon.com/Winegard-SW-0010-Tripod-Mount-Antenna/dp/B001DFZ5J2

I do have one step-down section where the top of the main roof line goes down about 4 feet where there is a second level which is about 3-4 feet wide.  I think perhaps I could use one of these on the roof top roof edge where this ledge is, but then I still need a tripod or base to put the pole into to rest on the lower roof:
https://www.amazon.com/Channel-Master-CM-9025-Heavy-Duty-Antenna/dp/B001RCMEEA

Thoughts?  Suggestions?  I don't want to put a tower up in my backyard as it is already very limited space, plus I don't know that I'll be at this location long enough for it to be worthwhile.  HF isn't my thing either.

KG6H
Mounting systems

Ok, so if I wanted to just put up a NanoBridge or similiar dish-style node, I believe I could get one mounted to a J-mount system like what a satellite dish uses, near the peak of the roof with this:
http://www.data-alliance.net/antenna-mount-for-tile-roof-suitable-for-dish-large-antennas/

Downside is that I could probably only hit the mountain peak nodes and not provide any coverage nearby.

Going much more expensive is this system looks very slick and totally professional as it is used for solar panel mounting.  I'm seriously considering having a local roofer install these so I could put up a large tripod at the peak of my roof anchored to this (two legs down on one side, one leg on the other) and four guy wires at the far edges of the roof:
https://www.youtube.com/watch?v=4cLt6YHGAFc

On second thought, I wonder if I couldn't use 3 of the first item I listed as tripod leg-mounting locations near the peak, as well as 4 of them for guy wire?  A bit pricey for 7 of them, but they don't require a puncher of the roof or having to reseal the roof or cutting of any tiles, just inserting the harder hooks under the tiles.

kg9dw
kg9dw's picture
So you really have a couple

So you really have a couple of options, but it depends on which antennas/radios you are using.

If you need a nanostation mounted on the side of your chimney, you could use some 3M heavy duty fastners. Like velcro only 20x better. Not really outdoor rated but would easily withstand the heat. http://amzn.to/28Lo4nr

If you want to put up sector antennas or nanobridges (dishes) you could use an old Dish/DirecTV roof mount. A bit tricky on tile, and I'd want to avoid putting anything on the tile myself. I've used them twice for side mounting to buildings and they work pretty good. A scrap yard might have some, or just look around the neighborhood. 

If you're putting up multiple radios on the same pole, you may need to do some isolation (search for ubiquiti shields). You definitely don't want them on the same channel. 

I'd move away from the j-pole by the way if you want better performance. I use a home-made one for a 2 mile analog repeater link, but use a $70 Diamond base station antenna with great luck for more distant work. 

wa2ise
wa2ise's picture
Swaying antenna and echo cancellation

Be aware that if your antenna sways by a large fraction of a wavelength, and the receivers have ghost (echo) cancelation, the sway could slow down the data transmission rate.  As the receiver is spending more time adjusting to the changing ghost conditions.  We see this in ATSC (American) digital TV broadcasts, as the tall towers the broadcast antennas are mounted on can sway in the wind around a UHF channel's wavelength distance.  Which can make most everyone's TV receiver have dropouts as they try to update their ghost cancelation parameters.

KA9Q
I'd be interested in any

I'd be interested in any experimental data on this. All the newer WiFi modes use OFDM to combat multipath, and the low symbol rate eliminates the need for adaptive channel equalization. For digital television, instead of selecting DVB-T (which is OFDM) like the rest of the world, the FCC chose ATSC, which uses a high symbol rate that needs equalizers. That's why ATSC to mobile receivers sucks so bad.

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