: OTA Mounts, Towers, Rigging Hardware
2010-10-13, 03:00 PM
I've read recommendations that indicate twice the height of the install away from the wires. Though this obviously isn't always practical...especially when you have a tower like myself.
In my opinion, if the install can fall over and hit wires, you're too close. You've got to think "worst case scenario": Should a major storm hit and blow stuff over, will it land on lines? If so, you've got to put it where it can't.
2010-10-14, 12:23 PM
Antenna is built and am satisfied w/ the results. Now the task is to permanently fix it. I live in a "townhouse" section, with high maple trees left right and centre. Mounting it on the roof is not an option (pool solar panels and its a new roof so the GF will shoot me). I can't fit in the attic (shoulders are too wide). I doubt my GF will let me set up a tower because of the neighbours and possible bi-laws.
I thought of getting a chiney kit w/ straps. Anyone have any experience w/ this?
2010-10-14, 12:29 PM
Use the Search This Thread tool to the upper right beside Thread Tools and put in "chimney" as your search term, and you'll find tons of posts and info. :)
I'm sure this has been dealt with here, but I couldn't find it.
If I'm installing an outdoor antenna, when passing the RG6 from outside to inside, should I drill a hole through the mortar between the bricks or through the brick itself?
2010-10-14, 06:33 PM
I've always gone with the mortar. Bricks are kiln-dried, thus moisture content is lower and the material is more brittle. You don't want cracked bricks. And it's easier to repair mortar.
Of course, it depends on which direction you're able to drill from. Sometimes, due to tricky angles and obstructions (especially true in old homes), it's necessary to drill from inside where it may not be possible to determine if you're hitting brick or mortar. Or, if you're drilling out from a room to feed it from outside along the wall. In this case, go slow so as not to fracture the brick.
2010-10-14, 11:50 PM
I'll have a sloped tripod, 1.25in OD, 16 gauge, with the main leg 5 feet high and 2 shorter legs of 3 feet long. On top of this 5 feet slope tripod, i'll install a CM rotor with a 4228hd.
What length should be the mast holding the 4228hd ? I already have a standalone, 5 feet, 1.66in OD, 16 or 18 gauge mast, should I cut it shorter ?
I wonder if I should expect lots of windload from a single 4228hd on a rotor and keep the mast length to a minimum. So far looking at it from its testing location, it looks like a 4228hd doesn't have a lot of windload. I would prefer keeping my mast intact, but on the other end I don't want it to be unsafe.
2010-10-15, 12:51 AM
I believe that you'll be safe with your 5' mast, provided that you manage to sink the lag bolts into roof beams. The antenna itself is approximately 2' high, so you really don't have much room to cut the mast anyways. Especially if you decide to add some sort of VHF antenna down the road.
EDIT: Just noticed that you intend to use the CM rotor. My recollection is that this rotor does not recommend more than 2' of mast length between rotor and antenna without a thrust bearing (which you obviously cannot use on a tripod). You may wish to confirm this in the rotor's documentation.
If that's the case, I don't believe an extra foot (5'-2'=3') would make a big difference. I've certainly seen CM rotors used with a longer mast....but that's a judgement call you'll need to make based on Channel Master's recommendation. The tripod can certainly accomodate the load...the question you have is the rotor.
2010-10-15, 01:05 AM
Now that you mention it, I've got 2 inch lag bolts that came as part of a "lag bolts and pitch pads" kit, and I wondered if it was deep enough. Even if I make sure it goes through trusses, it still needs to go through the tripod support bracket, shingles then plywood THEN trusses...
2010-10-15, 01:11 AM
My CM rotor manual mentions 3 feet antenna mast over the rotor assembly, which does not include the part where the mast attaches to the rotor. So make that 3.25 feet maximum mast where 0.25 is taken to attach to the rotor.
4228hd is 33inch high so it would mean I need to keep it as close to the mast attachment as possible and cut the mast at about 3.25 feet.
I always wondered if this was more of a rule of thumb for bigger and usually larger horizontal antennas which I assume would have a bigger wind load.
2010-10-15, 01:18 AM
2" seems too short.
I use 3.5" lags, and they've worked well. I have seen them for sale at The Source, but they're likely cheaper elsewhere.
2010-10-15, 11:50 AM
My recollection is that this rotor does not recommend more than 2' of mast length between rotor and antenna without a thrust bearing (which you obviously cannot use on a tripod).
You can get support bearings that can be used on a tripod (see picture below). Obviously they aren't as good as the type of bearing used with towers, but it is better than nothing. You just need to make sure the sections of mast between the rotor and the bearing are perfectly straight, otherwise the rotor will bind.
2010-10-15, 02:51 PM
I had checked out the TB-105 before, and after checking it again, I saw that it will only take a maximum of 1.5in mast inside and mine is 1.66in OD. It would not work for me. I'll likely cut down the mast to an acceptable height to be safe.
We're in an older neighbourhood where the allmost all homes' exterior walls are laden with coax wire, telephone wires, left-over antenna wire, etc. etc.
It is not un-common to wire-up the bedrooms by going through the exterior walls. I make this assertion because I have observed many homes in my neighbourhood where past cable guys have run coax along the outside second floor and just gone through the walls of each bedroom.
Most homes have no insulation nor vapor-barrier to damage. Also, the homes I am currently thinking about have no attic to attempt snaking wire through walls, etc.
So if I am wiring up a bedroom on the second floor, I must drill through the lathe & plaster and out through the aluminium siding. I must go from the inside out because I know of no other way to determine at what location on the outside wall to start to drill to end up at the desired location on the inside wall. Also, trying to drill through lathe and plaster from the back seems like a disaster waiting to happen. I am also able to better verify that I am not in danger of hitting electric wires if I drill from inside.
What can I do to the aluminium siding to make it less sharp so that the RG6 does not get damaged over time? i.e. Is there some type of rubber ring that can be forced into the hole? Some type of silicone gunk?
Is there another way to approach these situations altogether?
2010-10-25, 05:35 PM
There is a plastic bushing that you can get at Home Depot. It is designed primarily for those who want to push the RG6 directly through the Gyroc inside the house without a box or coverplate but it should work to cover the edges of the aluminun siding just fine.
2010-10-25, 05:44 PM
I've seen some coax wall bushings online. I have no experience with them and they would likely need extra silicone or sealants to make the connection waterproof anyways, but it would help with making your siding less likely to puncture the cable.
try "coax bushing" under Google image search.
2010-10-26, 02:11 AM
HWP: In Toronto, I've found that most older homes (50+ years) don't have complete metal duct work for return air ventilation to the furnace. The "duct" is an enclosed area between joists and the wall, with the bottom side of sheet metal (nailed to the joists) where the duct meets the basement to the furnace.
I've had success carefully drilling into the back or side of the vent (usually the vent is in a hall baseboard or floor). Then feeding cable down to the basement. You then carefully pry out the nails holding the metal to the joists in the basement, and pull out your cable and route it where necessary. Then reassemble the metal enclosure to the joists, ensuring that it's as air-tight as it was previously.
Obviously this won't work if your return air vents are nowhere near where you need cable. Or your return air path isn't straight down (most are).
Don't push sharp tools down the shaft (to assist with cable routing, etc), as electrical wires often cross the airway.
Plenum-grade cable is recommended for this type of installation, though I've used standard RG6 before (it's just room air in the vent).
Just another possible option for you....
I've seen the drill-to-outside approach (it's very common as you say). Fast and effective for a cable installer, but ugly. Especially when they use white cable on dark brick (eek!).
Thanks all for the tips. I'll try to locate some of those bushings. Maybe a satellite store. Thanks for the tip Jasse88 on running wire inside the main air duct. So far the homes I installed had hot water heat. But in my neighbourhood it seems like a mix of hot water and forced air (probably retrofitted). My neighbourhood is in the 80-year-old range.
For the one neighbour that I have already made the hole in the aluminium siding for, I'm thinking I might be able to use a rubber weather-proof coax end cover boot as a substitute for the bushing + some type of silicone or other gunk. Will silicone or tar interact poorly with the rubber?
By the way, I used black cable on the outside walls. It matched all of the other cable already on the walls.
2010-11-19, 01:31 PM
OK guys, is there any chance that if I add 10 feet to my tower, that reception could get WORSE on a channel? Is there such a thing as a vertical sweet spot?
I’m at 35 feet now and would like to go to 45 feet, but wonder if the risk is worth it…
Basic residential area, no large buildings/trees; at 35 feet, the top antenna just clears the roof peak, while the lower antenna is 5 feet below (does not clear roof). The 45 feet would easily clear all houses in the area for both antennas.
2010-11-19, 01:54 PM
For myself, adding height (going to 68' from 30' at the rooftop) dramatically improved reception. Though it also introduced occasional co-channel interference on channel 40 from London (also CFTO Toronto) and strong Detroit during tropo (which kills some other channels). I also believe height above most buildings and structures can help reduce multipathing on analog.
All in all, the pros outweigh the cons for my situation, as I'm also in an older area with lots of mature trees.
You're already on the mountain and have a clear signal path. Though the extra height would be nice to help your lower antenna clear the roof.
My recollection is that your TVFool results didn't vary much between a higher installation vs. your current one.
Difficult decision in your situation....
If you can acquire another tower section cheaply, and install it while keeping within recommended specifications, then I say go for it.
El Gran Chico
2010-12-04, 07:54 PM
A relative of mine is thinking about using a 10' section of EMT as a mast using a channelmaster 3079 wall mount to attach it to the house. The question is, how long can the emt be reasonably be extended above the top piece of the mount, and how far should the 2 pieces of the mount (top and bottom) be separated?
The antenna is a CM4221. Also if you have more on the mast (eg. a larger antenna like a 4228, or a rotor), would that change these measurements?