stampeder,

I see different opinions on the maximum unsupported tower heigth...

I may be installing a 30 ft tower, bracket to side of house at roof level (10 ft), only 1 story!

is leaving the other 20 ft above the roof (unsupported) too unstable...I know my neighb did it...but it hasnt been time tested with severe winds....also not sure about his base...I know he didnt put any concrete...

@balm: My understanding is that you're safe with up to two sections above the bracket. Any more than that requires guy wires.

the reason I doubt is I climbed a tower and after the second section it definitely swayed (moved) and I wasnt at the top, and no wind, also the top bracket was at 15ft on the roof....

the base was also poor because I noticed a dip in the overhang (roof) where the bracket was attached, meaning the tower's weight was being supported by the bracket, as opposed to the base...

I see different opinions on the maximum unsupported tower heigth...That is simply because towers are made by several different companies using their own different thicknesses of material, different geometries, different purposes, and different engineering. You must never assume that they are all equal. If you try to join one section from Delhi with a section from Radio Shack you'll see what I mean.

if your tower is brand new, the instructions and warranty will tell you exactly what is allowable and what is not. Do not exceed those specifications.

If your tower is used, hopefully you were given the instructions and warranty so that you can see what is allowable, and then the wise thing to do is purposely lower the strain below the new specifiations due to the wear and tear on the tower already.

If your tower is used but you were never given any engineering specifications (which is usually the case) you had better assume that the tower needs less strain than a new one!

If you intend to ever climb an old, used tower make sure that you have insurance coverage, that you've written a will, and that another person is spotting for you. If you are afraid of heights my advice is to not try it. Make sure to wear thick leather gloves so that you don't get cuts/infections from rust and bird poop. If you do get a cut you must go and get a tetanus (http://en.wikipedia.org/wiki/Tetanus) booster shot from a hospital or clinic asap.

If you intend to ever climb an old, used tower make sure that you have insurance coverage, that you've written a will, and that another person is spotting for you.

How does that work if I hire someone, do I have to make them sign a waiver...

Don't forget the harness!

I own one of these....

http://image.inkfrog.com/pix/werenotscared/TOWER_HARNESS_2015.jpg

That's what I need! Do you hook it to the tower or some other point?

One of my friends that I play hockey with was a career hydro lineman so he's got all that gear too for whenever I've needed it. He'd lend me his boot spikes too if I wanted to climb a wooden power pole or tree, but I don't think I'm in that good shape anymore! :eek:

With harnesses like that one in the picture you always clip one hook on above you to right where a cross-member is welded to the upright tower spar, climb up a few rungs, clip on the second one as high as you can above you, then unclip the lower one, climb up a few rungs, repeat, repeat, lather, rinse, repeat until you get to the top and clip both on while you do the antenna and/or rotor thing. No matter what you are doing going up or down, you always have one clip on at all times.

Be very careful using Fall Arrest equipment.
There have been several incidents in Canada over the past few years where accidents have happened due to the condition and age of the Fall Arrest gear.
Typically the harness,lanyards and rip cords are inspected annually and certified.
The users also take up to a 2 day training course to learn its usage.

Yes, great advice weehaggis!

Here in BC you can contact BC Hydro and ask about their high wire safety training courses taught by Mr. Haines - usually if you work for a cable co, tree pruner, phone company, utility company, fire dept, etc. they put you through his course.

I finally finished installing my antenna array. (Then why do I still have my tools out????) First let me start by listing the gear, On the top at 20' is a 300 ohm VHF high yagi style antenna. At 15' is a 300 ohm 8 bay bow-tie UHF, I removed the factory balun. Both are connected seperatly to a CM 0264DSB Spartan 3 Mast Mounted 2 Input Pre Amplifier with the FM trap on, which is placed in between the two antenna. This follows 85' of RG6 to a central location and connects to the power supply, out to a Pico Macom HLSJ VHF Band High-Low Antenna Separator out on high side only. This is connected to a distribution amp which feed an 8-way splitter to distibute through-out my house. The antenna is locked down to 21 degrees VHF and 18 degrees UHF which is directed to 4 stations 70 miles away (67-80%), I get 6 more close by (100%).

Now for the question... Is there an optimal distance between the antennas? As I move the UHF up closer to the VHF, the UHF gets wores but when I move the UHF to far down I get interferance on the VHF?????

Please explain.:rolleyes:

There are some threads in this forum that deal with ganging and stacking similar antennas. Ganging a VHF & a UHF seems quite unusual to me. Normally the rule would be to space the antennas about 1/2 wavelength apart [aprox 29"] to minimize conflicts, however this is just a basic rule based on theory. Real life mixes and matches may require some trial and error. If you have both twin leads from both antennas feeding into a single 300ohm pre-amp input, then you may want to try and reverse the twinlead connections on one of the antennas. It could be a phasing problem.

Post #16 in the OTA FAQ has all the info you will need about antenna separation.

out to a Pico Macom HLSJ VHF Band High-Low Antenna Separator out on high side only.

I am really curious why you have this. Do you have some really strong VHF-LO signals that you are trying to attenuate?

A reminder to all that a rooftop can be a very dangerous place:

http://www.bclocalnews.com/surrey_area/peacearchnews/news/44325257.html

Know at all times where you are in relation to power lines. Don't mount antennas within 3 metres/10 feet of a power line.

FM filtering. There are a lot close by.

FM filtering. There are a lot close by.
Ahh. That makes sense. Why not use an FM Trap instead? Do you not have any VHF-LO stations? Did you terminate the unused VHF-LO output?

Hi ,

Can anyone offer me your opinion on my antenna installation ?

Its mounted and working fine.
My antenna's are mounted using a chimney kit.
Can you look at the photo and tell me if there is too much mounted to my chimney?
Just your personal opinion.

The brick chimney is a dual flu style in very good condition.
There are 2 antenna's mounted.
There are 2 masts strapped together for rigidity.
The second antenna is an OMNI antenna.
The chimney straps are 3.5 feet apart.
The overall height is ~28 feet above ground
The CM4221's highest point is 9 feet above the chimney,,, the OMNI is 3 feet below on a offset mast .


It looks very sturdy and takes the wind with only a little wobble.
I just want to know if this looks like "too much weight / and or wind stressing " for the chimney and the chimney kit?

I just don't have enough experience to judge my installation to others.


thx
Michael

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CM4221 w/AntennaCraft 10g212 preamp - AntennaCraft OMNI HDMS9100 - Chimney mounted - LGTV w/QAM ATSC

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http://www.digitalhome.ca/forum/picture.php?albumid=217&pictureid=981

http://www.digitalhome.ca/forum/picture.php?albumid=217&pictureid=980

michael_lx6

Overall, it looks pretty secure to me... The only downside to a chimney mounted antenna is corrosion.

How much do you get out of the mini-state omni ?

The CM4221 with the adjustable 20-30db gain is a good choice.

Hi ,

Can anyone offer me your opinion on my antenna installation ?

Its mounted and working fine.
My antenna's are mounted using a chimney kit.
Can you look at the photo and tell me if there is too much mounted to my chimney?
Just your personal opinion.
Your chimney mount does look very sturdy. (Very neat install-nice job!!) I use 3 straps around the chimney, because I wanted to make the installation rock solid. I tried to post a pic, but for some reason the forum will not let me????????