: OTA Mounts, Towers, Rigging Hardware
2008-04-04, 12:00 AM
Okay, the antenna is up and I am now enjoying every channel a Torontonian can expect to get (pictures of the install will be up shortly, Stampeder). Now on to the next project: the second tv. In order to avoid the hassle of rigging up a splitter / amplifier / attenuator, I have been playing with the idea of just putting another 4221 on the mast (either one above the other or side-by-side) and running each tv as its own closed system. The two antennas won't be electrically connected, but I worry their close physical proximity will cause them to interfere with each other. As always, I turn to all of you. Thoughts?
2008-04-04, 12:04 AM
Identical antennas should ideally be spaced one full wave apart on the lowest channel (frequency) they're designed for.
That's ridiculous for big old VHF antennas (the separation on Channel 2 would need to be 18 feet!) so using a half or quarter wave is what should be attempted.
Thankfully with UHF frequencies the antennas should ideally be spaced one full Channel 14 wave apart, which is only 25 inches, but if that's not possible you could go with a half-wave at 12.5 inches and as a last resort a quarter-wave at 6.75 inches.
2008-04-04, 03:34 PM
Wow, very quick and very detailed. Thanks, Stampeder.
Now that I know how to do it, is this a good idea price and effort-wise, or am I overestimating the cost and hassle of splitting the signal?
2008-04-04, 04:12 PM
That all depends on what kind of signal you're getting.
It's alot cheaper to buy a splitter and test beforehand than to buy a whole other antenna setup.
If I were you, I'd try splitting it without amplification and see what happens.
(After all, a splitter costs like $1)
If you lose the signal then you're looking at similar cost for a preamp or another antenna, at which point its your choice ;)
2008-04-04, 05:25 PM
I've done the test, and splitting the signal just won't cut it for my Buffalo stations (especially NBC, which is hovering around 50% but rock solid unsplit). I have line-of-sight to the tower and very high numbers for the Toronto stations, so a preamp will definitely require an attenuator.
At any rate, it looks like I'll be splitting and amplifying because the Sony DHG-HDD250 I'm getting has only one ATSC tuner, which means I'll need a second STB on that tv if I want to record and watch something else at the same time (somebody correct me if I'm wrong on this, but I think that's what a single tuner means). Add to that the third STB the upstairs tv will require, and splitting three ways makes much more sense than three antennas.
So stay tuned for a bunch of newbie preamp questions from me (I'll read through the old posts first, of course).
Thanks to all for the help, and please keep it coming.
2008-04-05, 08:33 PM
It would be just like a traditional analogue tv, i believe the STB would have passthrough cable connection (I may be mistaken, I dont use a STB)
so you could record the signal on a DVR and still watch on the tv, much like you could watch tv while recording another channel with a VCR.
We're getting a little off topic, but hope that helps ;)
If I understand you right, a simple solution might be to gang a second 4221 antenna physically the same way Channel Master does in making the 4228, but run separate lines to each 4-bay array. If there's a distortion in the directional gain pattern, you'll get different stations on the two TVs, and would then want to stack vertically.
In that case, I'd recommend a 16" minimum separation between top and bottom antenna elements, the actual bow ties. The 4221 is built with an 8" element separation, corresponding to 1/2 wave at it's peak gain frequency, so 16" is 1 wave separation. Anything larger should be independent.
However, splitting the signal is far easier, and there are low-gain, single channel amps designed for this need. Channel Master and Winegard both have 13dB and 15dB indoor amps; Winegard even has a mast mounted 13 dB amp. Since you'll lose 4 dB in the splitter and 3-6dB if there's much of a cable run, there's not much amplification. A coil of coax could be your attentuator. It would sure be easier, since you'd be running the second coax line anyway.
2008-04-09, 08:22 PM
The aim here is to have HD programming avaialble remotely via computer network, using ATSC PCI card and software like BeyondTv or Sage
The remote computers on the 3rd floor would run Sage, which will get "live" video from PC with the tuner card in the basement
Channels avaialble to me are CBC and CTV (and presumably) Global fairly reliably, but they are E or ESE of me
Fox is pretty reliable, but to the SW
So the question is: can I have two antennas (one to the ESE, the other to the SW) feeding in to one ATSC card?
Any way to do this without interfering with signal?
Or is there some other way using Sage (or similar) to command the antenna to turn?
I did a forum search as this question may have been asked before, but couldnt readily find answer
Currently I use a CM4228 with a manual switch DC-powered RadioShack rotator; but have not got in to the networked Sage thing because of the the question above
2008-04-09, 08:40 PM
you can combine the signals together onto one coax, then adjust until you see no interference (if it occurs at all)
They also make remote rotors so you can turn an antenna to preset positions automatically, if you want to go that route
2008-04-27, 06:49 PM
I should be installing my tri-pod with CM4221 soon and would like to know what did u use to screw the tri-pod to the roof with.
2008-04-27, 11:12 PM
pshseek, I can't comment on ViperZ's install, but if it were me, I would use lag bolts that are at least 2" long. You need to be sure that you are screwing into something solid. If you only hit plywood, it might seem sturdy at first, but after several years of use, the bolts will become loose. Optimally you want to screw into the trusses, but it can be dificult to find them without drilling test holes (not reccomended for obvious reasons ;) ) and the spacing of the trusses probebly isn't the same as the spacing of your tripod. An alternate solution is to attach blocks of solid wood inside the attic where the holes for the tripod are and screw into those.
2008-04-28, 03:11 AM
pshseek, roger's advice is (of course!) excellent, and you can find several posts in this thread that discuss roof mounting in great detail. Just use the Search This Thread tool to the upper right with the search term "roof mount" and you'll get plenty of results.
2008-04-28, 07:54 AM
Thanks guys for the feedback. I've been considering lag bolts and thought maybe carriage bolts would be better/stronger. The last thing i want is to have it blown off and fall onto the hydro wires which are close by. i've already crawled into my attic and built up the underside of where the tripod will sit with 2x4's. I figure if my measurements are no more than 2-3 inches out, then i'll hit the "good wood" from the outside. I'll try to remember to take some pics whenever i get around to the last stage of my project and post them here. thx again.
2008-04-28, 11:58 AM
pshseek, I used 3-inch screws from Home Depot. Like Roger suggested, drill proper size holes in the trusses first, then attach tripod with the screws.
It is not that hard to find trusses by tapping on the roof with the hammer.
Be sure to seal the holes around tripod mounts and screws with outdoor silicone, and black tarp (sp?). You can also add rubber pads under tripod mounts for extra seal protection.
2008-04-29, 01:28 AM
The legs of three foot tripods will usually not line up with trusses. You stand a better chance with a five foot tripod.
With my install, I didn't bother to try and hit a truss. I just put the lagbolts where they felt like they would be between trusses, then had a friend hold up some 2' lengths of 2x4 where the lags poked through, to give them something solid to grip. The 2' pieces of 2x4 spread the load enough.
2008-05-11, 08:49 PM
This guy may be a red neck but he's all setup for HD
2008-05-20, 02:51 PM
I was trying to install a J-mount for the 4221 clone. I tried to drill the pilot holes for my 5/16 lag bolt (3" long). I put in the drill, it went right thu, without any resistance. There is some styrofoam pcs coming out. I try another 2 more places, same.
I was scratching my head, and its getting dark so i just plug those holes with silicone. Then i was google-ing and see why there is styrofoam under the stucco. And i found out my new townhouse is build with the EIFS wall system. Its the insulation on the outside with a layer of painted stucco on it.
I went to my neighbour house (which is still under construction) and check out the wall. There is a 3/4 plywood from the frame, then 2" styrofoam insualtion, then a layer of padding or sth. then spray on the stucco.
So i have 3" material to get thu before i hit the stud. Need to get some 5" lag screw to make it work......
2008-05-27, 03:50 PM
I would like to install a tripod on my roof. what is the best way to ground the antenna? I saw at Home Depot a RG6 cable with a ground wire. Is this good enough? I would be able to ground it to the electrical service of the house.
Your advice is appreciated?
2008-05-27, 06:32 PM
Friend of mine gave me 3 ten foot sections of tower. What would be the proper way of setting it up. Do I use a sonotube and concrete as well as some brackets with lag bolts to the side of my house? Any suggestions would be appreciated.
2008-05-27, 08:59 PM
what is the best way to ground the antenna?See this thread for all your Grounding questions: