: OTA Mounts, Towers, Rigging Hardware
2008-11-08, 11:49 PM
Thanks Stampeder! Great, so a single RG6 will do regardless of the option I choose. Regarding the rotor, should I infer then that different rotors require completely different wiring? There is nothing standard I could run while I can still get through the walls easily? Thanks again!
2008-11-08, 11:52 PM
The folks in the Rotors thread can answer all your questions. Some brands use 3 wires, some use 4.
2008-11-14, 07:21 PM
I obtained a ClearStream 4 antenna so I'm happy!
Anyway if you could recommend ways on the cheap to mount this outside...
Would this way be possible too? I was thinking of picking up a J-Mount, the ones found and used for satellite dish installations and using that for this antenna. I figure it should work. All I would do is mount it on the roof, or drill it with lagbolts through the brick of my house. Would the J-Mount work?
And after I'll have to run it to a grounding rod (learning at the specific forum for this).
Let me know thanks!
2008-11-14, 07:29 PM
Yep, if you put the term J-Mount into the Search This Thread tool you can see plenty of posts about using them.
Also let us know how that antenna does in the Antennas Direct thread when you get it up and running - the figure 8 element on it looks pretty far out. :)
2008-11-15, 12:08 AM
So, over the past 12 months I've managed to acquire most of the necessary components to resurrect my old tower.
Have a CM4228, CM7778 preamp, RG6 cable, new heavy duty HAM rotor & controller, new 10ft x 1 1/2" 14ga mast and a 40ft tower with existing combo UHF/VHF antenna (about 10ft long).
My plan is to mount the 4228 above the combo antenna on the same mast.
1) How much separation should I have to avoid interference?
2) How do I connect both antenna into the preamp?
3) Can/should I run the coax thru a ground block?
4) What about lightning suppressors?
5) Where the heck can I buy 6 conductor rotor cable?
6) Best to mount rotor inside tower on a plate or on a mast? I have the option to do either.
Any help is much appreciated.
2008-11-15, 11:41 AM
Welcome to OTA!
1) What do you plan to watch with the 4228? While it's marketed as a UHF antenna it actually is a pretty decent antenna for VHF-hi channels (7-13). Given your location you may be able to get CKVR okay even though it's on VHF-lo (2-6).
You may not need the combo V/U antenna. If you want to keep using it, I'd say space the 4228 about 3-4 feet above the current aerial.
2) The CM7778 pre-amp has separate V and U inputs. If you want to use both antennas you'll have to open it up and flip a switch inside (since it comes from the factory with a combined V/U input). See the instruction manual for details. Feed the 4228 into the U input and the combo antenna in the V input. A single coax run outputs from the 7778.
3) You should run the coax through a grounding block. They're readily available from Rona or Home Depot.
4) I.C.E products makes a lightning arrestor especially for OTA. If you use one of these you don't need a grounding block. Ensure you connect your lightning arrestor to at least one 8' ground rod preferably near the base of the tower.
I.C.E. also makes a lightning arrestor for rotor control cables.
5) People have used underground sprinkler cable before. Home Depot carries it. Alternatively you can buy rotor control cable at Radioworld in Toronto. It's expensive though: last I checked it was around 90 cents a foot.
6) Mounting the rotor inside the tower is preferable as it provides a stronger support for the rotor.
2008-11-15, 01:55 PM
stampeder, I'll keep searching for that j-mount.
In the meanwhile, I went ahead and constructed the C4 (worst packaging ever! Rattles inside were the items that killed and made gouges of everything).
I don't have a mast yet so I used my camera tripod as the temporary mast for indoor use. I pointed it outside of my window and obviously it's the best antenna Ive had yet, all of the channels jumped up in strength and gained one new channel in 29 fox. I won't post results yet since its temporary.
BTW: I tried hooking up the cheapo RCA amplifier that comes with my old antenna with the C4 at first and apparently the C4 doesn't work well at all with an amp like this. I later disconnected it and then the C4 worked perfectly. The amp isn't even powerful, but I guess it was over boosting it or interfering in some way.
2008-11-15, 01:57 PM
Make sure you read through this thread about towers and mounting - tons more info in there:
And I would add my agreement with mr. weather's point 6: with a rotor mounting plate inside the tower a few feet down the rotor base is securely attached to prevent torque-winding forces from causing it to shift, and the rotor's antenna mast goes upwards through what is called a thrust bearing before it emerges above the collar to where you attach your antenna(s). A thrust bearing takes the bending load of wind forces off of the rotor itself, prolonging its life for years.
Another trick I've seen done with thrust bearings is to have a conical piece of thin galvanized sheet metal (like furnace pipe) downwards from the thrust bearing collar to act as a rain shield for the rotor, but I don't think that's too important for places outside the south coast of BC. ;)
Rotor cabling is being discussed in the Rotors thread here:
2008-11-15, 02:05 PM
The Search This Thread tool is to the upper right, or you can click on this link to get to it:
Glad you're getting better signals already.
2008-11-15, 02:12 PM
Mr Weather, thanks for the info.
Would like to receive both VHF and UHF. I don't subscribe to either cable or satelite so the antenna is my only source. I can pick up Barrie (CKVR) with a coat hanger, but need to get the Toronto and Hamilton stations in VHF (5,9,11). As many UHF channels as possible is my goal. With a little luck I hope to maybe get a couple Buffalo stations although that might be a stretch as its about 130km as the crow flies.
Are the ICE products available on-line or from local suppliers?
I found some PVC grey jacketed 18ga 6 conductor for cheap, but not sure if it will stand up outdoors. Guess I could always clad it in split loom.
2008-11-15, 02:20 PM
OTAbound, you'll need to disconnect the UHF portion of your combo antenna or else the CM4228's performance will be compromised. It will have to stay up there to keep the combo antenna in balance, but you'll need to make sure the CM4228 is more than 2 feet higher. UHF antenna spacing is a minimum of 25 inches.
2008-11-15, 02:46 PM
Wow, so much info. I've got some reading to do for sure. Thanks Stampeder.
The tower currently does not have a thrust bearing. The old rotor (cm9512?) is mounted on a mast off the tower then the antenna is mounted to another mast off the top of the rotor. Its been there for about 14years and is still operational although it is rarely ever operated.
Are the trust bearings universal in mounting? I have an OLD tower. Where can I get one?
2008-11-15, 02:49 PM
I'd check Delhi's tower parts, or else you could have a local machine shop or metal shop fabricate one based on some drawings you'd make. I've had custom stuff done like that several times in the past.
2008-11-15, 05:50 PM
Would like to receive both VHF and UHF. I don't subscribe to either cable or satelite so the antenna is my only source. I can pick up Barrie (CKVR) with a coat hanger, but need to get the Toronto and Hamilton stations in VHF (5,9,11). As many UHF channels as possible is my goal. With a little luck I hope to maybe get a couple Buffalo stations although that might be a stretch as its about 130km as the crow flies.Actually, channels 5, 9 and 11 are already in digital and broadcast in the UHF band. No need for a VHF antenna.
Are the ICE products available on-line or from local suppliers?They're only available on-line. The company itself is out of the US.
I found some PVC grey jacketed 18ga 6 conductor for cheap, but not sure if it will stand up outdoors. Guess I could always clad it in split loom.It should be okay. The 18 gauge wire is good because it'll allow you to use a longer run of cable if you need to. What brand of rotor do you have? Yaesu or HyGain?
Stampeder: that's a good point about the UHF portion of the combo antenna. I hadn't thought of that. But given the digital channels around here VHF isn't really needed. The OP could probably get away with just the 4228.
2008-11-15, 09:34 PM
Sounding better all the time. Guess I can ditch the large combo antenna and reduce wind loading dramatically. That means I can go higher, yes ?;)
How can I identify the brand/make of my tower. My estimate is that it is from the 1970's or early 80's. I really like the idea of a bearing above the rotor. Looks like the Delhi towers use a simple sleeve type bearing. I can fabricate something like that.
2008-11-16, 12:14 AM
Guess I can ditch the large combo antennaI can pick up Barrie (CKVR) with a coat hanger
don't ditch the VHF until you get the coat hanger properly installed... that is assuming the you watch CKVR.
UHF antenna spacing is a minimum of 25 inches.25" for UHF but if OTAbound is still going to try for VHF channels, a UHF 25"inches away will still interact with the VHR=F antenna, NO?
2008-11-16, 01:28 PM
a UHF 25"inches away will still interact with the VHR=F antenna, NO? A UHF and a VHF antenna don't interact, or else we'd have never had combo antennas... ;) I've always left about 1 foot between separate UHF and VHF/FM antennas though.
As for the 25" spec, it applies only between 2 UHF antennas, because 25" is a width that is just greater than one full wavelength on the lowest UHF channel, 14. That means all the other UHF channels have higher frequencies and therefore shorter wavelengths so would be more than one full wave apart, which is what we want.
Post #16 in the FAQ has a detailed explanation of antenna spacing. :)
2008-11-17, 12:56 PM
Sounding better all the time. Guess I can ditch the large combo antenna and reduce wind loading dramatically. That means I can go higher, yes ?;) Potentially yes you could go higher. I would worry about going too high and placing too much lateral stress on the rotor where the antenna mast connects.
How can I identify the brand/make of my tower. My estimate is that it is from the 1970's or early 80's. I really like the idea of a bearing above the rotor. Looks like the Delhi towers use a simple sleeve type bearing. I can fabricate something like that.Delhi towers vary. The free-standing type (DMX-series) taper from bottom to top and have x-shaped cross bracing all the way up. The tv-tower style do not taper and have tubular legs and horizontal braces.
I use a DMX tower for my amateur radio antennas and have a thrust bearing at the top to take the vertical load off the rotor and transfer it to the tower structure.
2008-11-17, 01:54 PM
But given the digital channels around here VHF isn't really needed. The OP could probably get away with just the 4228.
Beware -- it's quite possible that CHCH and CFTO will revert to VHF in 2011. I know that CFCF 12 in Montreal plans to be on channel 12, not channel 21, after August 2011.
2008-11-18, 10:19 AM
Good point. That is the one unknown with respect to the Canadian digital transition.
Fortunately, I can receive CFTO analog (channel 9) quite well with my 4221. CHCH is doable but requires some antenna turning.