PDA

View Full Version : Combining two identical antennas?


snoopysbuddy
13-Sep-2011, 5:59 AM
Getting a signal in my house is a difficult thing because I live on the opposite side of a hill from the transmission towers. I've tried several antennas and found that the ClearStream2 mounted in my attic mostly works. The problem is, i get about 2/3 of the stations if I mount it on one side of the house and a different 2/3 if I mount it on the other side (about 1/3 overlap). There must be some interference from the ducting in the attic or something.

So it occurs to me that if I have a second ClearStream2, I could just mount one at each location and combine the cabling into one coax cable that feeds the TV. Since they are two identical antennas pointing at the same transmission source, it stands to reason there won't be any technical problems with ghosting or signal interference. Can anyone confirm that thought?

Also, in my case, I don't believe I need any sort of special antenna combiner. It seems I should be able to just splice the coax cables from each antenna together and call it a day. Am I right?

Thanks!!

Tower Guy
13-Sep-2011, 2:02 PM
I don't believe I need any sort of special antenna combiner.

It might work and it might not. Try a backwards splitter to combine the antennas. The second antenna may pick up multipath that would ruin reception of the good channels from the first antenna. If so, you may find locations for the two antennas that are better than others.

When two antennas are aimed in different directions the cable length to each antenna is less important.

From your previous post here is your TVfool report: http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d9fbeb6d4c0b87a

In your case the problem may be more that the C-2 is a UHF antenna and you have 4 VHF stations to pick up. (KABC, KCAL, KTTV, and KCOP) Instead of a second UHF only antenna, consider a VHF antenna (Y-10-7-13 or YA1713) and a UVSJ to combine them.

GroundUrMast
13-Sep-2011, 4:06 PM
@ TG, Thanks for bringing the TVFR link into this thread.

@ snoopysbuddy, The predicted signal levels indicate the need for a high gain antenna mounted in the clear. An attic mounted antenna is not my first choice. An attic mount C2 is way down the list. Back in 2010, in your first thread, Tigerbangs offered to detail an appropriate antenna system for your situation. It appeared to be an Antennas Direct XG-91 and a high-band VHF such as TG just suggested. I agree that you need more antenna than the C2 (a quality antenna, just not appropriate in your situation).

Ganging two C2's will not solve your problem (IMO).

snoopysbuddy
14-Sep-2011, 5:04 AM
@GroundUrMast - while I appreciate the advice I received with my first post in 2010, I was serious about a roof-mounted antenna not being an option. That being said, I went ahead and tried installing a roof-mount antenna inside my attic. I don't remember the models but I do remember one was Winegard and another was antennas direct (might very well have been the XG91). Neither antenna gave me any signals at all. The problem was that both units were so long I had trouble aiming them properly. Is there a shorter antenna that you might recommend?

@TowerGuy - that's an interesting point. I had no idea the C2 is UHF only. Guess I should have read the literature. I never did get KCOP or KCAL but I don't watch those channels anyway so it didn't bother me. I always got KTTV. KABC was good on most days and seemed to depend on weather.

I'm contented with the channel lineup i'm able to get now, with the exception of the two PBS stations KCET and KOCE that I don't get. I know where to place the C2 in order to get those two stations but it would mean I'd lose KPXN. I thought maybe I could leave my set up the way it is now but augment it with another C2 just to get everything ;-)

I think I've got enough to go on for the time being. I'll just have to get a UVSJ and try different combinations of antennas and location. I'll report back on this thread if I am successful.

snoopysbuddy
1-Nov-2011, 3:43 PM
Here's an update for anyone interested. I finally had a chance to mess around with the antenna situation over the weekend. The local Fry's hadn't restocked their antenna inventory since my last post so there wasn't anything readily available to me. However, I did find the HDTV antenna plans posted by Make Magazine. I had the scrap parts in my garage and clothes hangers in the closet so I thought it wouldn't hurt to give it a try. Much to my surprise, that antenna worked really well. So I learned a few things from this experiment.

First, the DIY antenna looks totally ghetto and sinister. But it seems to work just as well as the ClearStream 2. Swapping out two out, I the DIY antenna got all the same channels as the C2. So the first lesson is that I wasted $100 on the C2. Anyway, I placed the DIY antenna at a different part of the house so I got channels that the C2 wasn't getting, including the troublesome KABC.

Second, I didn't have a combiner offhand so I used a splitter (in reverse). That didn't work at all. I thought it would just provide a simple electrical connection but there must be some addition circuitry inside the splitter. Instead, I spliced together several coax cables and ran both antenna feeds into the input of the distribution box.

Third, having two different antennas on the same coax input feed does cause some interference with the signals. But that's not surprising since the problem has been pointed out a number of times on this forum. In my case, when both antennas are connected, several channels were lost (they were all spanish stations so I didn't care). On the flip side, I'm getting more channels I like. So it's working out for me.