Antenna help in SoCal

[wolfman334]

Hi everyone,

I'm about the ditch cable and I've just started researching antennas to try and pick up the local HD broadcasts down in San Diego. I'm very new to this so a little advice would be great.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3da362909c89b948

I'm in a two story home so the antenna could be roof mount which would put it around 20+ feet off of the ground. It would run one to two TVs. I have an AV panel with a built in amp but I've been bypassing it for my current cable feed.

There is a dish mounted on the 2nd story awning currently which would face in the correct direction I need. I planned on using the cable that is currently up there which is RG6.

I am in the mountains so I do have a bit of a terrain issue. The antenna I've seen suggested on these forums would be the Winegard HD-7696P which appears to have the range I need. My first question is whether that is correct or if I need a different antenna. My second question is whether I could get away with a fixed mount and still hit all three channel groupings by pointing at the 167 degree group.

There are also some pretty heavy duty power lines running directly behind my house which happens to be in the direction the antenna has to point. Will this be a problem?

Thanks in advance for the help!

[Dave Loudin]

The Winegard you're looking at will be OK to pick up KNSD or stronger. If you'd like to see XETV's eventual digital operation reliably, you should spring for the HD7698P. If the antenna does not have to look directly through the lines, you will definitely be fine. I'll let others comment to the situation of having the lines directly in the antennna's sight line.

[wolfman334]

Thanks for the suggestion! I've done a bit of looking around at that antenna and it gets pretty good reviews. There are only a few people complaining about plastic joints and lateral warping. Hopefully they just got either lemons or something damaged during shipping.

I'm hoping or assuming the antenna would be pointing below the electrical lines. They just installed new poles which are the giant metal ones. I believe those keep the lowest lines at least 20 feet from the ground.

[mtownsend]

Since most of your channels are in the "red" zone on your list and they have fairly low Noise Margin numbers (mostly around -5 to +5 dB), I'd err on the side of going with a larger antenna (like the HD7697P or HD7698P) and mast-mounted a pre-amp (like the Winegard AP-8275, Channel Master 7777, or Antennacraft 10G202).

To answer your question about the static antenna mount, yes, you should be able to pick up all of southern channels with a single antenna position. It might take a little bit of fine tuning to get the aim right initially, but I think it will work.

The channel spread is about 37º (that about +/- 18.5º from center). The first deep nulls in these kinds of antennas are at least about +/- 25º from center (and usually even wider for the lower channel numbers).

I would aim the antenna between the clusters at compass headings 138º and 154º. The cluster at heading 175º is entirely VHF channels, any they should have no problem getting in through the much wider VHF beamwidth of these antennas.



As for the power lines, it's hard to say. Any time there are objects in the field of view of the antenna (imagine a spotlight with a "beam width" of about 30º - 40º), there is the potential for excess signal reflections and interference to work their way into the signal feed.

Transformers have been known to generate a lot of interference sometimes, so if you don't have any nearby, consider yourself lucky.

If the signal must pass through a bunch of wires to reach you, then they WILL have an influence on your signals, but it's hard to say how much. The further away they are, the better off you will be. A picture might help us get a warm and fuzzy feel for the situation, but even then, all we can do is guess. There's no sure-fire way to know until you try it.



BTW, if the power lines are close enough to be touched by the antenna and/or the mast, be very careful when doing the installation to avoid getting electrocuted.