[andy.s.lee]

Originally Posted by herplace

I hope not to waste your time with my lack of understanding.

No problem at all! We're just trying to help.

I measured the stretch from the back of the one T.V. to the attic location of the old style outdoor roof antenna which I'm still not clear what to call. The distance is about 30' using thin coax. Never have thought of getting a pre-amp. That's a new concept to me and I'd like to know more about that! The antenna is what I think covers both UHF and VHF ranges. It's not huge but it spreads out horizontally at one end with thin aluminum tubes and then on the southwest side of the mounting mast the main boom has a smaller spread of aluminum fluted extensions in a tighter configuration. It pretty much gets in the way up there.

Sounds like a typical small combo antenna. The long elements at the back are part of a log-periodic antenna that handles VHF channels, and the short elements at the front are part of a yagi antenna that handles UHF channels.

NBC (WNYT) has their main transmitter on channel 12 (VHF), but they also have construction permits for two low power repeater stations on channels 18 and 45 (both UHF). All three of these probably map to the same virtual channel number 13.1.

I wonder which of these three signals you are receiving. One way to test may be to manually enter the real channel number into your receiver. If, for example, you type in channel 12 and your receiver automatically jumps to 13.1, then it probably means you're getting the real channel 12 off the air. Similarly for channel 18 and 45, if they automatically take you to 13.1, then it means that your tuner is able to lock on to each of those respective real channel numbers and map it to 13.1.

This will tell us whether or not the VHF or UHF portions of your antenna are responsible for getting NBC for you.

The "thin" coax you speak of might be RG-59. If there's any visible markings on the outer jacket of the coax, it may indicate the cable type. It is more common these days to use the slightly thicker RG-6 coax because it has less loss over distance and has better shielding.

The boom has a southwest/northeast orientation if I understand the pointing question right. The roof is slate but there is a metal ridge cap and there is no house wiring at the level of the antenna although there is some running along the floor. There are no power lines around this location either. Can you tell from the information regarding the broadcasters signals why only NBC comes in so well? Would a Pre-amp really give my T.V. more to work with?

One more detail: Back in the analog days I had three channels with snow on some more than others. Its hard to recall if NBC was the best back then. The attic antenna had a really old style flat wire running to the T.V. location. At one point I had some insulation installed and something got bumped up there and Fox never came in again. Actually all the channels disappeared until the antenna got re-set. At that point it was just NBC and CBS that remained and I think one of them came in a little better than before the insulation project. I'd be interested to get advice on how to really point the antenna correctly.

Most of your channels come from a cluster 58 miles away at azimuth 221º (on a map), which is 235º on a compass. Ideally, you would want the sweet spot of your antenna to point in this direction.

CBS (WRGB) is on channel 6, another VHF channel. If channels 13 (analog NBC channel) and 6 (analog CBS channel) were the only working channels before, then is sounds like you were relying on the VHF capabilities of your antenna.



It sounds like there are multiple steps you can try to improve your signal. Just thinking aloud, I'd consider the following:

• Install an antenna on the roof instead of the attic. Having the antenna outside gives it more signal to work with, but you'll need to consider the trade-off with protection from the elements (ie. snow) and having to go up on the roof.
• Upgrade to a better antenna. Your choices may be limited if you're cramped for space in your attic.
• Replace the RG-59 (if that is indeed what you have) with RG-6. This will reduce line loss and perhaps improve resistance to interference (eg., microwave ovens, electrical wiring, etc.) that might be present.
• Install a pre-amp near the antenna. This boosts the signal right after the antenna and overcomes the effect of line loss and splitters (if you have any) that come after the pre-amp. This effectively lets you keep as much of the signal integrity as possible right after the antenna.
• Re-check the aim of the antenna to make sure it is optimal.

If I were to re-order these from what I think is easiest and cheapest to try first, I'd probably approach this as follows:

1. Check the antenna aim and connections first. This doesn't cost anything and gives you a chance to inspect the antenna, all the connectors, and wiring for any obvious problems (broken/bent/cut/shorted/etc.). You'll also want to make sure that there are no metal objects near or in front of the antenna. Did your new attic insulation include any metal foil backing that might block signals?
2. Replace the coax with RG-6 if what you currently have is RG-59. RG-6 is generally easy to find and not that expensive, although you need to be comfortable with making your own cables (cut to proper length and add connectors to the ends). If this reduces your line-losses a bit, it might help you pull in a few more channels.
3. Install a pre-amp. This will overcome most of your line-losses and give your receiver a better signal to work with. It doesn't improve the raw performance of your antenna, but eliminating the line-losses can result in higher quality signal (SNR) at the receiver. The choice of pre-amp to buy depends on what kind of antenna you may or may not buy (see next step). BTW, the first choice that comes to mind right now is a Channel Master 7777. If you end up choosing an amp, be sure to find one with a low Noise Figure (NF) specification (3 dB or less is considered good) because this determines the quality of the signal coming out of the amp.
4. Get a better antenna. If your old antenna is broken (maybe when the insulation was installed) or deteriorating, then it may be time for replacement anyway. If the old antenna is still in good shape, then there probably isn't a good reason to switch just yet. If you do choose to try a new antenna, it would help to understand the space constraints in your attic to know what will fit.
5. To get the best possible signal, moving the antenna to the roof would be the next step. The signal is going to be better up there and you probably have the option of using a larger antenna (better performing) to make sure you're getting the strongest signals possible. However, snow and ice concerns might make this a non-option.

Best regards,
Andy