Help with weather related reception issues

Any antenna will work better outdoors, assuming it's designed for outdoor use.

In general, directional is better than omnidirectional, bigger is better, outdoors is better, higher is almost always better.

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Since your antenna is amplified, additional amplifiers will not help; most likely make things worst. The only rare exception to this rule would be if you have an outdoor, mast-mounted amp, a very long cable run, and need to split the signal at one room to multiple devices (even then not likely).

Weather generally does not affect reception, including fog, except for thunderstorms, or trying for exceptional long distances (60 miles for example). Lightning will cause interference and a complete loss of video with any antenna system even with close-in transmitters. Nothing will help with that problem short of moving to a state that does not have thunderstorms.

Freezing rain, sleet, hail, & snow will cause loss of reception and fog usually improves reception at my location.

Since both rain and fog are causing signal loss, signal attenuation is a possible cause. Signal is being blocked by air full of water. This would be most notable for fringe areas, like 60 miles away with an indoor antenna. Outdoors would gain some signal, but I don't know if it would be enough.

Actually he stated his antenna is UN-amplified.


I know this statement to be untrue.

Of course it's not entirely true. But... the attenuation due to precipitation at UHF and VHF is insignificant. The numbers are as follows;

At a precip rate of 100 mm/Hour, the attenuation of signals at 1000 MHz is approx .001 dB/KM. At lower frequencies the attenuation is even less. (Reference Data for Radio Engineers, fifth edition, HW Sams, 1968).

These low values are a result of the relatively long wavelengths of these signals as compared to water droplets.

I don't believe that information holds true for edge reception. There are just too many other variables to consider.

Pretty amazing you are getting any reception at all since this antenna is rated at 20 miles max. Moving it outside might be a little better but it probably still won't solve your problem. You will need a larger antenna mounted outside but probably not a preamp since your signal is good enough to get inside on good days. Plus your antenna is UHF only so you may want to get an upper VHF/UHF antenna to see if you can get more channels. A tvfool.com report would help with that.

Very interesting differences of opinion about some basic RF propagation facts. I see from your profiles that many of you have technical RF backgrounds, as do I, so it is only natural that we disagree on the basics.

First, thanks "BCF68" for pointing out that I got mixed-up about the OP's antenna with or with amplifiers. A senior moment. However, I stand by my statement that weather "generally" is not the primary cause of reception problems because most folks equate rain with signal loss, which as "NightHawk" points out is absolutely not true until you get up into the very high frequencies (~12GHz and higher). (Oddly, at those very high frequencies, rain is the only factor that is considered when calculating the reliability of a path. For point-to-point reliability calculations below ~12GHz losses caused by rain/snow/sleet/hail are not even considered a factor.) Bottom line, rain (and all its frozen cousins) are not a factor. However, that is not to say other weather issues cannot cause problems. Weather can cause a variety of bad things to happen to the transmitted beam that can cause loss of signal (LOS), mainly bending the beam so that the receive antenna completely misses the signal. That is why we have space diversity antennas in microwave systems. However, this is just as likely (maybe more likely) to happen on cool calm nights as during major weather events.

I am sure that most of you are aware that digital reception is a either "great or nothing" situation with very little difference (in dB or BER) in between, which is where the OP is at IMO. A loss of just a few dB, or a slight increase of BER, will cause a LOS. Under some cases the OP gets a great picture, but any degradation of signal causes a LOS, which is not surprising since the OP is talking 60 miles. I agree with "rm00K" that the OP is lucky to receive anything at all.

OP - - Just curious, what kind of OTA reception did you use to have with analog. My guess, a picture with some level of noise that you just lived with it. If that was the case, my guess would be that with digital you would see a nice blank screen most of the time.

Back to the OP's basic question; how to make this work (if even possible)? Without any TV Fool or similar information (or even knowing where you live), this would be my recommended design for most OTA systems:

1. Assuming that all desired TV stations are in the same direction from your house, use an outdoor, high gain, VHF/UHF antenna that is mounted as high as is possible/reasonable. (An old rule-of-thumb really applies here: you get about 6dB of system gain (less cable loss) every time you double the antenna height.) You want to receive the absolute best signal at the output of the antenna, if you don't, nothing downstream will help much, or be much less affective. High gain antennas are also good at reducing the "undesired" signals (every other TV station) by several dB, which is very helpful for the next step:

2. Use a good mast mounted pre-amp with at least 10-15dB more gain than the combined losses of all downstream devices (cables, splitters, etc.).

3. Do not use any other amps, with the possible exception of a "0dB gain splitter" at a location/room with multiple devices that need OTA connections.

4. Accept that you will lose signal during thunderstorms. At 60 miles, your outages will be prolonged and aggravating since the noise spikes will be widespread.

The steps outlined above is what my former employer has done for years to provide their customers (primarily Public Safety in my case) the best coverage possible. Analog or digital makes no difference to the basics of RF propagation, or to the antenna systems that we provided. The antenna systems that we provided stayed the same when we migrated to digital from analog. The only thing that really changed, from the users perspective, was them getting use to the sudden LOS when they reached the edge of their coverage area. They were use to the gradual roll-off of received AQ until it was nothing but noise (just like FM in your car). It was a real shock back several years ago when they discovered that their new digital radio coverage just "dropped off a cliff" even though the true "useable" coverage area was actually the same.

Does the Window get very wet? If yes then the signal is possibly getting absorbed and/or distorted by the water.

The thin film of water on window glass would also be an insignificant factor.
It's simply too thin to impact those wavelengths.

Okay, wet air and windows aren't the likely culprit. Would wet trees be a larger problem? An inversion could be the problem with fog, but not likely for rain. As an aside, I only receive one fringe channel indoors here (rf 7). I also receive two vhf channels that are green according to TVFool. If I place an arm near the dipoles, rf 7 breaks up. The other two vhf channels are never effected by a person being close to the antenna. Although, I can't say that rain has ever effected rf 7.

I do not believe that wet anything will be a problem. Trees present very little loss at VHF, so I would not consider them much of an issue either. With VHF, the biggest problem is usually a high noise floor casued by all kinds of things all of which are out of your control.

Since you are talking about getting different results from three different VHF channels, maybe the real difference is back at the transmitter site(s). Since the switch to digital, TV stations had to make many changes to their transmitters and antenna systems, and some changes reduced their coverage area.

You may want to check over at the Local HDTV Board for information about your specific area. If a TV station(s) cutover reduced their old coverage, you will read about it.

Shadesy,
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Since I'm mostly water, and my proximity to the middle of old-school rabbit ears always breaks up reception for KGO, regardless of weather conditions, I'm afraid that doesn't make sense. Further, regardless of my proximity to the same rabbit ears, I can not affect reception of KVIE or KXTV. What's happening here? It may be that the NM for KGO is about 24db, while the 2 Walnut Grove VHFs are 45db (NM) and above. Why does KGO break up?

Well ABC, PBS and Fox shouldn't be an issue. An indoor antenna of any kind is not going to get you CW, MyNetwork, ION, CBS or NBC. So you would need at least the ClearStream 4. Make sure where you have it you can point it SW. And to be honest the CW, MyNetwork, ION, CBS or NBC may only come in at night for the most part even with the CS4.

You seem to be implying that there is a relationship between the water in the human body and signal loss, no way! Your body presents what is nearly a solid mass to RF vs. rain drops that we are mainly talking about in this thread (weather issues), which present zero loss at these low frequencies. RF, with the exception of very, very low frequencies (just above DC) will not penetrate a solid mass of water, which is why submerged submarines have to use these extremely low frequencies to communicate, and very poorly even then. Your comparison is not an "apples & oranges" thing, more like "peas and elephants."

As I mentioned earlier, I have no experience in TV coverage in your area. Did you go over to the OTA Board and read the posts for your area as I suggested? If you do not find any posts there that reflect your problems, then post a question there. You will be much more likely to find area-specific help there than on this Board.

Rabbit eat antennas are a "try it and pray it works" situation at best. Personally, I would never use one unless I lived within sight of the towers that have the transmitters that I want to receive. There are just too many things that can cause signal loss when using these poor antenna, and most users do not have any signal to spare.

Shadesy's problem with rain seems to be a cause and effect situation. More substantial water than rain can cause problems with television reception. Are there areas where water collects near the antenna, a downspout perhaps? Do lots of puddles occur near the window on the ground? If water congregating is the cause, it might be unstoppable. Since there is a nearby body of water, do the problems with reception occur when that water is choppy rather than calm? That can be very bad for reception.

The Biloxi thread hasn't had a lot of activity, so contacting the various broadcasters might get better local info. If an inversion is causing the problems during fog, there may not be any solution.