trying to understand rain fade

[DarrellP]

PSB, I mounted my Dish 500 right under the eaves on the South side of the house and it keeps the snow off. Since I moved last year I didn't have a single outage and it snowed like heck in Portland this year, I was icebound for 5 days (luckily I had just received my projector so I was in heaven!).

 

[PSB]

Under the eaves works well as long as its not blocking out the top of your dish, up here the elevation angle for say DirecTV is 38 deg. its a lot steeper than folks seem to realise, I must say over the years I have had more problems with things overhanging the dish rather than whats in front of it! But if it works now it should work forever : )

A good tip is to cut out a bit of card or wood to your elevation angle, put it at the top of the dish (for eaves) make sure its square (spirit level) and look up along the edge of the card you will soon see if the dish is too far up under the eaves!
Less of a problem with Dishnotwork at an elevaion of around 33 deg. Voom is more like 30 deg. in these parts!

 

[DarrellP]

I have an elevation of 34 degrees and I ran a line of sight bouncing off the LNB prior to mounting, then gave myself an extra 6" lower just to be safe.

 

[PSB]

Line of sight starts at the top of the dish and ends at the bottom! With the LNB in the middle (near enough) Over the years I found this out the hard way : ) But your -6" rule seems to have done the trick at 34 deg. : ) Sometimes its best to loose a couple of inches at the top of the dish as a trade to keeping the dish out of the elements to some extent.

 

[Mr. Biggles]

My signal was wavering around 49 when it dropped out, using a 24" dish.

Geesh! I thought the 24" claimed a 75% improvement over the 18" when it came to rain fade.

 

[eschu97611]

Maybe the last time it drizzled, and you lost signal was because there were more clouds, and rain to the east of you in front of the signal your 18" dish is trying to recieve? This time maybe the clouds were moving more south, or north? I don't know but it may play a factor into it all. BTW, I had a very light rain last night and my signal fell to 95 from 99, and power from 89 to 85. So far so good on the 30" dish.

Ah, feels so good to live in the desert-rain, snow, etc not an issue-just sunny skies all year round(don't mean to rub it in)

 

[DarrellP]

Last night my signal was wavering in and out at 67 and the rain was harder with bigger drops. My picture went from pixelating to no image to ok back and forth for about 1/2 hour. The other night when it was drizzling, my picture hung in till the signal hit 48. Weird.

PSB, what I meant by "line of sight" was looking at the path that the signal takes coming into the dish, I know it is a higher angle than what the dish appears to be pulling in.

 

[shelly]

Geesh! I thought the 24" claimed a 75% improvement over the 18" when it came to rain fade.

Bill, Where did you get this figure?

I am scheduled for an upgrade to the 24" dish and this much improvement would solve my problem, yet some posters indicate that the 24" may not be a fail saafe solution.

Shelly

 

[DarrellP]

Shelly, where are you located? The 24" has helped a lot for me but it is not a fail-safe solution for us Left Coasters or low-azimuth locations.

 

[shelly]

Shelly, where are you located? The 24" has helped a lot for me but it is not a fail-safe solution for us Left Coasters or low-azimuth locations.

I'm in Carmel Valley CA which is just 12 miles inland on the central coast about 2 1/2 hour drive south of San Francisco and 5 1/2 hour drive north of Los Angeles.

My angle is 15 degrees with normal signal quality of 96 and signal strength of 95 and s/n of 15.xx with 18" dish. One light drizzle dropped my signal 40 points and I lost it all, while another light rain dropped signal only a few points with continued programming.

Voom approved a 24" dish replacement but not the 30" one.

Shelly

 

[DarrellP]

My normal signal strength with the 24" is 96, so hopefully this will help you out quite a bit. I'm going to have to go to a 30" to solve my signal issues.

 

[Walter L.]

Darrell if your normal signal is 96 it sounds like you may not get much more with a 30" dish.

 

[DarrellP]

Maybe not but it should hold up better during the rain (I hope).

 

[Taron1]

I’m in Sacramento California and the signal has been inconsistent for the most part. Using the standard 18th dish on a good day,

NO rain, or WIND, the signal: Quality 89 Strength 64 Great Picture

Some wind (not all the time) but: Quality drops in the 70’s Strength 64 or 63 Picture Break up or no picture.

Some light Rain (not all the time) but: Quality drops in the 70’s Strength 64 or 63 Picture Breakup or no picture

April 19th Day TIME Wind Break ups all day.
April 19th Evening Rain and Wind Quality 88, 76 Strength 64 Perfect picture.
THIS IS THE FIRST TIME AT Quality 76 the picture is Perfect.
April 20, 2004 Wind light Rain Quality 89, 90 Strength 64 Perfect picture.


I don’t understand it either but I think the problem is at the transmitter not the individual home. They had to make a change in the transmission because it is working find now with no adjustments.

 

[TechCop]

Walter:
Maybe a coat of RAINEX or TEFLON or a similar product would help?

In so far as the rain outages, It's not simply a matter of rain on top of you that causes the outage, it's the density of the rain BETWEEN the dish and the bird. If your shot is low on the horizon, a storm moving in may affect you more than one sitting right on top of you.

 

[Vince2]

I, too, get rain fade. However, even on a good clear day my best signal quality reading is in the mid-80's. Techcop is right IMHO. The problem with rain is the density. A dense light rain is worse than a big-drop hard rain because the signal has to penetrate a larger volume of water. Dense rain makes it like is trying to receive a signal under a sheet of water...there is significnt interference. The waves likely get around large dispersed drops. For us in the Pacific NW, we have two strikes against us: we have a long, low shot to the horizon and we have a long, dense rainy season. Oh yeah, make that three: We also have a lot of trees, something that is giving me fits these days (particularly now that my neighbor's deciduous ones are getting their leaves and I'm trying to shoot my dish through them!).

 

[Walter L.]

Hey Vince: any problems the last 2 days with the rain. I did (for the 1st time).

 

[Vince2]

Yes Walter, I've had a lot of problems. Last night the whole family gathered around to watch a show together and the pixellation was unbearable. Fine this morning though.

 

[GeneWildershair]

Yes Walter, I've had a lot of problems. Last night the whole family gathered around to watch a show together and the pixellation was unbearable. Fine this morning though.

Hey Vince, it sounds like you and Taron need your dishes peaked. You guys should be up in the 90's for quality and at least 70's for power. This would help a lot. If you still have problems with rain after peaking, then I would suggest maybe a bigger dish. I've had rain the last couple of days, and my new 30" dish is holding up very well. The lowest I've seen it drop was 95/85. on a normal day it will be 99/89 with the 30". I was getting 96/76 with the 18" but light rain would ruin the signal completely. Now as far as having your 18" dish peaked, you can call VOOM and get someone to come out and peak it. They should do this for you free of charge. You can also peak it yourself, using the signal meter screen, and getting up on the roof, and adjusting it very carefully. It is pretty simple to do, (I've done it twice now myself). If you do plan on doing it yourself, just remember to loosen the bolts just enough to move the dish. Just listen for the beep to get faster, and as soon as you get a steady fast signal, then you tighten everything up.

 

[Taron1]

It just so happen I was scheduled for the installer to come out today and peak the DisH. Strength is 66 (Highest) Quality is 95 (Highest).

Then some one at Voom Called today and said that my Larger Dish has been ordered and will be sent to the installer. But so far no problems slight wind today with lots of clouds. I now have the option for the larger dish if I have anymore problem with the signal.