Sat Dish Sensor

[Feelgood Ranch]

Any ideas for a sat dish sensor to detect snow (moisture) to turn on a dish heater?  Here in Mt., dish heater needed to melt occasional snow buildup preventing signal malfunction.  Dish is remotely located, and due to terrain, hard to simply broom dish free of snow.  Currently using a RF switch but many some times does not work due to distances RF signal needs to travel.  Heater often on when no snow present cause I forget to switch off.  A snow sensing switch would alleviate the aggravation!   

[Bushman]

Snow sensor are not easily obtained (at least at a reasonable price).  Rolling your own is not a cheap trick either.  There seem to be a lot of dish heaters for 60-120 bucks that use a thermostatic switch to turn the heater on/off based on temp only. 

[W3DRM]

You could always put some kind of a timer on the heater so it only stays on for certain of time. That would take come experimenting and would be impacted by the temperature, especially in Montana...

A snow sensor on the dish itself might be a bit of a challenge though. I am thinking of some kind of a pressure-sensitive device that would sense when something pressed against a paddle (i.e., snow or ice) and would turn the heater on for either a set period of time or until the sensor didn't detect any pressure. Something with a combination of these may solve your problem. I have the same problem here in Nevada when we get heavy snowfall.

KeithBC is a great inventor, perhaps he has some ideas on the subject.

[SoMDWx]

Would it be possilbe to do something like a heated rain guage? I us a thermistor-controlled heater so when the temps get below a certain value, it trips a relay to activate the heater... Then when the temps rises, it automatically shuts off, saving energy and not allowing the heater to cause damage to the internals of the gauge....

Jim

[Bushman]

There are  snow sensors (used for heated driveways for example).   They can differentiate between rain and snow and  have all sorts of temp limiters.The problem is they ain't cheap!

[W3DRM]

Would it be possilbe to do something like a heated rain guage? I us a thermistor-controlled heater so when the temps get below a certain value, it trips a relay to activate the heater... Then when the temps rises, it automatically shuts off, saving energy and not allowing the heater to cause damage to the internals of the gauge....

Jim

Sure, that would be possible but I think the trick is to find a way of sensing when snow or ice collects on the face of the dish AND turns on the heater to melt the snow/ice. A temperature sensing switch would prevent the heater from running during times when the temp was above freezing. I use a therm-cube switch for controlling my rain bucket heater. I could leave it on year-round, if I wanted to, as it only turns on the heater when the temps fall below 35F. It shuts off when tempts get above 45F.

We have a lot of wind here in Nevada so I would like to have something that has a delay built-in so the heater isn't triggered when the wind activates the sensor.

[Feelgood Ranch]

Thanks to everyone for their comments.  The current setup employs a commercial heater strip(s) with a thermostat switch, but as mentioned in posts, often temperature causes switch to be On yet no snow, so a waste of electricity.  Maybe the ThermocCube would be simplest option with its preset limits of temperature, but still not perfect solution as issue is snow (moisture) should be activator of switch.
Everyone keep scratching their brains...I appreciate it!!

[d_l]

You need a heated wetness sensor near the dish.  Something like the Davis leaf sensor with a heater attached.  A heater for the leaf sensor wouldn't only have to be a low power device as it is so small and it could be attached to a thermocube to only come on near freezing.

Then you need a logical device such as the Weatherlink for alarm output that would power up your dish heater when a certain wetness level has been reached and the temperature is near or below freezing.

I'm sure other logical devices exist, but they have to receive and interpret signals from whatever wetness sensor is used.  I imagine wireless signals would be preferred over hard wired.

[W3DRM]

Thanks to everyone for their comments.  The current setup employs a commercial heater strip(s) with a thermostat switch, but as mentioned in posts, often temperature causes switch to be On yet no snow, so a waste of electricity.  Maybe the ThermocCube would be simplest option with its preset limits of temperature, but still not perfect solution as issue is snow (moisture) should be activator of switch.
Everyone keep scratching their brains...I appreciate it!!

Ken,

Since you already have a heater, can you tell me if you get any RF interference on your satellite receiver? There is some thought that heater can cause problems when it is running. Is the heater commercially available?

[Feelgood Ranch]

The heater(s) are commercially available.  Peel and stick to back of dish and incorporate thermostat that switches off at 45 degrees..not sure what temp cuts on at.
Have experienced no interference on either dishes (sat internet and Direct TV) and installed for about 5 years.
 I Googled "snow sensor switches" and a litany of items....all pricey and probably overkill for my application.  The sensor is a simple wire grid, low voltage heated to melt snow and make water contact between two opposing grid wires and close circuit which then actuates a controller. 

[W3DRM]

Do you have a link to or a brand/model number of the heater you have?

[Feelgood Ranch]

I bought it at Kalispell, Mt.  Link: http://www.montanasatellite.com/satellite_dish_heaters.htm

[Feelgood Ranch]

ADDENDUM  It is the Ice Zapper model with thermostat integrated .

Sorry for lack of answer to question of prior posting question.

[W3DRM]

Have you thought about just getting one of the disk covers rather than a heated unit? I suspect most of your snows are pretty dry and maybe a cover would keep the snow from sticking to the dish itself.

Just a thought...

[LFWX]

Maybe you could use some type of alarm system light beam.
Place the transmitter at the bottom of the dish, the receiver at the top of the dish.
When the snow starts to accumulate, it blocks the light beam and switches the heater ON.

[DanS]

Maybe you could use some type of alarm system light beam.
Place the transmitter at the bottom of the dish, the receiver at the top of the dish.
When the snow starts to accumulate, it blocks the light beam and switches the heater ON.

I was also thinking about the light beam interruption idea but by using an optical sensor like the type used in printers. Place it in the lowest area of the dish and use it to switch on/off a power relay for the heater.

[Feelgood Ranch]

Interesting idea Dan!!
Maybe worth exploring concept.  Wonder about moisture/snow clogging sensor and shut off issues however.  Certainly would conceptually turn on heater.  Thanks.

[DanS]

Possibly use some rigid, non-corrosive (aluminum?) wire and attach to the feed arm to hold it in place and would provide something to run the wires along. I made a quick drawing what I'm talking about with the sensor enlarged to show it's positioning. I suppose insects could cause a blockage problem with this but in the winter maybe there aren't too many around. (and it doesn't provide any shelter for them).

Also added a crude schematic drawing to get an idea. The heater itself and the solid state relay are probably the most expensive components but everything combined when finished should be a lot less expensive than a commercially available setup.

[Feelgood Ranch]

 :grin:Thanks Dan...will develop it further when time permits.
Thanks to all forum members for their thoughts/ideas.