Use feedhorn cover or not?

[ancient]

With a c band dish and one of the newer LNB's that is all one piece with no moving parts is it considered better to use a feedhorn cover or leave it open to the air?

On one hand with the cover off the LNB would be much cooler but on the other hand the LNB is directly exposed to the elements. If the cover is used the bees find the inside of the feedhorn an attractive place to build a hive and the inside temperature must get quite high on a sunny day because the feedhorn cover is black plastic.

The cover is in really nice shape but would it shorten the life of the LNB to use it? Recommendations?

 

[Magic Static]

I don't use one. Mostly because a dual ortho feed doesn't fit under one. The LNB suffers from high heat. The other weak point is the "F" fitting leaking moisture into the LNB. So look toward preventing those problems and decide if you need it not, want it or not.

 

[Lone Gunman]

I think it would depend on how well your cable connections at the LNBF repel water. I no longer use the covers since I started assembling my cable ends with Vaseline petroleum jelly to keep water out and in the past 4 or so years I haven't seen any problems without the covers.

As usual though, what works for me may not be acceptable to others and "Your mileage may vary!"

 

[Cham]

I put mine on in the winter, keeps the snow out and likely helps to keep the LNBs a bit warmer when it's -40. When I had an LNBF on I didn't bother with the cover and didn't have problems, but on one of my other dishes I had a moisture issue on a C2 LNBF...

 

[migold]

I use half-gallon plastic milk 'bottles' for covers on my C-Band LNBFs, tied on with heavy string. I do this for two reasons, gives protection from weather, and prevents heating of the LNBFs from the direct sunlight. They do not last much over a year, but CHEAP to replace. I wonder how direct sunlight would affect the new PLL C-Band LNBFs, which have a heat sink....

 

[Titanium]

The black covers never made much sense to me during the summer. During the winter months in extreme cold regions they do protect the electronics from wild ambient temperatures and damage by the elements. If the connections are properly sealed there is little reason to install the cover in most regions. The electronics do benefit when shaded from direct sun and well ventilated. Cool electronics provides better performance.

In open LNBF mounts I install the C1-PLL so the heat sink is positioned on the bottom, shaded by the body. In theory, the lower temperature in the shade should help with the cooling fin efficiency. Inside of a cover, I might mount it on top. With the increased ambient temperature inside the cover, I am not sure it it would really matter.


Brian Gohl
Titanium Satellite

 

[xtgold]

without a cover here the throat would clog up with bees nests and other pests.
In my old primestar ku band dish, birds try making nests in the nooks and crannies.

 

[Titanium]

Assumed the op is asking about the bell or cover that covers the entire assembly, not the feedhorn cap. Agree that the feedhorn cap is a necessary evil. Yes, it slightly attenuates the signal entering the feedhorn, but much better than the critters that would attenuate with building their homes!


Brian Gohl
Titanium Satellite

 

[waylew]

I just use plastic bags on the Pinnacle,easy to reach.For the Paraclipse,15' to the feedhorn,I made one out of one of those waterproof folding chair caddies.

 

[FaT Air]

I have a gallon milk jug loosely fitted over the LNBF to protect from rain, only because I had a water problem with the original LNBF. ("F" fitting nut/seal not 'sealed') Cleaned it out and it works, and is now my spare, but don't want the same to happen to the C1 that replaced it. Fully ventilated and held on with a wire tie.
Being translucent, I don't have to remove to see if there's any unwanted guests. Probably won't be as seems they like dark places.

Vaseline??? I'd prefer to use silicone dielectric grease. It's meant for the job. Although, if Vaseline doesn't attenuate your signals, what the heck.

Plastic (Ziploc) I've had only a 6 month lifetime with them at best.

What I've thought of - is using two now unused servo wires to power a 60mm fan for ventilation(with a thermostat) if I ever 'feel the need' to put the black cover back on. (It would probably look better than the milk jug) Maybe a current sense circuit for an ON/OFF display ??

 

[primestar31]

I just use plastic bags on the Pinnacle,easy to reach.For the Paraclipse,15' to the feedhorn,I made one out of one of those waterproof folding chair caddies.

Same here, plastic bags from the IGA store. They last me well over a year, and are easy to replace. I put the bag over the lnb's on my ortho, and just cut the plastic bag "handles" in the middle then use that to wrap around the feed legs, and tie them together in a knot!

 

[waylew]

With the button hook I just put the bag over everything,scalar included,then twist whatever's hanging down and put a twist tie on it.I prefer the Kinney Drugs bags (a local chain) much higher quality than the grocery store bags.

 

[MikeI]

From 1988 to 1996 I never had one in so cal and had no problems on a10 footer with c and Ku lmbs and a servo.
My 8/ft kti dish I got last summer has one. I've had no problems with this one here in Rio Rancho New Mexico.

 

[ancient]

Seems like the consensus is not to use the cover which is what i thought. I always use waterproof connectors and put a layer of silicone sealant around them so not too concerned about water. Thanks guys.

Like the fan idea, could even have solar cell powering a couple tiny fans in the rim of the donut. But probably wont bother since it doesn't sound necessary.