Originally Posted by Channel Hopper

Venting the LNB circuitry directly to the air ( or a bespoke dehydrator system) achieves this without the need to tranfer the heat elsewhere.

Have you forgotten what it is we is supposed to b doin .... and your previous post... ... we is freezing an LNB... you said .. the extra heat produced (through the freezing process wot always produces heat as a by product I presumed you meant.. correct?) will help with condensation**.. but I said... we don't want that heat near it.. that would be counter productive (OWTTE).. we want the heat exchanger etc.. that gets rid of the by product heat.. some distance away... and the LNB as cold as possible. (but see below re feed horn cover face defrosting**).

but since the feed is in 'outside' air, venting occurs naturally ...

feed? by this you mean the feed horn/ (& wave guide etc)? .. it's sealed or it should be.

Lagging does not reduce condensation...... hmmm.

Yes it does/ or can ...

not in a house though ...

if a house was lagged and sealed it would produce masses of condensation .. because people (us) produce massive anounts of water .. sweat (eeer) / exhaled breath/ cooking/ laundry/ bathing/ open gas appliances.. all produce litres of water that have to be..... vented away***.

but a sealed LNB doesn't produce any moisture..

if you super cool it without any lagging, passing moisture in open air will condensate on it like crazy and freeze...
lag it and use the lagging to also seal it in and the lagging will drastically reduce the extreme cold coming in contact with the outside air... on the outer surface of the lagging it will be cold but nothing like the -30c inside... so condensation will be drastically reduced and limited to the outer surface of the lagging and if it (the lagging) is also sealed, then this will limit normal moist air getting in and giving up it's moisture to the -30c surfaces inside.

So lagging can drastically reduce condensation... in this case.


Absolute sealing is a problem.. I thought of sealing the LNB in a lagging block in a super dry environment and including a dry pack in a place that wouldn't cause a problem to at least limit it.... It's the feed horn cover face that is the most vulnerable- can't lag it and most plastic is x% porous. You can only limit it as you say... but most engineering process battle against the laws of physics and rarely win 100% - you just limit it, accept it.. and move on.

**Now... if you used some of the excess heat just on the face of the feed horn cover to keep ice from building up there... that might be a worth while compromise.... which is in part what you said.. (I think).