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Potting ADS-B LNA

Posted: Sat Sep 15, 2018 6:24 am
by Hampstershorts
I’m wondering if anyone on here has attempted to seal the ADS-B LNA/filter in potting compound to weatherproof it. Does anyone have any experience with any potting compounds for an application like this?

Thanks.

Re: Potting ADS-B LNA

Posted: Mon Sep 17, 2018 5:29 am
by rtlsdrblog
Haven't seen anyone try yet. Some concerns i'd have when choosing the potting material are heat transfer, and making sure the potting compound doesn't degrade and become hydroscopic (this happens to a few potting compounds).

Might be easier to just use a waterproof enclosure instead.

Re: Potting ADS-B LNA

Posted: Mon Sep 17, 2018 5:05 pm
by Hampstershorts
I had thought about a waterproof enclosure to be sure. I live on the Canadian prairies and as such we get pretty wild weather swings. I would be concerned about issues such as condensation, as the box wouldn’t be airtight. I’ve heard lots of stories about airtight enclosures being opened and having a lot of water in them. Any suggestions as to how to mitigate condensation? Or would that not be a concern? I live in an area where the temperature could be +35C to -40C. So condensation and frost are real issues.

I’d love any suggestions.

Re: Potting ADS-B LNA

Posted: Thu Sep 20, 2018 11:34 am
by rtlsdrblog
Usually to mitigate condensation you don't make the box airtight. You get a waterproof box, and drill a hole in the bottom. Then connect it to a short straw like pipe, or provide an additional non-airtight rain cover.

Also cover the circuit with conformal coating spray to reduce the risk of condensation shorts.

Re: Potting ADS-B LNA

Posted: Wed Oct 03, 2018 4:54 am
by snn47
You have all the advice on condensation, except for adding heating with temperature control to get rid of condensation.
Keep in mind that the coax connectors are also sensitive to weather too. Consider using a bucket upside down, acting as a sleever to protect Preamp and coax connector from weather.
Mechanical stress from swings between +35C to -40C can also proove streesfull to any compund in the long run creating pathes for condenstion.