Potting ADS-B LNA

Show off any of your RTL-SDR or cheap SDR related projects.
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Hampstershorts
Posts: 7
Joined: Thu Sep 13, 2018 4:18 am

Potting ADS-B LNA

Post by Hampstershorts » Sat Sep 15, 2018 6:24 am

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.

rtlsdrblog
Site Admin
Posts: 1858
Joined: Mon Nov 19, 2012 11:54 pm

Re: Potting ADS-B LNA

Post by rtlsdrblog » Mon Sep 17, 2018 5:29 am

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.

Hampstershorts
Posts: 7
Joined: Thu Sep 13, 2018 4:18 am

Re: Potting ADS-B LNA

Post by Hampstershorts » Mon Sep 17, 2018 5:05 pm

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.

rtlsdrblog
Site Admin
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Re: Potting ADS-B LNA

Post by rtlsdrblog » Thu Sep 20, 2018 11:34 am

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.

snn47
Posts: 102
Joined: Tue Dec 27, 2016 11:00 pm

Re: Potting ADS-B LNA

Post by snn47 » Wed Oct 03, 2018 4:54 am

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.

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