TCXO and high ambient temperatures

Discuss KerberosSDR - 4x Coherent RTL-SDR
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bobcat7677
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Joined: Thu May 09, 2019 2:21 pm

TCXO and high ambient temperatures

Post by bobcat7677 » Thu May 09, 2019 3:02 pm

I know there have been discussions about heat before here, but I did not see anything that sufficiently answers my questions.

While not specifically mentioned in the info on the KerberosSDR, being based on the R820T2, I am assuming it has the same <1PPM TXCO chips to prevent frequency drift at different temperatures. These chips have limitations though and I have found them to be completely inadequate to deal with the temperatures encountered in the Arizona desert. Temperature drift quickly becomes a problem in even average mid-day heat and the dongles burn themselves out when ambient temperatures often pass 45c in the summer. I switched to a dongle from NooElec.com that has a more precise TXCO (<0.5PPM) and is a bit more tolerant of the heat. It still tends to drift without active cooling after a while when ambient temperatures really get up there, but it's flat aluminium case makes attaching a heat sink more effective.

So I have seen the discussions on the KerberosSDR that say "just blow some air through it and you should be fine", but am dubious that that would actually be effective at the ambient temperatures I deal with; given that the discrete RXs can't handle it. So I am curious if anyone has actually run a KerberosSDR in that type of environment and if so, what specific temperatures were encountered and what specifically they did to keep it from overheating. I am also curious if there is any "official specification" for what temperature range the device should be able to tolerate. I saw something that said "0-25c" somewhere, but if that is truly the case, I will need a lot more than a fan to keep the thing operational in Arizona!

Thanks-

rtlsdrblog
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Re: TCXO and high ambient temperatures

Post by rtlsdrblog » Fri May 10, 2019 2:15 am

Temperature control might be required with the KerberosSDR for extreme environments. Since there are four RTL-SDRs inside the heat can grow. There is a thermal pad sinking the heat to the case, but if the outside is warm it might be an issue.

I do think that airflow should be sufficient to keep it cool, although at 45c you'd need a decent amount of airflow (larger fans).

What environment are you planning to run in? An outdoor dedicated unit?

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