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[RSP2] Short-circuit resilience of the Bias-T?

Posted: Sun Dec 11, 2016 1:06 pm
by 13dka
The bias-T "junction box" of the active Bonito Whip says in big letters "A short-circuit will destroy the device!". That made me wonder how much of a beating the bias-T in the RSP2 will take?

Re: [RSP2] Short-circuit resilience of the Bias-T?

Posted: Wed Feb 22, 2017 2:31 am
by 13dka
In a related matter, depending on the answer to the question above - the position of the checkbox on the ExtIO.dll GUI may or may not be bad/risky:
Knob_Position_Issue.gif
Knob_Position_Issue.gif (14.3 KiB) Viewed 14238 times
I always try to check the status of the bias-T and try to avoid using AntB if I can, so nothing can happen to the RSP2. However, to my surprise I occasionally found that the bias-T came on, even though I didn't have an active antenna attached in weeks.

You probably know the problem when mouse buttons start "bouncing". The first closing of the switch closes the antenna dropdown selection menu, the second "bounce" contact may now inadvertently switch on the bias-t because the mouse pointer is hovering right above the target area of the checkbox. Sometimes, when comparing signals on different antennas, or comparing the antennas you'll switch forth and back a lot, and then the bias-T can come on without you noticing.

Of course I couldn't capture such an event in the .GIF above. :) But if shorting the antenna input can be a problem (e.g. if you're running antennas with baluns on AntB), this checkbox should be moved.

Re: [RSP2] Short-circuit resilience of the Bias-T?

Posted: Wed Feb 22, 2017 8:19 am
by sdrplay
Thanks, I've made a note of it and it will be moved to the right on the next release.

Best regards,

SDRplay Support

Re: [RSP2] Short-circuit resilience of the Bias-T?

Posted: Thu Feb 23, 2017 1:39 am
by 13dka
Thank you very much1

Re: [RSP2] Short-circuit resilience of the Bias-T?

Posted: Tue May 09, 2017 11:10 pm
by supwiddiss
Brand new here. 24 hours on a RSP2pro.
Great question, although unanswered.
How much current can the Bias-T supply without causing internal damage?
Is it current limited when switched on?
A short in coax or an amp "gone south" and frying the SDR would not be too fun, not to mention USB internals in my computer.
Just in case I ever purchase a mast mounted preamp it would be a good thing to know.
Cheers...