RSP1A Bias -T

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mattltm
Posts: 9
Joined: Wed Mar 07, 2018 5:10 pm

RSP1A Bias -T

Post by mattltm » Wed Mar 07, 2018 5:15 pm

Is there a point on the RSP1A PCB that I can pick up the switched 5v that feeds the Bias-T and is there a component that I can remove to prevent the 5V being fed up the coax?

I want to experiment with using the Bias-T function to switch some outboard modules without having to tap it from the antenna connector.
Last edited by mattltm on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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IQbert
Posts: 10
Joined: Tue Jan 16, 2018 12:24 am
Location: North TX

Re: RSP1A Bias -T

Post by IQbert » Thu Mar 08, 2018 1:27 am

I haven't looked at the schematic, but typically a voltage is added to an RF line through an RF Choke/inductor. Remove that, and tap into the non-RF side. Good luck.

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mattltm
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Joined: Wed Mar 07, 2018 5:10 pm

Re: RSP1A Bias -T

Post by mattltm » Thu Mar 08, 2018 6:26 am

IS the schematic publicly available? I've had a quick Google search but can't find anything.
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DF1KZ
Posts: 29
Joined: Fri Nov 27, 2015 1:37 pm

Re: RSP1A Bias -T

Post by DF1KZ » Fri Mar 09, 2018 6:19 pm

Yes, there is a component you can remove - its an inductor on the pcb near the antenna plug. You remove it on your own risk. Your warranty will be void.
You can also use an external DC-block, a capacitor in series (depending on your lowest frequency 100nF-470nF, ceramic).
Imho there is no circuit drawing of RSP1A available but you can find pictures of the pcb.

Wolfgang

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SDRplay (RSP1, RSP1A, RSP2pro) with:
RFsystems DX-10 (14kHz to 50MHz), resistive splitter 1/4, 1:16 transformer on Hi-Z of RSP2
ICOM Discone AH-8000 (10MHz to 2GHz)
12m above ground

mattltm
Posts: 9
Joined: Wed Mar 07, 2018 5:10 pm

Re: RSP1A Bias -T

Post by mattltm » Mon Apr 02, 2018 4:53 pm

IQbert, I would love to reply to your PM but can't because I am not allowed to send any messages yet!

Please PM me your email address and I will send you what you need.

Thanks.
Last edited by mattltm on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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