Thanks everyone for your input. Transmitting and receiving will be on the same frequency. I'm leaning towards using the ZFLM-252-1WL-S+ power limiter as Kent Torell suggested to keep down the number of active components.
Best regards, Martin Elfvelin On Mon, Apr 19, 2021 at 11:33 PM Marcus D Leech <[email protected]> wrote: > I was thinking a switch would get moved to the RX port of the circulator, > which would see the TX power reduced by 20dB. Then into a switch that > switched the RX port of the circulator between a 50 ohm load and the RX > port. > > Sent from my iPhone > > On Apr 19, 2021, at 5:13 PM, Brendan Horsfield < > [email protected]> wrote: > > > Martin, Marcus, > > I don't see how adding a circulator will protect the Rx port of the USRP > without blocking the signal from the CubeSat as well. > > Are you transmitting and receiving on different frequencies? If so, you > could insert a filter between the Rx port and the switch to block the Tx > frequencies. > > On the other hand, if your Tx and Rx signals are in the same band, you can > add a second switch in cascade with the first one to increase the Tx-Rx > isolation. You can keep adding switches if necessary, until your isolation > target is met. > > Regards, > Brendan. > > On Mon, 19 Apr 2021, 23:52 Marcus D. Leech, <[email protected]> > wrote: > >> On 04/19/2021 09:49 AM, Martin Elfvelin wrote: >> >> Thank you for your input. Do you suggest adding a circulator to the >> system or rather replacing the switch with a circulator? >> >> Best regards, >> Martin >> >> I'd say add a circulator in addition to your switch. >> >> >> On Mon, Apr 19, 2021 at 3:43 PM Marcus D Leech <[email protected]> >> wrote: >> >>> A circulator can give you an additional 20dB isolation. >>> >>> Putting 5d!m into the RX2 port will likely destroy the RX amplifier in >>> the AD9361. >>> >>> Sent from my iPhone >>> >>> > On Apr 19, 2021, at 9:12 AM, Martin Elfvelin via USRP-users < >>> [email protected]> wrote: >>> > >>> > >>> > Hello all, >>> > >>> > I am planning on using a USRP B200 in a half-duplex communication >>> system to communicate with a CubeSat. The TX/RX port will be used for >>> transmitting and the RX2 port for receiving. The transmitting port will be >>> connected to a power amplifier with a 60W output, this will in turn connect >>> to an RF switch which will switch between the TX/RX (transmitting) and RX2 >>> (receiving). The RF switch has an isolation of ~40-43 dB which means from >>> the 47.78 dBm transmitted we will have roughly 5-8 dBm reflected to RX2. >>> Since the SDR is only rated to receive maximum 0 dBm I'm wondering if >>> someone has any ideas on how to handle this. I'm unsure if this power will >>> simply fry the board and I should implement a power limiter or if there are >>> other workarounds. >>> > >>> > Appreciate any help you can provide. >>> > Best regards, >>> > Martin Elfvelin >>> > _______________________________________________ >>> > USRP-users mailing list -- [email protected] >>> > To unsubscribe send an email to [email protected] >>> >> >> _______________________________________________ >> USRP-users mailing list -- [email protected] >> To unsubscribe send an email to [email protected] >> >
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