I've used my AirSpy Mini and FCD+ without any protection on the input without any damage, but your mileage may vary!
73,
Paul, N8HM
On Fri, Jan 11, 2019 at 12:55 PM Rolf Krogstad rolf.krogstad@gmail.com wrote:
I use a diplexer, such as the MFJ-916B or equivalent, and it provides enough isolation of the 2 meter signal to prevent problems.
Rolf NR0T EN34
On Fri, Jan 11, 2019, 11:14 AM Ryan Noguchi via AMSAT-BB <amsat-bb@amsat.org wrote:
Is a transmit/receive switch necessary, or would a simple duplexer suffice? Something like the MFJ-916B offers 55dB or better isolation, and fairly low loss (0.2dB). It's a lot cheaper and more convenient to set up.
My SDRPlay RSP1A arrived yesterday and I got it and my FT-857D working with CAT control using SatPC32 last night. I haven't worked a pass with it yet, though; maybe this weekend. The RSP1A is rated for 0dBm continuous, 10dBm momentary. The antenna is a dual-band Elk in the attic on a TV rotator, so there is no benefit of interantenna isolation. If I assume the duplexer's spec value of 55dB isolation, that would attenuate even 250W input down to less than 0dBm, correct? Patrick WD9EWK had commented on the subject of SDR protection in a QRZ.com posting, and has used a duplexer instead of a T/R switch with his SDRPlay SDR: https://forums.qrz.com/index.php?threads/kenwood-ts-2000-in-full-duplex-mode...
Would love to know if my math is wrong, if the RSP1A's spec isn't trustworthy, and/or if there are any other considerations that make a transmit/receive switch better (or necessary) than just a duplexer, before I let the magic smoke escape.
Thanks and 73, Ryan AI6DO
On Friday, January 11, 2019, 8:31:34 AM PST, saguaroastro <saguaroastro@cox.net> wrote:
Kevin, I've be looking at this. MFJ-1708. There are several versions. So look the up on Hro to compare
73Rick Tejera (K7TEJ)Saguaro Astronomy ClubWww.saguaroastro.orgThunderbird Astronomy ClubWww.w7tbc.org
-------- Original message --------From: Kevin Zari kk4yel@gmail.com Date: 1/11/19 06:40 (GMT-07:00) To: amsat-bb@amsat.org Subject: [amsat-bb] Protecting SDR For those of you with an SDR dongle, for example the Funcube Pro +, how do you protect it from not being damaged by TX energy? I’m thinking of hooking mine up to the 70cm antenna in my M2 LEO pack while I TX on the 2m antenna and was afraid I’d overload the SDR. I see folks using them for their RX on linear birds, so I’m just wondering how you have them hooked up. Thanks in advance for your advice.
-Kevin (KK4YEL)
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Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb