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)
----- The problem with the world is that the intelligent people are full of doubts, while the stupid ones are full of confidence.
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)
----- The problem with the world is that the intelligent people are full of doubts, while the stupid ones are full of confidence. _______________________________________________ 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
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)
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)
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
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)
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
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
When you say "without any protection on the input" do you mean you aren't using any diplexer or filter (external to the SDR) on the input RF path to the SDR, even for Mode J?
73, Ryan AI6DO On Friday, January 11, 2019, 10:03:30 AM PST, Paul Stoetzer n8hm@arrl.net wrote:
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)
Yes, I have. Though for Mode J, I would have a filter on TX or else the third harmonic certainly would overload it.
I haven’t extensively done this, but I haven’t encountered any problems when doing it. I would recommend using a diplexer or filter on the input. Just be sure you use something that’s very low loss.
73,
Paul, N8HM
On Fri, Jan 11, 2019 at 16:50 Ryan Noguchi via AMSAT-BB amsat-bb@amsat.org wrote:
When you say "without any protection on the input" do you mean you aren't using any diplexer or filter (external to the SDR) on the input RF path to the SDR, even for Mode J?
73, Ryan AI6DO On Friday, January 11, 2019, 10:03:30 AM PST, Paul Stoetzer < n8hm@arrl.net> wrote:
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)
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
Use a 2/70cm duplexer and put a 50 ohm resistor on the 70cm port. I use a Comet and have used a diamond. In fact, I run my 70 cm uplink thru the diplexer, and skip the Terminator. 73, N0AN
Hasan
On Fri, Jan 11, 2019, 3:55 PM Paul Stoetzer <n8hm@arrl.net wrote:
Yes, I have. Though for Mode J, I would have a filter on TX or else the third harmonic certainly would overload it.
I haven’t extensively done this, but I haven’t encountered any problems when doing it. I would recommend using a diplexer or filter on the input. Just be sure you use something that’s very low loss.
73,
Paul, N8HM
On Fri, Jan 11, 2019 at 16:50 Ryan Noguchi via AMSAT-BB < amsat-bb@amsat.org> wrote:
When you say "without any protection on the input" do you mean you
aren't
using any diplexer or filter (external to the SDR) on the input RF path
to
the SDR, even for Mode J?
73, Ryan AI6DO On Friday, January 11, 2019, 10:03:30 AM PST, Paul Stoetzer < n8hm@arrl.net> wrote:
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)
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
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
participants (6)
-
Hasan al-Basri -
Kevin Zari -
Paul Stoetzer -
Rolf Krogstad -
Ryan Noguchi -
saguaroastro