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CX2SA > SATDIG 08.05.20 21:25l 626 Lines 23872 Bytes #999 (0) @ WW
BID : AMSATBB15147
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Subj: AMSAT-BB-digest V15 147
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Sent: 200508/1919Z @:CX2SA.SAL.URY.SOAM #:30884 [Salto] FBB7.00e $:AMSATBB15147
From: CX2SA@CX2SA.SAL.URY.SOAM
To : SATDIG@WW
Today's Topics:
1. Re: FM vs Linear Transponders (Stephen DeVience)
2. Re: FM vs Linear Transponders (Zach Metzinger)
3. Re: FM vs Linear Transponders (Zach Metzinger)
4. Re: FM vs Linear Transponders (Paul Stoetzer)
5. Re: FM vs Linear Transponders (Zach Metzinger)
6. Re: FM vs Linear Transponders (Leffke, Zachary)
7. FM vs Linear Transponders (Stephen DeVience)
8. Re: FM vs Linear Transponders (Leffke, Zachary)
9. Re: FM vs Linear Transponders (Zach Metzinger)
10. APRS Birds (Brad Smith)
11. Re: FM vs Linear Transponders (Peter Goodhall (2M0SQL))
----------------------------------------------------------------------
Message: 1
Date: Fri, 8 May 2020 12:42:42 -0400
From: Stephen DeVience <sjdevience@?????.???>
To: amsat-bb@?????.???
Subject: Re: [amsat-bb] FM vs Linear Transponders
Message-ID:
<CAMPfQQCWiNK7eFYEqZfeZ1wem0_EyPzN6iivv=NuW_AgPL0KEQ@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
The ground station complexity for using the linear satellites is a real
issue, especially for anyone trying to rove or use a handheld antenna. I've
always found the suggestion to use two FT-817s strapped to your neck very
awkward (and pricey).
I'm starting to think of what would be needed for a handheld-size linear
satellite transceiver. It would have to do SSB on UHF and VHF, and the
Doppler correction could probably be handled by a phone app which would
also provide visual tracking. I know it's a bit more complicated than FM,
but at least you wouldn't need much power. Having separate U/V and V/U
versions would be even easier. It could be a fun project.
-Stephen, N8URE
------------------------------
Message: 2
Date: Fri, 8 May 2020 12:56:55 -0500
From: Zach Metzinger <zmetzing@?????.???>
To: amsat-bb@?????.???
Subject: Re: [amsat-bb] FM vs Linear Transponders
Message-ID: <327d1f4c-b1c4-227c-038e-9bb3140a98fe@?????.???>
Content-Type: text/plain; charset=utf-8; format=flowed
On 05/08/20 11:42, Stephen DeVience via AMSAT-BB wrote:
> The ground station complexity for using the linear satellites is a real
> issue, especially for anyone trying to rove or use a handheld antenna. I've
> always found the suggestion to use two FT-817s strapped to your neck very
> awkward (and pricey).
On the downlink (RX), one can use a very cheap SDR dongle such as:
Here's a demo from Drew (KO4MA) at Hamvention 2018:
https://www.youtube.com/watch?v=hBZvWCKxjcM
He's using a FUNcube dongle (not sure if Pro+ or not, but ~$155 for the
Pro+), but the same could be done with an RTL-SDR dongle ($35):
https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/
Gqrx, the software "receiver" already runs on a cheap Raspberry Pi 3:
https://gqrx.dk/download/gqrx-sdr-for-the-raspberry-pi
Your choice of transmitter includes an existing multi-band radio, or one
of many SDRs with transmit capability (assuming that one appropriately
filters the output before amplification).
> I'm starting to think of what would be needed for a handheld-size linear
> satellite transceiver. It would have to do SSB on UHF and VHF, and the
> Doppler correction could probably be handled by a phone app which would
> also provide visual tracking.
Well, if it were an _open_ digital voice format (down with AMBE!) with
error-correcting codes, one might create such a transceiver quite
easily, using highly-integrated modem ICs already on the market.
Someone might already be thinking about this.
--- Zach
N0ZGO
------------------------------
Message: 3
Date: Fri, 8 May 2020 13:00:18 -0500
From: Zach Metzinger <zmetzing@?????.???>
To: amsat-bb@?????.???
Subject: Re: [amsat-bb] FM vs Linear Transponders
Message-ID: <a11420f0-09fd-8612-839d-10a006e95368@?????.???>
Content-Type: text/plain; charset=utf-8; format=flowed
On 05/08/20 12:56, Zach Metzinger via AMSAT-BB wrote:
> On the downlink (RX), one can use a very cheap SDR dongle such as:
Non-linear thought processes during editing strikes again! Here are the
FUNCube Dongle URLs:
http://www.funcubedongle.com/?page_id=1073
http://funcubedongle.3dcartstores.com/checkout.asp
--- Zach
N0ZGO
------------------------------
Message: 4
Date: Fri, 8 May 2020 14:03:49 -0400
From: Paul Stoetzer <n8hm@????.???>
To: Zach Metzinger <zmetzing@?????.???>
Cc: AMSAT BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] FM vs Linear Transponders
Message-ID:
<CABzOSOrrH7tMsOjAPVheMqZE0O3y+okwZQae1z1VPqHA0Y7UXg@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
That's me, not Drew!
It was the FUNcube Dongle Pro+. Unfortunately, the FUNCube Dongle, despite
decent filtering, still struggles in environments like Dayton. In normal
conditions, it performs very well for this purpose. N8
Some form of integrated, small, full duplex VHF/UHF transceiver is
definitely the holy grail of linear satellite operations. I'd love a KX2 or
KX3 sized VHF/UHF full-duplex all-mode transceiver. Sadly, the maximum
sales figures for something like that are probably measured in the
hundreds, which makes it tough to justify commercially.
73,
Paul, N8HM
On Fri, May 8, 2020 at 1:57 PM Zach Metzinger via AMSAT-BB <
amsat-bb@?????.???> wrote:
> On 05/08/20 11:42, Stephen DeVience via AMSAT-BB wrote:
> > The ground station complexity for using the linear satellites is a real
> > issue, especially for anyone trying to rove or use a handheld antenna.
> I've
> > always found the suggestion to use two FT-817s strapped to your neck very
> > awkward (and pricey).
>
> On the downlink (RX), one can use a very cheap SDR dongle such as:
>
> Here's a demo from Drew (KO4MA) at Hamvention 2018:
>
> https://www.youtube.com/watch?v=hBZvWCKxjcM
>
> He's using a FUNcube dongle (not sure if Pro+ or not, but ~$155 for the
> Pro+), but the same could be done with an RTL-SDR dongle ($35):
>
> https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/
>
> Gqrx, the software "receiver" already runs on a cheap Raspberry Pi 3:
>
> https://gqrx.dk/download/gqrx-sdr-for-the-raspberry-pi
>
> Your choice of transmitter includes an existing multi-band radio, or one
> of many SDRs with transmit capability (assuming that one appropriately
> filters the output before amplification).
>
> > I'm starting to think of what would be needed for a handheld-size linear
> > satellite transceiver. It would have to do SSB on UHF and VHF, and the
> > Doppler correction could probably be handled by a phone app which would
> > also provide visual tracking.
>
> Well, if it were an _open_ digital voice format (down with AMBE!) with
> error-correcting codes, one might create such a transceiver quite
> easily, using highly-integrated modem ICs already on the market.
>
> Someone might already be thinking about this.
>
> --- Zach
> N0ZGO
>
> _______________________________________________
> Sent via AMSAT-BB@?????.???. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
>
------------------------------
Message: 5
Date: Fri, 8 May 2020 13:05:20 -0500
From: Zach Metzinger <zmetzing@?????.???>
To: AMSAT BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] FM vs Linear Transponders
Message-ID: <5239cd85-7fd3-a0b8-dd75-d7654d90968a@?????.???>
Content-Type: text/plain; charset=utf-8; format=flowed
On 05/08/20 13:03, Paul Stoetzer wrote:
> That's me, not Drew!
Doh! I'm sorry, Paul. I've got that problem with putting names to faces,
and we've even met in person a few times. :-)
--- Zach
N0ZGO
------------------------------
Message: 6
Date: Fri, 8 May 2020 18:21:43 +0000
From: "Leffke, Zachary" <zleffke@??.???>
To: "AMSAT-BB@?????.???? <AMSAT-BB@?????.???>
Subject: Re: [amsat-bb] FM vs Linear Transponders
Message-ID:
<CH2PR05MB70300BD20A013E4CB16A3E29DFA20@?????????????.????????.????.???????.??
?>
Content-Type: text/plain; charset="us-ascii"
You guys beat me to the punch on the replies......got distracted by a work
thing from the fun stuff.....
My inputs on the challenges for the Linear GS setup.....also trying to
highlight potential technical solutions that might enable solutions to the
operational issues being discussed (I have no dog in that particular race):
1. 100% agree with all that DIY/Open designs and demos for low complexity,
low cost GS solutions would be great!
2. Major challenge right now is a Handheld that transmits on
sideband.....there are few that receive sideband and can transmit NBFM.
Kenwood TH-F6A pops into mind (because I have one). It wasn't cheap as far
as handhelds go, but I believe cheaper than a pair of FT-817s. Its also a
tribander on TX, NBFM (2m/222/70cm) and a multimode/multibander on RX
(~1-1300 MHz)......but that doesn't matter if there aren't birds that could
support that .......
3. Lets not forget the transponders themselves......something that came up
on a thread a few years ago. Given that commercial solutions exist for FM
up and SSB down, hybrid designs for the transponders themselves should be
considered. I think this is a VERY important part of what the GOLF series
should seek to (and I believe will be able to ) demonstrate with the SDR
onboard....re-configurability. On launch day, maybe an FM single channel
transponder and some standard linear transponder waveforms (maybe stacked
side by side in the spectrum). Then maybe we can think about waveforms that
demodulate the FM uplink, and remodulate a sideband downlink stuck in the
passband of the existing linear transponder. I could list out all the
possibilities here, but the point is...hybrid architectures that can be
re-configured based on user demand and interest of the day. FMtoFM(single
and multi-user) / FM up to SSB down (multi) / SSBtoSSB (normal linear) /
digital modes /some of those things
simultaneously / etc. etc. . I mean it's just software right (hihi).
4. Standard caveat/disclaimer: doing any of those things might be possible
with GOLF, but that doesn't mean doing even the simplest transponder update
is trivial.....lots of design features to factor in, resiliency (don't want
to brick the bird with an update), procedural implications for ops and
controllers, power consumption concerns (especially if multiple TX systems
are active), even regulatory concerns/implications.......but maybe there is
a simple demo that might be possible to show in this area with one of the
GOLFs. I'm mainly using GOLF as an example given that it flying an SDR
based trasndponder....other missions (AMSAT or maybe University) could
do/demonstrate the same things.
5. Also, hardware designs should still be on the table. I know some older
birds had this 'cross mode' capability......maybe we should factor that into
future designs. Maybe older larger systems could be 'recreated' (and newer
capabilities added) in a more compact form factor given modern devices on
the market.
6. To circle back to the handheld discussion......maybe theres an avenue
for an open source/open hardware handheld transceiver design that support
SSB TX (and RX)......pretty big design effort, and maybe already
done........end goal of this thought is if there were something out there,
maybe it could be easily and cheaply mass produced and then sold through the
AMSAT store to make it easy for the end user to get their hands on. Given
the desirement (desired feature + requirement) for open source/open
hardware....it could also be something that the kit builders out there might
be interested in (right nothing new here.....buy the built version for X
dollars, buy the kit version for less and assemble yourself). I'm thinking
things as simple as Arduino microcontrollers to drive LCD displays and all
that......theses sort of components needed for this are all over the place
now, including the open source software to interact with many of them.
Organizations exit that might support some
thing along these lines, Kickstarter for one for funding. Of course...two
cruxs of the issue to overcome (at least).....where is that base design and
where are the volunteers to step up and get it all done (from the design
through deployment, including good documentation!). Definitely agree with
Paul that its probably not cost effective to the major manufacturers....so
maybe we (as in the collective AMSAT population) can literally DIY it.
7. Last thought....even simple SDR systems can be challenging to the masses
that don't play around with SDRs every day. So for # 6 above, I was
thinking a HW design that is more akin to what folks are comfortable with in
the kit building world, even if the first version is a huge clunky handheld
(that maybe only requires a multimeter to checkout)....that said I love SDR,
so let's do it all and go for HW and SDR designs!
Just my two cents....I hear these challenges to the operating community as
opportunities to come up with fun and novel technical solutions....and a
need for more birds...always more birds :-)
(and more volunteers with the time to get stuff done! I know I throw my two
cents out a lot, but never have time to follow up and make things
happen....something I wish I could change......)
-Zach, KJ4QLP
--
Research Associate
Aerospace & Ocean Systems Lab
Ted & Karyn Hume Center for National Security & Technology
Virginia Polytechnic Institute & State University
Work Phone: 540-231-4174
Cell Phone: 540-808-6305
-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces@?????.???> On Behalf Of Zach Metzinger via
AMSAT-BB
Sent: Friday, May 8, 2020 2:05 PM
To: AMSAT BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] FM vs Linear Transponders
On 05/08/20 13:03, Paul Stoetzer wrote:
> That's me, not Drew!
Doh! I'm sorry, Paul. I've got that problem with putting names to faces,
and we've even met in person a few times. :-)
--- Zach
N0ZGO
_______________________________________________
Sent via AMSAT-BB@?????.???. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 7
Date: Fri, 8 May 2020 14:39:49 -0400
From: Stephen DeVience <sjdevience@?????.???>
To: amsat-bb@?????.???
Subject: [amsat-bb] FM vs Linear Transponders
Message-ID:
<CAMPfQQDGyeY2xF_=qFfir-1BqaHEeiDd6teOxmBXR=vubqcpKQ@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
I'm thinking about some kind of hardware/software combination kind of like
this company's products:
https://www.hobbypcb.com/
I have two of their HF and VHF/UHF radios. All frequency control is done
via usb and an arduino nano, which I'm sure can be adapted to a phone app.
There are a lot of plans for simple SSB transceivers that could probably be
combined with that.
I like SDRs too, but then you probably need at least a laptop to get enough
computing power to do a good job.
I'm glad you're thinking about this too.
-Stephen, N8URE
------------------------------
Message: 8
Date: Fri, 8 May 2020 18:52:53 +0000
From: "Leffke, Zachary" <zleffke@??.???>
To: "AMSAT-BB@?????.???? <AMSAT-BB@?????.???>
Subject: Re: [amsat-bb] FM vs Linear Transponders
Message-ID:
<CH2PR05MB7030EF57D73880C4CAC48238DFA20@?????????????.????????.????.???????.??
?>
Content-Type: text/plain; charset="us-ascii"
Yes! This is right in line with what I was thinking. That VHF/UHF board
looks like the perfect base design....except that specific product appears
to be mainly for packet operations (full disclosure, I just skimmed the
page, they do mention single channel voice, my guess is NBFM).
But yes something like that! But add in the open source/open hw angle (for
kit enthusiasts) and SSB capabilities. The Arduino control feature sounds
like the perfect opportunity for a Bluetooth interface to a phone for the
Doppler control. I have visions of a cheap 'add-on' board with QLED or LCDs
and rotary encoders as well for manual control if desired if doing our own
version of this.
I'm even seeing key words that are resonating with me (hihi) like Qorvo
PAs/LNAs (also the PGA-103 from miniciruits for LNA), exactly to the type of
devices I would look at if starting from scratch. Plethora of devices on
the market for this sort of thing.
Good stuff.
-Zach, KJ4QLP
--
Research Associate
Aerospace & Ocean Systems Lab
Ted & Karyn Hume Center for National Security & Technology
Virginia Polytechnic Institute & State University
Work Phone: 540-231-4174
Cell Phone: 540-808-6305
-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces@?????.???> On Behalf Of Stephen DeVience
via AMSAT-BB
Sent: Friday, May 8, 2020 2:40 PM
To: amsat-bb@?????.???
Subject: [amsat-bb] FM vs Linear Transponders
I'm thinking about some kind of hardware/software combination kind of like
this company's products:
https://www.hobbypcb.com/
I have two of their HF and VHF/UHF radios. All frequency control is done
via usb and an arduino nano, which I'm sure can be adapted to a phone app.
There are a lot of plans for simple SSB transceivers that could probably be
combined with that.
I like SDRs too, but then you probably need at least a laptop to get enough
computing power to do a good job.
I'm glad you're thinking about this too.
-Stephen, N8URE
_______________________________________________
Sent via AMSAT-BB@?????.???. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 9
Date: Fri, 8 May 2020 13:54:58 -0500
From: Zach Metzinger <zmetzing@?????.???>
To: amsat-bb@?????.???
Subject: Re: [amsat-bb] FM vs Linear Transponders
Message-ID: <626878e0-6e42-f6a9-44a4-a5ebd37ebe8f@?????.???>
Content-Type: text/plain; charset=utf-8; format=flowed
On 05/08/20 13:39, Stephen DeVience via AMSAT-BB wrote:
> I like SDRs too, but then you probably need at least a laptop to get enough
> computing power to do a good job.
This is a bit of a misconception. Single-board computers (SBCs) have now
become ridiculously fast:
"The Raspberry Pi 2 Model B is approximately equivalent to an Athlon
Thunderbird running at 1.1GHz; again, it has the much higher-quality
graphics, which come from using the same GPU as previous models. The
Raspberry Pi 3 Model B is around twice as fast as the Raspberry Pi 2
Model B, depending on the benchmarks chosen."
(from https://www.raspberrypi.org/documentation/faqs/#pi-performance)
The Pi 4 is super fast, but also needs a heatsink...
A display can be had here:
https://www.sparkfun.com/products/14776
Here's a demo of someone putting it all together:
https://gqrx.dk/blog/pi-sdr-raspberry-pi-3-7-touchscreen-rtl-sdr-gqrx
Here's where we need a volunteer to put this onto a SD card for easy use
by those not familiar with Linux, etc.
My plate is full, but I'd be glad to test it out and give feedback.
--- Zach
N0ZGO
(P.S.: ".. only thorough the sorrows of men .." -- some really heavy
stuff right there.)
------------------------------
Message: 10
Date: Fri, 8 May 2020 19:07:44 +0000 (UTC)
From: Brad Smith <corlissbs@???.???>
To: amsat-bb@?????.???
Subject: [amsat-bb] APRS Birds
Message-ID: <2089561255.342272.1588964864521@????.?????.???>
Content-Type: text/plain; charset=UTF-8
<Also, there is a lot of bandwidth on the APRS satellites
(Falconsat-3,ARISS, NO-84) and the PSK birds (NO-84, NO-104) waiting for
moreusers. Remember, with APRS you can do more than just send yourposition,
you can send messages back and forth and have a decentconversation. So for
those tired of the QRM on FM, consider givingthem a try.>
I have mastered packet exchange through the ISS and would love to do packets
on the APRS satellites. However, I have not found an article, etc,. that
tells how to do it. I understand that it is not quite the same as the
ISS/digipeaters contacts. If one can't find an "instruction sheet", how can
one participate? I was hoping that this year's AMSAT satellite book would
give a clue, but due to obvious circumstances, the book has not been
published. Since I am the only one in my ham clubs who does any packets at
all, help is not going to come from local hams. I am very thankful for the
help from some hams around the US who elmered me, so far.? Brad KC9UQR
------------------------------
Message: 11
Date: Fri, 8 May 2020 20:11:02 +0100
From: "Peter Goodhall (2M0SQL)" <peter@????????.??.??>
To: Zach Metzinger <zmetzing@?????.???>
Cc: Amsat <amsat-bb@?????.???>
Subject: Re: [amsat-bb] FM vs Linear Transponders
Message-ID:
<CAFvUair5OvdOWpQ8WUT3hT-f16md-XDGec5rBLntmPCcyxOWjQ@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Zach,
Not sure what you think needs doing, there's already a pisdr image
available setup for most common SDRs on the market and most of the
common software tools see https://pisdr.luigifreitas.me
Think only improvements the image needs perhaps is the Fox decoder
added but its pretty much ready to use.
Peter, 2M0SQL
On Fri, 8 May 2020 at 19:58, Zach Metzinger via AMSAT-BB
<amsat-bb@?????.???> wrote:
>
> On 05/08/20 13:39, Stephen DeVience via AMSAT-BB wrote:
> > I like SDRs too, but then you probably need at least a laptop to get
enough
> > computing power to do a good job.
>
> This is a bit of a misconception. Single-board computers (SBCs) have now
> become ridiculously fast:
>
> "The Raspberry Pi 2 Model B is approximately equivalent to an Athlon
> Thunderbird running at 1.1GHz; again, it has the much higher-quality
> graphics, which come from using the same GPU as previous models. The
> Raspberry Pi 3 Model B is around twice as fast as the Raspberry Pi 2
> Model B, depending on the benchmarks chosen."
>
> (from https://www.raspberrypi.org/documentation/faqs/#pi-performance)
>
> The Pi 4 is super fast, but also needs a heatsink...
>
> A display can be had here:
>
> https://www.sparkfun.com/products/14776
>
> Here's a demo of someone putting it all together:
>
> https://gqrx.dk/blog/pi-sdr-raspberry-pi-3-7-touchscreen-rtl-sdr-gqrx
>
> Here's where we need a volunteer to put this onto a SD card for easy use
> by those not familiar with Linux, etc.
>
> My plate is full, but I'd be glad to test it out and give feedback.
>
> --- Zach
> N0ZGO
>
> (P.S.: ".. only thorough the sorrows of men .." -- some really heavy
> stuff right there.)
> _______________________________________________
> Sent via AMSAT-BB@?????.???. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Subject: Digest Footer
_______________________________________________
Sent via amsat-bb@?????.???.
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 member? Join now to support the amateur satellite program!
https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
End of AMSAT-BB Digest, Vol 15, Issue 147
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