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CX2SA > SATDIG 03.06.20 20:55l 738 Lines 30563 Bytes #999 (0) @ WW
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From: CX2SA@CX2SA.SAL.URY.SOAM
To : SATDIG@WW
Today's Topics:
1. Re: Hack-a-Sat Call for Participation (Michelle Thompson)
2. Re: Source for Affordable bias-Tees? (MICHAEL WILLIAMS)
3. Re: Terrible Repeater QRM on AO-92 (Ted Krempa)
4. G5500 issue (David Worboys)
5. Re: Terrible Repeater QRM on AO-92 (Andrew Glasbrenner)
6. FM signals heard on RS-44 (Mark Johns, K0JM)
7. Re: FM signals heard on RS-44 (Peter Goodhall (2M0SQL))
8. Alpha Spid Rotator (Dave)
9. Re: Alpha Spid Rotator (Leffke, Zachary)
----------------------------------------------------------------------
Message: 1
Date: Tue, 2 Jun 2020 13:42:11 -0700
From: Michelle Thompson <mountain.michelle@?????.???>
To: AMSAT BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Hack-a-Sat Call for Participation
Message-ID:
<CACvjz2XYFCboXgcNFnJ9TKeB+HxnYFWkJ6+MbG48Z9DuuJKwGg@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Greetings all!
1500+ teams registered for the event.
1283 teams scored at least a point.
Our team (Vaporsec) finished 20th.
The interdisciplinary nature of the team served extremely well! Amateur
radio satellite service operators made fundamental and significant
contributions to the final score, everyone learned a lot, and we all had
fun.
The challenges ranged from mastering Apollo-era assembly code, to reverse
engineering IQ files received from space, to controlling ADAC systems, to
correctly configuring star trackers, to understanding what's required to
precisely observe the Earth from orbit - and plenty more. The range and
breadth of the challenges was daunting, but our diverse and positive team
carried the day.
The finals are 7-9 August 2020. This is a virtual event held during the
weekend of DEFCON. All of the challenges from the qualification round will
be up until the final event at https://www.hackasat.com/
Even better news? A lot of us from the amateur radio satellite service
community will be participating in the finals with teams that made the top
ten and recruited us to add to their roster.
I can't wait to share what we learn and how we do in the finals. I'll be
with ADDVulcan.
Contests and competitions have a long and storied history in amateur radio.
The active and thriving Capture the Flag (CTF) scene should be familiar to
any amateur radio contester, because there are so many similarities. The
incorporation of advanced digital, computing, RF, and networking technology
into contesting, at events like Hack-a-Sat, is very exciting and it will
definitely test your skills. Being involved with a team that welcomes
people willing to learn is an especially enjoyable privilege! Some teams
are closed to newcomers and approach competitions more like a professional
sports team. Some teams are composed only of people that work at a
particular company, or know each other well.
Hack-a-Sat offered a very broad opportunity this year, so teams that were
open to newcomers were plentiful. We owe a debt to the organizers at the
Department of Defense (Thank you Air Force) for the high-quality outreach,
accessibility, and challenging and engaging content.
If you want to get involved with competitions like this, please write
me and I will help you. Hack-a-Sat was very difficult, but there are
contests at every level almost every weekend and a growing number
incorporate amateur radio.
Want to be involved with creating a real live CTF? I'm chairing the GNU
Radio Conference CTF this year (will be held in September, website is
https://www.gnuradio.org/grcon/grcon20/), and amateur radio has
traditionally been a very large part of this event in every way. Your ideas
for amateur radio satellite themed challenges are welcome and I look
forward to working with you.
Wouldn't it be great to see AMSAT host a satellite themed CTF? Especially
if the solutions of the challenges could directly support engineering
efforts. Many hands make light work!
-Michelle W5NYV
Director of AMSAT
Chair of GNU Radio Conference
CEO of Open Research Institute, Inc.
On Wed, May 20, 2020 at 3:03 PM Michelle Thompson <
mountain.michelle@?????.???> wrote:
> Thank you to the amateur satellite community for the response!
>
> The Vaporsec CTF team, specifically open to amateur radio operators, has
> seen the largest turnout for a Capture the Flag competition in team
> history, for this satellite-themed event. We have over 20 signed up for the
> qualifications event this coming weekend. We believe that based on the
> diversity, quality, and positive can-do spirit, that we have a chance at
> being competitive and moving on to the final round in late summer.
>
> We had a successful team organizational meeting last night are are looking
> forward to a Friday 5pm Pacific start time. I'm looking forward to being
> able to share how amateur radio operators and practical experience carried
> the day!
>
> Rules and link to the Hack-a-Sat website are up-thread. The point of the
> competition seems to be the Air Force wanting to see what the current level
> of competence is out there with respect to satellite operations and
> security. Hints have included backgrounders on ADAC, Satellite IoT platform
> security, protocols, ground control, and more.
>
> Something that we noticed is that an unsolved challenge in last weekend's
> DEFCON CTF qualifier round was from the same team that is putting on
> Hack-a-Sat CTF.
>
> So! If you are wondering what kind of challenges are posed to participants
> in a CTF, here is that satellite-themed challenge. We expect this sort of
> thing to be the starting point for an entire weekend of satellite reverse
> engineering, puzzle solving, and rogue-craft-wrangling.
>
> There are two files related to the challenge. The challenge text and the
> two files can be found at:
>
>
>
https://github.com/phase4space/research-papers/tree/master/interrupted_DEFCON_
CTF_Challenge
>
> See you on the other side of the CTF! We will have a write-up of the event
> and share any and everything we learn along the way.
>
> -Michelle W5NYV
>
>
>
>
> On Tue, May 12, 2020 at 1:17 PM Michelle Thompson <
> mountain.michelle@?????.???> wrote:
>
>> Thank you for the interest! We have 14 on the team and rising.
>>
>> The one question that has come up is whether federal contractors can
>> participate. There is a FAQ at the Hack-a-Sat website that addresses this.
>>
>> Q: Can my business team include contractors (not "Federal entities", not
>> "Federal employees", not "Federal Government Military or Civilian
>> employee") who support federal contracts?
>>
>> A: Yes.
>>
>> If this happens to be holding you back from participating, then know that
>> it should not. I understand that there are a complex variety of definitions
>> involved, but the FAQ was written to address a common case that isn't
>> disqualified from this particular event, organized through the Air Force.
>>
>> -Michelle W5NYV
>>
>>
>>
>>
>> On Fri, May 8, 2020 at 12:26 PM Michelle Thompson <
>> mountain.michelle@?????.???> wrote:
>>
>>> Greetings all!
>>>
>>> I've put out the call for participation for the Hack-a-Sat competition
>>> in the past, and would like to bring you all up to date on the
developments
>>> and opportunities that have developed since.
>>>
>>> The website is here: https://www.hackasat.com/
>>>
>>> Hack-a-Sat is an activity that was scheduled to happen at the in-person
>>> DEFCON event.
>>>
>>> As of today, yes, it's true. DEFCON has been cancelled.
>>>
>>> Those of you that have volunteered at Ham Radio Village in the past are
>>> familiar with the event. For those of you that are not, it's a
long-running
>>> hacking and cybersecurity event that has enthusiastically adopted
>>> everything RF and amateur radio.
>>>
>>> The United States Air Force, in conjunction with the Defense Digital
>>> Service, organized this year?s Space Security Challenge, called
Hack-A-Sat.
>>> This challenge asks hackers from around the world to focus their skills
and
>>> creativity on solving cybersecurity challenges on space systems. This
>>> competition is going to be held! It's now a virtual event.
>>>
>>> Security in the amateur radio sense of the word is fundamentally
>>> different from commercial and military applications. We have an advantage
>>> here, mainly due to the enormous leverage we have due to our context being
>>> completely different from what the Air Force and commercial interests
>>> assume. This is, essentially, a diversity advantage.
>>>
>>> If you want to participate on an experienced Capture The Flag (CTF)
>>> team, then I am here to extend an invitation. Anyone that reads through
the
>>> rules and can afford to spend some time during the event is invited to
>>> apply to join Vaporsec. This is a team that has a majority of information
>>> security professionals. There are some satellite industry people, some
>>> amateur involvement, and I'd like to make sure that anyone interested in
>>> competing from AMSAT-BB gets a chance to join a competitive team.
>>>
>>> The benefits to amateur radio are primarily technical, with policy and
>>> security a close second. The Air Force has some agendas here in terms of
>>> improving satellite security. Exposure to the challenges alone is a an
>>> excellent opportunity to learn more about modern satellite technology...
>>> and what a significant player in space wants to find out more about. Don't
>>> assume that that the challenges in the competition are going to be "too
>>> hard". What is trivial for one viewpoint is unsolvable for another.
>>>
>>> I'll be writing about the event and what we learned when it is over, so
>>> this sort of knowledge will not be secret. However, there is no
replacement
>>> for participation, and you could very well have the practical knowledge,
>>> gained from operating real satellites, that wins the competition. As you
>>> can see from the website, there is some real money involved and
>>> opportunities for technical writing.
>>>
>>> Let me know at w5nyv@????.??? if you would like to talk more about
>>> joining a CTF team for this really neat and unique event.
>>>
>>> Know someone that you think should participate? Please forward to them.
>>>
>>> -Michelle W5NYV
>>>
>>>
>>>
------------------------------
Message: 2
Date: Tue, 2 Jun 2020 17:34:17 -0400 (EDT)
From: MICHAEL WILLIAMS <k9qho67622@???????.???>
To: k0ekl@????????.???? amsat-bb@?????.???
Subject: Re: [amsat-bb] Source for Affordable bias-Tees?
Message-ID: <84961245.129220.1591133657652@???????.???????.???>
Content-Type: text/plain; charset=UTF-8
Check out: EME168-2-70 KIT at minikits.com.au.
You can by it as a kit of assembled. The dollar exchange rate is real good.
GL,
Mike (K9QHO)
------------------------------
Message: 3
Date: Tue, 2 Jun 2020 16:16:51 -0700
From: "Ted Krempa" <k7trkradio@???????.???>
To: "'Andrew Glasbrenner'" <glasbrenner@??????????.???>, "'Roy Dean'"
<royldean@?????.???>
Cc: AMSAT BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Terrible Repeater QRM on AO-92
Message-ID: <02e701d63933$e68612f0$b39238d0$@???????.???>
Content-Type: text/plain; charset="us-ascii"
Hi Andrew, any update on this issue?
Thanks and 73
Ted, K7TRK
-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces@?????.???? On Behalf Of Andrew
Glasbrenner via AMSAT-BB
Sent: Thursday, May 21, 2020 5:51 PM
To: 'Roy Dean'
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] Terrible Repeater QRM on AO-92 at 15:40z
Roy,
Thanks for the audio. In the weeks since this QRM came to light, with the
help of recordings from users, we have found the club whose repeater audio
is being retransmitted over AO-92. I do not believe this to be intentional.
Despite the coincidence of frequencies involved, I also do not believe it
to be a third harmonic. The audio is too clear, the signal is too strong,
and repeaters have too much filtering for that to be happening.
I reached out to the board of directors and the repeater trustees, sent
links to the audio including callsigns and their net ID. I explained that
based on experience that this was likely someone crossbanding into their
repeater with a poor choice of UHF frequency, and we could use their help in
finding the QRM source, and my goal was to educate and remove it, not point
fingers and place blame. The responses ranged from virtual shrugs, to claims
of atmospheric conditions, to "there must be something wrong on the
satellite end." A few suggested going to the repeater site and listening on
UHF while the repeater is active, which is a pretty good idea. Supposedly
they would make announcements about it on their nets.
I haven't given up on getting the club to help us find the QRM, but we may
need some more convincing. I'll send the new recordings and ask again.
Meanwhile, Is there anyone in the Gloucester, MA area that would like to do
a little foxhunting for AMSAT?
73, Drew KO4MA
AMSAT VP Operations
-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces@?????.???> On Behalf Of Roy Dean via
AMSAT-BB
Sent: Thursday, May 21, 2020 12:12 PM
To: amsat-bb@?????.???
Subject: Re: [amsat-bb] Terrible Repeater QRM on AO-92 at 15:40z
>
> Yes, terrible QRM during this pass. Have recording as well but no call
> signs from repeater chatter. Cal / N3CAL
https://youtu.be/4439iHT4vtM
--Roy
K3RLD
_______________________________________________
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
_______________________________________________
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: 4
Date: Tue, 2 Jun 2020 20:03:08 -0400
From: David Worboys <kg4zlb@??????.???>
To: AMSAT-BB@?????.???
Subject: [amsat-bb] G5500 issue
Message-ID: <EAFEED68-BF61-41DE-B757-493BFE32A76A@??????.???>
Content-Type: text/plain; charset=utf-8
Evening all!,
Further to my original posting I just wanted to take time to thank profusely
everyone who contacted me with help but specifically I would like to mention
Dino (VE7XDT) who patiently helped me diagnose the problem by way of a huge
amount of emails back and forth and me prodding at wires with a new
multimeter bought especially for this. His ultimate diagnosis of failed op
amps in the box was confirmed by Yaesu after another hour on the phone
performing the same tests to answer their questions. A quality company, they
took their time to ensure that I was totally aware of the issues.
Unfortunately the same can't be said about HRO in Atlanta (where I purchased
the rotator two weeks ago plus a hell of a lot of other equipment). The
implied irritation level that permeated down the phone line was palpable; i
asked them to send me a new one today, take a hold on my credit card for the
full value and I would send them back the defunct one using their packaging
and then they could release my credit card hold.
Keep a good customer happy ? No chance.
He actually tried to sell me a new complete G5500 and would then give me
store credit once i sent everything back - I am not taking down the
equipment and sending it all back and then have to put everything back up
again. So the controller is now on its way to Atlanta and the Store Manager
said that he had no stock of the controller on its own but could take out
the controller from the complete kit and send that - somehow I doubt that
will happen and this will drag on and on.
Sorry to rant, I just hate bad customer service.
Anyway, thanks everyone again - I look forward to working some of you on the
satellites It's about 11 years since the last time I was active but HRO may
drag that out even further. I hope not.
73?s
David
KG4ZLB
------------------------------
Message: 5
Date: Tue, 2 Jun 2020 20:29:26 -0400
From: "Andrew Glasbrenner" <glasbrenner@??????????.???>
To: "'Ted Krempa'" <k7trkradio@???????.???>, "'Roy Dean'"
<royldean@?????.???>
Cc: 'AMSAT BB' <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Terrible Repeater QRM on AO-92
Message-ID: <032601d6393e$09b99080$1d2cb180$@??????????.???>
Content-Type: text/plain; charset="us-ascii"
Nothing significant. I've not heard any recent reports of additional QRM
either. Whoever it was may have gotten the word.
73, Drew KO4MA
AMSAT VP Operations
-----Original Message-----
From: Ted Krempa <k7trkradio@???????.???>
Sent: Tuesday, June 02, 2020 7:17 PM
To: 'Andrew Glasbrenner' <glasbrenner@??????????.???>; 'Roy Dean'
<royldean@?????.???>
Cc: AMSAT BB <amsat-bb@?????.???>
Subject: RE: [amsat-bb] Terrible Repeater QRM on AO-92
Hi Andrew, any update on this issue?
Thanks and 73
Ted, K7TRK
-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces@?????.???? On Behalf Of Andrew
Glasbrenner via AMSAT-BB
Sent: Thursday, May 21, 2020 5:51 PM
To: 'Roy Dean'
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] Terrible Repeater QRM on AO-92 at 15:40z
Roy,
Thanks for the audio. In the weeks since this QRM came to light, with the
help of recordings from users, we have found the club whose repeater audio
is being retransmitted over AO-92. I do not believe this to be intentional.
Despite the coincidence of frequencies involved, I also do not believe it
to be a third harmonic. The audio is too clear, the signal is too strong,
and repeaters have too much filtering for that to be happening.
I reached out to the board of directors and the repeater trustees, sent
links to the audio including callsigns and their net ID. I explained that
based on experience that this was likely someone crossbanding into their
repeater with a poor choice of UHF frequency, and we could use their help in
finding the QRM source, and my goal was to educate and remove it, not point
fingers and place blame. The responses ranged from virtual shrugs, to claims
of atmospheric conditions, to "there must be something wrong on the
satellite end." A few suggested going to the repeater site and listening on
UHF while the repeater is active, which is a pretty good idea. Supposedly
they would make announcements about it on their nets.
I haven't given up on getting the club to help us find the QRM, but we may
need some more convincing. I'll send the new recordings and ask again.
Meanwhile, Is there anyone in the Gloucester, MA area that would like to do
a little foxhunting for AMSAT?
73, Drew KO4MA
AMSAT VP Operations
-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces@?????.???> On Behalf Of Roy Dean via
AMSAT-BB
Sent: Thursday, May 21, 2020 12:12 PM
To: amsat-bb@?????.???
Subject: Re: [amsat-bb] Terrible Repeater QRM on AO-92 at 15:40z
>
> Yes, terrible QRM during this pass. Have recording as well but no call
> signs from repeater chatter. Cal / N3CAL
https://youtu.be/4439iHT4vtM
--Roy
K3RLD
_______________________________________________
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
_______________________________________________
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: 6
Date: Wed, 3 Jun 2020 09:52:32 -0500
From: "Mark Johns, K0JM" <k0jm.mark@?????.???>
To: AMSAT-BB <amsat-bb@?????.???>
Subject: [amsat-bb] FM signals heard on RS-44
Message-ID:
<CADDbS5An--ufYuOEm15ig44=8XMe4LJyFkcgvkbYj+dW8bQ7Tg@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
There was an FM QSO taking place on about 145.95 just now (about 14:45z)
that was coming through the RS-44 downlink at about 435.655. The bird was
up toward the Pole, so New England would have been in the footprint, as
well as Canada and some northern states to the west. No callsigns heard,
but it sounded like amateurs and English was being spoken.
--
Mark D. Johns, K?JM
AMSAT Ambassador & News Service Editor
Brooklyn Park, MN USA EN35hd
-----------------------------------------------
"Heaven goes by favor; if it went by merit,
you would stay out and your dog would go in."
---Mark Twain
------------------------------
Message: 7
Date: Wed, 3 Jun 2020 16:08:59 +0100
From: "Peter Goodhall (2M0SQL)" <peter@????????.??.??>
To: k0jm@?????.???? "Mark Johns, K0JM" <k0jm.mark@?????.???>
Cc: AMSAT-BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] FM signals heard on RS-44
Message-ID:
<CAFvUaip9U9q+5pp5x5zazED5LcFj9kk6Tpmb7H68bkepu5Au0Q@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
AO-91, AO-92 anywhere inside the footprint?
On Wed, 3 Jun 2020, 15:53 Mark Johns, K0JM via AMSAT-BB, <amsat-bb@?????.???>
wrote:
> There was an FM QSO taking place on about 145.95 just now (about 14:45z)
> that was coming through the RS-44 downlink at about 435.655. The bird was
> up toward the Pole, so New England would have been in the footprint, as
> well as Canada and some northern states to the west. No callsigns heard,
> but it sounded like amateurs and English was being spoken.
> --
> Mark D. Johns, K?JM
> AMSAT Ambassador & News Service Editor
> Brooklyn Park, MN USA EN35hd
> -----------------------------------------------
> "Heaven goes by favor; if it went by merit,
> you would stay out and your dog would go in."
> ---Mark Twain
> _______________________________________________
> 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: 8
Date: Wed, 3 Jun 2020 13:19:55 -0400
From: Dave <kdcarlso@?????.???>
To: AMSAT BB <amsat-bb@?????.???>
Subject: [amsat-bb] Alpha Spid Rotator
Message-ID:
<CAG5zY2qwDWV2jatVw8QiXp+Hd4CMgxdMPVOjOMQUy3f-a_5qQg@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Is anyone using an Alpha Spid az/el rotor? If so how do you like it? Would
you recommend it over the Yaesu's and are there any issues using it with
SatPC32?
Thanks,
Dave
N2OA
------------------------------
Message: 9
Date: Wed, 3 Jun 2020 18:42:37 +0000
From: "Leffke, Zachary" <zleffke@??.???>
To: "AMSAT-BB@?????.???? <AMSAT-BB@?????.???>
Subject: Re: [amsat-bb] Alpha Spid Rotator
Message-ID:
<MN2PR05MB7037AC58B2EBD36D13B3957BDF880@?????????????.????????.????.???????.??
?>
Content-Type: text/plain; charset="us-ascii"
Hi Dave,
We use a lot of the RAS/HR and Big-RAS/HRs at VT in our ground station and
on other projects. My biggest recommendation is if you don't absolutely
need the resolution, don't get the high resolution variants (0.2 deg
resolution). It uses a quadrature encoder feedback mechanism that is highly
susceptible to EMI corruption leading to 'dropped counts' and a general slew
of problems related to calibration and reliable pointing knowledge. We have
constantly battled this problem since day 1 of the VTGS and still don't have
reliable resolution for the problem (but enough band-aid solutions to keep
limping along and periodic trips out to the tracking station to
recalibrate). The smaller Ras/HRs seem to generally do better on the
feedback front (still high resolution with the quadrature feedback) for some
reason, but we typically use those in 'deployable' scenarios and the
feedback cabling is much shorter (maybe 20ft or so)....so not necessarily an
apples to apples comparison with the perm
anently installed Big-RAS/HRs that have longer feedback cables (roughly
100-200 ft depending on which antenna stack we're talking about) and
generaly seem to be more prone to issues. I also personally own a Ras/HR
(smaller one) with the high res feedback and a 2.4m solid dish mounted on
it. It can handle the load just fine with proper counterweighting and so
far I haven't had any feedback issues (roughly 50ft feedback cable)....knock
on wood.
The 'non high resolution' (low resolution?...its still accurate to about 1
deg) variants use plain ol' potentiometer feedback. I don't have direct
experience with them, but have reports from some colleagues that they
haven't had any serious or repetitive issues with pointing calibration (some
radio astronomers in Physics dept are using one with a 2m dish). (I think
that one uses a different controller than the MD-01 that we use, but I think
the MD-01 or MD-02 could handle either type of feedback).
Other 'warnings' include realizing they have no mechanical stops in azimuth
(they do in elevation, roughly at 180 deg limits). That said, it isn't
really a problem as most controllers work reliably with 'software limits'
and the MD-01s at least have timeouts that help if things 'go wonky' with
feedback. There are some cases though that result in the perfect storm of
corrupted feedback that goes undetected by the MD-01 that could lead to a
bad azimuth situation; in our case we monitor antenna motion on a camera, so
are able to mitigate that scenario with human intervention (and our custom
control software looks for 'impossible speeds' as reported by the MD-01
positions that further helps mitigate that when the feedback goes awry).
Mechanically, they have done very well for us with the double-worm gear
design, imperceptible gear slip (if any). I've heard of folks having
mechanical failures, but I don't know the details, and that hasn't been my
experience. As an example, at the height of 'performance' I was able to
reliably track multiple S-Band downlinks with a 3m mesh dish antenna with no
discernible negative effects due to point errors or 'jiggle' in the system
(part of that is the ramp up, also part the counterweighting). In the 5 or
so years we've been running them, we haven't had any major mechanical
malfunctions (knock on wood), and part of that is probably due to periodic
maintenance (re-greasing and such), which I've done at least once (can't
remember exactly, maybe twice in that 5 year window). Part of that is also
the fact that we tend to use the yagi stacks with a lighter load a lot more
than the larger dish systems, I might be singing a different tune if the
dishes were used daily.
The MD-01 controller (and MD-02s as well for non-rackmount variants) does
have some nice ramp-up/ramp-down features, particularly useful for larger
systems (like our 4.5m dish). I do wish the API documentation for the MD-01
command interface was a little better...but we've been able to work through
it (for example, they changed the protocol a bit in a relatively recent
firmware update that broke compatibility with our software and presumably
things like rotctl in hamlib, but I think that has all been fixed/updated).
The API issue might not be a problem for most folks not interested in
writing their own software, or if you are using a different controller. The
overall documentation situation is a little 'meh' in general as there have
been a lot of versions and such released and they are on different websites
run by different folks.....but at least there is documentation at all and a
little reading and experimentation is usually enough to get what you need,
and the basics such as th
e wiring diagram hasn't really changed over the years.
I can't directly speak to the SatPC32 question because we don't use it.
Other than that firmware update hiccup, I'd be willing to bet it works fine.
Bottom Line: When they work, they seem to work well, at least in my
experience. If I were going to buy one today for personal use, I'd get one
with the potentiometer feedback if the intended use is for something like a
few Yagis and if I were planning a more permanent installation. If I were
going to buy something for VT/work with a better funding source than my
'hobby budget' I'd probably look for something better, like M2 products
(pretty significant jump in price point though).
I hope this helps.
-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 Dave via AMSAT-BB
Sent: Wednesday, June 3, 2020 1:20 PM
To: AMSAT BB <amsat-bb@?????.???>
Subject: [amsat-bb] Alpha Spid Rotator
Is anyone using an Alpha Spid az/el rotor? If so how do you like it? Would
you recommend it over the Yaesu's and are there any issues using it with
SatPC32?
Thanks,
Dave
N2OA
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End of AMSAT-BB Digest, Vol 15, Issue 182
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