AMSAT-BB May 2020

141 participants
209 discussions

by Roy Dean

> > Now the comment was relating to SDR devices for the RX side, depending on > what you have, some of these have very poor RF shielding so that in itself > is a real problem Tom Schuessler, N5HYP > EM12ms Just as another data point - I use an $20 RTL-SDR.com V3 Dongle for the downlinks on almost all the FM and SSB satellites (yep, the plan was always to upgrade but it's been working so well that I haven't found a huge need to spend money on a real SDR or traditional receiver). I have MFJ 916 diplexers at the mast acting as band pass filters. This has been working for me on all satellites except for SO-50 and FO-29. I can get receiver blowout on the 70cm downlink birds (LilacSat-2 and RS-44, for example) if I am not careful with my usage of my ARR pre-amps (located at the antennas) or the SDR gain setting, but ultimately I've had good luck on those. SO-50 and FO-29 don't seem to be workable no matter what combination of pre-amp and SDR gain setting I use. I haven't had an opportunity to try out HO-107 yet, so can't comment on my "el cheapo" setup on that bird. For SO-50 I just use my D710G, and I haven't had much opportunity to use FO-29 lately anyway. --Roy K3RLD

2 years, 2 months

Re: [amsat-bb] RS-44 VU noise from TX

by tjschuessler＠verizon.net

When I started setting up to the 145 up 435 down satellites, I experienced this issue badly. The best solution I found was to use two separate Diplexer to feed my Arrow on a tripod. I ended up using a triplexer for the 2 meter side and a diplexer for the 70CM side. The dual filtering seems to clean up all the third harmonic crud. Some folks recommend a 50 Ohm terminator for unused ports but I most of the time don't use one. I put my preamps on the inside of the diplexers as filters because the loss is small on the diplexer and filtering before the preamp will go a long way. Limiting power is also a help. Most of our linear birds are pretty sensitive so keeping our transmitters down to a very low transmit output is best for the satellite Now the comment was relating to SDR devices for the RX side, depending on what you have, some of these have very poor RF shielding so that in itself is a real problem Tom Schuessler, N5HYP EM12ms _______________ Message: Date: Sun, 24 May 2020 20:43:27 +0200 (CEST) From: mailto:[email protected] To: Andy Brian <mailto:[email protected]> Cc: amsat-bb <mailto:[email protected]> Subject: Re: [amsat-bb] RS-44 VU noise from TX Message-ID: <mailto:[email protected]> Content-Type: text/plain; charset=utf-8 Hoi, Instead of putting a diplexer as filter( best is to use 1 per band), if you have the possibilty to make stuff your own, just 'split' a diplexer by making an LPF (low pass filter) at the 2m antenne and a HPF ( high pass filter) at the 70cm antenne. Or find some to buy (MINI CIRCUITS maybe?). This way you have a filter at both antennas. Mostly a diplexer is used only on one antenna, while the other diplexer port is closed with a small dummy load. Keep in mind the tx-pwr! Best 73's Jerry,ON4CJQ

2 years, 2 months

Tablet for SatPC32

by Bob Hammond

I'm in the market for a tablet to take roving. I want to use SatPC32 so that means some version of Windows. Any suggestions on a Windows tablet? Bob W7OTJ

2 years, 2 months

Mounting Bracket

by BeetleJerald Oliver

I am looking for a Mobile Mounting Bracket ( MB-66 ) for my Yaesu FT-847. Anybody have one they don't need? Jerry KJ4EU

2 years, 2 months

G5400B Problem

by Richard Lawn

I'm experiencing a problem with an old G5400B. It works fine with a Fox Delta interface and then all of a sudden it lock up. I can't even move the AZ rotor manual with the control box. Is there some sort of thermal device that might need to be replaced? Rick, W2JAZ

2 years, 2 months

New version of the W1ANT Satellite Tracker apps available

by Heimir Thor Sverrisson

Hi all, New versions of the W1ANT Satellite Tracker Android apps are now available in the Google Play Store. These new versions address operational improvements suggested by Paul Philip AC9O. Centrally adding and removing satellites is now also much more robust. Big thanks go out to the hundreds of operators that have downloaded the app and to those that have given me constructive feedback. The free version app: https://play.google.com/store/apps/details?id=com.coolprimes.sattrack The no-ads paid version: https://play.google.com/store/apps/details?id=com.coolprimes.sattrack.pro Thanks & 73 /Heimir W1ANT

2 years, 2 months

RS-44 VU noise from TX

by Andy Brian

Hi any good suggestion how to reduce noise from VHF TX on receiving on UHF fo RS44 I'm using two antenna antena 8meters away each other but is hard to hear anything when TX. 73 Andy

2 years, 2 months

Re: [amsat-bb] HO-107

by Mark L. Hammond

Hello Jerry, I'm going to copy the -BB on this reply since "my spider senses" tell me the question may occur to others! The "live" telemetry is displayed here. http://www.amsat.org/tlm/health.php?id=6&port= If you click on a sensor value, it will show a graph of something like the last 100 values. You can also use this page to see telemetry from the whole Fox family. Scroll to the bottom/right of the page for links to the software, etc. https://www.amsat.org/tlm/leaderboard.php?id=0&db=FOXDB Now, if you really want to look at some data--you can download FoxTLM and do a full download of all the data for any of the "Fox and friends" family, which includes AO-85, -91, -92, -95, and HO-107. It's what we'll be using for Fox-1E when it's launched, and any of the other future partner payloads that AMSAT hopes will host the linear transponder (LTM). Tons of graphing and viewing options....most of us it take a while to get a feel for all the features in the program, but Chris AC2CZ (and team) has done an amazing job with the program and the documentation. A very versatile program. It's what we use to collect live telemetry feed to AMSAT servers as well. Give it a shot and see how you make out! WARNING--It may be habit forming! I started collecting telemetry back with FO-12, And Oscars 16/17/18/19/20/22/23... AO-40...and the list goes on. If you use any of scoreboard links above, you'll see I've spent a good portion of my hobby time collecting telemetry...while I certainly enjoy a voice QSO, I've always enjoyed the challenge of getting an automated system up and running and collecting telemetry for whomever needed it. If fact, we just set up a fully automated station at the university where I work. My wife and I donated all the equipment, and we hope to inspire the new engineering students in the school I started 4 years ago. The crazy pandemic was a mixed blessing---few people around so we could get on the roof (with some co-worker hams) to install it, but there were no students around to watch, help, or learn! That will come this fall, I hope. 73, Mark N8MH On Sun, May 24, 2020 at 10:03 AM Gerald Witalec <jplanner(a)sbcglobal.net> wrote: > Good morning Mark, > Just curious on what type of program is available for us to view the > telemetry > that would show temperature, voltage and so on within a particular > satellite? > > Thanks, > > Jerry...W8RQM > > > On Sunday, May 24, 2020, 9:45:06 AM EDT, Mark L. Hammond via AMSAT-BB < > amsat-bb(a)amsat.org> wrote: > > > Hi Jeff, > > No, it been quiet. Drew KO4MA mentioned this briefly a couple days ago. > Several days ago the satellite entered into a several day period of full > illumination. It looks like this full sun event may be the first such > period for the bird since its release into its current orbit. Temps were > getting pretty high according to some of the last telemetry heard. It > should be starting to cool down as eclipses have returned and are getting > longer, which should hopefully help. Rest assured the command team is > going to make attempts to try to get it back on the air. If you recall, > it's a satellite built by UW.and we're a payload/partner on the satellite, > so everyone is in uncharted territory here! > > In the meantime, we'll appreciate reports of hearing something from it. > > 73, > Mark N8MH > > On Sun, May 24, 2020 at 9:24 AM Jeff via AMSAT-BB <amsat-bb(a)amsat.org> > wrote: > > > > > Is anyone getting any telemetry from HO-107 ? > > > > 73 Jeff kb2m > > > > Sent from my iPhone > > _______________________________________________ > > Sent via AMSAT-BB(a)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: https://www.amsat.org/mailman/listinfo/amsat-bb > > > > > -- > Mark L. Hammond [N8MH] > > _______________________________________________ > Sent via AMSAT-BB(a)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: https://www.amsat.org/mailman/listinfo/amsat-bb > -- Mark L. Hammond [N8MH]

2 years, 2 months

RS-44 VU noise from TX

by Stephen DeVience

It's funny, I tried RS-44 for the first time yesterday and had the exact same problem. My SDR even picked up the harmonic when the coax connected to it was 50 ohm terminated, so my duplexer was not providing enough filtering. The solution will likely be a front-end filter attached directly to the device. -Stephen, N8URE

2 years, 2 months

HO-107

by Jeff

Is anyone getting any telemetry from HO-107 ? 73 Jeff kb2m Sent from my iPhone

2 years, 2 months

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AMSAT-BB May 2020