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Re: [amsat-bb] Lower your power!!!
by Zach Metzinger 06 Mar '20

06 Mar '20

On 2020-03-06 15:23, Michael Walker via AMSAT-BB wrote: > Once you hear yourself start dialling down your power until you don’t hear yourself. > > then, increase it slightly. > > Make sure you were wearing headphones. This seems wrong. 1. Listen for the beacon, which is warbly, but audible. If you can't hear that, don't transmit. Listen for others on the bird, as that can also give you a sense of what you expect to hear. 2. Make sure you use the one true rule for Doppler correction (stationary frequency at satellite transponder input). Computer correction is probably the best bet here, as it can tune as you do other things. 3. Start at your rig's lowest power, and increase gradually until you can hear yourself. As others have said, if you exceed 5W into a yagi, there's probably something wrong with your setup. 4. Even a cheap SDR on the down-link, gives you ultimate situational awareness. You can see the beacon, other people's signals, and your own. You can then judge your relative power to the beacon. Also see: https://amsat-uk.org/beginners/how-to-work-ssb-satellites/ and N0AN just posted his recording (working XW-2D) a few days on this list. Here is his video URL: https://drive.google.com/open?id=1lKYvARp4SyHUraAX9u6HQRbmnCiamJAM Grain of salt: I haven't worked linear birds in more than two decades. However, time is freeing up now and I'm getting my own Az/El setup going. Perhaps we'll make a contact on AO-7 soon! --- Zach N0ZGO

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Center of the rotator
by Thomas Schaefer 06 Mar '20

06 Mar '20

Hello all. Please forgive the novice question but I am new to dealing with Az/El rotator systems for satellites (always been the Armstrong method). I am finishing up the planning for my rotators. On my bench, I have my Az rotator and my elevations rotator (separate units—both AlfaSpids). I am using a Green Heron RT21 AzEl controller. I have PSTRotator in between SatPC32 and the Green Heron since SatPC32 does not control the GH AzEl directly. When I was testing, I went though a pass and when the Azimuth direction was 0, the rotator spun all away around since 0 was the bottom. That is no doubt a configuration point but it brings me to my question. When I have used various rotor controllers for HF beams, 180 degrees is always the bottom which works for us in the northern Hemisphere. But with the current fleet of workable satellites, is there a direction that makes more sense to use at the “bottom” of the rotator? I can rotate the AlfaSpid more than 360 degrees allowing for the coax loop. Is that the generally preferred way for maximum flexibility if one’s rotor supports it? Put another way, if I pick 180 as the “bottom”, will I have as many passes that the rotator will have to turn all the way around to get from 179 degrees to 181 degrees as I would have to go from 359 degrees to 1 degree? I am also using the Az rotator for a 6m beam so the usual sweep of 180 to 180 in a continuous arc is desirable but I was curious if I should allow an extra 90 degrees (to 470) for flexibility. The Green Heron will take care of not going too far from where it is programmed even though the AlfaSpid does not have limit switches in the Az rotator (but does in the elevation rotator). I hope that makes sense. Thanks, Tom NY4I Tom Schaefer, NY4I Blog: www.ny4i.com Madeira Beach, FL (Grid: EL87ot)

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WD9EWK @ DM51/DM52 next Friday (13 March 2020)
by Patrick STODDARD (WD9EWK/VA7EWK) 06 Mar '20

06 Mar '20

Hi! I will head to the DM51/DM52 grid boundary in southeastern Arizona next Friday (13 March 2020), where I plan to spend a few hours working various satellite passes. I hope to be on the air from DM51/DM52 for the AO-92 pass just after 1700 UTC, but might be on earlier passes if traffic through Phoenix and Tucson - and the weather - cooperates. I will park at a spot I have visited many times over the years, west of US-191 and south of I-10, near the town of Sunsites in Arizona's Cochise County. During my time out at DM51/DM52, I will post updates on my @WD9EWK Twitter account. These updates are visible in a web browser without a Twitter account at: http://twitter.com/WD9EWK In addition, I will run APRS as WD9EWK-9 during that day. My travels should show up online at sites like: http://aprs.fi/WD9EWK-9 All QSOs will be uploaded to Logbook of the World. If anyone wishes to receive a QSL card confirming a QSO with WD9EWK at DM51/DM52, please e-mail me directly with the QSO details. No need to first send me a card or an SASE. If you're in the log, I will send a QSL card. This is not the only time I might be in this area over the next couple of months. I have two other trips between late March and early May which may allow me to visit other grid boundaries in southeastern Arizona or even southwestern New Mexico. Stay tuned... :-) 73! Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/ Twitter: @WD9EWK or http://twitter.com/WD9EWK

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Where best to purchase LMR-240UF in the US?
by Hans BX2ABT 06 Mar '20

06 Mar '20

As in title. Need some 200 feet. Mail order is fine, delivery in Houston. Will be hand delivered to me in Taiwan, because I can't get the stuff locally. Cheers --Hans

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Re: [amsat-bb] sequencer
by MICHAEL WILLIAMS 06 Mar '20

06 Mar '20

Check out W1GHZ's "A Simple, Yet Fool-Resistant Sequencer" at http://www.w1ghz.org/small_proj/Simple_yet_Fool-Resistant_Sequencer_Rev_B.p… GL, K9QHO

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ANS-065 AMSAT News Service Special Bulletin - AMSAT Academy to be Held Prior to Dayton Hamvention
by Paul Stoetzer 05 Mar '20

05 Mar '20

AMSAT NEWS SERVICE SPECIAL BULLETIN ANS-065 The AMSAT News Service bulletins are a free, weekly news and infor- mation service of AMSAT North America, The Radio Amateur Satellite Corporation. ANS publishes news related to Amateur Radio in Space including reports on the activities of a worldwide group of Amateur Radio operators who share an active interest in designing, building, launching and communicating through analog and digital Amateur Radio satellites. The news feed on http://www.amsat.org publishes news of Amateur Radio in Space as soon as our volunteers can post it. Please send any amateur satellite news or reports to: ans-editor at amsat.org. You can sign up for free e-mail delivery of the AMSAT News Service Bulletins via the ANS List; to join this list see: http://www.amsat.org/mailman/listinfo/ans In this edition: * AMSAT Academy to be Held Prior to Dayton Hamvention SB SAT @ AMSAT $ANS-065 ANS-065 AMSAT News Service Special Bulletin AMSAT News Service Bulletin 065.01 From AMSAT HQ KENSINGTON, MD. DATE March 5, 2020 To All RADIO AMATEURS BID: $ANS-065.01 Come join us the day before Hamvention, for AMSAT® Academy – a unique opportunity to learn all about amateur radio in space and working FM, linear transponder, and digital satellites currently in orbit. AMSAT® Academy will be held Thursday, May 14, 2020, from 9:00am to 5:00pm, at the Dayton Amateur Radio Association (DARA) Clubhouse, loc- ated at 6619 Bellefontaine Rd, Dayton, Ohio. The $85 registration fee includes: • Full day of instruction, designed for both beginners and advanced amateur radio satellite operators, and taught by some of the most accomplished AMSAT operators. • Digital copy of Getting Started with Amateur Satellites, 2020 Edi- tion ($15 value) • One-Year, AMSAT® Basic Membership ($44 value) • Pizza Buffet Lunch • Invitation to the Thursday night AMSAT® get together at Ticket Pub and Eatery in Fairborn. Registration closes May 8, 2020. No sign ups at the door. No refunds, no cancellations. Registrations may be purchased on the AMSAT store at https://www.amsat.org/product/2020-amsat-academy-registration/ [ANS thanks Robert Bankston, KE4AL, Vice President - User Services for the above information] /EX In addition to regular membership, AMSAT offers membership in the President's Club. Members of the President's Club, as sustaining donors to AMSAT Project Funds, will be eligible to receive addi- tional benefits. Application forms are available from the AMSAT Office. 73 and Remember to help Keep Amateur Radio in Space, This week's ANS Contributing Editor, Paul Stoetzer, N8HM n8hm at amsat dot org

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Re: [amsat-bb] XW-2D Returns to Life!
by Hasan al-Basri 05 Mar '20

05 Mar '20

Hi George, (and anyone else who is interested in an easy way to evaluate your satellite rx performance) These remarks are with respective to linear birds, not FM Some of the satellite ops I work with run various SDRs (software defined radios like the FunCube Pro+). The software we use with them is called SDR Console v3 (Google SDR Radio or look at this group: main(a)sdr-radio.groups.io) What we do so we can compare apples to apples is the following: The software is designed to be able to measure relative signal levels at high accuracy (-dBM) 1. Connect a 50 ohm resistor to the antenna or preamp input. 2. Set the rx for maximum sensitivity (RF Gain) 3. Adjust IF Gain so that the 50 Ohm resistor produces a signal level of -95 dBM 4. This creates a common noise floor level calibration point so that we can compare local noise (environmental) as well as satellite signal levels. 5. Now disconnect 50 ohm resistor and change to "real" satellite antenna. Observe the increase in noise floor. If there isn't one, you have poor rx sensitivity. If there is an increase and it is 6 dB or more, you have local noise problems (environmental). If there is a small increase in noise, you likely have relatively low noise, and at least it exceeds the internally generated noise of your radio/preamp combo. Now, when we observe signals from the satellites, we can directly compare peak signal strength in dBm between our satellite setups. This includes, antenna polarity, antenna gain, feedline losses, differences in uplink power, differences in receiver noise figure, and locally generated noise like power line, WiFi hash, etc. All...easily and accurately done by having software that works correctly and a simple SDR Dongle using Simon's (G3ELI) software (which is free). For example: If KB7IJ has a noise floor of -76 and I have a noise floor of -90 (dBm), and he has a peak BEACON signal strength of -53 and I have a peak strength of --60, we can see two things; (these are real and typical measurements, btw) 1. His ambient noise is 14 dB higher than mine. He lives south of Dallas, Tx, and has to shoot thru the city to see sats. Lots of environmental noise! I live in rural Iowa. Much quieter. 2. His rx system has 7 dB greater gain than mine (antennas). That makes sense as he has 2x7 EL yagis and I have a single 5 EL Yagi. So all else being equal (and it almost never is), he should always see the birds 7 dB louder than I do (actual signal level, not SNR) Now look at SNR (Signal to Noise Ratio):...a much different story. How well do we hear the birds? His SNR (best): -76 dBm noise floor - (-53) signal = 23 dB SNR (signal is 23 above noise, loud!) My SNR (best ): -90 dBm noise floor - (-60) signal = 30 dB SNR So when we are both getting a satellite at our best signal level, I am hearing the bird 7 dB better than he is, even though his rx antennas are much better. Look what happens when the ssb signal is much weaker: If I am seeing the SSB signal at an SNR of 10 dB (the lowest signal strength that an SSB signal can be understood at): He is seeing it at only 3 dB SNR which is unreadable. In general, I nearly always hear both him and myself way better than he does, because my noise floor is so much better than his. Keep in mind, these are all RELATIVE measurements not ABSOLUTE. They are not meant to be lab grade, they are meant to be able to understand and measure reasonably well, how a satellite station is performing in the real world. Common calibration between stations allows us to compare how our systems are working. It's not perfect, but it is useful. (There are other factors, like the practical limit of SNR from any bird based on passband noise). If you can consistently see/hear passband noise, you are good. If you only hear it now and then, your rx system needs work) p.s. The software from Simon, also allows us to make MP4 recording (video and audio) of our satellite qsos, which can demonstrate some of the very dramatic ways to improve or ruin your ability to use satellites efficiently. That is to say, receive properly and not overdrive the satellite with excessive uplink power, because you can't hear worth a darn and don't know it. (Just continue to increase transmit power so you can hear yourself, taking more than your share of what is available, because it is a shared resource). I have hours or recordings of assorted stations doing exactly this (running excessive uplink power and thus producing downlink signals 6 dB or more louder than the CW beacon) and therefore stealing the available downlink power of others, driving them down into the noise floor. It's embarrassing. *The rule is simple: you should NEVER be louder than the CW beacon, period.* 73, N0AN Hasan On Wed, Mar 4, 2020 at 7:48 PM George Sakai <grsakai5120(a)yahoo.com> wrote: > Thanks for the info Hasan. What do you use to measure signal levels in > dBm? > > George N3GS > > On Wednesday, March 4, 2020, 03:43:43 PM CST, Hasan al-Basri via AMSAT-BB < > amsat-bb(a)amsat.org> wrote: > > > K7VNE reported to me this morning that he had been on XW-2D (long since > non-operational) and sigs were very good, but no one else was on. > > Signals were of good quality, no FM'ing of my SSB signal. > > I just checked it and had a pass of Max EL 2 deg to my East. It is there, > it is loud. *The CW beacon is raspy*. > > The passband was normal level and my signal was typical: > > Max Sig: -64 dBm > Noise Floor: -81 dBM > > I made an mp4 recording of the pass, with me calling CQ and announcing > Elevation and signal levels. > > https://drive.google.com/open?id=1lKYvARp4SyHUraAX9u6HQRbmnCiamJAM > > Download this mp4 file and play it back on any device (even a phone) and > you will see and hear what I did. > > I have seen no announcement about not using the satellite, but will watch > for same. > 73, N0AN > Hasan > _______________________________________________ > 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 >

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APRSdroid
by Steve Kristoff 05 Mar '20

05 Mar '20

Those of you who said that APRSdroid works were right. I'm not the sharpest knife in the drawer, but I got it working without much fuss. I just confirmed on AISAT-1 that it works on my phone hooked up to my HT. So, I agree, don't believe all the bad reviews you see on the app Play Store. Steve AI9IN

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Wide or Narrow?
by Steve Kristoff 05 Mar '20

05 Mar '20

When aiming at the APRS satellites (ISS, AISat, any others?) should I use Wide or Narrow FM? I vaguely recall reading that narrow is good, but I can't find the reference. Your assistance is appreciated! Steve AI9IN

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Fwd: [Nouvel article] Rencontre Spatial Radioamateur 7 & 8 mars 2020 – Dernier jour pour vous inscrire !
by christophe.mcr 05 Mar '20

05 Mar '20

Nouvel article sur *AMSAT Francophone* <http://site.amsat-f.org/?author=2> Rencontre Spatial Radioamateur 7 & 8 mars 2020 – Dernier jour pour vous inscrire ! <http://site.amsat-f.org/2020/03/04/rencontre-spatial-radioamateur-7-8-mars-…> par Xtophe <http://site.amsat-f.org/?author=2> <http://site.amsat-f.org/wp-content/uploads/2020/02/RSRtitre.jpg> La cloture des inscriptions aux journées sera faite le *5 mars 2020 à 14h*. Elle nous permettra de mettre en place la logistique nécessaire notamment pour les Il ne reste que quelques places disponibles. La capacité du lieu ou se situe l'événement est limitée. *Pour réserver vos places, utilisez le lien ci dessous : * https://www.billetweb.fr/troisieme-rencontre-spatial-radioamateur *Xtophe <http://site.amsat-f.org/?author=2>* | 4 mars 2020 à 10 h 33 min | U

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