FT4 Satellite Operations: My Setup + RS-44 Demo

[@barndweller4573]

That was interesting, I am new so I did not understand what is going on yet. I will watch it a few more times. Thank you for making the video.

[@stevenwilliams6258]

Wow, other than satellite and a few other words I had no idea what was really being said or what was going on! Will need to see other videos and an About page. Looks interesting!

[@RogerWilco486]

Neat video! I'm practically your neighbor since I'm also in FN20 over in the Boyertown area. I must say I'm shocked at how well those egg beaters are working, especially UHF. I'm new to sat ops and just got a pair of Wimo X-Quads with a G-5500 AZ/EL rotator, and unless RS-44 is practically overhead I'm barely able to copy SSB with 50ft of LMR400 between the antennas and transceiver. VHF downlink is no problem, for example ISS is S9+40. Last night was the first good pass where I actually saw some S-Meter deflection and could clearly hear the other stations. A UHF preamp is on the way but I'm beginning to wonder if it's caused by the fact that everything is temporarily setup on a 2" pole hammered into the back yard for testing, so the antennas are less than 6 feet from the ground. It'll be going up on the house once I've got everything tested and ready.

[@RobertResearchRadios]

I have like 100ft of LMR-400 with no pre-amp for this. RS-44 definitely seems to have good days and bad ones. The transponder power is probably varying based on it's battery charge state for that day. It may also be a good idea to have selectable polarization for your wimo x-quads. If you can get a setup a switched phasing harness to quickly jump between vertical/horizontal and RHCP/LHCP that would give you some additional flexibility during ops. The eggbeaters have served me well, but I think directional antennas and rotators are a better tool in a lot of cases if only to not be taking in environmental noise from other directions. There's a ham around here (FN20ish) i spoke to once who has radomed QFH antennas that weren't too expensive. Those have much better weather resistance than my setup. I've had to go up there and sand off corrosion on wire contacts for the UHF eggbeater antenna a couple of times now.

[@RogerWilco486]

I received my MiniKits UHF masthead pre-amp kit, and after assembling and installing it, it's made a HUGE improvement. With the gain adjusted to about +25db, I went from only being able to copy when the pass was directly overhead, to starting to copy at

[@RogerWilco486]

As an update, I've got my masthead preamp kit built and installed, and I also discovered my azimuth was off by almost 20 degrees. Since then, RS-44 comes booming in now, and even IO-117 (Greencube) squawks give me S9+ meter deflection. So the X-QUADs turned out to be an outstanding investment, I couldn't be happier with them. Can you work IO-117? I've only recently tried making QSOs over it since the news of it's planned decommission was announced a few days ago, but I've had tons of success with it so far. @@RobertResearchRadios

[@RobertResearchRadios]

I don't have a setup for IO-117. Looking to build a setup capable of that some day even if GREENCUBE does decommission before then, but mostly just running the satnogs station and then working linear birds with voice/CW out of a camera bag on my hip and using an arrow antenna lately. Got 6 or 7 QSOs in one pass as W0NT on FD in 2023 that way.

[@RobertResearchRadios]

Notes/Errata & Links: -NU1U's Tutorial Video: kzbin.info/www/bejne/h5nJhoaIirVsZ5I -WSJT-X SNR Number Explanation: tapr.org/pdf/DCC2018-KC5RUO-TheReal-FT8-JT65-JT9=SNR.pdf -AMSAT Status (Please Update when you Access a Bird): www.amsat.org/status/index.php -Apparently The Mod Mic Wireless goes Mr. Roboto a bit sometimes when recording, so that might be getting returned. Sorry for the echo there.

[@alzeNL]

Very interesting, I'm using HRD to control the 9700, i have satpc32 as well, but found HRD easier to use and aesthetically better. I'm just on M2 2m/70cm eggbeater with an amp on 70cm, but I will give this a try when RS-44 visible again.

[@stevendodd6477]

why use satpc and Gpredict? what does satpc give you over and above?

[@RobertResearchRadios]

SatPC32 is receiving direct development support for current Ham Radio birds, and the community keeps updated doppler files around that were ready for use with RS-44 on FT-4. I'm using SatPC32 to do doppler correction on my IC-9700 and G-Predict to do doppler correction on my SDR panadapter. I prefer the user interface from GPredict for getting an idea of what's going on inside and outside the amateur radio constellation, but GPredict is not receiving updates or support since 2018, so I'd rather use the maintained dedicated Ham Radio software to drive my radio. I don't know if I could drive multiple radios from G-Predict, but this division of labor between the computer programs leans into their strengths and away from their weaknesses. It's just my way of doing it I guess; one integrated solution would be great, and I look forward to what can replace G-Predict for hobbyist use with >5000 satellites of interest now in the catalog. It's starting to lose its edge as a tool for general situational awareness when trying to render 5000+ objects with >20 overhead at a given time... I'm not sure how G-Predict is going to handle running out of NORAD SATCAT ids, but it's already clear it can't handle that many birds.

[@stevendodd6477]

@@RobertResearchRadios thanks for your response. Does the AFC on the ic9700 not manage doppler for you?

[@RobertResearchRadios]

To my understanding, and I caveat this with that I've never needed/wanted to use the AFC, the AFC only works for FM signals and to track the carrier center freq for you during like ISS repeate passes where 6 or 20kHz doppler shift over the pass is less than the FM deviation of 25kHz. The frequency control required for FT4 is so much more precise than what the AFC is meant to do when just following an FM carrier freq as it is observed that with SSB modulation for FT4 (MFSK in the 3kHz AF) you really need a computer to do it with precise orbital elements from the interwebs and software to back out the doppler. Also, Hot take 🔥 but IMO the 9700's AFC and Autotune features are mostly a meme for satellite ops. They're more useful for saving you time in center tuning to a fixed transmission.

[@stevendodd6477]

@@RobertResearchRadios ta, I am thinking of buying an ic9700; I looked at the egg beaters and discounted them because of the low gain, I was looking at the Leo sat cross yagis, but discounted them because I didn't want to fork out an extra thousand pounds for a rotator that did elevation. At the moment I am thinking rotating horizontally polarised yagis fixed at 15 degrees and accepting the fades as and when they occur.. Do you have any advice?

[@stevendodd6477]

Will be my first radio and I would like to experiment with other comms not just exclusively satellite; I live next door to a two story building that I will struggle to clear which will block out half of the horizon below 15°

[@dougzemler]

you do not use preamps to your 9700?

[@RobertResearchRadios]

Not yet. Do you have any recommendations? I originally didn't have them so my 440MHz eggbeater could cover 400MHz but my interest in that band has waned significantly and the 9700 filters it out anyway, so now it's just a cost thing. Haven't needed them to do my ops yet, so I haven't bought them.

[@dougzemler]

@@RobertResearchRadios I do not have any recommendations. I am just getting into satellites and came upon your videos. I ran across some other videos that said that preamps were recommended. I watched your video and it seemed to work great without it! Appreciate your response!