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Author Topic: Other Sat Newbie Questions  (Read 339 times)

F4JAW

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Other Sat Newbie Questions
« on: August 15, 2022, 12:32:52 PM »

Hello fellow hams,

My only experience with satellites is limited to receiving SSTV images from the ISS using a Baofeng UV-B5 (https://www.miklor.com/UVB5/) recording the audio to a nearby iPhone and then decoding it on a PC.

I'm now thinking about trying ISS repeater QSOs (and maybe other satellites with FM repeaters).

I'm aware of some of the challenges involved like doppler effect frequency correction, varying polarisation, full duplex requirement to monitor transmission on real time and antenna gain. I'm also aware that besides FM repeater operations, there is SSB, packet, APRS and God-knows-what more.

At first, I tried to configure my Baofeng to do simple split operation but failed. The offset is limited to 99.999 mhz and the transmit priority only works on dual watch mode, which means that the radio gets stuck on the receive frequency and will completely ignore the transmit priority.

So, I think I need a new radio. Now, VHF/UHF radios go from 70eur (Yaesu FT-4XE) to 2000eur (ICOM IC-9700).
I personally find very difficult to understand which radios support full duplex operation and (given the comments I saw in the other newbie questions topic) among the ones that do, which ones can effectively isolate crossband interferences while transmiting in full duplex. Also, should I choose a radio with one or two antenna plugs?
Another thing is the "all mode" radios. Will I want to use SSB? Given the price of the all mode V/U radios I can only imagine that therer are very few operators using it. Is this the case?

Regarding antennas (maybe the most important part), I'm thinking something directional like a yagi-uda should be the way to go. But what about polarisation? Should I go with something with circular polarisation? Switchable RHCP/LHCP? Single or two independant coaxial connections?

My scenario of operation will most likely be portable as I live in an appartment. To begin with I'd like to try FM voice but also APRS/packet. I already use a portable computer (for logging and digital) when I operate portable on HF. Can I use the computer to do packet/APRS with U/V radios that don't have support for it builtin? If sat SSB is widely used, I might want to try that as well in the future.

Any help pointing me in the right direction regarding radios and antennas is highly appreciated!

73
Pedro F4JAW
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KU4UV

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Re: Other Sat Newbie Questions
« Reply #1 on: August 15, 2022, 12:51:50 PM »

I have made contacts through ISS repeater and SO-50 satellite using nothing more than my UV-5R and a homemade 1/4 wave ground plane 2 meter antenna in my attic.

73,
Michael KU4UV
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AC9O

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Re: Other Sat Newbie Questions
« Reply #2 on: August 15, 2022, 03:48:54 PM »

Hi Pedro,

Sounds like you got the bug. That happened to me a little over 2 years ago. I live in a HOA (restricted) area so I understand your predicament.

For FM sats, I would suggest the following setup, which worked well for me.

First, get an Arrow II hand held 2 band antenna. This is probably the most common one used as it has both 2m and 70c with separate feeds. If you get a duplex HT, it can come with a duplexer to make the connection easy.

I started with a Kenwood THD-72 which supports full duplex. It's a great radio and I had many contacts. One thing it doesn't have is a voice recorder. This can come in handy for recording passes and transcribing afterward. You can use your smart phone, but it may only record your side of the QSO, or hard wire a separate recorder to record both.

I ended up purchasing a second HT that I used for the downlink, and it had a built in recorder. Problem solved!

The cheap way would be to use 2 cheap HT's. This would be the most cost effective. A possible problem may be desense on the downlink if the cheap HT isn't very good.

Check out SAT ops on Twitter (look me up) and that will be a great resource for you to learn and experiment. Using a 5 watt HT should get you into most FM birds for most of the pass. Simple antennas may work ok sometimes, but once you get the "bug", you will find them inadequate.

Hope you get a good start.

73
Paul, AC9O
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KF4HR

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Re: Other Sat Newbie Questions
« Reply #3 on: August 15, 2022, 07:26:16 PM »

Hello Pedro - Reference your statement, "At first, I tried to configure my Baofeng to do simple split operation but failed. The offset is limited to 99.999 mhz..."

It sounds like you may be getting mixed up between standard "repeater offset or split" frequencies which are used to communicate through ground based FM Repeaters, and the VHF/UHF uplink/downlink split frequencies which required for satellite operation.  I don't own any BaoFang equipment but I scanned through the UV-5B manual.  From what I can tell it looks your HT should be fully capable of communicating through the ISS VHF/UHF FM Repeater and other FM satellites. 

Depending on which FM satellite you wish to work through, it should just be a matter of setting the uplink frequency on one of your displays (VHF or UHF), and your downlink on the other display (UHF or VHF).  You will use one band for the uplink and the other band for the downlink, and depending on which satellite you which to communicate through, your uplink might be VHF or UHF, and of course the opposite band will be your downlink frequency.  You can find the proper uplink and downlink frequencies here: https://www.amsat.org/status/

For example if you wish to work through the ISS Repeater, set 145.900mhz on your upper display (you will need to also set a PL tone of 67hz).  This is your uplink or transmit frequency.  Then on your lower display set it to 437.800mhz.  This is the ISS's downlink (and your receive) frequency.  After making these frequency settings you should be ready to go. 

Odds are you won't be able to work the birds with just your rubber duck HT antenna.  You will need some sort of small VHF/UHF antenna system, at least a small VHF/UHF hand held yagi system.  One example is the Arrow II handheld yagi's: https://www.amsat.org/product/arrow-ii-146437-10bp-handheld-yagi/

As for Doppler shift.  You shouldn't need to be concerned with Doppler shift for the FM ISS Repeater or any of the FM single channel satellites.  There of course is a Doppler Shift on the FM Satellites but the FM filtering is wide enough to handle Doppler Shift without you needing to adjust your frequencies. 

Note: Doppler shift does become important if you decide to linear transponder (SSB/CW) satellites.  You will need different equipment to work these satellites.  The BaoFang HF you mentioned does not have this capability.)

I hope you find this information helpful.  GL
« Last Edit: August 15, 2022, 07:46:11 PM by KF4HR »
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N7WE

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Re: Other Sat Newbie Questions
« Reply #4 on: August 16, 2022, 03:44:50 AM »

Pedro-
Check out Clint's - K6LCS - pages.  https://www.work-sat.com/index.html  Probably the best beginner instructions on Sat operations going.  GL
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N4UFO

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Re: Other Sat Newbie Questions
« Reply #5 on: August 16, 2022, 05:10:39 AM »


I personally find very difficult to understand which radios support full duplex operation and (given the comments I saw in the other newbie questions topic) among the ones that do, which ones can effectively isolate crossband interferences while transmiting in full duplex.

Another thing is the "all mode" radios. Will I want to use SSB? Given the price of the all mode V/U radios I can only imagine that therer are very few operators using it. Is this the case?

Regarding antennas (maybe the most important part), I'm thinking something directional like a yagi-uda should be the way to go. But what about polarisation? Should I go with something with circular polarisation? Switchable RHCP/LHCP? Single or two independant coaxial connections?

My scenario of operation will most likely be portable as I live in an appartment.


List of full duplex radios (click the tabs for HTs / Mobile / Base) https://www.dropbox.com/sh/v3byggtuqw33fkk/AAAamatWbd9657AQfXhM6-wPa/Articles/Full-duplex_radios_for_satellites.xlsx?dl=0

The "linear birds" have less operators, but in the US this is a GOOD thing. The FM birds are so crowded here, it is currently almost impossible to make a QSO on some passes. For linear birds, the most common portable setup (which I use) is a pair of FT-817 radios. Next to that, but more difficult to transport, would be the older IC-820/821 radios.

If you are portable, go with a handheld antenna. In the US, the by far most popular is the Arrow: https://www.arrowantennas.com/arrowii/146-437.html
Next to that is the Elk: https://elkantennas.com/product/dual-band-2m440l5-log-periodic-antenna/
Or you might try building one: http://www.wa5vjb.com/references/Cheap%20Antennas-LEOs.pdf
(I have a regular Arrow, an Alaskan Arrow (longer) and two Elks, one to hold by hand and one I have on a tripod.)

A hand held antenna allows you to rotate the antenna to match the polarity of the satellite in the moment. So, no need for circular polarity. (Circular polarity is sometimes used with home stations where the antenna is fixed and not able to rotate to match the satellite.) Most satellites use linear antennas now (whips) and the polarity changes as the satellites 'tumble' in orbit.  Watch this video for a demonstration of polarity and rotatng the antenna: https://www.youtube.com/watch?v=XTqjQ9xIQQE

As for number of antenna connections, it varies with radio(s) and antenna design. I chose to have single connections and use a duplexer to separate the bands, which adds the extra benefit of some filtering and helping to eliminate the crossband interference you mention. (as long as the interference is not inside the radio)

As for Doppler shift.  You shouldn't need to be concerned with Doppler shift for the FM ISS Repeater or any of the FM single channel satellites.  There of course is a Doppler Shift on the FM Satellites but the FM filtering is wide enough to handle Doppler Shift without you needing to adjust your frequencies.

I would have to disagree with this... doppler does not matter that much on the 2m uplink/downlink but DOES on the UHF side. On my full duplex HT, I will have about 5 frequencies in memory on the UHF side for each satellite and start off on the higher ones for downlink, lower one for uplink. You start off at one end as the satellite rises gradually, adjusting to the middle frequency when the bird is highest, and going to the other end as it goes back down to the horizon. It is MUCH easier to adjust with UHF downlinks as you listen to the signal get 'noisy/off frequency', you click to the next channel and it comes back in clear again. On UHF uplink, if the satellite is busy, you cannot be sure if you do not hear yourself because you are off frequency or because someone else is also trying to transmit. So for uplinks, just have to make an educated guess.

One thing to note, while Baofengs have been used to make satellite contacts, my personal experience is that they do not work very well. The nature of the 'radio on a chip' design makes them susceptible to interference, and missing the signal due to 'scanning', etc. I have an older IC-W32a... I am told the Yaesu FT-530 is a good HT as is the Kenwood TH-72a. BUT there may be some differences between US versions and EU versions that would affect things. (Like allowed transmit frequencies, etc.)

Some notes... you need to have an OPEN squelch. The signals are often so weak they will not break the squelch even on the lowest setting. I would recommend that you try out the FM birds first to get the 'hang' of things. The linear (SSB/CW) birds are a bit more to learn with regards to doppler, etc. and the radios are usually more expensive. (Antennas are the same though.) Besides it may take you a little while to figure out what will work best for you... there is no 'one way' to operate satellites in regards to which radio, antennas, etc. I always tell people to 'find what works for you'. I have some pictures of my portable gear on this webpage: https://www.qrz.com/db/N4UFO/P But I am experimenting with trying an antenna mounted to a tripod with a very adjustable swivel base (to allow for polarization adjustment). Most satellite ops detest tripods, but some have figured it out...  :D 8)  Again, find what works for you.

I have long ago taken down and sold my home satellite station that I had at a former QTH... once I completed the 488 CONUS grids for the Gridmaster Award. (Took just over 5 years.) After moving across the country, I don't quite see wanting to start over and do that again! Now, I would just like to work Hawaii so I can finally complete the WAS award. You will hopefully find it fun to talk to people, maybe chase grids, Pedro. When I was on the East Coast of the US, talking to ops in France and Europe was a lot of fun! Often I had to be awake in the middle of the night here to do it though.  :D Find what you enjoy!

Hope this info helps! 73, Kevin N4UFO
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F4JAW

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Re: Other Sat Newbie Questions
« Reply #6 on: August 18, 2022, 02:18:36 PM »

Thanks a lot for all the useful information.

I just ordered a Wouxun KG-UV9D Plus and I'm still deciding on the antenna. I'm leaning towards a dual band single feed point yagi. Still deciding if I'm going to build it or buy it.


I personally find very difficult to understand which radios support full duplex operation and (given the comments I saw in the other newbie questions topic) among the ones that do, which ones can effectively isolate crossband interferences while transmiting in full duplex.

Another thing is the "all mode" radios. Will I want to use SSB? Given the price of the all mode V/U radios I can only imagine that therer are very few operators using it. Is this the case?

Regarding antennas (maybe the most important part), I'm thinking something directional like a yagi-uda should be the way to go. But what about polarisation? Should I go with something with circular polarisation? Switchable RHCP/LHCP? Single or two independant coaxial connections?

My scenario of operation will most likely be portable as I live in an appartment.


List of full duplex radios (click the tabs for HTs / Mobile / Base) https://www.dropbox.com/sh/v3byggtuqw33fkk/AAAamatWbd9657AQfXhM6-wPa/Articles/Full-duplex_radios_for_satellites.xlsx?dl=0

The "linear birds" have less operators, but in the US this is a GOOD thing. The FM birds are so crowded here, it is currently almost impossible to make a QSO on some passes. For linear birds, the most common portable setup (which I use) is a pair of FT-817 radios. Next to that, but more difficult to transport, would be the older IC-820/821 radios.

If you are portable, go with a handheld antenna. In the US, the by far most popular is the Arrow: https://www.arrowantennas.com/arrowii/146-437.html
Next to that is the Elk: https://elkantennas.com/product/dual-band-2m440l5-log-periodic-antenna/
Or you might try building one: http://www.wa5vjb.com/references/Cheap%20Antennas-LEOs.pdf
(I have a regular Arrow, an Alaskan Arrow (longer) and two Elks, one to hold by hand and one I have on a tripod.)

A hand held antenna allows you to rotate the antenna to match the polarity of the satellite in the moment. So, no need for circular polarity. (Circular polarity is sometimes used with home stations where the antenna is fixed and not able to rotate to match the satellite.) Most satellites use linear antennas now (whips) and the polarity changes as the satellites 'tumble' in orbit.  Watch this video for a demonstration of polarity and rotatng the antenna: https://www.youtube.com/watch?v=XTqjQ9xIQQE

As for number of antenna connections, it varies with radio(s) and antenna design. I chose to have single connections and use a duplexer to separate the bands, which adds the extra benefit of some filtering and helping to eliminate the crossband interference you mention. (as long as the interference is not inside the radio)

As for Doppler shift.  You shouldn't need to be concerned with Doppler shift for the FM ISS Repeater or any of the FM single channel satellites.  There of course is a Doppler Shift on the FM Satellites but the FM filtering is wide enough to handle Doppler Shift without you needing to adjust your frequencies.

I would have to disagree with this... doppler does not matter that much on the 2m uplink/downlink but DOES on the UHF side. On my full duplex HT, I will have about 5 frequencies in memory on the UHF side for each satellite and start off on the higher ones for downlink, lower one for uplink. You start off at one end as the satellite rises gradually, adjusting to the middle frequency when the bird is highest, and going to the other end as it goes back down to the horizon. It is MUCH easier to adjust with UHF downlinks as you listen to the signal get 'noisy/off frequency', you click to the next channel and it comes back in clear again. On UHF uplink, if the satellite is busy, you cannot be sure if you do not hear yourself because you are off frequency or because someone else is also trying to transmit. So for uplinks, just have to make an educated guess.

One thing to note, while Baofengs have been used to make satellite contacts, my personal experience is that they do not work very well. The nature of the 'radio on a chip' design makes them susceptible to interference, and missing the signal due to 'scanning', etc. I have an older IC-W32a... I am told the Yaesu FT-530 is a good HT as is the Kenwood TH-72a. BUT there may be some differences between US versions and EU versions that would affect things. (Like allowed transmit frequencies, etc.)

Some notes... you need to have an OPEN squelch. The signals are often so weak they will not break the squelch even on the lowest setting. I would recommend that you try out the FM birds first to get the 'hang' of things. The linear (SSB/CW) birds are a bit more to learn with regards to doppler, etc. and the radios are usually more expensive. (Antennas are the same though.) Besides it may take you a little while to figure out what will work best for you... there is no 'one way' to operate satellites in regards to which radio, antennas, etc. I always tell people to 'find what works for you'. I have some pictures of my portable gear on this webpage: https://www.qrz.com/db/N4UFO/P But I am experimenting with trying an antenna mounted to a tripod with a very adjustable swivel base (to allow for polarization adjustment). Most satellite ops detest tripods, but some have figured it out...  :D 8)  Again, find what works for you.

I have long ago taken down and sold my home satellite station that I had at a former QTH... once I completed the 488 CONUS grids for the Gridmaster Award. (Took just over 5 years.) After moving across the country, I don't quite see wanting to start over and do that again! Now, I would just like to work Hawaii so I can finally complete the WAS award. You will hopefully find it fun to talk to people, maybe chase grids, Pedro. When I was on the East Coast of the US, talking to ops in France and Europe was a lot of fun! Often I had to be awake in the middle of the night here to do it though.  :D Find what you enjoy!

Hope this info helps! 73, Kevin N4UFO
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F4JAW

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Re: Other Sat Newbie Questions
« Reply #7 on: August 18, 2022, 02:25:01 PM »

In this radio, as far as I can understand, the dual frequency display only serves for the "dual watch" function. I couldn't find a way for it to operate in simple split mode. I found others on Youtube configuring Baofengs (not this one) using the offset to do crossband/split operation but those radios accepted a 3 digit offset frequency allowing to effectively have 2 frequencies a band appart.

Hello Pedro - Reference your statement, "At first, I tried to configure my Baofeng to do simple split operation but failed. The offset is limited to 99.999 mhz..."

It sounds like you may be getting mixed up between standard "repeater offset or split" frequencies which are used to communicate through ground based FM Repeaters, and the VHF/UHF uplink/downlink split frequencies which required for satellite operation.  I don't own any BaoFang equipment but I scanned through the UV-5B manual.  From what I can tell it looks your HT should be fully capable of communicating through the ISS VHF/UHF FM Repeater and other FM satellites. 

Depending on which FM satellite you wish to work through, it should just be a matter of setting the uplink frequency on one of your displays (VHF or UHF), and your downlink on the other display (UHF or VHF).  You will use one band for the uplink and the other band for the downlink, and depending on which satellite you which to communicate through, your uplink might be VHF or UHF, and of course the opposite band will be your downlink frequency.  You can find the proper uplink and downlink frequencies here: https://www.amsat.org/status/

For example if you wish to work through the ISS Repeater, set 145.900mhz on your upper display (you will need to also set a PL tone of 67hz).  This is your uplink or transmit frequency.  Then on your lower display set it to 437.800mhz.  This is the ISS's downlink (and your receive) frequency.  After making these frequency settings you should be ready to go. 

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F4JAW

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Re: Other Sat Newbie Questions
« Reply #8 on: August 18, 2022, 02:26:28 PM »

Pedro-
Check out Clint's - K6LCS - pages.  https://www.work-sat.com/index.html  Probably the best beginner instructions on Sat operations going.  GL

Thanks!
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