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Author Topic: The new satellites for 2013  (Read 10835 times)
AF5CC
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Posts: 820




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« on: June 13, 2013, 07:58:14 PM »

QST had a nice article on the new satellites that are supposed to be launched this year!  Sounds like there will be quite a few of them.  Are most of them going to be Mode B or Mode J?  Will they probably be fairly easy to work with a simple satellite setup-2m and 70cm horizontal yagis with no elevation?

73 John AF5CC
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N4UFO
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Posts: 181




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« Reply #1 on: June 14, 2013, 03:19:10 AM »

I didn't see that article, but from my own web research they will all be LEOs, so you shouldn't need anything different that what is needed for the current LEOs... But I would not use horizontal yagis. A tilt of about 30 degrees would be good. Otherwise, you might loose the birds when they are overhead. As for frequencies... the one already launched will be mode J, the rest will be mode B.

TURKSAT-3USAT
Uplink: 145.940 to 145.990 MHz
Downlink: 435.200 to 435.250 MHz
CW Beacon or 9600 bps data: 437.225 MHz

To be launched
Fox-1  FM: 435.180 up / 145.980 down
Funcube-1:  435 up / 145 down
UKube with FunCube-2:  435 up / 145 down
Delphi-N3xt:  435 up / 145 down

What issue was this article in? The only one I remember was the FD article and I think some of the info was stale. (Like telling people to adjust TX frequency working SO-50... experienced ops advise not to.)

73,

Kevin, N4UFO
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N4UFO
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Posts: 181




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« Reply #2 on: June 14, 2013, 10:12:17 AM »

Ah... I found what you were talking about in the latest QST. I would imagine a great many of those satellites spoke of are not carrying transponders... just sending telemetry data to ground stations for experiments. His point at the end of the article is one that has occurred to me many times. The amateur satellite service frequencies are being targeted for use by anyone wanting to send up a non-commercial satellite... whether their interest is amateur radio or not. This is akin to people that used to get a ham license and HT because they couldn't afford other services (such as mobile phone, GMRS, etc.) to keep in touch with family. They didn't care about ham radio at all. But on the flip side, these bright young minds with time and resources are likely to be the ones to build the next set of linear transponder and FM sats for hams to use. At least a couple of the ones I listed above are dual purpose ham transponder and satellite experiment birds.

As for me... I am investing even more in my home sat station and looking forward to working new birds.  Grin

73, Kevin
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AA9G
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Posts: 82




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« Reply #3 on: June 14, 2013, 10:12:38 AM »

Current issue. Just came in the mail yesterday.
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Ex KC9EEV.
AF5CC
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Posts: 820




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« Reply #4 on: June 14, 2013, 10:19:47 AM »

The article made it sound like they are all carrying transponders.  This was the article by Steve, WB8IMY, not the one on the cubesats.

Is TURKSAT-3USAT already on the air?

73 John AF5CC
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K7WDO
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Posts: 20




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« Reply #5 on: June 14, 2013, 10:54:32 AM »

TURKSAT-3USAT is in orbit, but the last I heard, the transponder is not active.

Also, Fox won't be going up until 2014.  FunCube 1 & 2 should be later this year, though.

73,

Scott/K7WDO
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N4UFO
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Posts: 181




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« Reply #6 on: June 15, 2013, 06:42:55 AM »

The article made it sound like they are all carrying transponders.  This was the article by Steve, WB8IMY, not the one on the cubesats.
DOH! Yeah, I just figured that out as I finally had time to start reading through the rest of the issue.

Quote
Current issue. Just came in the mail yesterday.
I get mine digital only and they hadn't sent the e-mail yet... had to find it on my own.  Tongue

But back to your question John, the Steve Ford article answers your question doesn't it? Or is the online version different? Mine lists all the bands and modes. Six with Mode B, one Mode J and one with a 2.4 Ghz downlink possible.  And I would still tilt my beams up 25-30 degrees.  Wink
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KC0MYW
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Posts: 5




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« Reply #7 on: July 23, 2013, 11:03:08 PM »

I'm pretty new to the whole sat thing, but why the change from UHF downlink and VHF uplink (like AO-27, SO-50, FO-29) to VHF downlink and UHF uplink (all the ones mentioned in this thread)....

For the most part I guess it is just a matter of knowing, however, I think it could be an issue as well, especially on the FM birds:

A newbie to the sats (such as myself) operating with a handheld Arrow antenna and a dual band HT (half duplex) -> the doppler is more pronounced on the UHF side and with SO-50 for example (because that is the experience I have) just by listening to the receive can determine what frequency to be on to account for it, can (and do) leave the TX (VHF) on the same frequency for the entire pass. With the switch to UHF uplink, doppler will be more significant on the TX side, but someone operating half duplex would be less able to account for it. They will be able to hear just fine for the entire pass without adjusting (because it is less significant on VHF) but be less readable to other operators and more likely to cause QRM.

Perhaps I am completely wrong and someone can explain it a bit more clearly to me, and/or speculate as to why they are going this route. I AM new to the sats.
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N8HM
Member

Posts: 81




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« Reply #8 on: July 24, 2013, 05:58:52 AM »

I'm pretty new to the whole sat thing, but why the change from UHF downlink and VHF uplink (like AO-27, SO-50, FO-29) to VHF downlink and UHF uplink (all the ones mentioned in this thread)....

For the most part I guess it is just a matter of knowing, however, I think it could be an issue as well, especially on the FM birds:

A newbie to the sats (such as myself) operating with a handheld Arrow antenna and a dual band HT (half duplex) -> the doppler is more pronounced on the UHF side and with SO-50 for example (because that is the experience I have) just by listening to the receive can determine what frequency to be on to account for it, can (and do) leave the TX (VHF) on the same frequency for the entire pass. With the switch to UHF uplink, doppler will be more significant on the TX side, but someone operating half duplex would be less able to account for it. They will be able to hear just fine for the entire pass without adjusting (because it is less significant on VHF) but be less readable to other operators and more likely to cause QRM.

Perhaps I am completely wrong and someone can explain it a bit more clearly to me, and/or speculate as to why they are going this route. I AM new to the sats.

The 2 meter satellite band, 145.800-146.000, is crowded with illegal traffic in many areas. Non-satellite traffic is often heard on the Mode V/U or J birds because of this, interfering with amateur traffic. That's why AO-51 and SO-50 have used PL tones, to prevent them from being triggered by non-satellite traffic, but the illegal traffic still interferes.

The second reason is that there's less path loss on 2 meters. Generally, users are using much more power than the satellites are, 5 watts or more instead of 250 mW - 1 W. With less path loss, it should be easier to hear the satellite, which will reduce the problem of people who can't hear the satellite transmitting and interfering. Path loss on the 70cm uplink isn't as important when most are running more than five times the power of the satellite.

The third reason is that desense can be a problem on Mode V/U (J). Transmissions on 145 MHz can blast your receiver on approximately the third harmonic, 435 MHz, and prevent you from hearing yourself on the downlink. I still haven't kicked that problem. I have no trouble hearing myself on Mode B, but Mode J is another story.

As for tuning for Doppler while running half duplex on the Mode U/V (B) FM satellites, it shouldn't be too bad. You'll have to get the feel for it, but it should involve tuning about 5 kHz roughly every 4 minutes during a 20 minute pass.
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KC0MYW
Member

Posts: 5




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« Reply #9 on: July 24, 2013, 07:52:03 AM »

I'm pretty new to the whole sat thing, but why the change from UHF downlink and VHF uplink (like AO-27, SO-50, FO-29) to VHF downlink and UHF uplink (all the ones mentioned in this thread)....

For the most part I guess it is just a matter of knowing, however, I think it could be an issue as well, especially on the FM birds:

A newbie to the sats (such as myself) operating with a handheld Arrow antenna and a dual band HT (half duplex) -> the doppler is more pronounced on the UHF side and with SO-50 for example (because that is the experience I have) just by listening to the receive can determine what frequency to be on to account for it, can (and do) leave the TX (VHF) on the same frequency for the entire pass. With the switch to UHF uplink, doppler will be more significant on the TX side, but someone operating half duplex would be less able to account for it. They will be able to hear just fine for the entire pass without adjusting (because it is less significant on VHF) but be less readable to other operators and more likely to cause QRM.

Perhaps I am completely wrong and someone can explain it a bit more clearly to me, and/or speculate as to why they are going this route. I AM new to the sats.

The 2 meter satellite band, 145.800-146.000, is crowded with illegal traffic in many areas. Non-satellite traffic is often heard on the Mode V/U or J birds because of this, interfering with amateur traffic. That's why AO-51 and SO-50 have used PL tones, to prevent them from being triggered by non-satellite traffic, but the illegal traffic still interferes.

The second reason is that there's less path loss on 2 meters. Generally, users are using much more power than the satellites are, 5 watts or more instead of 250 mW - 1 W. With less path loss, it should be easier to hear the satellite, which will reduce the problem of people who can't hear the satellite transmitting and interfering. Path loss on the 70cm uplink isn't as important when most are running more than five times the power of the satellite.

The third reason is that desense can be a problem on Mode V/U (J). Transmissions on 145 MHz can blast your receiver on approximately the third harmonic, 435 MHz, and prevent you from hearing yourself on the downlink. I still haven't kicked that problem. I have no trouble hearing myself on Mode B, but Mode J is another story.

As for tuning for Doppler while running half duplex on the Mode U/V (B) FM satellites, it shouldn't be too bad. You'll have to get the feel for it, but it should involve tuning about 5 kHz roughly every 4 minutes during a 20 minute pass.

Thanks for the explanation and information. Where I'm at there isn't an illegal traffic problem so hadn't considered that. I can definitely see some benefits regarding path loss, so like the idea for that reason.

I'm still a bit concerned about tuning for Doppler, especially with regards to 'knowing' when to tune. It's probably a 'get the feel for it' type thing like you mentioned, and I'm really thinking I should try full duplex anyway which will make it easier. Currently, in tuning the 5kHz steps on the downlink I often go back and forth between two frequencies a couple of times during the pass trying to decide which one is better until one is significantly better than the other, then leave it on that one until it starts fading pretty bad, then repeat the process with that and the next freq. I'm realizing that this "tuning by ear" method would not be possible on the new birds when running half duplex and trying to figure out a solution. Going full duplex is probably about the only answer.

Thanks again for the information. Whatever mode they use, it's exciting that there's going to be a few more sats in the air.
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N8HM
Member

Posts: 81




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« Reply #10 on: July 24, 2013, 09:41:34 AM »

Thanks for the explanation and information. Where I'm at there isn't an illegal traffic problem so hadn't considered that. I can definitely see some benefits regarding path loss, so like the idea for that reason.

I'm still a bit concerned about tuning for Doppler, especially with regards to 'knowing' when to tune. It's probably a 'get the feel for it' type thing like you mentioned, and I'm really thinking I should try full duplex anyway which will make it easier. Currently, in tuning the 5kHz steps on the downlink I often go back and forth between two frequencies a couple of times during the pass trying to decide which one is better until one is significantly better than the other, then leave it on that one until it starts fading pretty bad, then repeat the process with that and the next freq. I'm realizing that this "tuning by ear" method would not be possible on the new birds when running half duplex and trying to figure out a solution. Going full duplex is probably about the only answer.

Thanks again for the information. Whatever mode they use, it's exciting that there's going to be a few more sats in the air.

I think it will be able to be managed half duplex, but a Baofeng UV-3R+ is $29.99 on Amazon and that includes an earphone. All you'd need besides that for is an adapter for your antenna. With the proliferation of extremely cheap Chinese HTs, everyone should be able to manage full-duplex on the FM satellites.
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KQ6EA
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Posts: 609


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« Reply #11 on: July 25, 2013, 08:44:08 PM »

N8HM: Google "Mode J desense filter" and you'll find an article on using a duplexer as a filter.

Or you can buy a Mode J filter from PAR Electronics.

73, Jim
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