May 2020 - AMSAT-BB - mailman.amsat.org

FM vs Linear Transponders
by Ray Soifer 08 May '20

08 May '20

Being neither a grid-chaser nor a ragchewer, I hesitate to get involved in this debate, but my flak jacket is on so here goes. There is a fundamental difference between FM satellites and linear transponders: every LEO FM satellite that has been put up so far has only one channel, while linear transponders can accommodate several QSOs at the same time. Thus, for those of us operating from densely populated areas, using an FM satellite to talk with friends seems a misuse of available resources. It also creates an incentive to run excessive power in order to keep others from taking over the channel. A linear transponder is much better suited to that type of operation. Rapid-fire grid-chasing, state-chasing or DX chasing, on the other hand, can easily make 3 or 4 QSOs per minute, a more efficient use of a single-channel transponder. That's my input. Now I'll go back to CW. 73 Ray W2RS

3 3

Re: [amsat-bb] APRS Birds Summary Page
by Robert Bruninga 08 May '20

08 May '20

Here is the summary page for all APRS satellites: http://aprs.org/sats.html Though they say nothing about how to operate normal APRS. Assumed... Bob, WB4APR -----Original Message----- From: AMSAT-BB <amsat-bb-bounces(a)amsat.org> On Behalf Of Brad Smith via AMSAT-BB Sent: Friday, May 8, 2020 3:08 PM To: amsat-bb(a)amsat.org Subject: [amsat-bb] APRS Birds <Also, there is a lot of bandwidth on the APRS satellites (Falconsat-3,ARISS, NO-84) and the PSK birds (NO-84, NO-104) waiting for moreusers. Remember, with APRS you can do more than just send yourposition, you can send messages back and forth and have a decentconversation. So for those tired of the QRM on FM, consider givingthem a try.> I have mastered packet exchange through the ISS and would love to do packets on the APRS satellites. However, I have not found an article, etc,. that tells how to do it. I understand that it is not quite the same as the ISS/digipeaters contacts. If one can't find an "instruction sheet", how can one participate? I was hoping that this year's AMSAT satellite book would give a clue, but due to obvious circumstances, the book has not been published. Since I am the only one in my ham clubs who does any packets at all, help is not going to come from local hams. I am very thankful for the help from some hams around the US who elmered me, so far. Brad KC9UQR _______________________________________________ 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

1 0

APRS Birds
by Brad Smith 08 May '20

08 May '20

<Also, there is a lot of bandwidth on the APRS satellites (Falconsat-3,ARISS, NO-84) and the PSK birds (NO-84, NO-104) waiting for moreusers. Remember, with APRS you can do more than just send yourposition, you can send messages back and forth and have a decentconversation. So for those tired of the QRM on FM, consider givingthem a try.> I have mastered packet exchange through the ISS and would love to do packets on the APRS satellites. However, I have not found an article, etc,. that tells how to do it. I understand that it is not quite the same as the ISS/digipeaters contacts. If one can't find an "instruction sheet", how can one participate? I was hoping that this year's AMSAT satellite book would give a clue, but due to obvious circumstances, the book has not been published. Since I am the only one in my ham clubs who does any packets at all, help is not going to come from local hams. I am very thankful for the help from some hams around the US who elmered me, so far. Brad KC9UQR

4 3

FM vs Linear Transponders
by Stephen DeVience 08 May '20

08 May '20

I'm thinking about some kind of hardware/software combination kind of like this company's products: https://www.hobbypcb.com/ I have two of their HF and VHF/UHF radios. All frequency control is done via usb and an arduino nano, which I'm sure can be adapted to a phone app. There are a lot of plans for simple SSB transceivers that could probably be combined with that. I like SDRs too, but then you probably need at least a laptop to get enough computing power to do a good job. I'm glad you're thinking about this too. -Stephen, N8URE

4 4

APRS Birds
by Stephen DeVience 08 May '20

08 May '20

PSAT (NO-84) works exactly the same way as the ISS, and you can even use ARISS as the path. Unfortunately its digipeater has been off lately. NO-103 should also work the same way, whenever it eventually will be turned on. For those who can reach it, IO-86 works the same way, but the path is YBSAT. All are on 145.825 MHz. Falconsat-3 is V/U mode and 9600 baud. Some Falconsat-3 instructions are here: https://www.amsat.org/wordpress/wp-content/uploads/2018/03/FalconSAT-Stodda… https://andrewbnortham.com/ke8fzt/falconsat/ Aisat looks to have stopped working, as has the APRS portion of NO-104. One issue I notice when using my TH-D72 is that some people send packet messages that are not in the full APRS format, so they aren't decoded properly. This shouldn't be an issue when using software like Xastir or UISS. Also, the longer the message, the more likely it will pick up errors and not be digipeated or decoded. So shorter is better. -Stephen, N8URE

1 0

PacComm Spirit 2
by James Johnson 08 May '20

08 May '20

Would anyone have a copy of the manual for this TNC. I have lots of PacComm manuals but the Spirit II was designed for satelitte work. I know I'm playing with old technolgy but just like old tube gear its fun to get it working. James VE7HJ Victoria BC

1 0

Re: [amsat-bb] FM vs Linear Transponders
by Stephen DeVience 08 May '20

08 May '20

The ground station complexity for using the linear satellites is a real issue, especially for anyone trying to rove or use a handheld antenna. I've always found the suggestion to use two FT-817s strapped to your neck very awkward (and pricey). I'm starting to think of what would be needed for a handheld-size linear satellite transceiver. It would have to do SSB on UHF and VHF, and the Doppler correction could probably be handled by a phone app which would also provide visual tracking. I know it's a bit more complicated than FM, but at least you wouldn't need much power. Having separate U/V and V/U versions would be even easier. It could be a fun project. -Stephen, N8URE

4 5

FITSAT-1 5 GHz transmitter?
by Michelle Thompson 08 May '20

08 May '20

Greetings all! I have a few questions about the 5 GHz transmitter from FITSAT-1, based on the block diagram. Anyone here involved with that particular design? If you're interested - It's an excessively lengthy link to a PDF paper about the mission, but if you put "Development and operations of nano-satellite FITSAT-1 (NIWAKA)" into Google Scholar, then it shows up and is accessible. -Michelle W5NYV

1 0

Re: [amsat-bb] Just an observation
by Stephen DeVience 07 May '20

07 May '20

"More orbiting bandwidth means more people participating in any way they want to, be it grid-chasing, DX, or simply chatting casually with an old or new friend." Absolutely, and it's a testament to the interest in this part of the hobby that we are fighting over bandwidth, rather than complaining that there's no one answering our CQ. It's a good sign! Also, there is a lot of bandwidth on the APRS satellites (Falconsat-3, ARISS, NO-84) and the PSK birds (NO-84, NO-104) waiting for more users. Remember, with APRS you can do more than just send your position, you can send messages back and forth and have a decent conversation. So for those tired of the QRM on FM, consider giving them a try. Stephen, N8URE

1 0

Just an observation
by Steve Kristoff 07 May '20

07 May '20

FWIW- If you are going to admonish someone for poor behavior on an FM satellite, it is probably not the best idea to do it during the pass. Done that way, the admonishment becomes as bad as the original QRM. Steve AI9IN

2 2