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That Miraculous Device: Onboard Radio
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Newt Offline
Flying Buttress
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Post: #21
RE: That Miraculous Device: Onboard Radio
Thank you very much for that, Kanojo. Trying to contact them now.

About heat management, that should mostly be for another thread, as its scope goes far beyond what the radio is doing, and it will probably take quite a bit of looking at all components once they have been mostly brought together. I do not know per say of any software that does this really well, but I am pretty sure that some versions of solidworks have a tool for this purpose, and I would lean to that because we already are working on solidworks models.
01-13-2015 09:58 AM
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HenryRasia Offline
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Post: #22
RE: That Miraculous Device: Onboard Radio
For reference, there was this guy back on the KSP forum that knew about radios: elfnet. No idea if he joined this forum yet.

Here's a quote:

elfnet;1561461 Wrote:Might I make a suggestion?
I work in communications and designs systems & antenna solutions to send and receive voice and data and remain efficient doing so
For radio traffic communications through the bird I can suggest you use a transmitter with some muscle. Not this 1 - 5 watt garbage the Hams throw up. I have a few 40 Watt UHF 12VDC transceivers that I can interface into a repeater unit and use very little power and nor weight all that much. I am not a fan of using ham radio frequencies simply because the hams in the states here consist of jackasses who know it all and think they own every radio frequency they can tune into. I on the other hand hold a few commercial radio licenses (16) and I have no issue letting this project use one of the frequencies.

The problem with using the ham radio VHF bands is the ham community will run the bird until the batteries do run flat and will no longer charge. Most of them do not know when to stop and since they didn't have to fund the project why would they care?

For batteries. it seems you would go with some type of Li-Ion or polymer battery if they can take the conditions of course. With Li-Ion from my own experience I am able to run a 10 watt beacon transmitter in UHF (470MHz) for 3 1/2 hours. Granted I had to series parallel them to get the amperage up but the whole package was pretty reasonable.

S band you looking at a pretty penny in cost as mentioned BUT you could use the Ku band where the TV birds operate. The receivers are very cheap and may need some modification of course but may be something to look into.
For imaging how about doing what NOAA does in their LEO birds, a similar WEFAX type system? You can use it in VHF like NOAA does in 137 MHz band though Its a slow image but reliable and can be received by a very cheap USB SDR dongle with proper software or a regular ole police scanner radio tuned to the frequency and fed in via soundcard input to decode the fly-by image

Also why not place it in geo-sync orbit..

EDIT: And my response, compilating discussion on radios, heat, and power (may be severely outdated):

henryrasia;1561572 Wrote:Hey elfnet! First of all, thanks for offering a frequency for us! We really appreciate it.

As for geosync orbit, that's a no-go I'm afraid. The whole cubesat needs to return to Earth within a reasonable timeframe, no space junk allowed. A geosync orbit would require thrusters to do that, which is a whole new level of complexity our team just could not make feasible at this point. I guess if we got $200k in the first week of kickstarter (or some ridiculous amount like that) we could see to expanding the whole operation for "proof of concept" mission objectives (like thrusters). Realistically, though, a first mission with the bar set low will break the status quo of cubesats not being a hobby, but yes a second-job-hobby. This will then bring confidence in our small enterprise to make bigger, better, longer missions later on (with the ultimate objective being a Phobos soft landing, woo!). Until we can ACTUALLY DO THIS first mission in real life, however, that is out of the question.

Similarly, a 40 Watt transmitter scares me because of the wattage. This is a very critical discussion we are currently not taking with the seriousness and accuracy of estimates it needs. Since you're into radio operating, here's some links that K^2 posted. He apparently knows a little bit about radios too.

Ground stations
Thermal control (short)
Batteries
Recharging time
Solar panel configurations
Especially this last one. The highest recharge rate is 10W, that's not even discounting other components' use...

We choose to go to the Moon and do the other things not because they are easy but because they are hard. -JFK
(This post was last modified: 01-15-2015 03:29 AM by HenryRasia.)
01-15-2015 03:10 AM
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MBobrik Offline
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Post: #23
RE: That Miraculous Device: Onboard Radio
Just found something interesting - a single chip GFSK transmitter, 300 - 930 MHz, up to 1.2 - 500 kbps, Just add power amplifier and our transmitter is completed. datasheet
01-18-2015 06:38 AM
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MBobrik Offline
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Post: #24
RE: That Miraculous Device: Onboard Radio
A single chip transceiver, all we need to add is LNA on the receiver side and a 3W power amp on the transmitter side.
(This post was last modified: 01-23-2015 05:55 PM by MBobrik.)
01-23-2015 05:55 PM
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MBobrik Offline
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Post: #25
RE: That Miraculous Device: Onboard Radio
LNA and power amp. we got transceiver, we got both LNA and power amp, all we need is someone to put it together.
01-24-2015 05:13 AM
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NERVAfan Offline
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Post: #26
RE: That Miraculous Device: Onboard Radio
Did we ever find out any more about the possibility of using Iridium for communications?
11-21-2015 03:08 PM
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cdugas4 Offline
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Post: #27
RE: That Miraculous Device: Onboard Radio
There was an article I read a year or more ago about a cubesat getting commands and sending data via a cellular style network. The team would just send a text or email with the commands and the satellite would open and process the commands. I've been looking for it but maybe I'm not using Google correctly for once. Anyone else have any idea what project that was?
12-04-2015 02:23 PM
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NERVAfan Offline
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Post: #28
RE: That Miraculous Device: Onboard Radio
(12-04-2015 02:23 PM)cdugas4 Wrote:  There was an article I read a year or more ago about a cubesat getting commands and sending data via a cellular style network. The team would just send a text or email with the commands and the satellite would open and process the commands. I've been looking for it but maybe I'm not using Google correctly for once. Anyone else have any idea what project that was?

Exploro found this and mentioned it in today's IRC chat:
http://orbitalhub.com/?p=686

This is about using Iridium, and it mentions a PicoPanther project from Florida International University. Could that be it?
01-18-2016 10:44 AM
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Exploro Offline
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Post: #29
RE: That Miraculous Device: Onboard Radio
You actually gave me an idea when you mentioned the Nanoracks on the ISS during the meeting. The thought occurred to me the ISS has 24/7 communications (video, audio, and telemetry) with ground controllers. "Could we use the comm system of the Space Station?" was my first thought. But then I looked into what the communications system employed by NASA on the ISS was I discovered that the system; the Tracking and Data Relay Satellite System, can be used for Cubesat applications.
(This post was last modified: 01-18-2016 11:15 AM by Exploro.)
01-18-2016 11:08 AM
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cdugas4 Offline
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Post: #30
RE: That Miraculous Device: Onboard Radio
(01-18-2016 11:08 AM)Exploro Wrote:  You actually gave me an idea when you mentioned the Nanoracks on the ISS during the meeting. The thought occurred to me the ISS has 24/7 communications (video, audio, and telemetry) with ground controllers. "Could we use the comm system of the Space Station?" was my first thought. But then I looked into what the communications system employed by NASA on the ISS was I discovered that the system; the Tracking and Data Relay Satellite System, can be used for Cubesat applications.

WHOA! I never knew TRDS was an available option!
01-18-2016 01:12 PM
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