PICAXE is in Space

MFB

Senior Member
Thanks for the antenna link. Now all I have to do is wait for Baofeng to start making LNAs that cost significantly less than £150!
 

srnet

Senior Member
Baofeng to start making LNAs that cost significantly less than £150!
'Someone' ought to offer to do a review of the performance of the various kits available for LNAs, or indeed design and produce a custom kit for a low cost one.
 

MFB

Senior Member
I think I might know who you have in mind but he is probably still asleep in his part of the World.
 

manuka

Senior Member
Well I for one am still awake (just) down under, but you'd probably a certain Australian in mind. I agree that a Baofeng UV5R makes a fine engine for such a project, & it's versatility means it'll suit other uses too. I'd suggest something based around the Dorji/Hope smart modules be first looked at too.

My favourite roll your own UHF antenna these days are tape measure based - see => www.instructables.com/id/433-MHz-tape-measure-antenna-suits-UHF-transmitte/ Magnificent PC based software abounds of course.

Any LNA (Low Noise Amp) preferences? Although long familar with their benefits, LNA offerings are not a field I've recently followed, although I'd a heads up with a cheap Ramsey LNA kit a few years back.

Wee hours of morning update: This time! I stayed up for a favourable pass, & was delighted to hear a brief tone morse beacon of ~10wpm suprisingly clearly at ~12:58pm UTC. Some FSK was also apparent, as was a much higher pitched "growl" that ran on for longer. My DIY 6 element Yagi & Baofeng UV5R (set to 437.505MHz) were the workhorses. Quick Pythag. indicates the apparent pass was at best some 1200 km away.
Stan.
 

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srnet

Senior Member
Any LNA (Low Noise Amp) preferences?
It needs to have a minimum gain of 20dB, less than 1dB noise, be unconditionally stable, operate off small batteries, have good input overload protection and of course be very cheap.

I am not concerned if its a kit, because I am sure someone will build me one for the price of a virtual pint, I will offer to pay for the cost of the components however.

And my requirement is urgent, so can you PM me as soon as its ready.

Meanwhile, back to the real world.
 

srnet

Senior Member
Wee hours of morning update: This time! I stayed up for a favourable pass, & was delighted to hear a brief tone morse beacon of ~10wpm suprisingly clearly at ~12:58pm UTC.
Screen shot shows your tracking Unisat 5 ?

Did you update Orbitron with the 2013-066W TLEs ?

Unisat 5 is now about 5 minutes adrift of $50SAT.
 

srnet

Senior Member
We just had a reception report, the $50SAT data (FSK RTTY) was picked up at 2,600km, not all of the data packet, but the battery voltage and some other stuff was there OK.

Its the equipment that is notable, "a very simple setup – RTLSDR with a 70cm preamp and a homebrew 1/4 wave GP antenna"

To translate, the RTLSDR is one of those $10 DVB TV dongles, I dont know the specifics of the preamp, and the antenna is just about the simplest, cheapest one you can build.
 

Paix

Senior Member
@Stewart, You may wish to update/replace your
Latest orbital parameters (TLE) 031213.txt
and
$50SAT-Eagle2 5 Day Orbit Predictions 031213.txt
files on Dropbox as the latter is expired.

Code:
EAGLE 2
1 39436U 13066W   13345.17096100  .00014971  00000-0  17851-2 0   145
2 39436 097.8018 057.3713 0031269 146.9505 213.4091 14.84023653  2937
I take my info from space-track.org Norad catalogue object 39436 "DNEPR OBJECT W"
the EAGLE 2 title I have edited to better reflect what you may wish to see.
 

MFB

Senior Member
Another skinflint question. Would the type of TV 'masthead amplifiers' that are readily available for about £10 be suitable for this application? As they seem to have a useful performance at the frequency of interest.
 

srnet

Senior Member
$50SAT-Eagle2 5 Day Orbit Predictions 031213.txt
files on Dropbox as the latter is expired.
It has, and 5 days from 03121213 is the 8th, which is why another was added several days ago;

$50SAT-Eagle2 5 Day Orbit Predictions 081213.txt

Which expires is a couple of days time.

Sorry if that confuses people.
 

srnet

Senior Member
I take my info from space-track.org Norad catalogue object 39436 "DNEPR OBJECT W"
the EAGLE 2 title I have edited to better reflect what you may wish to see.
Fair enough, have you been able to verify by monitoring the change in Doppler shift that the TLEs you have just posted are correct ?

Ignore for a moment what NORAD want you to believe.
 

srnet

Senior Member
Another skinflint question. Would the type of TV 'masthead amplifiers' that are readily available for about £10 be suitable for this application? As they seem to have a useful performance at the frequency of interest.
No idea, maybe.

Why dont you try one and report back ..............
 

manuka

Senior Member
Paix/Stuart: Thanks for the tracking & TLE updates,which indeed relate closely to my reception last night. I'll check a few passes today with a simple setup. We really need to YouTube upload some typical signals to pre-alert listeners - I may try to do this in fact.

Great on the TV dongle report, but although fun these things are pretty deaf (especially near a computer!) unless significantly RF pre-amped! The price of a suitable LNA may hence make the total cost excessive. IMNSHO skinflints will be better advised to organise a decent antenna, which furthermore can probably be rustled up with items at hand. Numerous designs for this ~430MHz "70cm" ham band have long abounded. Stan. (ZL2APS)
 

Paix

Senior Member
Sorry, I didn't realise that there were more than one similar document there. I expected only one that was current and found what I thought I was looking for.

I have yet to hear the bird. My opportunities are limited by other things, but so far not a peep. I thought that I had heard it soon after launch, but that obviously wasn't the case.

What Norad want me to believe? Hmmmm sounds a little cynical! You mentioned that the best guess was OBJECT W, which became reported in the catalogue around seven days or so after launch. Seemingly Identified, but with no reliable information or TLE generated, probably due to size.

There were seventeen objects unreported in the catalogues at that early date, immediately before the launcher body entry. Today there is but one missing. Reasons for items missing can be due to size or 'National Security'. Celestrack get their information from the same place that I do, so I don't expect there to be any mystery about it all. I may have used Celestrack, but at the time I was becoming interested, a few years ago, Celestrack were cut off from the data. Temporary as it turned out to be, it was not obvious at that time if it would be a long term or permanent problem. I therefore subscribed with the source of the information rather than a downstream supplier.

The Norad catalogue number is the unique and unambiguous identifier for any given object. By unambiguous I mean 39436, rather than DNEPER OBJECT W, $50SAT, EAGLE 2, or EAGLE-2 (as Celestrak is likely to interpret the space as a hyphen).
 

srnet

Senior Member
Sorry, I didn't realise that there were more than one similar document there
There are currently two documents there clearly visible and yes they have similar names;

$50SAT-Eagle2 5 Day Orbit Predictions 031213.txt
$50SAT-Eagle2 5 Day Orbit Predictions 081213.txt

Although I guess in retrospect it could confuse.
 

srnet

Senior Member
What Norad want me to believe? Hmmmm sounds a little cynical! You mentioned that the best guess was OBJECT W, which became reported in the catalogue around seven days or so after launch. Seemingly Identified, but with no reliable information or TLE generated, probably due to size
Well exactly; "seemingly Identified, but with no reliable information".

There is a suspicion, suggested by people in the know, that NORAD cannot track the PocketQubes at all, due to the small size and the TLEs being put out are are based on extrapolation only.

Whilst we, or at least I, have been measuring the reality. If there is difference worthwhile posting, the parameters on the Dropbox will be updated.

Out of interest what was the difference, in seconds between the set of TLEs on the Dropbox and the apparent new set ?
 

Paix

Senior Member
All points taken on board Stewart. I can understand what you are saying about the tracking. The fact that it took the trackers around seven days or more to come up with figures for what appears to be around 16 very small birds supports what you are saying. Usually when enough people start independently coming up with the same conclusion there tends to be more than a grain of truth in it.

An close anology is like looking for a very weak carrier in among a lot of noise. If you look long enough at a display of the signal accumulating over time, the hits from the carrier will tend to trace a faint line.

I wouldn't say that they can't track it, but only with great difficulty. Good job you didn't give it a coat of stealth paint . . .

I didn't look at the differences in any timings in the TLE. I noticed only that the given TLE on Dropbox was for revolution 048, the new one I believe had an epoch around revolution 147 and the TLE was more than a week old. The fact that I haven't picked it up yet was good enough reason for me to ensure that I minimised any problems by ensuring that I was using the latest information available.

In the event, I got snatches of signal, but can't reliably attribute it to EAGLE 2 and the band, at least around the frequency of interest, appeared full of impulse noise, not akin to to car ignition noise, but looking out over the road to the commercial area indicated no vehicles likely to have their engines running.

I suspect that without a LNA, that I will need to employ an antenna with a bit of gain and poke it in the general direction. Station G0PAi is not doing very well on this one. :-( The communications budget must be all but spent by the time my antenna gets hold of it.
 

manuka

Senior Member
Brains Trust et.al: Before designing something for skinflints it may be worth pondering diverse issues & merits arising,since of course the $50sat works in the ~420-450 MHz "70cm" ham band. Although reception of signals is unrestricted,transmission (other than in the weak ISM slot at 433.920MHz) requires a licence & a keen awareness of numerous regulations & technicalities. Perhaps the most crucial of the latter is that satellite receivers are very sensitive & their unobstructed view of the earth below means some idiot can all too easily overload/lock up an overhead transponder.

Although not onerous for a typical PICAXEr, a ham exam must be passed for a licence issue. Once ham certified a flood of distracting high spec. "Ya-Ken-Com" (Yaesu-Kenwood-Icom) & Chinese hardware abounds (with older gear often very cheap),& a multitude of OSCAR (Orbital Satellites Carrying Amateur Radio) birds are available. I recall from the early 90s the powerful OSCAR-13 (in a Molniya orbit) gave "arm chair" & near Doppler free comms. Sadly it's close earth swings meant an early decay due to atmospheric drag.

Being ham licenced is usually VERY worthwhile for folks with electrons in their blood,as it speaks volumes about ones self propelled skills. However interest in the satellites may soon drift away as other ham activities (& the callings "culture") take over instead.

Pass update: Morse from the 12/12/2013 11:53am local time pass heard OK at 437.505 MHz on a Baofeng UV5R with just its rubber ducky antenna. Reception quality was much inferior to last nights 6 element Yagi beam detection however. For less than optimal passes this suggests an antenna with gain is highly recommended.

LNA consideration: I've just put in some browsing & text time, looking at both cost effective LNA pre amp circuitry & off the shelf offerings. All up the <US$20 (shipped) Ramsey Electronics PR40 kit offers simplicity & (presently) perhaps the best bang for buck. YMMV.

Stan. (ZL2APS since 1967)
 

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MFB

Senior Member
Thanks for the LNA tip and my best bet is to purchase the Ramsey kit from eBay. I'm being a bit lazy and also thinking of purchasing a ready made antenna, having been some what discouraged by the apparent complexity of making a Quadrifilar Helix Antenna (which look a bit like those interlinking metal puzzles that you get in Christmas crackers).
 

eclectic

Moderator
Thanks for the LNA tip and my best bet is to purchase the Ramsey kit from eBay. I'm being a bit lazy and also thinking of purchasing a ready made antenna, having been some what discouraged by the apparent complexity of making a Quadrifilar Helix Antenna (which look a bit like those interlinking metal puzzles that you get in Christmas crackers).
The "real" ones are works of metal-bashing art.

However, would one made from string / pipe and RG58 work?

Something like
http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=14606

The design is for 137 MHz, but online calculators
will provide measurements for 437 MHz

e
 
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eclectic

Moderator
See posts #41 and #160
Yes, I have seen them.
But others may not have.

Or, they may not be prepared to minutely scrutinise nineteen pages,
in the hope of possibly finding some information.

I see nothing wrong with providing information again.

Recapitulation and consolidation. :)

And, on a happier note, I finally heard the little blighter.

20.49, a quick burst of Morse.

Yaesu FT-7900, 437.505 FM,
Roof-mounted "white stick".

e
 

srnet

Senior Member
Revised orbit parameters, TLEs, are to be found at the Dropbox;

https://www.dropbox.com/sh/l3919wtfiywk2gf/-HxyXNsIr8

The measurements I have made suggest that $50SAT is maybe 10 seconds (equals 75km) ahead of the predicted orbit so its still not clear that the object 2013-066W that NORAD are tracking is $50SAT.

Can I ask that, in order to reduce confusion, if suggestions for Orbit parameters are posted in here as a result of NORAD updates, the timings are checked first. We are still in a position that NORAD may publish updates for 2013-066W, but its not actually $50SAT.
 

Paix

Senior Member
GGG026.png

Currently the position appears to be that we are listening for $50SAT and tracking catalogue #39436, object 2013066W. it is for the satellite operators, Stewart and other project members, to eventually determine if this object is indeed their bird or not.

For up to date TLE, readers can either check Dropbox or take the data direct from the horses mouth while it has currency and decide for themselves where any ten second timing issues might lie.

If I occasionally come across as being a bit negative, then I apologise. It is the very last thing on my mind.
This is a wonderful project which Stewart and his pals have put a lot of work into in order for it to happen and have shared it here because of the Picaxe content, which is pretty much the whole shop window when the project presence is via the radio signal from space.

We don't have to share the same opinions on everything however. I have sought to ask questions and cause spaces to be filled in in order to help flesh out the detail needed for more complete understanding by those that have not previously followed satellite tracking issues. Obviously, I have a long way to go. My theory is a bit better than my station which hasn't heard a peep, but it is currently set up for rag chewing and falls a long way short of being satellite ready.

That doesn't mean that I'm not following the project as best I can, given other commitments etc.
 
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lbenson

Senior Member
I for one have appreciated the theoretical fill-in. I have one of the Baofeng devices (and a license to transmit with it--KB3OHV), but zero experience, so am holding off until those with more experience have better luck in hearing $50SAT. Besides, I'm in the wrong part of the planet to get the data Stewart is looking for now. (And, Baby, it's cold outside.)

Congratulations, Stewart, on a most admirably done project.
 

manuka

Senior Member
A Baofeng UV5R with rubber ducky antenna will hear the beacon on a good pass. Just stand by a suitable window & open the squelch.
 

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Paix

Senior Member
I have put the TLE for Norad catalogues #39432 through 39446 (Object T through Z and AA through AG) into Orbitron and the nearest contender to DNEPR OBJECT W is Norad catalogue #39435 DNEPR OBJECT V. This is around four minutes ahead of 39432 and therefore from what you have said already, this seems a very unlikely candidate.

Your ball Stewart. What Norad objects do you still have as possible contenders please?

When you all give the appropriate object it's Satellite name, will it be EAGLE 2 or $50SAT? I notice that a number of the smaller objects have now been positively identified already and the last catalogue slot 39446 now has TLE and a name.
= = =
Nothing heard at the 22:40 pass this evening.
 
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Paix

Senior Member
GGG028.png
Simulation Wednesday 25 December 2013 11.40

Notice that with TLE from 30 Nov 2013066W and 11 Dec Eagle 2, same Norad object, that by lunchtime on Christmas day there is a significant separation, which is a good indication that TLE should be kept up to date. Seven days is a good figure to aim at. Notice also that cat 39435, Object V is slowly being overhauled, although the TLE for that bird was actually 13 Dec, so may have some bearing on it. I don't imagine that the B*Drag coefficient will generally decrease as time passes. I don't know how much effect it has, but the numbers appear to steadily increase over time.
 

srnet

Senior Member
I have put the TLE for Norad catalogues #39432 through 39446 (Object T through Z and AA through AG) into Orbitron and the nearest contender to DNEPR OBJECT W is Norad catalogue #39435 DNEPR OBJECT V. This is around four minutes ahead of 39432 and therefore from what you have said already, this seems a very unlikely candidate.

What Norad objects do you still have as possible contenders please?
The TLE for 2013-066W is accurate to within 5-10 seconds.

A 5-10 second error makes no difference to your ability to hear $50SAT, so stick with the TLEs I posted on the dropbox, there are no better ones.
 

Paix

Senior Member
Ok, a ten second error makes little difference, I will agree with you there, but you seem to be acknowledging that cat 39436 / 2013-066Wis the your object, but insist that last year's bus timetable is the one to use. I'm sure that you will see my difficulty, although I won't press the point any further. It's beginning to sound very e e e a little political.
 

lbenson

Senior Member
So yesterday, December 13th, I decided to look into Orbitron, having zero experience with looking at satellites (other than the ISS visually) and the same with ham-works, other than having gotten my license and the never-used Baofeng. I DLed the TLE from Stuart's dropbox, DLed and installed Orbitron, plugged in the TLE and my coordinates in Milton, Nova Scotia--65.1167 W, 43.7000 N.

Lo, a pass directly overhead, minimum distance 655km, at 10:09:55pm the following day. And just then, I got a PM from Paix, offering encouragement and guidance. So I went searching for the Baofeng. We had moved in the spring, and I didn't know where it was, though I had seen it. After 40 minutes of searching, I was ready to give up, but my wife suggested one more spot, and there it was.

And so, read the manual, push the buttons. I entered 437.507 (per Stuart's cold-adjusted finding). The Baofeng read back those numbers, but repeatedly reset to 437.500 (would that be a problem?).

Then at 10pm I went upstairs to a window facing south of south-south-east, and held down the monitor button for 11 minutes. Sorry to say I heard nothing but noise.

Did I do something wrong or is the gear not up to it, or the conditions unfavorable (it was overcast)?

2013-066W
1 39436U 13066W 13334.92116224 .00010453 00000-0 12579-2 0 48
2 39436 97.8016 47.3524 0031124 180.4630 179.6396 14.83741097 1417
 

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manuka

Senior Member
Gasp- "never used Baofeng"! Those things are such a near "all you ever want" handheld station that you can near shelve other VHF/UHF gear. Give it some exposure! On top of the UV5R's versatility & laughable cheapness, the set has a very sensitive UHF receiver. It's capable of detecting much the same super weak signals as many near order of magnitude more costly "Ya-Ken-Com" handhelds.

My own set,tuned to 437.505 MHz, readily-but briefly- hears the $50sat beacon, just via it's stock rubber ducky antenna. That "jump" to 437.500 indicates you have not set it to 5kHz spacing however! Do you understand the UV5R's menus? Are you using the esteemed Chirp (which needs the programming cable)?

Although it's showing a NZ passover within seconds of Orbitron's prediction,the $50sat is travelling at ~7km/sec so coverage is fleeting! VERY fleeting! Factor in Doppler shift & it's calling for sharp timing! Even with a 6 el. "cotanga" Yagi (pictured-coat hanger wire), & "point & shoot" hand held tracking, I've never got more that ~2 minutes total reception of it's beacon/traces of data. Hence double check your clocks & watches, & ensure that you're not foiled by daylight saving (as I initially was).

If you've ever watched for the huge ISS (International Space Station) then insights into the blistering LEO satellite passover speeds will be appreciated. They're akin to a high flying jet on steroids! Here's the TLE I used a few days back to good effect (it may since have been tweaked)-
Code:
EAGLE 2
1 39436U 13066W   13345.17096100  .00014971  00000-0  17851-2 0   145
2 39436 097.8018 057.3713 0031269 146.9505 213.4091 14.84023653  2937
Confirmation: A wee hours of the morning close pass detected OK with stock Baofeng - screen shot below.

Nostagia moment: Late 1950s Sputnik era riddle " Q. Why is a satellite like bottled milk? A. Because they're both "past-your-eyes" before you see them!
 

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lbenson

Senior Member
Not only "never used Baofeng", never used any ham equipment, so very much in newbie territory. Thanks for the suggestion about 5kHz spacing. I have the programming cable, but having done nothing with the device, I haven't used it either.

I think my timing was right--UTC minus 4. I monitored for 8 minutes, from before Orbitron's proposed first contact until well past peak. Would the .005 mismatch on frequency be likely to account for my having heard nothing?
 

crowland

Member
Also a total newbie but would the polarization of the Yagi receiving antenna matter? Will the satellite settle in one particular orientation or be tumbling?

Chris
 

Paix

Senior Member
@Crowland, it will be tumbling, so you may experience some very fast fading, which is probably the least of the problems. With a rubber duck, don't forget that it is at it's most sensitive broadside onto the antenna, so don't point it in the general direction like you would a yagi. For this reason, often a pass to one side or another might be advantagious.

@LBenson, what effect would tuning 437.500MHz make?
From what Stewart has said, the bird is likely to be radiating on 437.507MHz due the effects the cold whilst it is eclipsed (out of the sun).

The pass was within 20 degrees of the overhead at downtown Milton, Nova Scotia at 02:09:23 (all times UTC). The pass information is for a minimum satellite elevation of 45 degrees above the horizon, which gives a total pass time of 4mins and 24secs (A0S 02:08:11 and LOS 02:10:35)

Running an Orbitron simulation shows that the 437.507MHz will be seen at the Milton Groundstation (big it up &#8211; you are an Earth Station now!) after Doppler correction as 437.500419MHz at 02:10:33 moment before dropping below the arbitrary 45 degree elevation. So the effects of being tuned to 437.00MHz are that the signal will enter the useful part of your receiver passband late in the bird's overhead transition. in your NNE, well away from Southerly window.

As Stan has said, the FM tuning step can be changed on the Baofeng through the Chirp program and the receiver's programming cable. I know nothing about that though &#8211; some will say, thank goodness! I selected FM on my Icom IC7000 and the steps are 12.5kHz and I couldn't be bothered digging out the manual. I can fudge it by tuning to an odd frequency on USB and then changing mode to FM, but of course any touch on the tuning and I'm back to FM channelisation. I use USB and set watch at around 437.511MHz in the hope of picking up a signal on the inbound phase, with the intention of tracking it manually to read the Morse beackons. My listening to passes is very sporadic and I have not been luck yet. Alas, computers are downstairs and the radio is upstairs and not currently integrated or sensitive enough.
GGG031.png
 

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lbenson

Senior Member
Paix,

Thanks for your explanations. I was at 437.500 MHz, not 437.000, and I wouldn't have known to point a yagi at the target, so I was holding the Baofeng so that the antenna was broadside to the approach. Vertical, tho--perhaps I should have tilted it as it went overhead.
 

manuka

Senior Member
Thought: Could some kind PICAXEr "up top" please evaluate the US$9.95 Ramsey PR40 preamp kit.

I'd do so myself, & am happy to Paypal, but ridiculous shipping costs of ~$30 are being quoted down under. Alternatively- does anyone in Aust/NZ fancy joining a bulk order? I've pondered assorted LNA approaches,many based around the VHF/UHF 2SC2570 (a BJT). However this cheap Ramsey kit seems to offer the best bang for buck, especially since it comes with a PCB,making it hence hardly worth rolling ones own design.

Rev. Ed are considering educational promotion of the "PICAXE Sat.",& this kit (or-ahem- DIY clones) seems a worthwhile weak signal booster when used in conjunction with a decent antenna. It may also suit general 433 MHz RX application of course.

Ibenson: Typo ? I think you meant 437.505 MHz,which is the frequency at which I've heard the $50sat.
 

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Paix

Senior Member
So the effects of being tuned to 437.00MHz are . . .
Should have of course read 437.500MHz my typo Stan and Lance . . . sorry!

The point was that Lance's Baofeng's nearest frequency due to the stepping in use was 437.500MHz at the time.
= = =
The Ramsay kit here looks like just about $10 which is not a bad price, then they ask for £23+ postage, stick it all on the customs declaration and the Border Agency smile and charge £1.50 VAT, collected by the Royal Mail who add on their £8 handling charge. I think that we are agreed that the kit shows promise, but unless someone manages to get it on a slow boat from China, it's not going to happen any time soon I suspect.

Worth keeping a weather eye open for a similar device at an all up good price though.
 
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