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Author Topic: OT could use some guidance  (Read 12317 times)

8P6SM

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OT could use some guidance
« on: July 04, 2012, 10:12:24 PM »

It's been a long time since I worked the birds, and my gear has been in mothballs for so long I don't know how much of it could be made operational again.  And due to my absence, I don't know what the state of the art/hobby is.  As my interest in amateur satellites starts to reawaken, I've been doing a lot of reading and googling, but I'm still not sure what equipment is in use these days. 

I'd appreciate a pointer to a page that gave an indication of what sort of stuff might be found in the shacks of the up-to-date satellite operator.  Software, radios, antennas, and all the rest.  So as I go through my old gear, piece by piece, and decide what has to be replaced, I have an idea what I should consider replacing it with.  I've searched AMSAT's site but can't seem to find anything that is useful.  (Their "Documents for New Satellite Users" doesn't contain much dated after 2004!)

So anyone want to point me to a suitable page?  Or simply post a list of the top few bits of kit in each relevant category?

Also, what is the premiere/popular choice of satellite(s) for the modern satellite operator?  AMSAT's "Sat Status" page lists 42 satellites, 5 of which are dead or of unknown status, 28 of which only have operational beacons/TLM of some sort (and I want to QSO because I am not a SWL), and of the 9 remaining birds, 4 are only semi-operational or in "weird" modes.  Leaving only 5 workable birds.  And all with circular orbits.   Can that be right?  Or are there some more satellites up there that AMSAT doesn't know about?  Or doesn't want me to know about?

Anyone feel like pointing me in the right direction, I'd really appreciate it!
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de Gus 8P6SM
The Easternmost Isle

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RE: OT could use some guidance
« Reply #1 on: July 05, 2012, 09:00:05 AM »

Try http://www.work-sat.com ...

Updated DAILY. Everything you need to work the FM sats with minimal equipment.

AO-27 and SO-50 are the current, easy-to-work FM voice birds.

Clint Bradford K6LCS
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Clint Bradford, K6LCS
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RE: OT could use some guidance
« Reply #2 on: July 05, 2012, 01:01:45 PM »

We currently have have 5 workable satellites for voice/CW QSO's, 6 if you include the International Space Station.
The FM satellites are AO-27, and SO-50, and the Space Station is also FM.
The linear (CW/SSB) satellites are AO-7, FO-29, and VO-52.
AO-7 alternates between Mode A (2 meter up, 10 meter down), and Mode U/V (70cm up, 2 meter down). Listen for the corresponding beacon to see what mode it's in. A beacon at 29.502MHz means it's in Mode A, and a 145.977 beacon means it's in Mode U/V.
FO-29 uses Mode V/U, with 2 meter up, and 70cm down.
VO-52 uses Mode U/V, with 70cm up, and 2 meter down.

73, Jim
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8P6SM

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RE: OT could use some guidance
« Reply #3 on: July 05, 2012, 09:58:49 PM »

Jim,  Thanks for the useful information.

I've started on the slow process of resurrecting my gear and deciding what needs to be replaced.

I have a pair of Cushcraft A270-10S beams which were my emergency/field antennas, and they look like they will be just fine.  Don't know about the CP phasing harness.  The coax looks fine, but it's old...  The circularity switchers on my Mirage/KLM 2M-22C and 435-40CX yagis will probably be shot, but maybe they can be refurbished.  I can't find any comparable yagis should the KLMs need to be replaced.  Any recommendations?

It's going to take a while to clean the cobwebs out of my beloved IC-970H and in any case, I doubt it will come back to life after all this time.  The replacement rig seems to be the IC-9100, and it will even work with my AG-25 and AG-35 preamps (assuming THEY will work).  My "Heavenly Twins" are, regretfully, both dead.

What will need to be replaced is my tracking hardware and software.  The Yaesu G-5400B will probably work, and if not the 5500 looks good.  But the KCT&T is a definite non-started, and I don't have an ISA/DOS box to put it in anyway.  I've got to identify a replacement that plays well with the rotors (whatever they may be) and GPredict (seeing as InstantTrack is -- like me -- a bit ancient now).

As for my old DSP-12 (by L.L. Grace).....

So, thanks again for the info on the workable birds.  When I get the Cushcraft antennas refurbished I'll probably hook up to my cheap, Chinese, dual-band HT and see if I can make a QSO or two on the FM satellites.  And we'll take it from there.  It would be nice to QSO with ISS crew, just for the fun of it!

Meantime, any comments/suggestions well appreciated.

Thanks, and 73!
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de Gus 8P6SM
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RE: OT could use some guidance
« Reply #4 on: July 07, 2012, 12:19:34 PM »

Ummmm....I don't know how worthwhile having switchable CP is these days. In the old "Phase III" days, with the satellites out at 35,000 km, it definitely helped, as did the huge antennas.

If you're working an FM bird with a hand-held antenna, the guys who do it all the time say that rotating the antenna in their hand can help, but since I rarely operate like that, I can't really comment.

For the current linear transponder birds, I just use an M2 2M7 2 meter 7-element antenna, and an M2 420-450-11 70cm 11-element antenna. These are linearly polarized, and while I occasionally get some fade on AO-7, the simplicity outweighs the "niceness" of having switchable polarization. I have them mounted at a 45* angle to my cross-boom, so they're at 90* to each other, which cuts down the cross coupling between them.

I've got a KLM 435-CX40 in the garage, but it's HUGE, and I don't have enough room to use it in my back yard. The times I've used it at Field Day show it to be an excellent antenna, but it's just too cumbersome here at home.

If you have the room, and the budget, M2 has 2 meter and 70cm CP antennas. They currently sell 2MCP14, 2MCP22, 436CP30 and 436CP42UG.
They don't use the folded dipole driven element like the KLM antennas do, but they're typical M2 quality.

There have been several threads on the AMSAT-BB about rebuilding the polarization switch boxes on the KLM antennas, and the only problem is getting an exact replacement relay. The original KLM design is not weatherproof, and the foil on the circuit board tends to disintegrate with time, and water gets in the relay. If yours is still in good condition, consider building some kind of protective housing for it.

The AG-25 and AG-35 preamps are old designs, and suffer from a high noise figure. Current preamps favored by satellite operators are SSB Electronic (what I use) and Advanced Receiver Research (ARR) models. The ARR preamps don't seem to be as weatherproof as the SSB ones, and there are several reviews here on eHam from guys that had them fill up with water.

Again, if you build an enclosure for them to keep them dry, or seal them up with RTV, they'll work very well.

For tracking, I really like SatPC32. It can control your rotors, and correct for Doppler, and ALL of the proceeds from the purchase of the program go to AMSAT.

I'm using SatPC32 with an "LVB Tracker" box a G-5400B, and a Yaesu FT-847, and it all integrated perfectly. Since my laptop has no serial ports, I use a Keyspan 4-port serial-to-USB converter. After some initial work on configuring everything, it's now "Plug-and-Play", and on Field Day weekend, I just take everything apart, load the trailer, and reassemble it at the Field Day site, and it works.

FB on the 970H. I have one I got from an estate sale, and I'm slowly rebuilding it. It's probably worth more for parts, as it has *every* option that ICom offered for it. It was owned by a heavy smoker, and was covered in a layer of brown tar when I bought it. I had to completely disassemble all the buttons and knobs from the front panel to clean them. One of these days I'll finish rebuilding it and align it, and see how well it works compared to a newer rig.

Can't help you with the digital satellites, as I've never had the equipment to work them, other than bouncing APRS packets through the Space Station.

73, Jim
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8P6SM

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RE: OT could use some guidance
« Reply #5 on: July 07, 2012, 06:16:46 PM »

I don't know how worthwhile having switchable CP is these days. In the old "Phase III" days, with the satellites out at 35,000 km, it definitely helped, as did the huge antennas.

Ah!  Oscar 13!  It brings a tear to my eye.  My first weekend on the air I missed the first half of the pass on Saturday, because I was building the beams from scratch.  Just as I went operational... the bird switched to Mode-S.  But when she switched back to B, I worked it right until it went over the hill.  And the Sunday, I worked AOS to LOS.  It was a total of 197 QSOs, all over Canada, the USA, SA, EU, and as far afield as A21 and as close as J39.  And the 970 was an absolute dream, even for a rank never-worked-a-bird, novice like me.

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If you're working an FM bird with a hand-held antenna, the guys who do it all the time say that rotating the antenna in their hand can help, but since I rarely operate like that, I can't really comment.

I gotta tell you that standing in the garden, waving around a broomstick-beam and hoping for a 20-second QSO with a nearby station?   Doesn't compare with leaning back in my chair, with my feet on the desk, a fortified coffee at my elbow, and ragchewing for hours into the night.  Or hearing the SA crowd working local simplex FM unaware that AO-13 was racing by at perigee, only 900 Km over their heads.  Oh, well.  Maybe those days will come again before I QRT once and for all.

But I will give the LEO FM birds a try.  The second A270-10S is now ready to be phased with the first for either +3dB or CP.   Alas, the wonderful IC-970H is dead.  And given where I am, getting it revived is prohibitively expensive, when I compare with the price of a new rig.  But to be honest, the footprints are so small that there is mostly only water for me to talk to.  Or SA, and I No hablo.

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For the current linear transponder birds, I just use an M2 2M7 2 meter 7-element antenna, and an M2 420-450-11 70cm 11-element antenna. These are linearly polarized, and while I occasionally get some fade on AO-7, the simplicity outweighs the "niceness" of having switchable polarization.

Well, the two Cushcraft mini-beams might work out for me then, until something gets launched that needs a 'real' antenna!  :-)

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I've got a KLM 435-CX40 in the garage, but it's HUGE...

But it shore works good!  I've even copied W5UN and other stations with those two KLM yagis, in CW and even some verrrry weak SSB, off the moon!  But of course, with ~50 watts output, they didn't hear me...

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If you have the room, and the budget, M2 has 2 meter and 70cm CP antennas. They currently sell 2MCP14, 2MCP22, 436CP30 and 436CP42UG. They don't use the folded dipole driven element like the KLM antennas do, but they're typical M2 quality.

No, I don't have the room, but that can be fixed.  No, I don't have the budget, but if you live on bread and water long enough, you find you can afford most things.  I've looked at the M2 antennas and they look good but the driven elements strike me as unnecessarily complicated.  But who knows?  Maybe the KLMs can be refurbished!   I'll check out the AMSAT-BB archives and see what I can find out about it. 

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The AG-25 and AG-35 preamps are old designs, and suffer from a high noise figure.

Agreed.  But they gave a useful boost to signals and they really played well with the old 970, which sequenced them without effort and even supplied power up the coax.

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For tracking, I really like SatPC32. It can control your rotors, and correct for Doppler, and ALL of the proceeds from the purchase of the program go to AMSAT.

For religious reasons, nothing manufactured in Redmond may enter my house.  So I have to look elsewhere for my tracking software.  :-)  But I need to get the G-5400B assessed before I make any plans in that direction anyhow. 

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Can't help you with the digital satellites, as I've never had the equipment to work them, other than bouncing APRS packets through the Space Station.

Well, it was the days of the launch of the Magnificent Seven and I had to try it out.  Pretty good fun, but all the effort was prior to AOS.  Once the system acquired the bird, you sat back with your hands in your lap and let the groundstation software do all the work.  I don't even know if there are any Store'n'Forward satellites flying!  But there are enough terrestrial digital modes, and if I get some hardware for that, I'll have to be sure it can handle digital satellites as well.

Long post!  Sorry about that.  (Ragchewer at heart!)  I'll try to restrain myself from now.  Once again, thanks for getting back to me.  So, for now...

73.



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de Gus 8P6SM
The Easternmost Isle

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RE: OT could use some guidance
« Reply #6 on: July 07, 2012, 06:48:04 PM »

No need to restrain yourself, Angus! We have a good conversation going here about the linear birds, and it might educate some of the people who don't know much about them.

I made *ONE* QSO on AO-10 before it went down for the count, and that was using the two antennas I'm still using. They were on an azimuth-only rotor, so I had to pick my passes carefully! The times I've used the big 70cm KLM, signals came booming in, and I'm sure my uplink was awesome, too.

Not sure how you'd go about phasing the two Cushcraft antennas if you wanted more gain out of them. Do they have separate feedlines?

The M2 driven elements are quite simple, actually. The network in the sealed box, the little coax balun, and the mechanical arrangement of the other fiddly bits make up the "T Match", and once it's set, it's set. I always put a generous glob of Penetrox on all the pieces to keep the salt air out here from corroding them. Works well, so far.

How "bad" are your KLM antennas? The ones I have/had (sold the 2 meter one unassembled, new-in-the-box) seem fairly robust. The only bad points I can see are how the coax attaches, and of course, the polarization switch box. The rest of them looks almost identical to the M2 antennas; elements mounted through the boom with plastic spacers, which *appear* to be the same size as the M2 ones. M2 sells replacements, so if any of your insulated "buttons" and keepers that hold the elements in place are bad, you can get new ones.

There are several websites that detail the complete rebuilding of the G-5400 rotors, so if it needs it, you'll have good guides with lots of pictures available. I somehow keep "collecting" these rotors, and at last count I had SEVEN complete G-5400's in the garage. Some were given to me, and some I bought for $50. I don't think I'll ever need to buy a new Az/El rotor in my lifetime!

Too bad about your 970. Want to sell me the carcass? :-)

I much prefer Linux myself (that's the PC I'm using right now), but I'm still working on getting GPredict to talk with my hardware. I tried GRIG, but it doesn't seem to keep the settings I enter, and requires too much manual intervention every time I start it, so I don't play with it anymore. One of these days, I'll devote an entire weekend to hammering out GPredict, and then I'll be Windoze Free, at least on Field Day. Unfortunately I still need a Windows PC to run my Flex 5000. The new series of Flex radios use a client/server model, with all the code *in* the radio, but I don't feel like shelling out $7k for one!

There's a several digital satellites up there, but since I don't operate them, I'm not sure what protocols they use. At one time I was going to do it, and had Pb/Pg setup, and "The Station" program running, but the more I looked into it, the more hardware I needed to buy, and at that time I couldn't afford it. This was when you needed some arcane modems, and my 1200 Baud KPC-3+ just didn't cut it.

73, Jim
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8P6SM

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RE: OT could use some guidance
« Reply #7 on: July 08, 2012, 07:43:03 AM »

No need to restrain yourself, Angus!

Restraint is never a bad thing!

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I made *ONE* QSO on AO-10 before it went down for the count, and that was using the two antennas I'm still using. They were on an azimuth-only rotor, so I had to pick my passes carefully!

I worked a guy in Alabama via AO-10, who only had an AZ-only rotator.  To tell truth, I don't have that many logged on AO-10.  The transponder worked fine, but with the IHU fried you could never predict what mode it would be in, and the squint angles were usually all over the place.

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Not sure how you'd go about phasing the two Cushcraft antennas if you wanted more gain out of them. Do they have separate feedlines?

They are two 5-el yagis, each with it's own SO239, mounted in the same plane but on opposite sides of a common boom.  To use two you just use a coax power divider to feed each antenna.  Feedline of 50 ohm coax any length into a tee, and from each side of the tee an odd number of 1/4-wave section of 75 ohm coax to each antenna.  Voila!  3dB gain!  Switch one side of the tee to 50 ohm coax and prefix with a 1/4-wave phasing line of 75 ohm coax and you have CP instead.

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The M2 driven elements are quite simple, actually. The network in the sealed box, the little coax balun, and the mechanical arrangement of the other fiddly bits make up the "T Match", and once it's set, it's set.

That's good to know, in case I decide to go that route.

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How "bad" are your KLM antennas?

Mechanically, pretty good.  I still need to inspect the insulators and see if they need replacing.  If they look at all crumbly, it might be a good idea to simply buy a set of spacers and push-nuts and replace them all, just for peace of mind.  (Lot of work, though...)  It's the switch-boxes which worry me.  I know they weren't in the best of shape, years ago when last I used them!

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There are several websites that detail the complete rebuilding of the G-5400 rotors, so if it needs it, you'll have good guides with lots of pictures available.

I have not got to the rotors yet.  I have to spend some time on my other hobbies.  (I am an R/C pilot.)  I have high hopes that they will be OK.  They've been stored indoors.  I just wish I could find a controller that worked off of DC. 

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Too bad about your 970. Want to sell me the carcass? :-)

Got any idea what it would cost to ship it from me to you?  :-)  I will try to make an attempt to see if it can be revived.  If not, I suppose it could be of some use for parts.  But I have to enjoy some months of bread and water before I can send it off to be assessed.

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I much prefer Linux myself (that's the PC I'm using right now), but I'm still working on getting GPredict to talk with my hardware. I tried GRIG, but it doesn't seem to keep the settings I enter, and requires too much manual intervention every time I start it, so I don't play with it anymore.

What hardware?  You mean the rotators?  That's one of my chores.  To find an interface with the 5400 to allow autonomous tracking.  Or do you mean the Rig Control of GPredict?  Again, one of my chores.  I have a CI-V box around here somewhere...  but my computer doesn't have a DB9/serial port.  Maybe one of my USB to serial cables can be used...

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Unfortunately I still need a Windows PC to run my Flex 5000.

Flex radios sure look good....  Pity about the software.  $7k?  That will translate to about $20k to me.  That's a lot of bread and water!

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This was when you needed some arcane modems, and my 1200 Baud KPC-3+ just didn't cut it.

Hence my DSP-12.  Brilliant piece of hardware in it's day.

Ok, Jim, I'd better get about the business of the day, so I'll sign off now.  Thanks again, and...

73
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de Gus 8P6SM
The Easternmost Isle
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