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Author Topic: getting started in sat's. NEWBIE!!  (Read 668 times)
KG4LJF
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« on: November 20, 2005, 09:06:02 AM »

Hi all. I have a Yaesu VX5R on the way right now.. Can i do sat. work with this ht? What do I need? How do you do sat work? I have read abut the doppler shift to do a QSO, and this seems confusing. Would it be better to put a load of shifted freqs. into the memory, or just do the contact in VFO mode? Since this is repeater, I assume I'll have to enter them all into memory. Where can I find the freqs.? What else do I need to know?

Many thanks and 73.
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KA8SYX
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« Reply #1 on: November 20, 2005, 06:04:14 PM »

Hi, welcome to satellites!  Don't be too intimidated by stuff like Doppler shift and compensating for it; there's only a slightly steeper learning curve on successful satellite operating, but it's not insurmountable.

I don't own a VX-5R, but I do understand that it isn't a "dual-receive" HT,  in that it doesn't have a built-in diplexer.  The result is that while your HT has the ability to transmit on one band and receive on another (a crucial asset in operating via satellites,) you cannot do both at the same time (another crucial asset in operating via satellites, because of how important it is to be able to hear your own downlink coming back to you; without it, you will not know if you are even getting into the satellite or if you are causing QRM to users who're successfully accessing it.)  It cannot be stressed enough how important it is to be able to monitor your downlink as you transmit; it's key to knowing whether you are using too much uplink power or not, whether you're transmitting on the right frequency (or conversely, listening on the right frequency, hi) for the uplink/downlink conversion and doppler shift at the given point in the pass or not, whether you're QRMing anyone or not.

I think the ARRL's Satellite Handbook, edited by Martin Davidoff, is IMO, the best single source of information on how to get started.  In the meantime, you can certainly use your HT to listen to passes as they occur.  That will help you learn how a pass progresses, how the other ops communicate, etc.  You can use your HT for the FM repeater/easy-sats, but because it cannot receive in SSB/CW you will not be able to hear activity on the passes of linear transponder birds like FO-29 and VO-52.  Although they are visible during passes for amounts of time similar to the FM birds like AO-51, SO-51, and AO-27 (about 10-20 minutes but more like 15,) the style is quite a bit more relaxed since more than one op can get on at a time.  Myself, I much prefer the linear transponder birds on phone or CW for that reason.  Access for one guy doesn't come at the expense of denial of access for everyone else.  There's room for 20 different QSOs going on!

I presume you have a home computer since you've left your post here.  Get yourself some freeware satellite pass prediction software, which you can download and install on your computer generally for free.  Some authors ask for a small contribution, maybe to AMSAT or some other organization in satellites.  For the longest time, I used WinOrbit 3.6, because it could produce a list of pass times, indicating where the bird is in any time increments by azimuth and elevation and what the doppler offset is.  It helped a lot when I first starting making regular QSOs.  I now still use WinOrbit, but just as frequently use Satscape, written by Scott Hather, a UK satellite enthusiast.  It's really cool and more versatile and up to date than WinOrbit.

There are lots of good web references out there, too, to help you along.  There are a few good articles on satellites and operating in the ARRL online Technical Information Service (TIS,) too.

Just don't get discouraged; operating on satellites is challenging but really fun when you get the hang of it.  There are just as many facets of operating on satellites as there are in all of ham radio, and you'll find yours.  Good luck!

73, Ray KA8SYX
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K6LCS
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« Reply #2 on: December 17, 2005, 02:55:30 PM »

YES - You should be able to work AO-51 with your HT!!!

Some general comments for working AO-51...

The two primary modes of operations for AO-51 are FM analog voice and 9600-baud packet. AO-51's transmitters have a variable power output, and can operate as high as 8 Watts output on 70cm. Amateurs are successfully working the satellite with handheld radios.

In one mode, the UPLINK (to AO-51) frequency for voice is 145.920MHz with a 67.0Hz CTCSS tone. The DOWNLINK (from AO-51) frequency is 435.300MHz.

First, you need to know WHEN and WHERE the satellite will be passing over your location. There are several computer programs that will tell you. In the home office, I use Nova for Windows[1]. Outside, though, I use PocketSat[2] on my Garmin iQue 3600 PDA. Both programs are easily updated with current satellite tracking data that is available on the Internet.

Or, you can go to...

http://www.heavens-above.com -or- http://www.amsat.org

...and sign up. Using your longitude and latitude coordinates, you can access amateur satellite pass information (and a lot more!).

The one "absolute" for success is to open up your squelch. Working satellites starts off as a process of finding weak signals, so don't expect the satellite to be anywhere as strong enough to break squelch like your local repeater. I know it's noisy, but that's part of the process. Noise can also be an aid in locating the satellite because when the frequency starts to exhibit QUIETING, that's a sure sign that you are hearing the satellite, and you should get ready.

Use a good antenna for your handheld. A good gain whip antenna (like Pryme's AL-800[3]) will make the difference. Using an Arrow dual-band handheld antenna[4] is better, and if you prefer to homebrew your antenna, Alex Diaz XE1MEX[5] has an excellent Yagi-Uda design.

Set up your radio so you can to tune for the doppler effect. Start listening 5 KHz above the center frequency - you will hear the satellite sooner and clearer. When you hear the downlink signals get scratchy or fuzzy, tune down 1KHz at a time, and reception should be clearer. Follow the signal down in frequency as the pass continues.

Don't hold your whip antenna upright. Vertical antennas are not good, and a HT held upright isn't either. The satellite isn't on the ground (which is what HTs and vertical antennas were designed for). TILT IT about the same amount as the satellite's ELEVATION. This means that if you are FACING the satellite, tilt it down towards the ground from HORIZONTAL an equal amount. If the satellite is to your back, tilt it up an equal amount away from the satellites position off the vertical. You will be surprised at the difference.

Some hams use headphones - especially if working full duplex. If you have a full duplex HT (like an Icom IC-W32A) you can listen to your own downlink (a good thing). Your brain is far better at discriminating signals than most expensive DSPs.

Knowing your gridsquare - and having a gridsquare map - is a quick way of identifying locations of what you will be hearing. The ARRL and Icom have some dandy gridsquare maps, the latter of which are free at most amateur radio stores[6].

Remember the "three Ps" for working amateur satellites: preparation, planning, and patience. Not every pass is workable with an HT or listenable with a scanner - so don't go after the 10 degree passes. Pick your passes, and work the ones you know will give you the best chance.

When you hear others, try to find a break in the action, and announce your callsign, grid square, and op mode, like this:

"KILO-SIX-LIMA-CHARLIE-SIERRA, D-M - ONE-THREE, handheld."

Many hams record their sessions for later review. Even if you don't make contacts, it helps to accustom yourself to the callsigns, voices and personalities of the other operators. When I first started out, I found it more valuable to know which contacts I missed rather than the ones I made.

Ask questions! Find an elmer or look up the AMSAT[7] area coordinator for your area. Posting specific questions on the AMSAT bulletin board will also help you find answers.


Clint Bradford, K6LCS
909-241-7666 (cell)
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Clint Bradford, K6LCS
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N0MUD
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« Reply #3 on: January 11, 2006, 06:28:38 AM »

  The VX-5r won't work you need a dual band radio that does dual receive like the Kenwood THF-6a which will do 2 meters, 220 and 70 centimeters and five watts on all three bands.
  The HT is a dual receive, I know I have one.  It will also receive only on all HF bands which is fun because you can listen to other Hams and how they talk on the radio and hopefully can give you good procedures to use.  
  Anyways I know the VX-5r won't work because I had one once.  I sold it just as fast as I bought it.  You can't talk cross town on any of the three bands here in Colorado Springs.

  Now the Kenwood THF-6a is not a cheap HT so you might have to pull some of those hidden big bills you have hiding in your wallet so you can afford the HT.  But with everything that it does you won't go wrong.

73's and good Hammin on the bands.

N├śmud





























f-6a.  I have that HT and it works perfectly on the two freqs, ie: uplink/downlink.  I had a VX-5r once so thats how I know it won't work.  Now the Kenwood THF-6a is not a cheap rig it will cost you some bucks you have hidden in the back of your wallet but like I said it will do dual receive.  It does 2/220/440 meters and five watts on all three bands plus the HT will receive all HF freqs, but won't of course xmit on them.

Good luck, I am also new to SAT work but a friend and I are working together so we are both learning together so hopeflly you will have an Elmer that can help you get started.

73's and good luck and good Hammin,

N0mud
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K6LCS
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« Reply #4 on: January 11, 2006, 07:58:07 PM »

YES - You can absolutely use your VX-5R to work AO-51!!!

You do NOT need a "true dual-receive" HT (which the TH-F6a is NOT, by the way...you cannot hear yourself on B Band when transmitting on A Band, for example).

I have posted a couple times here a tutorial on how to work AO-51 with your dual-band HT. If you cannot find it, I will email it to you!

Clint Bradford
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Clint Bradford, K6LCS
http://www.work-sat.com
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