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EME / Moonbounce for a beginner?

Discussion in 'Satellite and Space Communications' started by G1VVP, Mar 29, 2010.

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  1. G1VVP

    G1VVP Ham Member QRZ Page

    Just wondering if there is any point in a little station like mine attempting moonbounce on 2m.

    After reading this month's RADCOM I discovered that even a relatively simple station setup could, potentially (wth the wind behind them ;0) achieve 2m EME. It inspired me to give it a go.

    I would need to build a decent 2m beam of at least a dozen elements. OK, that's one thing. My max power at 2m is currently 50W. It might just about enough but I accept I would need to work at it. There is no way I am ever going to have a large tower with a dozen multi-element beams for this.

    Your thoughts appreciated. Maybe somebedy here has achieved some half-decent 2m EME results with a basic setup.

    Cheers all.

    John
    G1VVP
     
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    With a single yagi and relatively low power you might be successful using WSJT (probably JT65) which of course requires an SSB rig, a computer and a computer interface. Success using any other mode is very unlikely.

    I'd ask for help from a local successful moonbouncer or two to go see how they do it and learn what it's like.
     
  3. WA9SVD

    WA9SVD Ham Member QRZ Page

    Concentrate on your receiving end first, and that INCLUDES the antenna and low-loss feedline.
    Remember, if you can't HEAR them (or detect them with computer software, such as WSJT as Steve mentions) there's no point in spending more $, Pounds, or Euros on the transmitting end.
    Take your time, no matter how good a set-up. EME isn't going to happen overnight or in a weekend.

    Good luck.
     
  4. N4KZ

    N4KZ XML Subscriber QRZ Page

    Use of the WSJT digital modes have revolutionized VHF moonbounce because of the modes' abilities to dig very weak signals out of the noise and decode the information contained -- call signs, signal report, confirmation, etc. Over the last few years, increasingly smaller and smaller stations have been successful at 2 meter EME, thanks to WSJT. (Google it.) I've read where stations using beams as small as 4 elements have made successful EME QSOs. I wouldn't recommend using an antenna that small unless it was absolutely necessary but it does illustrate just how modestly one can go with his station. But as WB2WIK said, you will absolutely need a 2 meter SSB rig. And a computer with an interface and the WSJT software, which you can download for free. And chances are you will also need a very good receiving preamp. And running as much power out as you can will help tremendously too. There's a lot of info on the Internet about this. Google WSJT and moonbounce and start reading. It's really quite fascinating.

    73, N4KZ
     
  5. KC8VWM

    KC8VWM Ham Member QRZ Page

    With 50 watts and a single Yagi you *could* work some of the EME superstations like W5UN or KB8RQ and others.

    Output power is certainly one variable in this equation but even more important are the design considerations of the actual antenna used regardless of output power used.

    So using a "single Yagi" isn't the main issue. Nor are the "number" of antenna elements attached to the Yagi itself for that matter. The most important factor for an EME station using a single Yagi is the physical length representing how long the boom is constructed, how quiet the antenna is designed, raw gain, antenna pattern characteristics and any losses associated with the design.

    Feedlines need to be short as practical and represent the lowest loss possible. There's no point in designing and constructing a 15 dBd Yagi only to loose any acquired gain in the feed lines etc.

    EME is not a compromise antenna design situation. You must take measures to reduce losses to a minimum. Avoid using a myriad of patch cords and connectors in the shack. Antenna switches and external meters are taken out of the antenna connection equation etc. In fact, if there was a way to connect the rig directly to the antenna itself, that would be better than using feedline. Not very practical.. but it would be better :)

    Some favorite EME antenna designs are included on this comparison list. These antenna choices represent the current "players" in EME antenna design.

    Spinning the VFO at random to find EME stations is not likely to achieve many positive results. Success depends on where the stations are located on the dial and knowing exactly when these stations are supposed to be transmitting. N0UK is a live EME chatroom on the internet where you can find out what frequencies stations are transmitting on in real time. That alone can make a huge difference in terms of your success and making a contact with another EME station.

    If you are intending to operate a single Yagi station, make sure you put up the largest Yagi you can and learn how EME works. Learning all there is to know about operating EME certainly cannot all be covered in a single reply on this message forum. You need to read, read and read some more to learn about it.

    Here's a copy of the 2010 EME handbook to help get you started.
     
    Last edited: Mar 29, 2010
  6. EI2GLB

    EI2GLB Guest

    I completed with W5UN and a few others using a 11el tonna yagi at 20m agl and 160w using one of the WSJT modes. it was on my moonrise as i have no elevation rotator.


    get some of the eme programs and see when there is low degradation (sp) and arrang a sked thats what i did,

    I have also done EME on 6m with 100w and a 6 el yagi. EME was allways something I wanted to try as I feel its the holy grail of amateur radio it was for me for me anyway.

    you really need to ge up to speed using WSJT as the signals will be very small and you might have to fish them out of the noise.

    here is W7GJ being recieved on 6m

    [​IMG]
     
  7. EI2GLB

    EI2GLB Guest

    sorry about the typo's I need to learn to type
     
  8. G1VVP

    G1VVP Ham Member QRZ Page

    This is all really interesting. Thank you very much for the useful information. I feel I have learnt a lot already!

    My inspiration for EME came after reading the VHF/UHF section in the April 2010 edition of RADCOM where there is a mention of the EME QSO between G0KSC and RA6AX using relatively simple equipment and not fantastically high power. It also inspires me when I think of the potential for working countries which otherwise would not be possible on 2m, at least via traditional voice/phone modes.

    I appreciate the necessity for me to attempt to work the bigger guns first. Timing does indeed seem critical in more ways than one. I was unaware of the EME chat room too.

    As for WSJT, this is something else I have been considering for a while.

    Lots to think about here. This will be a project for the very near future.

    Many thanks once again.

    John
    G1VVP
     
  9. WA9SVD

    WA9SVD Ham Member QRZ Page

    Also consider that modes such as WSJT are the ONLY way you will have a chance to achieve an EME contact with a "modest" antenna system and medium transmit power. You will NOT be able to have a voice contact, not even SSB; even CW with those restraints is questionable. but the computer enhanced modes can result in some success, but much of the "work" and effort will be achieved by the other end of the contact.
    Nonetheless, GOOD LUCK, and keep us informed as to your progress!

    ADDED:

    I meant keep us informed of your progress and ultimate success!
     
  10. KF5FEI

    KF5FEI Ham Member QRZ Page

    All this fancy stuff is new to me too, but it seems more logical (and less expensive) to cut your teeth on some satellite work first. From the limited research I've done so far, some of the satellites can be worked with a dual-band HT and a hand-held yagi. It and getting on the HF bands are on my short list.
     
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