EME / Moonbounce for a beginner?

[G1VVP]

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

[WB2WIK]

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.

[WA9SVD]

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.

[N4KZ]

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

[KC8VWM]

With 50 watts and a single Yagi you *could* work some of the EME superstations like W5UN (http://www.w5un.net/EME%20Array.JPG) or KB8RQ (http://www.spasalon.com/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. (http://www.vhfdx.net/VE7BQH.html) 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 (http://www.chris.org/cgi-bin/jt65emeA)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 (http://physics.princeton.edu/pulsar/K1JT/EME_2010_Hbk.pdf) to help get you started.

[EI2GLB]

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

http://i154.photobucket.com/albums/s261/fatboymotorsport/firstEMErx.jpg

[EI2GLB]

sorry about the typo's I need to learn to type

[G1VVP]

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

[WA9SVD]

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

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!

[KF5FEI]

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.

[KC8VWM]

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.

Unlike the sats and working on HF, EME is especially technically challenging and yes it can even lead to much frustration. Some stations don't make a contact even after a year of trying.

The rewards are many if you manage to experience success but it doesn't come easy. EME is not for someone who wants to simply flip a switch and expect to start making contacts.

My Best,

Station KC8VWM Mooncam view - 03/28/10 02:15 GMT

Azimuth 120 degrees - Elevation 31 degrees


http://i629.photobucket.com/albums/uu18/kc8vwm/MVC-003F-8.jpg

[WB2WIK]

Unlike the sats and working on HF, EME is especially technically challenging and yes it can even lead to much frustration. Some stations don't make a contact even after a year of trying.

The rewards are many if you manage to experience success but it doesn't come easy. EME is not for someone who wants to simply flip a switch and expect to start making contacts.

Yes, that's sure true. My first EME work was on 70cm back in the late 1970s. With 1kW output power to four stacked 19 element K2RIW optimized yagis fed with 7/8" hard line I could not hear my own reflections. Thankfully, some others could and after about a month of trying I finally made my first contact (CW) -- then I was hooked. I screwed around for more than a year before I heard my own echo.

WSJT makes all this easier now...but it's still not even close to a "plug & play" mode of operation.

[W9GB]

EME "Moonbounce" -- Wikipedia
http://en.wikipedia.org/wiki/EME_%28communications%29

The Earth-Moon signal path loss over the 770,000 kilometer return distance is extreme (around 250 to 310 dB) depending on VHF-UHF band used.
WJST / modulation formats; Doppler shift effects; amount of TX power available and high-gain antennas (> 20 dB) are components that are typically used in assembling an EME station.

My first EME contact (CW) was with KA0Y's 40 foot EME dish in 1984 .... it is quite an experience .. tracking the moon with a Heathkit H-100 computer!

w9gb

[WA9SVD]

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.

Current satellite work is NOTHING like EME. As you state, satellites CAN be worked with nothing more than H-T's. (I've made several sat contacts with two H-T's (2 Meter mono-band H-T for the uplink and a 440 MHz-1.2 GHz dual-bander for the downlink) with (aftermarket ) whip antennas.
EME is a WHOLE different ballpark; particularly with a "modest" station, the signal levels from EME can easily be 20-30-40 dB LESS than that received from an Amateur satellite, (even when using computer assisted detection for EME) and a directional antenna will be an absolute necessity. Accurate aiming of the antenna will also be critical; you can't just point the antenna in a "general direction" and expect results, as you can often do with the 'birds. Unless a person has proper tracking rotators and software abilities, terrestrial success will be limited to the moon being only a few degrees above the horizon, so a clear horizon view will be a consideration. If there are objects in the way (dense forest, buildings) chances of making a contact (or even reception) are greatly reduced.

EME is probably THE ultimate "weak signal" challenge.

Good luck to all that try, and keep us posted!

[KF5FEI]

I think maybe my point was missed. If you are unfamiliar with construction / use of directional antennas and aiming them at moving objects, satellite work is a good way to start out, especially if you don't have someone in the area who can help you out with the EME stuff.

Doctors don't start off doing brain surgery -- they dissect dead people first, then work up to simple surgeries and later, more complex stuff. The easiest path to disappointment is to blindly jump into something way over your head and expect instant gratification.

[WA9SVD]

I think maybe my point was missed. If you are unfamiliar with construction / use of directional antennas and aiming them at moving objects, satellite work is a good way to start out, especially if you don't have someone in the area who can help you out with the EME stuff.

Doctors don't start off doing brain surgery -- they dissect dead people first, then work up to simple surgeries and later, more complex stuff. The easiest path to disappointment is to blindly jump into something way over your head and expect instant gratification.

If there were birds like AO-40, AO-13, or AO-10 still in operation, that would CERTAINLY be true. But with the LEO birds, aiming an antenna and getting a response merely requires hitting the "broad side of a barn."
Surely, if one DOES have an AZ-EL rotator system, one can practice tracking the Amateur satellites with even a small directional antenna. But it's nowhere near the precision required for EME work.
I do agree, however, that with a directional antenna, (preferably a highly directional antenna) the birds can be a place to start. And as is true in any of our Amateur Radio endeavours, "if you can't hear 'em, you can't work 'em."

[G1VVP]

After reading the last few posts I realise I will have my work cut out. Voice contact was my original intention but I see this may not be a consideration with relatively simple equipment.

There's certainly no harm in trying. I have plenty of aluminium and should be able to make a reasonable yagi antenna in excess of 13 elements.


Thank you WA9SVD for your confidence in me. :)

73 all.

John
G1VVP

[WB3BEL]

Working EME on 2meters using WSJT is not all that hard. If you have about 100+ Watts and an 8 or so element yagi on 2wl boom you can work the big guns when conditions are favorable. When you start out you don't need a super low noise preamp. If you don't have some TX power you don't need to hear weak stations that you can't work. You might make a few contacts with 50W but 160W brick amps are pretty affordable and will help a lot. You still will have to fight for every contact but it's fun to get started with what you have.

If you want to build a decent yagi check out the DK7ZB designs:

http://www.qsl.net/dk7zb/start1.htm

As far as getting your feet wet with the technology using WSJT I can strongly recommend trying meteor scatter. The program is the same just using a different mode FSK441a for meteor scatter versus JT65B for EME.
You get used to the tools and meet some of the guys you might hear later on EME.

If you want to make an EME contact you certainly can with simple equipment and antennas.

[KC8VWM]

"A cut and paste report - JT65 EME moon bounce reception at station KC8VWM"

144.125 MHz.

*** 043500 3 -18 2.0 0 3 * CQ K6MYC DM07 ***

Hmmm.. EME conditions are in pretty good shape from California to Oklahoma tonight. :)

Martin, DK7ZB has some excellent "low noise" EME antenna designs and his 12 element Yagi design is probably the most popular antenna build I would recommend to get started on EME.

What I like in particular about the "German engineered" DK7ZB antenna designs is the fact these are actually "real world" antenna's. They are not just simulated computer model designs that only look good on paper. These designs stick with actual DL6WU's real world optimized antenna design principles. Not just plug and play antenna modeling data. One of the better designs in terms of real world antenna's with a proven and tested history.

My Best,

[WB2WIK]

After reading the last few posts I realise I will have my work cut out. Voice contact was my original intention but I see this may not be a consideration with relatively simple equipment.

There's certainly no harm in trying. I have plenty of aluminium and should be able to make a reasonable yagi antenna in excess of 13 elements.


Thank you WA9SVD for your confidence in me. :)

73 all.

John
G1VVP


"Voice" isn't gonna work for e.m.e., about 99% of the time, even for the best equipped station with hundreds of elements and kilowatts.

I understand the Arecibo (Puerto Rico) radiotelescope dish will be activated for a period of time coming up, on 70cm (not 2 meters). That antenna has so much gain that SSB contacts might be possible, if they choose to do so; but it's one of the few antennas ever activated in the amateur bands having that kind of gain. With enough antenna gain, FM e.m.e contacts are possible! But the gain required is enormous and beyond the scope of amateur setups, so on "one end" of the circuit it will take a radiotelescope-type antenna.

Some info on the Arecibo dish: http://www.naic.edu/public/the_telescope.htm

[AD6KA]

Just out of curiousity.....what's the lowest band a
successful EME QSO has ever been made on? 2m, 6m?

Have any engineers/EME gurus ever just for grins & mental excercise tried to figure
out on paper what it would take to do it on say, 10m or 20m?

[KR2D]

Just out of curiousity.....what's the lowest band a
successful EME QSO has ever been made on? 2m, 6m?



40 meters. Well, actually just outside the 40m ham band, and it wasn't really a 2 way QSO. HAARP did an EME experiment and the echo was heard by many listeners, including me, with simple wire antennas.

Info here: http://www.haarp.alaska.edu/haarp/mbann.html

[WB2WIK]

Just out of curiousity.....what's the lowest band a
successful EME QSO has ever been made on? 2m, 6m?

Have any engineers/EME gurus ever just for grins & mental excercise tried to figure
out on paper what it would take to do it on say, 10m or 20m?

Lowest frequencies hams use is 50 MHz (6m), and it's quite common.

The government research HAARP system (High Frequency Active Auroral Research Program) runs 3.6 million Watts in the 2.8 - 10 MHz region and can get lunar reflections.

That's a bit more power than I can run from home.:p

[AB9LZ]

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.

I've done that a few times with nothing more than an Alinco DJ-G7, a whip antenna and some headphones. It's really not that hard and it's lots of fun.

73 m/4

[WB3BEL]

Just out of curiousity.....what's the lowest band a
successful EME QSO has ever been made on? 2m, 6m?

Have any engineers/EME gurus ever just for grins & mental excercise tried to figure
out on paper what it would take to do it on say, 10m or 20m?

The most common band for EME is 2meters. There are operators on 6meters and on the higher bands all the way to SHF.

10meter EME has been done. Check this link:

http://list-serv.davidv.net/pipermail/moon-net_list-serv.davidv.net/2005-September/001089.html

SSB QSOs are possible but they are pretty hard. They are easier on the microwave bands with a big dish antenna and some Transmit power.
There are some youtube videos you can probably find if you hunt a bit.

But most starting stations will have small antenna systems and will limit them to working the superstations on WSJT using JT65B mode

As Steve mentioned the huge dish at Arecibo P.R. was activated a little over a week ago on 70cm. They worked some CW and some SSB stations. It was a dry run for the Echoes of Apollo special event scheduled for 16,17,18th April.