What is moon bouncing all about in ham radio? Other then it being cool to bounce radio signals off the moon, what else is it used for? And how much power do you need to use and what kind of antenna? A beam antenna?
Moonbounce?
- Thread starter Rt169Radio
- Start date
- Status
jhooten
Member
The moon is a big passive reflector in orbit. If both stations can see it they can communicate with each other no matter the distance between them including being as far as on opposite sides of the planet.
Yes it takes a beam, preferably a big one, even more preferably many big ones properly stacked and phased with an automatic tracking system. Or it takes a lot of power on transmit and a very sensitive receiver. Or the best option a combination of all the above.
A quad stack of 22 element beams with 150 watts and a Very low noise high gain preamp will put you on the lower side of mid pack.
It can serve as a back up long distance means of communication when HF propagation has been disrupted.
Yes it takes a beam, preferably a big one, even more preferably many big ones properly stacked and phased with an automatic tracking system. Or it takes a lot of power on transmit and a very sensitive receiver. Or the best option a combination of all the above.
A quad stack of 22 element beams with 150 watts and a Very low noise high gain preamp will put you on the lower side of mid pack.
It can serve as a back up long distance means of communication when HF propagation has been disrupted.
I believe there are contests using moon bounce (EME or Earth-Moon-Earth).
http://www.sm5bsz.com/wsjt/mixed.htm
I've never done it and probably won't in the near future. It looks fascinating, though!
http://www.sm5bsz.com/wsjt/mixed.htm
I've never done it and probably won't in the near future. It looks fascinating, though!
Last edited:
For an example of the lengths some hams will go to for EME contacts, take a look at this:
I think that about the bare minimum for 2m EME contacts is a rig capable of 100 watts on CW and 10 element or larger Yagi antenna. There are some newer digital modes, such as JT65, that are very popular with the EME folks because they send very short bursts of high-speed data.
I think that about the bare minimum for 2m EME contacts is a rig capable of 100 watts on CW and 10 element or larger Yagi antenna. There are some newer digital modes, such as JT65, that are very popular with the EME folks because they send very short bursts of high-speed data.
Last edited:
AgentCOPP1
Member
- Joined
- Nov 16, 2011
- Messages
- 296
W9BU, that is some serious stuff right there. Somebody has a lot of money! I'm just disappointed that there really is no "cheap" alternative for EME because I would love to do that stuff. I just don't have the money to make the appropriate arrays to do it.
Token
Member
“cheap” and EME don’t normally go together. It often requires both high power and big antennas. But it can be done at a reasonable cost if you build the station slowly and home brew a bit of it.
I am not currently active on EME, but 10 or 12 years ago I was.
The simplest setup I have ever accomplished a 2-way EME QSO with was, on my end and using ground gain and no elevation drive, a single KLM 20LBX and 270 W of CW, but I have heard of it being done with this class antenna and 100 W. Moving up to 400 W I was able to work a few more of the big guns in the EME world, but most of the credit has to go to people on the other end. Upgrading to a 4 bay array (4x H, purchased all 4 antennas on closeout and paid less than $550 for them and the H rig) and 400 W CW really broadened my possible contact base, moving up to 1200 W made it better, but this antenna setup was narrow enough that it made elevation positioning a requirement.
On 70 cm I ran a quad bay (again 4x H) of M2 30+ foot long 432-13WLA antennas (picked up all 4 used over time, and had less than the cost of one new today in them) and 500 W and made quite a few contacts before I drifted away from EME.
I even did a couple of 6M EME contacts with a 120+ foot long wire beam, I want to say it was 19 or 20 elements, but I honestly don’t remember, I took that antenna down 10 years or more ago.
EME can be quite addictive, it really is just about the ultimate DX. But unlike HF DX there is little to consider for propagation. You can run the math for any two stations setups and determine if they are likely to be able to make contact or not. Once the SNR in the calculations gets above a certain point the contact is almost assured, assuming both parties do their parts correctly.
Today the arrays are gone here, although I still use a single 20LBX on 2M and a single 432-13WLA on 70 cm for weak signal work.
T!
I am not currently active on EME, but 10 or 12 years ago I was.
The simplest setup I have ever accomplished a 2-way EME QSO with was, on my end and using ground gain and no elevation drive, a single KLM 20LBX and 270 W of CW, but I have heard of it being done with this class antenna and 100 W. Moving up to 400 W I was able to work a few more of the big guns in the EME world, but most of the credit has to go to people on the other end. Upgrading to a 4 bay array (4x H, purchased all 4 antennas on closeout and paid less than $550 for them and the H rig) and 400 W CW really broadened my possible contact base, moving up to 1200 W made it better, but this antenna setup was narrow enough that it made elevation positioning a requirement.
On 70 cm I ran a quad bay (again 4x H) of M2 30+ foot long 432-13WLA antennas (picked up all 4 used over time, and had less than the cost of one new today in them) and 500 W and made quite a few contacts before I drifted away from EME.
I even did a couple of 6M EME contacts with a 120+ foot long wire beam, I want to say it was 19 or 20 elements, but I honestly don’t remember, I took that antenna down 10 years or more ago.
EME can be quite addictive, it really is just about the ultimate DX. But unlike HF DX there is little to consider for propagation. You can run the math for any two stations setups and determine if they are likely to be able to make contact or not. Once the SNR in the calculations gets above a certain point the contact is almost assured, assuming both parties do their parts correctly.
Today the arrays are gone here, although I still use a single 20LBX on 2M and a single 432-13WLA on 70 cm for weak signal work.
T!
gunmasternd
Member
You can also use a Dish for moonbounce. But putting up a antenna array is more eye candy.
Token
Member
A dish, for a private party, is applicable from roughly 70 cm and up, but on 2M and 6M it is not really practical. The following calculations are back of napkin, but should be pretty close.
A minimal 4x H quad bay of 13 wavelength (about 30 feet long) 70 cm Yagi antennas (each Yagi roughly 20.5 dBi) might have a gain of a tad over 25.5 dBi. To get this same gain using a dish antenna and a feed of 70% efficiency will require a dish diameter of at least 16 feet, along with the structure to support and move it. This is petty doable, and might be mechanically easier than the Yagi array.
On 2M if you have a 4x H quad bay of four 40’ish foot long Yagi’s (eah Yagi roughly 17.25 dBi), and they are properly done in the phasing and mechanical setup, you can end up with about 22.5 dBi, or a little over, gain. But to get this same gain on 2M with a dish will take a dish diameter of at least 34 feet, and possibly more than that, depending on the efficiency. Mechanically moving that beast in azimuth and elevation is more difficult, and costly, than moving the 4 bay Yagi.
A single 70 foot Yagi on 6M can have as much as 16+ dBi of gain, to get that in a dish antenna requires a dish of at least 45 feet diameter. 45 foot dishes are VERY expensive, and very hard mechanically to move and support. I don’t know for sure, but I would be surprised if there are more than one or two dishes that size in private use, most in that realm or bigger are going to be educational facilities, commercial concerns, and government agencies. However I know several hams with 70 foot 6M Yagi’s.
T!
Spankymedic7
Member
AHA! But there IS an inexpensive and simple option. Do you have a 2m SSB radio that has 50W output? Do you have a PC? Do you have a 2m yagi antenna? If you have all of the aforementioned gear, then you CAN do moonbounce. Check out this link...
EA6VQ - Get ready for 2m MoonBounce communications
AgentCOPP1
Member
- Joined
- Nov 16, 2011
- Messages
- 296
No.
Yes.
Yes.
Your reply seems like a twisted real-life infomercial lol. I guess I just need to get the 2m SSB radio and I'd be set. The only desktop radio I have right now is a Kenwood TS-430S, and it only goes up to 10 meters. Is it possible for me to use a transverter to get me up to 2m? I hope so. I'll keep your website in my bookmarks so that once I get the right radio, I can try it out for myself.
Although I've never run EME from home beyond hearing my own echos, I have done it, and participated in several group efforts.
Outside of using WSJT, or similar mode, it's not a trivial effort, and not something that's done casually, or cheaply. In order to achieve audible echos, you need exceptional station performance, and that's not easy to come by. It's a good idea to get your feet wet with terrestrial weak signal work first to hone your skills and get your station up to the required performance.
Now, with some of the new PC sound card based digital modes, the advantage there is that it can detect and demodulate signals that are almost 30 db below the audible noise floor, something your ear can't do. So, people are working EME on 6 meters, with 100 watts and a 3 element beam. A caveat there is, the guys who do it the hard way frequently look at the WSJT crowd as "cheating", since a very mediocre station becomes capable of working a signal reflected off the moon. There's nothing like building your own station and antenna, and hearing your own echos by ear.
Picking out what band to use can be challenging. 2 meters requires huge arrays for high performance, or you can content yourself with ONLY working the big guns with your 100 watts and single long boom yagi.
You can go up in frequency where antenna gain is easier to come by, but radio performance can be challenging. Especially when it's a band where no one sells commercially made gear. I've seen EME done with tripod mounted yagis and small dishes, to dishes large enough that you have to pick and choose which crater on the moon you aim at to get the best reflection.
Outside of using WSJT, or similar mode, it's not a trivial effort, and not something that's done casually, or cheaply. In order to achieve audible echos, you need exceptional station performance, and that's not easy to come by. It's a good idea to get your feet wet with terrestrial weak signal work first to hone your skills and get your station up to the required performance.
Now, with some of the new PC sound card based digital modes, the advantage there is that it can detect and demodulate signals that are almost 30 db below the audible noise floor, something your ear can't do. So, people are working EME on 6 meters, with 100 watts and a 3 element beam. A caveat there is, the guys who do it the hard way frequently look at the WSJT crowd as "cheating", since a very mediocre station becomes capable of working a signal reflected off the moon. There's nothing like building your own station and antenna, and hearing your own echos by ear.
Picking out what band to use can be challenging. 2 meters requires huge arrays for high performance, or you can content yourself with ONLY working the big guns with your 100 watts and single long boom yagi.
You can go up in frequency where antenna gain is easier to come by, but radio performance can be challenging. Especially when it's a band where no one sells commercially made gear. I've seen EME done with tripod mounted yagis and small dishes, to dishes large enough that you have to pick and choose which crater on the moon you aim at to get the best reflection.
Yes. You can roll your own, or buy a kit. Downeast Microwave has transverter kits. One thing to keep in mind is that JT65 requires really good frequency stability, so a stock transverter kit may be a bit difficult to work with.
n5ims
Member
- Joined
- Jul 25, 2004
- Messages
- 3,993
A ham friend of mine got a deal on an 11 meter (that's size, not frequency) dish from the local cable TV company. It was their original dish and was no longer in use and just taking up quite a bit of space. The deal was he got it at no cost except if it "wasn't gone by next Monday morning, you'll have to pay rent!". The biggest expense was building the large concrete mounting pad it would be moved to. I suspect the next largest expense was gas for all the trips to haul the thing to his house.
We took it apart, transported it to his home, and put it back together again. Fortunately all of the waveguides and control systems were still in great shape. He used it for moonbounce for several years. It was loads of fun watching that huge dish shrink down to nothing and back again in its new home.
We took it apart, transported it to his home, and put it back together again. Fortunately all of the waveguides and control systems were still in great shape. He used it for moonbounce for several years. It was loads of fun watching that huge dish shrink down to nothing and back again in its new home.
Wow. That's huge!
I'm jealous, but I'm supposing my wife would be glad it wasn't me that dragged that thing home. I've had to turn down more than one large dish because I just didn't have the resources to deal with it.
What band did he end up using it on? Even on two meters, it would have over 20 db of gain, if one could build an efficient feed system for it.
kayn1n32008
ØÆSØ Say it, say 'ENCRYPTION'
Years ago(mid-late 90's) there was a dish on the cover of CQ, the owner purported hearing his own SSB echos on 70cm with only 5w.
Sent from an unknown place...
Sent from an unknown place...
kayn1n32008
ØÆSØ Say it, say 'ENCRYPTION'
Now feed it with 1kw... What a fun station that would be...
Sent from an unknown place...
Does moon bouncing only work if you can see the moon? This is probably a dumb question but does it have to be a full moon?
Token
Member
Yes, you must be able to see the Moon, and no, it does not matter what phase the Moon is in.
T!
T!
AgentCOPP1
Member
- Joined
- Nov 16, 2011
- Messages
- 296
If it requires good stability, I might be a little wary of a transverter then. I could spend a hundred or so dollars on one just to find out that it isn't stable enough. I could possibly build my own, but my circuit building skills are somewhat limited. I would love to try though and just see how it goes.
EME communications is interesting, but it is far from the only mode available to you with this kind of equipment. Troposcatter has been known and used the the likes of Marconi and it can be used to reliably communicate across distances of 900 km or more.
VHF and UHF communications can be quite fascinating. Try it...
VHF and UHF communications can be quite fascinating. Try it...
- Status
Similar threads
