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Posted: 8/12/2017 10:20:04 PM EDT
So its no secret I am a big Metor scatter person. I was planning on upgrading my rotator and both my 6m and 2m antenna for a little more RX/TX gain. Then I ran across this little gem this morning.
Attached File So now here I am in a Hotel room in Charlotte NC, for the final push to GA to pick this beast up. So 432 is on the table, with a small delay in the 2M and 6M ant upgrade. Calculated ERP after coax loss with 100w at the shack is just over 11.5kw |
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Yaesu AZ EL rotor. And controller
4 15el 432 antennas with Stackig frame, power divider coax. And a 2m7 2m yagi |
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Are you going to take it apart to transport it, or leave it as-is and carry it in a truck or trailer?
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Nice score.
Why take it apart? Mount it in the truck just like the vhf rovers EME mobile! |
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I've never tried EME. However I'm planning to point my 2m Yagi at the moon for the upcoming EME contest to see what I can hear. I can do 180 watts on 2m so there's a tiny chance I'll be able to work one of the big gun stations.
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Well just got back to the QTH. Got a 10 foot tower section and 8 foot tower top section for 50 buckes. And scored 2 37' sections of 7/8 hardline terminated to N connectors for 50 bucks.
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So the 70cm yagis are YU7EF designed 4x EF7015 that were home brewed. The phasing system is 75 ohm belden 9222 cable.
Modeled gain is 20.8 dbd Im not sure what I am going to do. If I am going to run this array on the tower section planted in the backyard or attempt to put it on the roof tripod. With about 5 feet of mast it would clear at full elevation since the tripod is on the north end of the house near the edge. Also if I go roof mount how do I get my little moxon on it? Any input is appreciated |
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So the array is up, seems to work well thus far. I can hear beacons on 432 I have never been able to hear before with my previous 15el Yagi.
Tried to listen today for signals off the moon, and could not hear any. Went outside and found the array had turned, and was stuck in a 15degree elevation. Had to tighten the mast mount and Elevation rotor. Attached File Attached File Currently trying to find a brick type amp, since my 706 only puts out 10w on 432 |
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Partial Success today!
Attached File First copy of someone off the moon. He was booming in at -15 to -12. If you notice in the bottom of the screen there is a curve to the RX signal. This is the cool down frequency drift after a 45 second 10w TX cycle He was not able to see my trace, but with the 110w PA on its way that should help. So now I will be hunting a High Stability Crystal Oscillator for my IC-706. I have a fan mod done to it, and it does help but not enough at UHF Frequencies |
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Can you tell me more about the IC-706 mods?
I have an IC-706 which I'm contemplating using to get started with EME, and have just ordered an M2 2M5WL yagi, and would love to try 432 after that. |
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Quoted:
So now I will be hunting a High Stability Crystal Oscillator for my IC-706. I have a fan mod done to it, and it does help but not enough at UHF Frequencies View Quote |
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Dude, everything else you are doing is so epic, you need to get yourself a Flex or an Apache Labs radio, put a GPSDO frequency reference on it, and then use a transverter. That way you will be stable to a thousandth of a Hertz, or better. The Chinese BG7TBL GPSDO's are going for around $150 on eBay, and ANAN-10E's are going for around $600 on qth and the like. So for around $750 you can have an exciter that is essentially perfect. Not sure who's who in the zoo where transverters are concerned. DEM has some for around $500 new. View Quote View All Quotes View All Quotes Quoted:
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So now I will be hunting a High Stability Crystal Oscillator for my IC-706. I have a fan mod done to it, and it does help but not enough at UHF Frequencies |
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DEMI and Elecraft are the main transverter manufacturers right now. View Quote So the plan is to do a GPSDO with 10Mhz output, Tripler for 30mhz output injected into the IC-706. When the time comes and I build a DEMI Transverter for 144 and 432 I will build them with the 10Mhz reference input. The stability of the IC-7300 at the 28Mhz IF will be fine, 10Mz will lock the Transverter Mixer. I have the fan mod done on the IC 706, but after the TX cycle there is still about 100hz drift during cool down of the RX signal. If I can cut that down to about 50 with the TXCO i will be able to work stations until I can Build a GPSDO. This is the plan http://jwatrous.org/706-new/706.html ETA: This AM HB9Q peaked in at -7db and NC1I peaked in at -9db on JT65, so the RX is Good. |
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Eventually I may go Transverter route for the IC-7300. But for the time being, I am going to try a Chicom CR-282 off of ebay. But GPSDO has been in the future for a while now. The word is from other EME guys that the CR-282 is still not stable enough for EME use. So the plan is to do a GPSDO with 10Mhz output, Tripler for 30mhz output injected into the IC-706. When the time comes and I build a DEMI Transverter for 144 and 432 I will build them with the 10Mhz reference input. The stability of the IC-7300 at the 28Mhz IF will be fine, 10Mz will lock the Transverter Mixer. I have the fan mod done on the IC 706, but after the TX cycle there is still about 100hz drift during cool down of the RX signal. If I can cut that down to about 50 with the TXCO i will be able to work stations until I can Build a GPSDO. This is the plan http://jwatrous.org/706-new/706.html ETA: This AM HB9Q peaked in at -7db and NC1I peaked in at -9db on JT65, so the RX is Good. View Quote View All Quotes View All Quotes Quoted:
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DEMI and Elecraft are the main transverter manufacturers right now. So the plan is to do a GPSDO with 10Mhz output, Tripler for 30mhz output injected into the IC-706. When the time comes and I build a DEMI Transverter for 144 and 432 I will build them with the 10Mhz reference input. The stability of the IC-7300 at the 28Mhz IF will be fine, 10Mz will lock the Transverter Mixer. I have the fan mod done on the IC 706, but after the TX cycle there is still about 100hz drift during cool down of the RX signal. If I can cut that down to about 50 with the TXCO i will be able to work stations until I can Build a GPSDO. This is the plan http://jwatrous.org/706-new/706.html ETA: This AM HB9Q peaked in at -7db and NC1I peaked in at -9db on JT65, so the RX is Good. |
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I have a Flex-1500 and one of the cheap 2m transverters from eBay (previous generation). I put a lot of effort into getting it working but despite being able to talk with an HT, I cannot get it to key up a repeater. It only puts out about 1.5 watts which gets about 6 watts out of my 180w amplifier. There's nothing to adjust on the transverter board so I think I'm going to scrap that project and get a Demi. View Quote The guy I got the roator and yagis from uses them, said the front end it hot and they will hear stuff the DEMI and Elecraft will not, but he could not get them on frequency. Have read that on the internet also. If you can correct for it they will work fine and are cheap. |
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I know the Transverter Store guy in the Ukraine has some pretty good stuff, the only negative I have heard is they are off frequency a bit. http://transverters-store.com/ The guy I got the roator and yagis from uses them, said the front end it hot and they will hear stuff the DEMI and Elecraft will not, but he could not get them on frequency. Have read that on the internet also. If you can correct for it they will work fine and are cheap. View Quote View All Quotes View All Quotes Quoted:
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I have a Flex-1500 and one of the cheap 2m transverters from eBay (previous generation). I put a lot of effort into getting it working but despite being able to talk with an HT, I cannot get it to key up a repeater. It only puts out about 1.5 watts which gets about 6 watts out of my 180w amplifier. There's nothing to adjust on the transverter board so I think I'm going to scrap that project and get a Demi. The guy I got the roator and yagis from uses them, said the front end it hot and they will hear stuff the DEMI and Elecraft will not, but he could not get them on frequency. Have read that on the internet also. If you can correct for it they will work fine and are cheap. PowerSDR compensates for frequency errors just fine. I had 4 other hams over after a club meeting a while back and we tried everything we could think of for an hour. I think I'm just going to cut my losses. Which is annoying since I built a custom enclosure, heat sink, fan, PTT switching system.. sigh. |
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Can you tell me more about the IC-706 mods? I have an IC-706 which I'm contemplating using to get started with EME, and have just ordered an M2 2M5WL yagi, and would love to try 432 after that. View Quote |
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So the plan is to do a GPSDO with 10Mhz output, Tripler for 30mhz output injected into the IC-706. ...until I can Build a GPSDO. This is the plan http://jwatrous.org/706-new/706.html View Quote But you still need to go full SDR |
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To be honest I have not been too impressed with the M2 offering for the price. I have had very good luck with the Directive Systems Rover Yagi. I have an M2 older 2m7 2m yagi on my EME array, and it is a very noise antenna..... Now there may be some coupling because of the close proximity, I am going to be swapping the M2 out for my DS antenna soon and will update. I have my tower half I have to put up so I can get back up on 6m. View Quote View All Quotes View All Quotes Quoted:
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Can you tell me more about the IC-706 mods? I have an IC-706 which I'm contemplating using to get started with EME, and have just ordered an M2 2M5WL yagi, and would love to try 432 after that. I'd be interested in knowing more about the problems that you had with your M2 - as you say, it could be related to coupling to the other nearby metal. But if I'm not mistaken, don't M2 and Directive Systems have similar construction methods, with passive elements passing through the boom via insulators? I have not compared the DE configurations or element lengths and spacingss, nor have I looked in depth at the (modeled or measured?) performance characteristics side by side. I ended up ordering the M2 from R&L Electronics - they had a much better price than DX Engineering or others. But I guess that I will find out. I was originally intending to do a cheap refurbishment of an old Cushcraft, but after investigating what would be required, it would not have been as inexpensive as I had originally hoped. And I liked the construction of the M2 antenna better than the current long-boom 2m Cushcraft. |
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It's not worth your while to build one (unless you just want the challenge). The BG7TBL designed units are available on eBay for under $150. They come with a variety of OXCOs installed, and they all use the excellent uBlox GPS receiver chip. You can run the uCenter software to monitor it, and it even has a 1PPS output if you want to do a native, local NTP server in your PC. While there is some risk in buying from a Chinese source, the guys who show the photos of which OXCO is installed are pretty legit. I wouldn't buy unless you know which OXCO you are getting, although they are, in general, all very good ones. There's plenty of room to install a tripler inside the case and add a 30MHz output connector. But you still need to go full SDR View Quote |
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Which Directive Systems 2m yagi? The DSEFO144-19 19-element 34' boom or a different one. I briefly looked at that one, but as the price was listed as "call for price" I guess that I interpreted that as meaning "out of stock". I do know someone in VA who sometimes operates from K8GP (probably not for VHF contests, as he generally goes roving for those, but maybe for FD?) and probably should have checked with him. I'd be interested in knowing more about the problems that you had with your M2 - as you say, it could be related to coupling to the other nearby metal. But if I'm not mistaken, don't M2 and Directive Systems have similar construction methods, with passive elements passing through the boom via insulators? I have not compared the DE configurations or element lengths and spacingss, nor have I looked in depth at the (modeled or measured?) performance characteristics side by side. I ended up ordering the M2 from R&L Electronics - they had a much better price than DX Engineering or others. But I guess that I will find out. I was originally intending to do a cheap refurbishment of an old Cushcraft, but after investigating what would be required, it would not have been as inexpensive as I had originally hoped. And I liked the construction of the M2 antenna better than the current long-boom 2m Cushcraft. View Quote The Directive systems has worked FB for me, netted contacts out to 1072 miles on FSK441 with 175w at 30' with trees all over. Worked into southen GA, Upstate NY, Indiana, MA on SSB at 15'-30'. Im am sure you will be happy with the M2, they seem to be good antenna's, just a bit pricey. |
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Too bad that sucker isn't a 2 meter rig. I probably could have worked you this morning by just pointing that thing to the west. Huge inversion in the misouri river valley. Southern kansas was booming in here with a stacked beam. S9+. I know for a fact he had a qso into minnesota. I was catching stations upto 150 miles still full scale while the band was up. With your erp and gain we probably could have made it work.
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Too bad that sucker isn't a 2 meter rig. I probably could have worked you this morning by just pointing that thing to the west. Huge inversion in the misouri river valley. Southern kansas was booming in here with a stacked beam. S9+. I know for a fact he had a qso into minnesota. I was catching stations upto 150 miles still full scale while the band was up. With your erp and gain we probably could have made it work. View Quote |
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http://aprs.mountainlake.k12.mn.us/
Looks like its opening up again but more of a north south line tonight so far. I know earlier 2 was down. I was struggling to get out of the river valley and 40 miles. That should be an easy trip for me. Eta: yup. Surf is starting up. Southern kansas (382 miles) just came up and fluttered out. Northern iowa also in good. Time to spin the yagi and spin to 146.52. |
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It turns out that phase locking the 706 to 10 MHz reference is pretty easy. Sorry, I can't find the link right now, but there is a right up regarding a 3 or 4 turn link coil wrapped around the 706's standard reference oscillator almost exactly the same as what I did here.
You don't need to bother with a tippler - it locks up just fine to the 10 MHz square wave reference. I've done this to both of my 706's,using retired rubidium standards. No detectable drift on 432 WSPR service. |
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It turns out that phase locking the 706 to 10 MHz reference is pretty easy. Sorry, I can't find the link right now, but there is a right up regarding a 3 or 4 turn link coil wrapped around the 706's standard reference oscillator almost exactly the same as what I did here. You don't need to bother with a tippler - it locks up just fine to the 10 MHz square wave reference. I've done this to both of my 706's,using retired rubidium standards. No detectable drift on 432 WSPR service. View Quote |
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There used to be a web page that showed the few turns wrapped around the osc tuning coil so close to mine that it wasn't worth me taking pix, but I can't seem to find it now. Give me a few days, and I'll snap a few pix and post them.
The mod simply was one end of the tiniest wire you can find soldered to the shield, 3 turns wrapped carefully around the xtal osc tweaker coil, and a 100 ohm resistor or so to the center conductor of a small coax that snaked out through the rear access port. Naturally, the shield of the coax was also soldered to the shield. |
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The next question that I'm going to face is figuring out what kind of structure to mount it to.
The long-boom 2m antenna does not have a lot of wind load, and for various reasons I will need to mount it "close" to the ground. There will likely be some unwanted pattern effects if I have it too close to the ground, however. But unlike a satellite antenna, I won't need to be able to point the thing straight up. So, what are you using for your EME antenna support, how high are you mounting the antennas, and what is the max elevation that you are planning to handle? You did mention the 10' tower section (Rohn 25G?) and the shorter top section, and your uncertainty about ground or roof mount. I do have a short Rohn 25G top section, and will need to do ground mounting, but beyond that I have not figured anything out. I have a Ham-IV rotor and a Yaesu G500 elevation rotor. But I may just start out with a quick-and-dirty system to point it toward the horizon to see if and what I can hear from big stations at moonrise. |
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When did they install a repeater on the moon? Must be the Russians, using the repeater to spy on peace loving American democrats.
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When did they install a repeater on the moon? Must be the Russians, using the repeater to spy on peace loving American democrats. View Quote |
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The next question that I'm going to face is figuring out what kind of structure to mount it to. The long-boom 2m antenna does not have a lot of wind load, and for various reasons I will need to mount it "close" to the ground. There will likely be some unwanted pattern effects if I have it too close to the ground, however. But unlike a satellite antenna, I won't need to be able to point the thing straight up. So, what are you using for your EME antenna support, how high are you mounting the antennas, and what is the max elevation that you are planning to handle? You did mention the 10' tower section (Rohn 25G?) and the shorter top section, and your uncertainty about ground or roof mount. I do have a short Rohn 25G top section, and will need to do ground mounting, but beyond that I have not figured anything out. I have a Ham-IV rotor and a Yaesu G500 elevation rotor. But I may just start out with a quick-and-dirty system to point it toward the horizon to see if and what I can hear from big stations at moonrise. View Quote I used to eclipse today to verify antenna alignment. I found out I was 15 degrees off!!! Some of the big stations seem to think I should have been able to work them with my 10w, and they may be right. No one was on at moonset tonight, but now I am excited to see where I will be at with the antenn aligned correctly. |
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Success!
Attached File Worked 3 stations yesterday, Switzerland, Germany, and Connecticut! Still need to work on an LNA and do some antenna work. Now for a 2m setup! |
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I know the Transverter Store guy in the Ukraine has some pretty good stuff, the only negative I have heard is they are off frequency a bit. http://transverters-store.com/ The guy I got the roator and yagis from uses them, said the front end it hot and they will hear stuff the DEMI and Elecraft will not, but he could not get them on frequency. Have read that on the internet also. If you can correct for it they will work fine and are cheap. |
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I've been really tempted to pick up one of those for 222. View Quote Just the fact that the AGC can be turned off on the 7300 is a huge factor for weak signal EME on the high bands. I also picked up a Fox Delta satellite tracker controller for my rotator. Need to finish assembly and interface. |
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I was looking into the possibility of building one (or up to four) YU7EF EF7015 yagis, but discovered that the photos seem to be 'broken' on his site (both the home page at https://www.yu7ef.com/ and the EF7015 build page at https://www.yu7ef.com/ef7015.htm).
It doesn't seem to be a photobucket problem, as the image URLs reference his site (for example, https://www.yu7ef.com/PopaYU7EF.jpg). By any chance have you located some other source for the dimensions and build details? Do yours have the driven elements made from coax, with a matching network inside a plastic box? I can't tell for sure from the photos - Are the elements attached to the booms with nylon or plastic element mounting brackets that sit on top of square cross-section aluminum booms, with a single screw through the center of each element, or do the elements go through the booms with insulators and with clips to hold the elements in place? |
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For you more knowledgeable EME guys - for an average amateur station, what would you say is the minimum RF output and antenna gain you need to work EME (2m or 70cm) on JT9/JT65?
I've seen a 100w & 12db yagi spec on the interwebs...but I have no idea if that's anywhere near accurate. |
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