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Needed Hardware requirements for succesfull EME work

	OZ1LPR Team member	#1 - Posted: 19 Jan 2009 08:41
Basic requirements When people start thinking on EME they conclude this is not for me. EME is simply out of reach for me. I can't put up the needed antennas. But with the introduction of the K1JT's WSJT program EME has become a game for everybody. Even the smallest stations can work many contacts. 50W and a 5elem will make EME contacts with all over the world. After working al the possible ones, you will need a bigger antenna and more power. If you settle with a 3WL (6 meter) long antenna and 500W, you will be able to make hundreds of QSOs. During good EME conditions, you will be able to work a lot of the 2 yagi EME stations. Most 4 Yagi stations can be worked. As mentioned before every dB counts, so if you put up 4 Yagi. You will be able to work almost all stations. For a typical 4 Yagi station a limit of single Yagi 3WL and 100W is workable during good conditions. Faraday rotation One of the EME people worst enemy is the faraday rotation. An EME signal being reflected on the moon can change up to 90degrees in polarity. When the polarity does not match up, you get a lot of attenuation. That figure can easily be an additional loss of 20dB. This will make an EME QSO impossible unless you have very big antennas. Take a look here to see how the faraday rotation works. Even sometimes you can get cross polarity. If you can't switch polarity between RX and TX you will have one-way connections. Using X-pol antennas or polarity rotation If you install X-pol antennas and use a Horizontal/Vertical switch you will have much more luck in working EME. If you can change polarity and the rotation is 45 degrees you will only have an extra loss of 3dB. This figure is much better than the 20dB. Also it is fairly rare the rotation is exact 45 degrees. Sometimes you can get cross polarity. This is the time where polarity is different between you and your QSO partner If you can't switch polarity between RX and TX you will have again a one-way connection. More and More are getting polarity adjusting programmes installed (Linrad). This on the otherhand requires some more hw to be installed. It must be possible to RX both polarites at the same time. But then the computer can compensate for polarity errors for best signal. Preamp Be sure to install a low noise preamp at the tower. Again, any cable loss has to be avoided to make sure, that as much signal as possible reaches the receiver. A preamp having 0.5-0.7dB noise figure is sufficient. Power Power levels seen on EME are very individual. Levels from 25W up to several kW are seen. Of course the more power you use, the larger the signal. Elevation You can choose either to have elevation, or only work EME when moon is near the horizon. By using only horizon you will be able to work EME up to about 16-20degrees of moon elevation depending on your antenna length. It is always best to have elevation. This gives you many more QRV hours, and also noise from nearby noisesources (PC etc), will be substantially lower. Groundgain By using the moon when out in the horizon, you may get a big ground gain. This can be up to 6dB gain both RX and TX. But this ground gain varies a lot with the area around you. Houses and trees and hills will lower the ground gain. Computer and soundcard For making these EME QSOs in JT65 mode you need a computer with a soundcard. The best is to go with something in the range of 1GHz PIII or better. You will need a relatively good soundcard. A 24Bit Soundblaster is widely used with good result. A Small modem must be build to connect radio to the PC. On the internet a lot of simple modem designs can be found. For Setup up of the computer read the K1JT manual over the WSJT programme. The manual can be found where you download the programme. Check this link.

	DL4KG Forums Member	#2 - Posted: 15 Jan 2012 14:35
I can prove everything what OZ1LPR said: Actually I my equipment consists of a Kenwood TS-2000X (100 W), a single 2.1 WL (4.4 m) DJ9BV yagi, a standard SSB SP-2000 preamplifier. Between antenna and the TS-2000 I have 25 m Aircom+ coaxcable. With this "normal" setup I worked 35 different stations and I am able to do EME quite regularly with the big guns. It is true that conditions have to be cooperative but it is fun to be able to work EME with this setup. So, everybody with a good tropo station should try EME. 73 de Gerald - DL4KG P.S.: if you want to have a look: http://www.mydarc.de/dl4kg/144init.html

	DG0JMB Forums Member	#3 - Posted: 15 Oct 2012 16:14
Hallo Gerald, ich habe einen FT857, etwa 200Watt, und eine 12el. M2 Yagi für 2m. Kabel sind 25m CellFlex 7/8. Wann auch immer ich meine Antenne Richtung Mond drehe, um einfach erst nur mal zu hören, höre ich nix. Hast du noch ein paar Tips für mich? VG Jörg DG0JMB

	DL4KG Forums Member	#4 - Posted: 17 Oct 2012 17:59
Hallo Jörg, erstmal musst Du sicher sein, dass Deine Antenne wirklich den Mond anpeilt. Das Programm WSJT gibt Dir die entsprechenden Daten für Elevation und Azimuth. Über den N0UK-logger (http://www.chris.org/cgi-bin/jt65emeA) kannst du einige Big Guns (z.B. W5UN, KB8RQ) für einen Test ansprechen. Mit Deinem Setup sollten QSO über den Mond eigentlich möglich sein, wenn Du einen Vorverstärker hast. Um den Empfangspfad zu testen, kannst Du die Antenne mal auf die Sonne ausrichten. Dann solltest Du einen Rauschanstieg hören bzw. in WSJT sehen. Wenn dies nicht funktioniert, hast Du ein RX-Problem. Du kannst mich bei weiteren Fragen gerne über dl4kg@darc.de kontaktieren. 73 de Gerald - DL4KG

	DD0VF Forums Member	#5 - Posted: 5 Nov 2012 21:01
Hallo Jörg, die Sonne ist auf 2m etwas ungeeignet, wenn sie ruhig ist bemerkt man sie auf diesem Band gar nicht. Zum hören (ja das richtige hören ohne PC ) eignet sich sehr gut der GRAVES Radar auf 143,05 MHz. Am besten geht das, wenn am Standort des Radars (JN27SI) der Mond zwischen QTF 90 und 270 steht. Ab einer Elevation von ca. 40 Grad wird das Signal schwächer. Auf dem Wasserfall kann man auch sehr gut den Doppler zwischen MS (Tropo) und dem Echo sehen, aber natürlich auch hören. Das Echo kommt nicht als Dauerton an, da die Antennen ständig im Halbkreis durch schalten weitere Infos dazu hier: http://www.itr-datanet.com/~pe1itr/graves/ Für JT65b einfach diese Seite ansurfen: http://www.livecq.eu/ Hier posten in Echtzeit einige Stationen automatisiert (auch manuell) empfangene CQ oder QRZ-Rufe mit Zeit, QRG, Signalstärke etc... 73 Steffen - DD0VF

	DK1KW Forums Member	#6 - Posted: 5 Dec 2015 08:05
Hallo, @DD0VF: GRAVES ist wirklich eine tolle Bake. Wäre schön wenn es vergleichbares auch auf 70cm gäbe. Hast Du Erfahrung wieviel dB GRAVES Echos stärker sind als die Echos von z.B. 4 Yagi Stationen? Ich möchte gerne MAP65 mit single polarity nutzen, habe aber Verständnisfragen zur Hard-/Software: - kann ich MAP65 mit einem billigen DVB-T RTL-Dongle nutzen? - brauche ich dazu z.B. Linrad oder läuft es auch ohne? 73 Werner DK1KW

	GW4LWD Forums Member	#7 - Posted: 5 Jun 2020 23:12
Check out my post on polarity , and the new way of doing it, I. All it the GW4LWD DPS , Dynamic Polarity System, You can rotate the Yagi array on the fly , from H to V and anywhere in between. There is No switching , no extra yagis or element, crossed etc . Use an existing array. WILLIAM GW4LWD.

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