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EME: Earth-Moon-Earth communication on 144 MHz
Update 22-April-1010:
I've exchanged the 2m EME Pre-Amp with another brand today (MHP-145, specially trimmed for 144.150 MHz).
From the first receiving results it looks like the new one is performing significantly better.
Fewer birdies and less noise.
I will continue checking this change and report here.
Some hints for Newcomers to EME: here
Update 04-Jan-1010:
We've spent part of last night at our /p EME location working JT65B mode via 2m EME. The SPID rotator is
keeping up quite well despite the low temperatures. No issues so far.
Signal reports to and from VK and JA, as well as ZS6 have been very reasonable given the size of our antenna
array. ZL (one station) was sort of a challenge which we were not able to finish successfully yesterday night.
The future changes to our EME antenna array have manifested: we will be converting the array from a 4x 8
Element horizontal-only array to a 4x cross-Yagi (switchable H and V polarisation) array during spring of 2010.
We are expecting much better antenna performance from this change in accordance with Faraday rotation
propagation for long-distance contacts.
Update 06-Dec-2009:
Today I managed to run my first EME QSO in CW mode from our /p EME location at the farm.
The partner was LA8YB with a very loud signal. I had taken my MP3 player with me. The player has a
built-in microphone for voice recording. So, I just held the recorder with it's internal microphone towards the
loudspeaker of the transceiver and recorded LA8YB's EME signal from there.
When I was back home later this morning I looked up LA8YB's information in the web. Whow! What an antenna!
No wonder that I could hear him with such a strong signal!
Listen to his signal here (direct recording from the FT-847 speaker, background noise is from the final amplifier, sri):
LA8YB's EME signal (ca. 420 kB)
Also heard SP7DCS in CW (audio file here, ca. 420 kB), but was not ready yet with the amplifier and therefore could
not call him.
Also heard SV1BTR with a very good signal (audio file here, ca. 3.4 MB, sri for the voices in the background), whom
I tried to reach a little later than this recording was done. Unfortunately propagations had dropped-down by then and
we could not complete the QSO.
Update 21-Oct-2009:
Mid of October we managed to work South America for completing our first target of achieving "Worked All Continents"
2m EME in JT65B mode of operation.
We will now focus more on the 2m EME CW mode of operation. That's going to be much more of a challenge, for sure!
lifting the antenna mast
DK3QN
working 2m EME in JT65B
After about 6 months of preparation, May 31st, 2009, became a very special date for me.
On that day I had my first QSO via EME using JT65B mode! The first station I contacted over the
moon was RX1AS, Sergei in St. Petersburg, Russia.
Together with my friend Michael, DL2MHO, in December 2008 we'd started to learn everything
that was needed to become QRV in EME. So I spent numerous hours in the Internet googleing for
everything re. EME which could be supportive for us. And there is lots of good stuff you can read
and learn about EME!
As we could not install antennas and operate EME actively from our home locations, we ended
up in installing the whole system at the property of a "ham-friendly" farmer. This proved to be
a very positive opportunity and decision!
Our current EME system consists of the following building blocks:
TRX:
Yaesu FT-847
Amplifier:
I0JXX MosFET power amplifier (visit "Amplifiers"
page for more details)
Antennas:
4x I0JXX 8-Element horizontal Long-Yagis (2.1wl),
stacked in an "H" config
Antenna combiner Lambda/2 combiner/splitter by I0JXX
Pre-amplifier: made by TGN, 0.25 db NF
Coax-relais: dual coax relay made by EME
Antenna phase line Aircell-7
Antenna feed line 20m EcoFlex-15
Rotator SPID RAS hor/vert
PC
2
PC, #1 is running JT65B and #2 (a Netbook) is running the Internet
chatroom
at N0UK via UMTS (no cable Internet
available in the shack)
Interface
microHAM DigiKeyer USB, with integrated sound
card and sequencer
Here is the Link to my local ham radio club website (in German) describing our EME activities.
First EME QSL cards arrived via direct mail:
Today, Tuesday, 18-Aug-2009, we finally found the source of our occasional high SWR problems!
As the SWR went "sky-high" during our tests yesterday, we took the whole antenna system through a thorough
analysis process. As a findings result, the antenna combiner/splitter proved to be faulty! One of the antenna
"N" connector solder joints inside the combiner had been broken. This may have been the "final" stage of an
on-going process of "things (SWR) getting worse". So, in case you are experiencing similar situations: check
your combiner first!
After changing the combiner with a substitute (another brand), SWR turned out to be 1.16 consistently!
EME signal reception improved dramatically as well as TX reports.
... to be continued
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