2m EME and moonrise ground gain at ON7EH
The main intention of this page is to provide some audio files,
representative for the strength of signals that are reflected off the moon on a
modest gain antenna, without a low noise amplifier and under typical moon
conditions on the 144MHz band.(2m moonbounce)
The morse speed is medium and most signals are better than average so you do not
need to be very CW-skilled to enjoy the sounds that have travelled through outer
Here starts my story:
After having heard greek amateur station Jimmy, SV1BTR before, via the moon, he
was heard again on my 18 September 2005 moonrise.
His signals were rather good and at the lowest moon elevations, he was called by
many european EME-stations, including several single yagi stations, I could hear, on
At this time, I was called away from the station to provide necessary assistance
to the XYL.
Kids usually do stupid things when left unattented, we are no
I came back to the station 1 hour later and Jimmy
was still heard calling
CQ around 144.048 MHz.
Midwhile, the moon had risen to an elevation of
The antenna here is an old single 12element Mē without
elevation control, fed by about 8m of old Aircom+ coaxial cable. (10mm diameter)
The yagi antenna with a boomlength of under 6 meters is sited 10m above the
ground and fixed to the house wall.
It clears the rooftop by less than 0.5m and the antenna remains close to the photovoltaic cells on the roof.
The QTH is suburban and evolving to urban but still 25m above sea level.
The eastern headings (moonrise)
are mostly fields with some farmer housing in some directions. The slope to the
slightly rising but further away dropping.
For the 2m setup on the attic, I decided earlier not to use any
receive low noise amplifier for several reasons.
The hard to reach antenna
position, the low antenna line loss, the high RF interference environment (very
near to airport with plenty of paging, cellular towers)
being the most important
The system noise figure is estimated to be in the 1.5dB range. (cable loss + PA
relay bypass loss + transverter noise figure)
The audio samples are unprocessed
and they are heard as I've heard them through my headphones of my shortwave
transceiver's 500Hz Xtal-filter.
Here, you can hear SV1BTR calling CQ:
You may have to play with your mixer sound control settings to hear the dits and
The MP3-files are in excess of 100kB and require a decent internet connection to
You should be able to clearly hear his message, containing CQ CQ CQ de SV1BTR
on several occasions.
The signals are rather strong and consistent.
After this CQ-period, I called him with a message like this: SV1BTR de
OO7EH OO7EH OO7EH
(this is called a "1 by 3"-call sequence to stress my own call)
that my call is not yet known at the greek side. BTW: my calling periods
SV1BTR clearly had difficulties recognizing, who had been calling him, by his
sending of many periods of QRZ's:
The first sequence is the weakest but his signal gradually gets better and
better to become fully
I am not willing to let him go so I peacefully continue calling him,
period after period, with a "1 by 3"-call sequence, in between his many periods of
After some time, I am lucky since he copied, at least enough morse
characters, to think it is OO7EH calling him...:Listen here:
You can very clearly hear QRZ QRZ OO7EH with some '? ? ?'
indicating, there is still some doubt about my callsign.
Knowing he's struggling but also knowing he's finally got my call correct, I
start my next transmission with some RRR's, to confirm he's got it all right,
followed by several other
"1 by 3"-call sequences to make up a full calling period. (1 minute)
Once he's really convinced of my callsign, Jimmy starts sending both calls.
He must have been really excited since he starts sending some errors:
Could you locate them?
Immediately after both calls (OO7EH de SV1BTR), he adds a report being 'O''O''O':
(it is typical on 2m and frequencies higher up, to use TMO-reporting)
When I hear the O's (and already having heard both calls so many times), I start sending "report confirmation sequences" RO's.
Apparantly, Jimmy copied the RO's easily since he quickly turns into sending
both calls with series of RRR's:
and even RRR with GL (good luck's).
The latter sequence is getting weak which is not so surprising with the moon at
nearly 18° of elevation and leaving my last workable antenna lobe.
It is clear that ground gain helped a lot to enhance the
signal level on the albeit modest gain antenna.(12.85 dBd)
I hope you enjoyed the EME-signals, as much as I did!
Thanks Jimmy for your nice signals and the QSO!
In the QSO with SV1BTR, the power at the antenna was about
250W. His nice antenna consisting of 16 x 6el can be seen, here.
How you can make improve your signal by another 6dB is explained,
This text was written on special request for a friend and for the
commemoration of my father ON5SP, Roland, who
respectfully died on the 12th of
Michel (Mike), OO7EH
The special OO-prefix was used in 2005 for 175 years of belgian
OO7EH is a difficult EME call just like ON5RR, whose 23/13cm EME station I
From January 1st, I'll be signing ON7EH again.
On 9-11-2007, Marc, ON5RR and I, helt a presentation with the title:
"Introduction to EME" to a local radio club.
It can be found, here. Although the text is
in dutch, there are plenty of pictures in English...!
A brief recap of the agenda:
ON7EH concentrated on the global part and 2m.
Marc described his adventures on 23 and 13cm EME.
The bloc diagrams of the different stations were shown and detailed.
ON5RR's latest masterpiece is also included, a homemade hydraulic elevation
system, based upon a reworked 24" actuator!