G4HUP and DL4MUP EME History on 2m 23cm and 13cm
G4HUP EME on 2m
Having assembled a station with good Auroral and MS operation capabilities at my new location in the early 1990's,
I started to listen for signals on setting
and rising moons.
Because of a very long feeder run (70m) I had installed
an MGF1302 preamp at masthead, and this enabled me to hear the larger US EME stations. Very shortly
in 1991, I made my first 2m EME QSO with K2GAL, closely followed by W5UN! Over the next 3 years I extended the
station up to 4 yagis, with full
elevation, MGF1801 pre-amp and a Tempo 2002 PA. I enjoyed the EME operation,
until the antenna was destroyed by strong winds - thus proving that it was
MGF1801 Preamp information written by G4SWX and WA5VJB from VHF/UHF DX'er (defunct UK specialist magazine) is
These are scanned pages from
the magazine, - I lay no claim to the contents, but wish to ensure the information is
My initial list for 2m is here.. If anyone still needs a QSL
card, please contact me!
Due to pressure of work that had been building up, I never did get round to re-building
the array. This was also partly because I wanted to do other things as well, and the 4 x 18 array did not give
much room for other antennas on the tower!
DL4MUP EME on 23cm and 13cm
DL4MUP 1296 MHz EME
Thanks to Guenter, DL4MEA, I was able to use his 3m dish and TH347 PA for 23cm EME
activity. Using this excellent facility, I have made over 50 initials.
The system has a single stage cavity preamp based on metalwork from KB2AH, with an NE 32484 - currently this is
giving abt 0.4dB NF - not as good as can be
achieved with this device, and not as good as we have previously
measured. Evolution of this pre-amp can be seen in the gallery pages.
This is followed by a DJ9BV type second stage with an FXH35, both preamps mounted behind the feed.
An old R&S
weather satellite tracking system provides the dish mount and mechanism, with added optical encoders for feedback.
The tracking software used is
Nova, with the control interface being designed and built by Guenter. Resolution in
both az and el is 0.1 degree.
The prime mover is my FT847, followed by a DD9DU transverter, and a modified
ex-GSM PA giving 80W drive to the TH347. We experienced a lot of frequency
stability problems initially, spending
the first 15-20 seconds after any TR changeover tracking the freq drift! This was solved by replacing the internal
xvtr LO with a DF9LN external LO. Spectran is the 'DSP of choice' for observing signals on the band - currently in
use with a Toshiba Tecra laptop.
Experiences with this and with Fujitsu-Siemens machines are OK, but I was not
happy with the performance of the previous Tosh Satellite Pro on the audio
2003 ARRL EME contest log is here.
2002 ARRL EME contest log is here.
2002 REF/Dubus contest log is here.
2001 ARRL EME contest log is here.
We have used circular polarisation on 23cm from the beginning, using the N7ART Diagonal
Waveguide Feed. This feed remains on the dish for 23cm. More
recently we have found a method of simplifying the
way of launching RF in this feed by using probes (like VE4MA) in place of the very critical crossed
published by K9BCT - this makes the set-up much easier, as was proven by our attempts to set up a scaled DW feed
for 13cm. Using the
cross-dipole arrangement as per N7ART simply would not align on this band, and after
investigation on a network analyser it was realised that the slots
used to allow the dipoles to be mounted through
the back plate were actually resonant, and seriously degrading the performance.
At EME 2002, OK1KIR group
presented a septum polariser feed for 23 (and higher bands) at EME 2002. The OK1DFC article is to be recommended,
and I have a
set of metalwork ready to assemble and try out. The big advantage of this variant is that there are
no polariser screws to set up.
See Rectangular Waveguide Septum Transformer
Circular Polarised Feed
With the addition of the 13cm feed, the positioning of the feeds at the focus of
the dish has been mechanised, using a satellite screw-jack actuator.
The mechanism can be seen in the picture
below, with the 23cm feed above the 13cm feed. A simple pulse counter is used in the shack to indicate where the
feed is pointing.
2320 MHz EME
The scaled version
of the N7ART Diagonal Waveguide feed, with signals launched by monopole probes rather than the crossed dipoles is
now installed on the
dish. So far testing is taking place Rx only.
The preamp is a DJ9BV 2 stage, giving approx
0.55dB NF at 2320, and 40dB gain at 2304 and 2320, falling to 38dB at 2424Mhz
A G3WDG transverter shares a common
enclosure with my DB6NT 23cm transverter - see the picture below for details. The 2320 LO is a DF9LN osc, inside
xvtr enclosure, and the 2304 LO is provided by an external Adret synthesiser - a front panel switch selects
internal/external LO. I had hoped to cover 2424
in the same manner, but have found that the LO strip tuning is
too narrow to cope with it! A revised LO is under design.
On the left side of the case is the switching - RF at the front and DC at the rear. Next to that is the DB6NT xvtr
for 23cm, with an M57762 PA behind it -
a cheap computer fan sends enough air through the heatsink to keep it cool.
Towards the right side of the case is the 13cm G3WDG xvtr with a G4DDK LO strip 'piggy-backed' on top.
In front of them is the DF9LN osc for 90.66667
(2320), and the LO relay is just behind it. On the rear panel are
1W and 10W PA's from G3WDG.
There is a single Rx input to the box, switched between the 2 bands, and each band
has a separate Tx output. External LO input is also switched between
the bands. When the Band select switch
(front panel, left) is in the center position, the IF input is routed out to another socket on the back panel so
more transverters can be fed from a single IF rig without having to change cables over, etc.
amplifier using MRF21120 modules is currently being assembled.
Page created: 02.12.2004
Last updated: 29.032012