12 July 2013 - heard beacons HB9EME (824km) and EA2TZ (877km).
6 July 2013 at home - very good tropo conditions - worked EA2TZ/P (863km), TM7G (877km), DF0MU (694km).
3 Mar 2013 - portable contest operation from IO91RF with some good
tropo to DJ5BV (531km), PI4GN (547km), DK2ZF/P (748km), DF0MU
(549km) and GM4CXM (582km).
Another nice tropo duct on 15 November 2012 gave me contacts with DC8UG
(731km) and OK1MAC at 1238km. HB9EME beacon was again audible at
up to 529. Stations in south east England heard or worked
OE5VRL/5, but there was no trace here - would have been 1248km.
beacon heard on 6 Sept 2012 at
2058z. (mp3, 57sec, 449kB). The beacon
transmits a ramp of 4 second tones separated by –6dB steps from 12W
down to 12mW (0 to –30dB); and is audible here to -24dB level (or
I noted an interesting effect on 20 Dec 2011 whilst listening to the
Bristol beacon GB3USK on 1296.875 (about 32km but direct path is obstructed - see below).
The signal had been quite good a couple of days previously, but on this
evening (of the UKAC contest), the strength had dropped by 18dB, and
the signal was auroral sounding, presumably due to rain scatter.
It certainly was raining at the time. You can hear the effect here
and the spectrum shows a spread of about 80Hz LF of the carrier, as
shown below. The drift is probably due to my transverter.
Terrain plot of my direct path to GB3USK, where there's a much reduced signal on
23cm. The recording and spectrum above was taken beaming about 35 degrees NE
of the direct path.
PS. 18 July 2012
More rain scatter, only this time in the
"summer"! The following was recorded on 18 July 2012 at about
1456z. It is of GB3USK (nominally due north) whilst I am beaming
between 065 and 075 degrees. Scatter is evident around 90 to
170Hz LF of the carrier. Surface temperature at my QTH was 19.2C,
max wind speed 30kph. A sound clip is here
(.mp3 format, 410kB, 52 sec).
Click on image for full size
The image is of spectrumlab showing the scatter signal LF of the carrier, both of which are audible.
My 23cm system
K3 transceiver driving a homebrew 2m transverter driving a DB6NT
23cm transverter (MKU13G3) running about 3W.
This drives a PE1RKI
module amp which then drives a linear to 150W output. About 33W reaches the antenna, a Wimo
44ele yagi at 13m agl.
I have built a masthead
preamp, details as follows:-.
The completed PCB is shown here
. I bought a cheap microscope to help put the SMD components in.
After several disasters I have ditched the 24V coax relays in the preamp box (see picture here
as they seem unreliable, indeed some of them have a tendency to stick
on receive when powered for transmit - the preamp does not survive
The new layout (here
uses a 12v Ducommun 2N1B11 relay with a separate feeder for
transmit. The relay is specified as handling 270W at 1.3GHz and
has measured isolation of about 70dB.
I have modified my sequencer (based on the W6PQL
design) to accommodate both 12v and 24v relays. My sequencer
drives the relays and the 12v bias supply to the PA. Schematic is
The complete transverter is shown here:
The interior view shows (left to right) 28V 13A PSU, 23cm filter, DB6NT
transverter, relay drive circuit (now replaced with sequencer), PE1RKI
module amplifier, PE1RKI PA and fan.