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M0UNI ONLINE LOGBOOK (Also covers previous call-signs 2E0UNI, M3GXJ)
I have an online logbook which can be accessed by clicking on the link above. If you've had a QSO with me and have wandered by here, you can see the entry in the log. This online log is updated at least every 24 hours, often immediately after the QSO. The log runs on a server operated by my good friend Ken M0DQS (previously KE4UYM).
M0UNI Radio Station
This photograph (and the others at the top of this page) show some of my amateur radio station. On the desk (right) are the Kenwood TS-570D HF transceiver and the Vectronics HFT-1500 ATU that I use. With them are a PC Computer, Shure 526T desk mike, Bencher CW paddle and my home made "digi-mode" interface (blue box behind the mic). This side is mostly used for contest working. On the rack (left) is the restored Heathkit SB-200 linear amplifier and a Ten-Tec Paragon transceiver. These are mostly used for SSTV working and DX chasing. There is also the backup Trio / Kenwood TS-430S transceiver, dummy load, Philips oscilloscope (for monitoring the TX and testing), frequency meter (fitted with a precision OCXO) and my home made GPS time standard clock. Various power supplies and other test instruments are also housed on the rack.
A close up of the desk area is in the picture below.
Oh yes, there are Unicorns on top of the SB-200 and ATU (and in a few other places) they help to improve the signal 8-)
Operating bands, modes and DX activities.
Annually myself and Ken M0DQS can be found assisting Shropshire County RAYNET (of whom we are members), usually manning the TTU on top of the Long Mynd in Shropshire which helps to provide emergency radio coverage for the Long Mynd Hike event in October.
I recently bought a 1973 vintage Heathkit HW-101 Transceiver through that well known online auction site 8-) The exterior and interior condition were in excellent condition, Looks nice alongside the Heathkit SB-200 Linear. Electrically it needed a bit of tender loving care to get it working 100% right again. It's just done it's first QSO's since the repairs including three 'over the pond' to the USA during the Russian DX SSB contest. The story and more photo's of the project are coming here soon.
Ten-Tec Paragon 585
Project.
I bought this Ten-Tec Paragon I (model 585) as a non-working transceiver from an auction, intending to give it an overhaul before using it on the station here. Here is some of the story of the repair work on the Ten-Tec Paragon 585 Repair page. This transceiver is now in regular use and was used during the CQ WW SSB Contest.
Heathkit SB-200 Linear Amplifier
Project.
A while ago I bought an old Heathkit SB-200 Linear Amplifier from an auction, intending to give it an overhaul before using it on the station here. I didn't realise what a poor condition it would arrive in ! The full story of it's restoration can be found on the SB-200 Restoration Page
Kenwood TS-570D
FSK input failure due to common power grounds.
They do say the do's and don'ts in the instruction manual are there for a reason. I had this recently proved when I had to diagnose an off-frequency TX fault and dead FSK input on my Kenwood TS-570D. Click here for more of this story.
Reducing computer generated QRM with fibre-optic network cables.
Some recent changes I made here that made an improvement to my radio station were not done to the radios or antennas at all. I was having problems with interference from the computers on HF and VHF, and losing the internet link while transmitting.
Myself and M0DQS run a number of computers on two
floors of our flats which were linked by various copper wire LAN cables and
hubs. Some of the computers are DEC Alpha servers which run many things
including parts of this website and the online radio log. One of these cable
runs between two of my room was identified by elimination as the cause of
interference being induced in my 20m folded dipole. Another caused high noise
levels at certain frequencies on the 2m band. One option was to use a wireless
radio LAN setup, we had tried this but it wasn't 100% reliable. We finally
decided to remove the copper wire LAN and replace them with a fibre channel
system using fibre-optic cables !
The photo shows two of the D-Link DMC-300SC media converters that convert the fibre-optic signals to normal 10/100-Base-T LAN signals. A pair of these is required, one at the end of each fibre-optic cable length. They are placed next to each PC or network switch so that the CAT-5 copper wire LAN cable lengths (hence RF radiation) can be minimised. The normal white LAN cables and the orange fibre-optic cable pairs with their grey 'plug in' connectors are clearly visible in the photograph. For one fibre link, a fibre cable pair is needed (one for each direction). Installing the fibre-optic cables is easy, just like normal copper cables. The only care needed is to not bend or kink the cable more than the specified bend radius limit which would damage it or impair the light transmission, and of course, don't to try and cut and solder them <grin>. Two converters were used in the photo above as one is for the cable run to M0DQS's flat and his servers, the other to my radio shacks computers. All the fibre-optic equipment including cables was purchased from Ebay auctions.
One advantage is that you can do what is
shown above, run the fibre cables alongside the antenna cables ! Something you
could not even think of doing with normal copper LAN cables ! The photo shows my
outgoing HF antenna cables with the orange fibre cable pair alongside.
So far the improvements have been dramatic ! A two S-point reduction in
background noise has been achieved on some bands. The internet connection stays
up when transmitting at 100W too, no more losing the DX cluster or online
logbook when on the air.
M0DQS is currently experimenting with a fibre optic switch and an Optical Time
Domain Reflectometer (OTDR).....stay tuned !
Other Amateur Radio Projects....
UTC "Shack" Clock, updated from a
GPS Module.
At the moment I am designing a clock for my shack that
displays the time in UTC and is automatically updated. Initially I made one using the 60Khz MSF time
standard signal controlled by the NPL (The National Physical Laboratory). Many
clocks are available that automatically display the current UK time including
the 1Hr British Summer Time offset, but not the correct UTC time. The MSF signal
automatically sends the current UK time including the offset, so I've had to add
a correction for this in my software.
The latest version uses a GPS module as the clock source instead. This sends UTC
time as standard within the NMEA data strings. Another advantage of this is that I can also display my
location information too, something that's very useful when working portable. A
photo of the prototype clock in use is shown below.
The clock uses a PIC18F4480 CPU driving a
dot matrix graphic VFD display. Below are some photo's of the clocks
display. So far the software and design prototype are working OK.
High Stability Frequency Meter.
At a recent radio rally (Ham Fair) at Winsford I picked up
a Maxcom MX-1100F frequency meter to replace my ageing Racal one. Although it
worked OK, the accuracy was not as good as the Racal was as it didn't have a
oven stabilised crystal oscillator. At Elvaston radio rally M0DQS and I saw some
TCO-6730 10Mhz Oven controlled crystal oscillator modules (OCXO) for sale. We
bought one and have now fitted it to the Maxcom frequency meter. After setting
up and calibrating against our HP GPS time / frequency reference source, the
frequency meter is now stable to +/- 1 Hz at 100 Mhz after 30 minutes warm up,
as well as being an accurate 10Mhz reference signal source. It is also better
now than the Racal was too.
Fully Isolated Data (CAT)
Interface.
I recently came across a pair of fibre-optic
modems on Ebay. They were made by Varian and had the model number 820-A on them but no other
information. I decided to get them to make a fully isolated RS232 interface for
the transceivers CAT interface. The two modem modules basically are an optical
transmitter-receiver pair using a pair of fibre-optic cables for the data (one
up link, the other a down link). The y are based around a HP optical transmitter
receiver pair and the good old 'MAX232' RS232 transceiver IC. They required a 9-20V supply (I used a pair of
mains adaptors set for 9V) and have a 25 way D connector for the RS232
communications at one
end, and the two fibre-optic connectors (TX and RX) at the other. After reverse
engineering them to draw a schematic and making a few minor modifications I
hooked them up between my Kenwood TS-570D transceivers COM socket and the PC. They worked fine,
giving me total signal isolation in conjunction with with my isolated "digi-mode"
audio interface. I've
used this fully isolated interface link on a number of RTTY contests now (using
MMTTY and N1MM logger) with no problems at all. I now have another pair to make a similar isolated link for APRS operation on my 2m
transceiver.
M0UNI "Digi-Mode" interface -
revisited.
I designed and built the original MK1 version
of this interface in 2004. It has transformer isolation for the audio signals
and an opto-isolator for PTT switching isolation. It also has switching relays
to switch between the PC and a Kantronics TNC. In late March 2006 I fitted a new board
into it which I'd designed, an FSK-Data converter board. This converts the RTTY
FSK audio TX signal from a PC + RTTY software into a 5V logic signal which is
then fed to the digital FSK modulation input (instead of the audio modulation
input) of the Kenwood TS-570D. By using this and the TS-570D in FSK mode it
allows me to receive RTTY using the 1.5Khz to 250Hz DSP filter options as well
as having direct FSK modulation of the transmitted carrier. The PC + RTTY
software is then used to demodulate the received signal in the usual way. The
FSK-Data converter uses the tried and trusted Exar XR2211 FSK demodulator / Tone
Decoder / PLL IC. It's setup for 1275 Hz, 170Hz shift. The PLL centre frequency
is 1360Hz. The demodulator comparator has a hysterisis of +/- 35Hz to ensure
that the data transitions are clean. The PLL loop filter / VCO components are
setup to cope with a input frequency error of +/- 50Hz before the PLL lock
failure detector clamps the data. I've used this MK2 version with the new board
for a few months during a number of RTTY contests now and it's worked 100% OK. I'd like to thank WA8SWV in Kalamazoo MI for
being my first QSO with the new MK2 "Digi-Mode" interface.
CHIP64 data mode.
I've recently been experimenting with the
CHIP64 Spread Spectrum
digital mode by IZ8BLY. I've
had some success, having my first QSO's with it including a transatlantic QSO on
05/02/2006. More details on this mode can be found on the
IZ8BLY website. There
is also a CHIP64 Yahoo Group
for this mode too.
Olivia data mode.
An earlier project was setting up the station to use the Olivia data
mode on HF. Olivia is a new data mode which is excellent for poor signal
working. It's a wideband data mode using error correction and a modulation
method similar to MFSK. I've already had several QSO's now and have been
impressed the performance of this mode on weak signals.
Wire Antenna Matching
Transformer
Another recent project was a simple matching transformer for my end fed long
wire. This was made by making a tri-filar winding on a ferrite ring core to form
a tapped secondary to the antenna. Tests using my 30Mhz Anritsu network analyser
showed that the response was linear from 1.8Mhz to 30Mhz with no significant
losses. On air tests
went 100% OK. SWR matching is much easier and it has operated OK up to 200W. I've
had many DX QSO's on 80m, 40m and 15m using the antenna since making the changes.
PSU Modifications
Last year I modified a 30 amp HQ-POWER PS1330 linear PSU
I bought at a ham fair. It worked OK, but the heat sink size was insufficient
when running long QSO's on SSTV.
The poor old 2N3055's got a bit too warm ! I've added a series of cooling
fans onto each heatsink bank (which I got the at the same ham fair) which solved
the problem very well indeed. A switch and LED indicator was added to the front
to switch them off as a "quiet mode" when running at lower powers or duty
cycles. So far that is working 100% too. I used to use a switch mode PSU which I
modified for 13.8V, however I was getting noise problems on some bands from it.
Antennas:
A previous project was a 20m band Folded Dipole
antenna of my own design which is built into my loft. This is now my main
Antenna for 20m band working.
The design was prompted by the discovery that loft of the
three floor house I live in is almost exactly 1/2 wavelength long at 20m and lines up in a
North-South direction, at a height of around 10m (does anyone else measure their houses in bands?).
It's basically made of a loop of antenna wire tuned to 20m, with approx. 3"
(8cm) "folds" at each end. It's centre fed at the lower half directly from a Moonraker balun which also serves as part of the mechanical support. The wire folds
are kept apart by a series of wooden spacer dowels, each with a pair of holes
drilled through 3" (8cm) apart. Two more of these (with additional grooves to
guide the wire) hold the ends of the antenna to which the support lines attach.
The balun at the centre point of antenna itself (it forms part of the structure)
is fed directly to the transceiver through UR67 (M)
cable. Thanks too to Ken M0DQS (KE4UYM) for the help he gave me to install up
there.
The first tests from on the first few days since it was erected were very promising indeed.
There were
several SSTV QSO's with operators in Puerto Rico including KP4EMP, and an RTTY
QSO with VK3FM in Australia (confirmed by QSL card). It was the first time I'd worked stations in either
of those countries so I guess you could say it radiated well. It also tuned
very well too, the SWR is below 1.2:1 across the entire 20m band. It continues
to work extremely well, having worked Indonesia, Guadeloupe, Reunion Island and the Patagonian region of
Argentina for the first time with it too as well as SSTV QSO's as far away as
Paraguay (6300 miles) ! It also works well with an ATU on 17m, I worked
two Japanese stations using PSK31 on that band too. I think this
project definitely gets put into the "success" file !
If anyone wants more details of the design then please send me an email (see QRZ.COM) or chat to me on the air. I also have a design file for the MMANA antenna design program which I can email too. It was designed originally on the back of an envelope, and checked out OK using this software after I built it ! Don't you just love it when the math works out 8-)
I also use a very simple outdoor 10m long sloping wire antenna (end fed) for other bands and local 20m band work. Sadly this antenna seems to suffer from an unusual problem, it often gets damaged by vandals (they climb onto my garage roof to get to it). It's often completely destroyed in the process too. Does anyone else living in a city have problems with their antennas being damaged by vandals?
Geoff M0UNI History
