How do you get QRV on 23 cm band and what
can you expect from this first microwave band
Getting QRV on this band is not very difficult, but as with
all bands the better your antenna and equipment, the better results you
will get.
The last few years this band has been my most interested band for tropo
and aircraft scatter operation.
The 23 cm band runs from 1240 - 1300 MHz
Weak Signal BANDPLAN
Frequency
MHz
Maximum
Bandwidth
MODE
USAGE
1296.000
1296.150
500Hz
Telegraphy
MGM
1296.00-1296.025 Moonbounce
1296.138 PSK31 centre of activity
1296.150
1296.800
2700Hz
Telegraphy
SSB
MGM
1296.200
Narrow-band centre of activity
1296.400-1296.600 Linear transponder
input
1296.500 Image center (SSTV, Fax etc)
1296.600 Narrowband Data center
(MGM, RTTY,..)
1296.600-1296.700 Linear transponder
output
1296.750-1296.800 Local Beacon (10W ERP max)
1296.800
1296.994
500Hz
Telegraphy
MGM
Beacons
exclusive (b)
Most weak signal contacts in CW or SSB are made within the
frequency segment of 1296.150 to 1296.280.
During periods of high activity these ranges might be a bit larger.
Equipment:
Equipment for weak signal communications is available on the
market
A popular transceiver for the 23cm band is a Kenwood TS-2000X
A bit more old fashioned is the FT736r with a 23 cm module
In my opinion this new transceiver will be a chance for some new activity.
In the way the transceiver is specified for 23 cm it will not be a game changer
For real weak signal work on 23 cm it's only part of what you will need
All amateurs starting 23 cm using an IC-9700 must realise that for Weak Signal
working on 23 cm
and wanting to work DX you will need a good antenna.
A vertical will not do the job, using a vertical probably will get you on
the nearest repeater
but you will not work many stations without the help of the repeater
Using a good (high gain) antenna will get you forward in working DX in SSB or CW.
For real DX and airplane scatter you will need more output power and a pre-amp
mast mounted
I am a bit afraid that many Hams buying a IC-9700 will become frustrated with 23
cm using too small antenna's with bad take-off
and too little power. Only 10 Watt output and then a few dB cable loss to your
antenna is just
not good enough to work the fun during an activity contest
In my opinion the IC-9700 probably will bring a bit more activity with new
stations becoming active on the band,
many of them will be using a repeater if available, but the IC-9700 will not
become a game changer for the 23 cm band
More popular is to use a transverter from 144 MHz (or 28 MHz)
to 23 cm
I am using a DB6NT 23 cm Kit, working fine for many years now.
Other option is a power amplifier with tubes,
I am still using an old TV broadcast amplifier with a TH308 tube able to give 250 W or even
more depending on PSU up to 500 Watt
Feeder Loss Feeder loss on 1296MHz can be quite significant. It’s easy to lose
over half of
your signals (both ways) through feeder loss. It therefore pays to use good
quality low loss feeder. I would suggest that UR67 should be considered the
absolute minimum, if new feeder is to be purchased. Depending on the length
of run, an even better feeder such as the Westlake 103, Ecoflex15plus or
Heliax should be seriously considered.
In comparison with the lower v.h.f. and u.h.f. bands, it’s very expensive
to generate power at 1296MHz. Don’t forget that it’s almost always cheaper
to use better feeder than try to make up for feeder losses with more power.
Reducing feeder loss is also a ‘big win’ when receiving!
Pre amplifier For receiving it's even better to have a mast mounted
pre-amplifier and coax relay.
For RX you can use a less quality cable and for TX use a very low loss cable.
For TX
I am using a low cost bamboo 3 cable length 12 meter which is 75 ohm.
Using a home made tuner I can easily correct VSWR for this.
For RX I use a bamboo 6 cable, no need to correct for impedance error.
My preamp is a home made giving me a Nf off 0,6 dB which is good enough for an
antenna aiming at the horizon.
Antenna
Get your antenna as high as needed, at least higher than most
obstacles in your area.
Obstacles will be buildings, trees etc.
If possible get as much antenna gain as possible, I prefer to
have minimum gain of 21 dB but even more is better.
For this I am using a 2.5 meter dish, mounted at 10 meter above ground level.
When using a dish a minimum diameter of 1.5 meter should be considered.
A 2.5 meter dish is good for 28 dB gain, a 1.5 meter dish will bring about 23 dB
gain.
A 26 element loop yagi would bring about 17 dB
In my early years on 23 cm (1975) I have been using such an
antenna, I even build many of these for selling to other hams.
here you can find how this is build
From 1996 on I have been using the 2.5 mtr dish mounted at 10
meters over ground.
It survived many heavy storms up to windforce 12.
The bigger the antenna, the better your rotor system should
be, first of all to withstand the forces on it during a storm.
Also important is
to have a solid and good indication of the heading your antenna is aiming at.
With a 2.5 meter dish the opening angle of the beam is about 5 degrees,
so any
misalignment will make a QSO more difficult or even impossible.
What can we work
With a good setup one can work quite a lot of stations. Thanks
to tropo scatter and aircraft scatter contact over 600 to 800 km
are always possible with a well performing station.
Just an example what I worked on 23 cm during the October
contest 2015
Activity Unfortunately most of the time there is not much activity, don't
expect too much.
This is a typical band with only activity during special occasions.
During contests, activity evenings and special events there is good
activity.
During tropo lifts there can be good activity but the last few years this is not
that big as in the years 1970 or between 1990 and 2000.
During periods of high activity one can work 30 stations, depending on location
within Europe this will differ quite a lot.
In United Kingdom some stations work up to 80 contacts during a 4 hour evening
activity night.
Within Europe I guess there are between 800 and 1200 Hams able to be active on
the band.
Most active stations have a good system with nice possibilities to work DX.
There are also many stations with only a small setup with possibilities mostly
limited to a working range of up to 400 km.